---------------------------------------------------------- Pietenpol-List Digest Archive --- Total Messages Posted Thu 12/23/04: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:06 AM - Re: Winter construction (gbowen@ptialaska.net) 2. 11:00 AM - Correct resin for fiberglass fuel tank? (N321TX@wmconnect.com) 3. 12:10 PM - Re: Correct resin for fiberglass fuel tank? (Richard Navratil) 4. 01:02 PM - Fiberglass Construction (Rcaprd@aol.com) 5. 02:02 PM - Re: Correct resin for fiberglass fuel tank? (gbowen@ptialaska.net) 6. 02:08 PM - Re: Fiberglass Construction (gbowen@ptialaska.net) 7. 02:23 PM - Re: Fiberglass Construction (alexms1@comcast.net) 8. 02:53 PM - Re: Fiberglass Construction (gbowen@ptialaska.net) 9. 08:14 PM - Re: Fiberglass Construction (Rcaprd@aol.com) 10. 08:24 PM - Re: Fiberglass Construction (N321TX@wmconnect.com) 11. 11:06 PM - Re: Fiberglass Construction (Gary Gower) ________________________________ Message 1 _____________________________________ Time: 06:06:34 AM PST US From: "gbowen@ptialaska.net" Subject: Re: Pietenpol-List: Winter construction --> Pietenpol-List message posted by: "gbowen@ptialaska.net" Since I spent the last 40 years of my working life as a chemist in the epoxy and urethane industry, including formulating Rutan's Rutan Aircraft Epoxy for the first Vari and Longeze's and Saf-t-poxy, feel homebuilders can benefit from a few tips that we didn't put on "official" data sheets. 1) Don't believe everything you read. Data sheets are sales tools used by manufacturers to sell more product. I've "doctored" enough data sheets in my working life to fill a book, due to the request of the guys in sales. Every technical data point has a range, the sales guys always want the most attactive, not the mean or average data point. 2) Almost every hand lamination resin starts with Epon 828 (formerly Shell) as the feed stock. There's 80 custom manufacturers of epoxy systems in the USA alone, including System 3. Every one of them uses Shell's Epon 828, it's the industry standard. This basic resin is cut with reactive and unreactive solvents, because it's too high in viscosity to use by hand laminators. 3) Reactive solvents are more costly but more functional for homebuilders than non-reactive solvents. The cheaper the solvent the cheaper you can sell you epoxy system. So don't buy your resin system based on price. 4) The reaction rate rule of thumb previously given is good for all non-catalyst type reactions. Polyesters and derakane vinyl esters are catalyst type reactions. If you lower the temperature of cure of an epoxy amount of time it takes to come to full cure. 5) Most all hand-laminates never come to full cure. The only way to get a full cure on an epoxy is to get the temperature of the laminate up to the glass transition temperature of the resin, or about 180 degrees F. 6) No matter what is says on any data sheet, you will not get full physical properties unless the epoxy has seen it's Tg. You get very close but no max properties are possible without a post cure of the laminate. 4 hours at 180F is the standard post cure given a laminate in the labs before physicals are tested and reported. 7) If you warm the resin to 25C before using your get the approx. mixed viscosity and gel times reported by the manufacture, but as soon as you smear it on your work, all bets are off. The gel and cure times change dependent on the mass (ie. a thin film takes longer to cure) and the ambient temperature. 8) Back to thread- working in cold climate. a) buy System 3's fast amine, b) experiment until you know the working time you've got, and vary the batch size to make it all smeared out before it gels. c) make yourself a little "postcuring" oven out of your workbench. d) don't be afraid to experiment a little, the only thing you can screw up is the mix ratio of part A to part B. As long as you keep this ratio as posted by the manufacturer, you cannot go wrong. Gordon Bowen Original Message: ----------------- From: Clif Dawson CDAWSON5854@shaw.ca Subject: Re: Pietenpol-List: Winter construction http://www.systemthree.com/index_2.asp http://www.systemthree.com/members/tds/T-88_TDS.pdf The first link is their homepage. Go here and sign in as a member. The second is direct to the pdf tech pages for T88. The second page tells you that it is formulated for full strength cure down to 35 F, just takes a lot longer. Be carefull with heating and mixing. I warmed mine in hot water and it hardened before the pieces were properly put together.Good thing it was something small!! On page one you will see a shear verses temp blurb on glue/Alum. I take this to mean the glue failed. IF this is so then the same would apply to wood/glue. IF this is so then spruce, at a shear strength of 1120 lb would equal the T88 strength at approx 170. This doesn't sound good until you calculate the square inches of material being glued and realize that the OVERALL strength of that joint probably exceeds the required strength by a fair margin. If you have a joint that will be subjected to no more than 1000 lb but the area of that joint is 3 sq in. then the joint is capable of handling 3000 lb at 180 so will be safe to some higher temp. A good thing if you live in Florida or Texas. None of our flying planes have fallen apart yet even though some have some pretty dark paint on them. If you want Wood Strength tables go here. Scroll to the bottom; http://clifdawson.ca/Tools_and_Tips.html Clif ----- Original Message ----- I did some glueing last night and checked the T-88 containers. They recommend 50 deg. I left the hangar at 50 and my joints were set tonight. Dick Doe anyone know the temperature restrictions for T88 epoxy? I would like to do some fuselage work in my garage this winter, but am worried about the glue not curing properly. Temperatures are above freezing but still get quite cold. John Fox ________________________________ Message 2 _____________________________________ Time: 11:00:11 AM PST US From: N321TX@wmconnect.com Subject: Pietenpol-List: Correct resin for fiberglass fuel tank? I'm going to be making a fuel tank for an air camper soon. #1. Who is a good source (Aircraft Spruce?) for the resin and cloth? #2. What weave material is recommended? Thanks, Sterling ________________________________ Message 3 _____________________________________ Time: 12:10:53 PM PST US From: "Richard Navratil" Subject: Re: Pietenpol-List: Correct resin for fiberglass fuel tank? I bought mine from ACS. Check page 34 in cataloug un the heading of Polyester Resins, read carefully. You will want to use #6060-5 resin. You will need to use a combination of heavy roving and mat. If you havent done fiberglass work before you may want to do some reading on it or get with someone from your EAA chapter first. Dick N. ----- Original Message ----- From: N321TX@wmconnect.com To: pietenpol-list@matronics.com Sent: Thursday, December 23, 2004 12:59 PM Subject: Pietenpol-List: Correct resin for fiberglass fuel tank? I'm going to be making a fuel tank for an air camper soon. #1. Who is a good source (Aircraft Spruce?) for the resin and cloth? #2. What weave material is recommended? Thanks, Sterling ________________________________ Message 4 _____________________________________ Time: 01:02:48 PM PST US From: Rcaprd@aol.com Subject: Pietenpol-List: Fiberglass Construction --> Pietenpol-List message posted by: Rcaprd@aol.com In a message dated 12/23/04 1:00:37 PM Central Standard Time, N321TX@wmconnect.com writes: << I'm going to be making a fuel tank for an air camper soon. #1. Who is a good source (Aircraft Spruce?) for the resin and cloth? #2. What weave material is recommended? Thanks, Sterling >> Sterling, Are you using the fuel tank mould that I loaned you ? If so, please use enough release agent, so as not to destroy it !! There is a couple of other folks that will need it. It's a really good mould (capacity - 10.7 gal.), and we can pass it around to others, when you are done with it. (It is for the nose cowling fuel tank for plans dimension short fuselage.) I designed it so the bottom of the tank slopes forward, when the tail is on the ground, so any water in the fuel finds it's way to the outlet. There is no place where a pocket of water will collect. I might need it again, too, if I ever get any alcohol in my fuel !! Here is the way I built both my tanks, and J3 type nose bowl: I used Polyester Resin (for auto body repair) on both tanks. It's cheaper than Epoxy, and is a lower viscosity which aids in wetting out the fabric. However, if I build another tank, I will use the West System Epoxy Resin 105, with the 206 hardener. If you go this route, it is very convenient to buy the pumps that go with the cans, which dispenses the material at the proper ratio. Never handle any cloth with your bare hands, or touch any area where you are going to do an additional lay-up, or skin oil will prevent the resin from saturating the cloth in that area. You have to be FAST if you use the Polyester Resin, because after you put the hardener in...it Kicks in only about 5 to 7 minutes, depending on how many drops you put in. West System has a lot longer pot life (work time). Have all the fabric cut, pre-fit, and stacked in the order they lay. I can't say enough about preparation, before you add the hardener. You can lengthen the working time some, by using a few drops less than recommended, but once it starts to jell, forget about proceeding any further. The challenge of doing composite work, is to get 100% saturation, using as little resin as possible, with no fabric separation. The way we achieve this at work, is 'Vacuum Bagging'. One of the faults of the Polyester Resin, is that it is NOT alcohol resistant. So far, I haven't had any problem. Fiberglass Cloth: I have a source here in Wichita, where I purchase the cloth, in all sizes. It ain't cheap !! Seems like I had over $35 or $40 bucks for the cloth in the nose tank and nose bowl. I used two different weigh fabric - Light weight, and Medium weight. The first layer down, I used light weight. Then two layers of medium weight, then the last layer down in the Mould I used another layer of light weight. The difficult part is to get the cloth to stay down in the corners. It always wants to spring back out of the inside corners, no matter how many times you poke it back in. Light weigh cloth stays down in the corners much easier, because the cloth is thinner, and bends easier. This is the reason I used corner pieces in the mould, so the fabric only has to form to 45, instead of 90. After the resin cures, and you pop the bottom and top out of the mould, you need to carefully sand the edges, so you get a nice tight fit, preferably a 45 miter fit (that's what I did) then glue them together with the resin you've been using. After they are glued together, put 3 layers around the entire corner edge, stepping out from 2" for the first layer down, up to about 4" for the last layer down. You always have to sand the shinny off, before adding any additional layers. After complete, leak test with a balloon, like Tony Bengalis recommends. Then you should calibrate it at the gas station. Set the tank in the static laden position (the angle it will be at when the tail is on the ground), and add one gallon of fuel at a time, dip your 'Calibrated Dip Stick' in, and mark each gallon increment. The distance between these marks vary, because of the shape of the tank. I didn't have any leaks in either of the fuel tanks I built. I built the Smoke Tank with just two layers of fiberglass, moulded around cereal box the right dimension, but used the West System Epoxy. It seemed like the cloth was wetted out good, but it had two places where the baby oil seeped through, and dripped about one drip every 6 minutes. I fixed them by cleaning first with Brake Clean, then sanding the area, then some more Brake Clean (with clean cloth and no finger prints), then used 5 minute epoxy, and two layers of cloth. Chuck Gantzer NX770CG Merry Christmas To All !! ________________________________ Message 5 _____________________________________ Time: 02:02:54 PM PST US From: "gbowen@ptialaska.net" Subject: RE: Pietenpol-List: Correct resin for fiberglass fuel tank? --> Pietenpol-List message posted by: "gbowen@ptialaska.net" Spruce and Wicks both carry a glass weave called 7781. It's a tight weave in the satin style that drapes over edges very nicely. Stay away from "box weaves" because they give you problems in compound curves. Just about any good laminating epoxy resin will work, but Derakane epoxy based vinyl ester has better chemical resistance. You work Derakane just like you do a polyester (ie. boat type resins). A little dab of catalyst, you have to work in small batches. Whatever you do don't use polyester resin on gas tank, it'll get "fried" by the fuel additives and leak. EZ Poxy and Aeropoxy were both approved by Rutan for composite fuel tanks. I ain't got no dog in that fight no more, but I still use EZ Poxy from Epoxical for my laminates. My Piete rebuild came with a galvanized steel tank but if I were going to build a fuel tank today I'd use the following technique: 1) shape a block of styrofoam to fit the area you want, round the corners for ease of lay-up 2) laminate over the carved block with min. 6 plies of 7781 glass and Derakane. Derakane doesn't need a post cure to completely cure but I'd let 3 weeks pass at Room Temp (25C) before I put fuel in any composite tank. 3) Put the drains and vent blocks thru a 1/4" aluminium block I'd laminate into the first 3 plies and cover with balance of plies. Laminate in the filler cap ring, too. 4) drill and tap the al block for the fittings. 5) Cut the entire laminate and foam block in half 6) use acetone or gasoline to dissolve the foam and pour out the mess. 7) using min. 4 strips of glass and Derakane reglue the now empty tank back together. Piete purest can forget the above techique. Back to the dark ages. Gordon Bowen Original Message: ----------------- From: N321TX@wmconnect.com Subject: Pietenpol-List: Correct resin for fiberglass fuel tank? I'm going to be making a fuel tank for an air camper soon. #1. Who is a good source (Aircraft Spruce?) for the resin and cloth? #2. What weave material is recommended? Thanks, Sterling ________________________________ Message 6 _____________________________________ Time: 02:08:32 PM PST US From: "gbowen@ptialaska.net" Subject: RE: Pietenpol-List: Fiberglass Construction --> Pietenpol-List message posted by: "gbowen@ptialaska.net" As a polymer chemist I highly recommend to anyone considering using polyester resin for construction of a fiberglass fuel tank to make a small test. Make a 2" by 4" test laminate of polyester and fiberglass. Put into a quart jar of AVGAS and MOGAS for about 1 month. You could weigh before and after if you've got an accurate scale, but I think you'll discover the discoloration of the AVGAS and MOGAS plus the somewhat slimy feel of your test coupon will change your mind about the chemical resistance of polyester resins. Gordon Original Message: ----------------- From: Rcaprd@aol.com Subject: Pietenpol-List: Fiberglass Construction --> Pietenpol-List message posted by: Rcaprd@aol.com In a message dated 12/23/04 1:00:37 PM Central Standard Time, N321TX@wmconnect.com writes: << I'm going to be making a fuel tank for an air camper soon. #1. Who is a good source (Aircraft Spruce?) for the resin and cloth? #2. What weave material is recommended? Thanks, Sterling >> Sterling, Are you using the fuel tank mould that I loaned you ? If so, please use enough release agent, so as not to destroy it !! There is a couple of other folks that will need it. It's a really good mould (capacity - 10.7 gal.), and we can pass it around to others, when you are done with it. (It is for the nose cowling fuel tank for plans dimension short fuselage.) I designed it so the bottom of the tank slopes forward, when the tail is on the ground, so any water in the fuel finds it's way to the outlet. There is no place where a pocket of water will collect. I might need it again, too, if I ever get any alcohol in my fuel !! Here is the way I built both my tanks, and J3 type nose bowl: I used Polyester Resin (for auto body repair) on both tanks. It's cheaper than Epoxy, and is a lower viscosity which aids in wetting out the fabric. However, if I build another tank, I will use the West System Epoxy Resin 105, with the 206 hardener. If you go this route, it is very convenient to buy the pumps that go with the cans, which dispenses the material at the proper ratio. Never handle any cloth with your bare hands, or touch any area where you are going to do an additional lay-up, or skin oil will prevent the resin from saturating the cloth in that area. You have to be FAST if you use the Polyester Resin, because after you put the hardener in...it Kicks in only about 5 to 7 minutes, depending on how many drops you put in. West System has a lot longer pot life (work time). Have all the fabric cut, pre-fit, and stacked in the order they lay. I can't say enough about preparation, before you add the hardener. You can lengthen the working time some, by using a few drops less than recommended, but once it starts to jell, forget about proceeding any further. The challenge of doing composite work, is to get 100% saturation, using as little resin as possible, with no fabric separation. The way we achieve this at work, is 'Vacuum Bagging'. One of the faults of the Polyester Resin, is that it is NOT alcohol resistant. So far, I haven't had any problem. Fiberglass Cloth: I have a source here in Wichita, where I purchase the cloth, in all sizes. It ain't cheap !! Seems like I had over $35 or $40 bucks for the cloth in the nose tank and nose bowl. I used two different weigh fabric - Light weight, and Medium weight. The first layer down, I used light weight. Then two layers of medium weight, then the last layer down in the Mould I used another layer of light weight. The difficult part is to get the cloth to stay down in the corners. It always wants to spring back out of the inside corners, no matter how many times you poke it back in. Light weigh cloth stays down in the corners much easier, because the cloth is thinner, and bends easier. This is the reason I used corner pieces in the mould, so the fabric only has to form to 45, instead of 90. After the resin cures, and you pop the bottom and top out of the mould, you need to carefully sand the edges, so you get a nice tight fit, preferably a 45 miter fit (that's what I did) then glue them together with the resin you've been using. After they are glued together, put 3 layers around the entire corner edge, stepping out from 2" for the first layer down, up to about 4" for the last layer down. You always have to sand the shinny off, before adding any additional layers. After complete, leak test with a balloon, like Tony Bengalis recommends. Then you should calibrate it at the gas station. Set the tank in the static laden position (the angle it will be at when the tail is on the ground), and add one gallon of fuel at a time, dip your 'Calibrated Dip Stick' in, and mark each gallon increment. The distance between these marks vary, because of the shape of the tank. I didn't have any leaks in either of the fuel tanks I built. I built the Smoke Tank with just two layers of fiberglass, moulded around cereal box the right dimension, but used the West System Epoxy. It seemed like the cloth was wetted out good, but it had two places where the baby oil seeped through, and dripped about one drip every 6 minutes. I fixed them by cleaning first with Brake Clean, then sanding the area, then some more Brake Clean (with clean cloth and no finger prints), then used 5 minute epoxy, and two layers of cloth. Chuck Gantzer NX770CG Merry Christmas To All !! ________________________________ Message 7 _____________________________________ Time: 02:23:20 PM PST US From: alexms1@comcast.net Subject: RE: Pietenpol-List: Fiberglass Construction Gordon, I take it you are strongly recommending epoxy resin for the fiberglass tank, right? I have never been a fan of polyester resin compared to epoxy. Alex Sloan -------------- Original message -------------- > --> Pietenpol-List message posted by: "gbowen@ptialaska.net" > > > As a polymer chemist I highly recommend to anyone considering using > polyester resin for construction of a fiberglass fuel tank to make a small > test. Make a 2" by 4" test laminate of polyester and fiberglass. Put into > a quart jar of AVGAS and MOGAS for about 1 month. You could weigh before > and after if you've got an accurate scale, but I think you'll discover the > discoloration of the AVGAS and MOGAS plus the somewhat slimy feel of your > test coupon will change your mind about the chemical resistance of > polyester resins. > Gordon > > Original Message: > ----------------- > From: Rcaprd@aol.com > Date: Thu, 23 Dec 2004 16:02:25 EST > To: pietenpol-list@matronics.com > Subject: Pietenpol-List: Fiberglass Construction > > > --> Pietenpol-List message posted by: Rcaprd@aol.com > > In a message dated 12/23/04 1:00:37 PM Central Standard Time, > N321TX@wmconnect.com writes: > > << I'm going to be making a fuel tank for an air camper soon. > > #1. Who is a good source (Aircraft Spruce?) for the resin and cloth? > #2. What weave material is recommended? > > Thanks, > Sterling >> > > Sterling, > Are you using the fuel tank mould that I loaned you ? If so, please > use > enough release agent, so as not to destroy it !! There is a couple of > other > folks that will need it. It's a really good mould (capacity - 10.7 gal.), > and > we can pass it around to others, when you are done with it. (It is for the > nose cowling fuel tank for plans dimension short fuselage.) I designed it > so > the bottom of the tank slopes forward, when the tail is on the ground, so > any > water in the fuel finds it's way to the outlet. There is no place where a > pocket of water will collect. I might need it again, too, if I ever get > any > alcohol in my fuel !! > > Here is the way I built both my tanks, and J3 type nose > bowl: > I used Polyester Resin (for auto body repair) on both tanks. It's > cheaper than Epoxy, and is a lower viscosity which aids in wetting out the > fabric. > However, if I build another tank, I will use the West System Epoxy Resin > 105, > with the 206 hardener. If you go this route, it is very convenient to buy > the > pumps that go with the cans, which dispenses the material at the proper > ratio. > Never handle any cloth with your bare hands, or touch any area where > you > are going to do an additional lay-up, or skin oil will prevent the resin > from > saturating the cloth in that area. > You have to be FAST if you use the Polyester Resin, because after you > put > the hardener in...it Kicks in only about 5 to 7 minutes, depending on how > many drops you put in. West System has a lot longer pot life (work time). > Have > all the fabric cut, pre-fit, and stacked in the order they lay. I can't > say > enough about preparation, before you add the hardener. You can lengthen > the > working time some, by using a few drops less than recommended, but once it > starts to jell, forget about proceeding any further. The challenge of > doing > composite work, is to get 100% saturation, using as little resin as > possible, with > no fabric separation. The way we achieve this at work, is 'Vacuum > Bagging'. > One of the faults of the Polyester Resin, is that it is NOT alcohol > resistant. So far, I haven't had any problem. > Fiberglass Cloth: > I have a source here in Wichita, where I purchase the cloth, in all > sizes. It ain't cheap !! Seems like I had over $35 or $40 bucks for the > cloth in > the nose tank and nose bowl. I used two different weigh fabric - Light > weight, and Medium weight. > The first layer down, I used light weight. Then two layers of medium > weight, > then the last layer down in the Mould I used another layer of light weight. > > The difficult part is to get the cloth to stay down in the corners. It > always > wants to spring back out of the inside corners, no matter how many times > you > poke it back in. Light weigh cloth stays down in the corners much easier, > because the cloth is thinner, and bends easier. This is the reason I used > corner > pieces in the mould, so the fabric only has to form to 45, instead of 90. > > After the resin cures, and you pop the bottom and top out of the mould, you > need to carefully sand the edges, so you get a nice tight fit, preferably a > 45 > miter fit (that's what I did) then glue them together with the resin you've > been using. After they are glued together, put 3 layers around the entire > corner edge, stepping out from 2" for the first layer down, up to about 4" > for the > last layer down. You always have to sand the shinny off, before adding any > additional layers. After complete, leak test with a balloon, like Tony > Bengalis > recommends. Then you should calibrate it at the gas station. Set the tank > in the static laden position (the angle it will be at when the tail is on > the > ground), and add one gallon of fuel at a time, dip your 'Calibrated Dip > Stick' > in, and mark each gallon increment. The distance between these marks vary, > because of the shape of the tank. I didn't have any leaks in either of the > fuel > tanks I built. > I built the Smoke Tank with just two layers of fiberglass, moulded > around > cereal box the right dimension, but used the West System Epoxy. It seemed > like the cloth was wetted out good, but it had two places where the baby > oil > seeped through, and dripped about one drip every 6 minutes. I fixed them > by > cleaning first with Brake Clean, then sanding the area, then some more > Brake Clean > (with clean cloth and no finger prints), then used 5 minute epoxy, and two > layers of cloth. > > Chuck Gantzer > NX770CG > Merry Christmas To All !! > > > > > > > > > > > > > > > > > > > Gordon, I take it you are strongly recommending epoxy resin for the fiberglass tank, right? I have never been a fan of polyester resin compared to epoxy. Alex Sloan -------------- Original message -------------- -- Pietenpol-List message posted by: "gbowen@ptialaska.net" As a polymer chemist I highly recommend to anyone considering using polyester resin for construction of a fiberglass fuel tank to make a small test. Make a 2" by 4" test laminate of polyester and fiberglass. Put into a quart jar of AVGAS and MOGAS for about 1 month. You could weigh before and after if you've got an accurate scale, but I think you'll discover the discoloration of the AVGAS and MOGAS plus the somewhat slimy feel of your test coupon will change your mind about the chemical resistance of polyester resins. Gordon Original Message: ----------------- From: Rcaprd@aol.com Date: Thu, 23 Dec 2004 1 6:02:25 EST To: pietenpol-list@matronics.com Subject: Pietenpol-List: Fiberglass Construction -- Pietenpol-List message posted by: Rcaprd@aol.com In a message dated 12/23/04 1:00:37 PM Central Standard Time, N321TX@wmconnect.com writes: I'm going to be making a fuel tank for an air camper soon. #1. Who is a good source (Aircraft Spruce?) for the resin and cloth? #2. What weave material is recommended? Thanks, Sterling Sterling, Are you using the fuel tank mould that I loaned you ? If so, please use enough release agent, so as not to destroy it !! There is a couple of other folks that will need it. It's a really good mould (capacity - 10.7 gal.), and we can pass it around to others, when you are done with it. (It is for the nose cowling fuel tank for plans dimension short fuselage.) I designed it so the bottom of the tank slopes forward, when the tail is on the ground, so any water in the fuel finds it's way to the outlet. There is no place where a pocket of water will collect. I might need it again, too, if I ever get any alcohol in my fuel !! Here is the way I built both my tanks, and J3 type nose bowl: I used Polyester Resin (for auto body repair) on both tanks. It's cheaper than Epoxy, and is a lower viscosity which aids in wetting out the fabric. However, if I build another tank, I will use the West System Epoxy Resin 105, with the 206 hardener. If you go this route, it is very convenient to buy the pumps that go with the cans, which dispenses the material at the proper ratio. Never handle any cloth with your bar e hands, or touch any area where you are going to do an additional lay-up, or skin oil will prevent the resin from saturating the cloth in that area. You have to be FAST if you use the Polyester Resin, because after you put the hardener in...it Kicks in only about 5 to 7 minutes, depending on how many drops you put in. West System has a lot longer pot life (work time). Have all the fabric cut, pre-fit, and stacked in the order they lay. I can't say enough about preparation, before you add the hardener. You can lengthen the working time some, by using a few drops less than recommended, but once it starts to jell, forget about proceeding any further. The challenge of doing composite work, is to get 100% saturation, using as little resin as possible, with no fabric separation. The way we achieve this at work, is 'Vacuum Bagging'. One of the faults of the Polyester Resin, is that it is NOT alcohol resistant. So far, I haven't had any problem. Fiberglass Cloth: I have a source here in Wichita, where I purchase the cloth, in all sizes. It ain't cheap !! Seems like I had over $35 or $40 bucks for the cloth in the nose tank and nose bowl. I used two different weigh fabric - Light weight, and Medium weight. The first layer down, I used light weight. Then two layers of medium weight, then the last layer down in the Mould I used another layer of light weight. The difficult part is to get the cloth to stay down in the corners. It always wants to spring back out of the inside corners, no matter how many times you poke it back in. Light weigh cloth stays down in the corners much easier, because the cloth is thinner, and be nds easier. This is the reason I used corner pieces in the mould, so the fabric only has to form to 45, instead of 90. After the resin cures, and you pop the bottom and top out of the mould, you need to carefully sand the edges, so you get a nice tight fit, preferably a 45 miter fit (that's what I did) then glue them together with the resin you've been using. After they are glued together, put 3 layers around the entire corner edge, stepping out from 2" for the first layer down, up to about 4" for the last layer down. You always have to sand the shinny off, before adding any additional layers. After complete, leak test with a balloon, like Tony Bengalis recommends. Then you should calibrate it at the gas station. Set the tank in the static laden position (the angle it will be at when the tail is on the ground), and add on e gallon of fuel at a time, dip your 'Calibrated Dip Stick' in, and mark each gallon increment. The distance between these marks vary, because of the shape of the tank. I didn't have any leaks in either of the fuel tanks I built. I built the Smoke Tank with just two layers of fiberglass, moulded around cereal box the right dimension, but used the West System Epoxy. It seemed like the cloth was wetted out good, but it had two places where the baby oil seeped through, and dripped about one drip every 6 minutes. I fixed them by cleaning first with Brake Clean, then sanding the area, then some more Brake Clean (with clean cloth and no finger prints), then used 5 minute epoxy, and two layers of cloth. Chuck Gantzer NX770CG Merry Christmas To All !! < ________________________________ Message 8 _____________________________________ Time: 02:53:51 PM PST US From: "gbowen@ptialaska.net" Subject: RE: Pietenpol-List: Fiberglass Construction --> Pietenpol-List message posted by: "gbowen@ptialaska.net" Each resin has it's place and function. In terms of chemical resistence it goes like this: epoxy based vinyl ester is best, a post cured epoxy is next and then comes polyester for some things like water. If MOGAS and AVGAS was pure aliphatics C-7 and C-8's hydrocarbons then maybe polyester would hold up better, but gasoline of all types has a lot of aromatics and some ethers in it now that lead is dead in fuel. MOGAS changes from region to region and season to season to fit the climate, these additives love to scarf up polymers like polyester. When no-lead came out 25 years ago, we had to redo all the test on RAE and Saf-t-poxy for Rutan to insure the composite planes of his design didn't dissolve into a great big puddle of plastic. These tests were 2 years of submersion in all types of gasoline, weighed before and after on a scale accurate to 0.001 grams. Epoxy holds up. If someone out there has a polyester tank, and leaks do appear or your fuel filters/carb gets a gummy deposit, step back and punt. Or take the thing out, dry it out, cut it in half, relaminate the inside with Derakane and a couple plies of glass. One of the steps I left out in my last email for those using the "lost mold" method of making their composite tanks: if you don't use epoxy and decide to use Derakane, you have to coat the foam mold with a layer of plaster to keep the styrene in the Derakane from eating the mold while you're making your laminates. Go to Home Depot and buy a gallon of normal plaster patching compound, spread it thin and smoothly on the carved stryo and let dry, then go ahead with your laminations. Gordon Bowen Original Message: ----------------- From: alexms1@comcast.net Subject: RE: Pietenpol-List: Fiberglass Construction Gordon, I take it you are strongly recommending epoxy resin for the fiberglass tank, right? I have never been a fan of polyester resin compared to epoxy. Alex Sloan -------------- Original message -------------- > --> Pietenpol-List message posted by: "gbowen@ptialaska.net" > > > As a polymer chemist I highly recommend to anyone considering using > polyester resin for construction of a fiberglass fuel tank to make a small > test. Make a 2" by 4" test laminate of polyester and fiberglass. Put into > a quart jar of AVGAS and MOGAS for about 1 month. You could weigh before > and after if you've got an accurate scale, but I think you'll discover the > discoloration of the AVGAS and MOGAS plus the somewhat slimy feel of your > test coupon will change your mind about the chemical resistance of > polyester resins. > Gordon > > Original Message: > ----------------- > From: Rcaprd@aol.com > Date: Thu, 23 Dec 2004 16:02:25 EST > To: pietenpol-list@matronics.com > Subject: Pietenpol-List: Fiberglass Construction > > > --> Pietenpol-List message posted by: Rcaprd@aol.com > > In a message dated 12/23/04 1:00:37 PM Central Standard Time, > N321TX@wmconnect.com writes: > > << I'm going to be making a fuel tank for an air camper soon. > > #1. Who is a good source (Aircraft Spruce?) for the resin and cloth? > #2. What weave material is recommended? > > Thanks, > Sterling >> > > Sterling, > Are you using the fuel tank mould that I loaned you ? If so, please > use > enough release agent, so as not to destroy it !! There is a couple of > other > folks that will need it. It's a really good mould (capacity - 10.7 gal.), > and > we can pass it around to others, when you are done with it. (It is for the > nose cowling fuel tank for plans dimension short fuselage.) I designed it > so > the bottom of the tank slopes forward, when the tail is on the ground, so > any > water in the fuel finds it's way to the outlet. There is no place where a > pocket of water will collect. I might need it again, too, if I ever get > any > alcohol in my fuel !! > > Here is the way I built both my tanks, and J3 type nose > bowl: > I used Polyester Resin (for auto body repair) on both tanks. It's > cheaper than Epoxy, and is a lower viscosity which aids in wetting out the > fabric. > However, if I build another tank, I will use the West System Epoxy Resin > 105, > with the 206 hardener. If you go this route, it is very convenient to buy > the > pumps that go with the cans, which dispenses the material at the proper > ratio. > Never handle any cloth with your bare hands, or touch any area where > you > are going to do an additional lay-up, or skin oil will prevent the resin > from > saturating the cloth in that area. > You have to be FAST if you use the Polyester Resin, because after you > put > the hardener in...it Kicks in only about 5 to 7 minutes, depending on how > many drops you put in. West System has a lot longer pot life (work time). > Have > all the fabric cut, pre-fit, and stacked in the order they lay. I can't > say > enough about preparation, before you add the hardener. You can lengthen > the > working time some, by using a few drops less than recommended, but once it > starts to jell, forget about proceeding any further. The challenge of > doing > composite work, is to get 100% saturation, using as little resin as > possible, with > no fabric separation. The way we achieve this at work, is 'Vacuum > Bagging'. > One of the faults of the Polyester Resin, is that it is NOT alcohol > resistant. So far, I haven't had any problem. > Fiberglass Cloth: > I have a source here in Wichita, where I purchase the cloth, in all > sizes. It ain't cheap !! Seems like I had over $35 or $40 bucks for the > cloth in > the nose tank and nose bowl. I used two different weigh fabric - Light > weight, and Medium weight. > The first layer down, I used light weight. Then two layers of medium > weight, > then the last layer down in the Mould I used another layer of light weight. > > The difficult part is to get the cloth to stay down in the corners. It > always > wants to spring back out of the inside corners, no matter how many times > you > poke it back in. Light weigh cloth stays down in the corners much easier, > because the cloth is thinner, and bends easier. This is the reason I used > corner > pieces in the mould, so the fabric only has to form to 45, instead of 90. > > After the resin cures, and you pop the bottom and top out of the mould, you > need to carefully sand the edges, so you get a nice tight fit, preferably a > 45 > miter fit (that's what I did) then glue them together with the resin you've > been using. After they are glued together, put 3 layers around the entire > corner edge, stepping out from 2" for the first layer down, up to about 4" > for the > last layer down. You always have to sand the shinny off, before adding any > additional layers. After complete, leak test with a balloon, like Tony > Bengalis > recommends. Then you should calibrate it at the gas station. Set the tank > in the static laden position (the angle it will be at when the tail is on > the > ground), and add one gallon of fuel at a time, dip your 'Calibrated Dip > Stick' > in, and mark each gallon increment. The distance between these marks vary, > because of the shape of the tank. I didn't have any leaks in either of the > fuel > tanks I built. > I built the Smoke Tank with just two layers of fiberglass, moulded > around > cereal box the right dimension, but used the West System Epoxy. It seemed > like the cloth was wetted out good, but it had two places where the baby > oil > seeped through, and dripped about one drip every 6 minutes. I fixed them > by > cleaning first with Brake Clean, then sanding the area, then some more > Brake Clean > (with clean cloth and no finger prints), then used 5 minute epoxy, and two > layers of cloth. > > Chuck Gantzer > NX770CG > Merry Christmas To All !! > > > > > > > > > > > > > > > > > > > ________________________________ Message 9 _____________________________________ Time: 08:14:15 PM PST US From: Rcaprd@aol.com Subject: Re: Pietenpol-List: Fiberglass Construction --> Pietenpol-List message posted by: Rcaprd@aol.com Gordon, I wish I would have seen this post about all this epoxy stuff. I built my wing tank in December of '98, and used a sloshing solution called '5000L'. At the time, this is the method that several local builders used. Maybe the sloshing solution saved the polyester resin. I've done quite a few inspections inside the tank, and it still seems all right. I didn't use the sloshing solution in the cowl tank, that I built in January '03. I've never found any goo, or fibers, in the gascolator, and I inspect it regularly. I'll have a very close look inside both tanks, with my bore scope, as regular inspections. I'm very careful not to use fuel with alcohol, and the fuel I use at my home airport is 100LL. Ya never know, though. The next two tanks I build, will be for my Wittman Tailwind W10. I'll use West System Epoxy resin, and I plan on using Carbon Fiber for the 35 gallon tank behind the firewall, and an auxiliary tank in the baggage compartment. The West System dosen't mention weather it is epoxy based vinyl ester. Gordon, is the West System epoxy based vinyl ester ? Chuck G. ________________________________ Message 10 ____________________________________ Time: 08:24:03 PM PST US From: N321TX@wmconnect.com Subject: Re: Pietenpol-List: Fiberglass Construction Yep, I'm going to be using your mold. I just forgot what you used when I picked it up from you several months ago, and it'll stay here until I get word who gets it next. Thanks, S.B. ________________________________ Message 11 ____________________________________ Time: 11:06:43 PM PST US s=s1024; d=yahoo.com; b=r63VFQU7EhOCGjRVQoMr4vfsvEbTC+AefvZ/8d5PHs+UcornVPoXmWkmbnAMwr/cvkob0dvOpflR1sS2wC6kXFQD458wTV/PlSnqLIibzZjFoPvCj+nWBGSc9h/XNjmYPS2pACU3hfhZtODuVc+kTsLXJMZCQIKCkhj4ZDJkC+Y= ; From: Gary Gower Subject: Re: Pietenpol-List: Fiberglass Construction We have used here Poyester Resin in our tanks for 20 plus years, with no problem, only they get yellow, the brown, later dark brown, cant see the level of gasoline though, but no internal damage.... Ol' Ironsides a Tailwind look alike built inthe 60's (If I remember correct) used the same and stlll in working condition (read the article a few years ago, maybe my memory is not all correct. Is a Fiberglass plane but not complete sure if the gas tank is fiberglass... Saludos Gary Gower. Whats the name of that German guy that is stolling my memory? :-) :-) Rcaprd@aol.com wrote: --> Pietenpol-List message posted by: Rcaprd@aol.com Gordon, I wish I would have seen this post about all this epoxy stuff. I built my wing tank in December of '98, and used a sloshing solution called '5000L'. At the time, this is the method that several local builders used. Maybe the sloshing solution saved the polyester resin. I've done quite a few inspections inside the tank, and it still seems all right. I didn't use the sloshing solution in the cowl tank, that I built in January '03. I've never found any goo, or fibers, in the gascolator, and I inspect it regularly. I'll have a very close look inside both tanks, with my bore scope, as regular inspections. I'm very careful not to use fuel with alcohol, and the fuel I use at my home airport is 100LL. Ya never know, though. The next two tanks I build, will be for my Wittman Tailwind W10. I'll use West System Epoxy resin, and I plan on using Carbon Fiber for the 35 gallon tank behind the firewall, and an auxiliary tank in the baggage compartment. The West System dosen't mention weather it is epoxy based vinyl ester. Gordon, is the West System epoxy based vinyl ester ? Chuck G. --------------------------------- Send a seasonal email greeting and help others. Do good.