---------------------------------------------------------- Pietenpol-List Digest Archive --- Total Messages Posted Fri 11/23/07: 15 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:01 AM - Re: The Pietenpol is a Chick Magnet! (MikeD) 2. 07:13 AM - Re: Adhesives article (MikeD) 3. 07:29 AM - Re: Adhesive comparison test results (MikeD) 4. 07:50 AM - Re: Re: elevator control question-- do not archive (Tim Willis) 5. 08:26 AM - Re: Lengthened control tube (Rick Holland) 6. 08:42 AM - Re: View The Video (MikeD) 7. 08:44 AM - Re: Re: The Pietenpol is a Chick Magnet! () 8. 10:08 AM - Re: Re: Adhesives article (Gordon Bowen) 9. 10:46 AM - Re: Adhesives article (MikeD) 10. 10:56 AM - Re: Re: Adhesive comparison test results (Gordon Bowen) 11. 11:04 AM - Re: Re: Adhesives article (Brian Kraut) 12. 11:50 AM - Re: Re: elevator control question (del magsam) 13. 07:33 PM - Re: Adhesives article (MikeD) 14. 07:38 PM - Re: Adhesive comparison test results (MikeD) 15. 08:16 PM - Re: Re: Adhesive comparison test results (Gordon Bowen) ________________________________ Message 1 _____________________________________ Time: 07:01:15 AM PST US Subject: Pietenpol-List: Re: The Pietenpol is a Chick Magnet! From: "MikeD" kmordecai001(at)comcast.n wrote: > Fellow Pieters, > Pulled the throttle back to idle, and tried to explain to the attractive-lady-about-my-age-or-younger that I had 96 lbs fuel onboard and we would be over gross weight, not to mention that the front cockpit headset was back home in the hanger and a step-stool is needed to get in. > Dave Mordecai > Panacea, FL > NX520SF 1. Don't put so much fuel in next time. 2. Always have the other headset with you. 3. A girl that say she doesn't need to talk (before or after) is worth investigating. 4. If your wife catches you, tell her that the passenger's husband bought her a ride. Carry $50 cash in your pocket at all times. 5. Good luck! Now I can't wait until mine is done. MJD -------- Piet-builder-who-hopes-to-be-flying-next-summer Read this topic online here: http://forums.matronics.com/viewtopic.php?p=148055#148055 ________________________________ Message 2 _____________________________________ Time: 07:13:50 AM PST US Subject: Pietenpol-List: Re: Adhesives article From: "MikeD" [quote="gbowen(at)ptialaska.net"] 2) if you have problems with gap filling and/or runouts of the glue, use microballons to "bulk-up" and then a pinch of cotton flox or silica to eliminate sag of the glue before curing. The flox and silica are thixotropes, kinda like long fibers under a microscope, this gives thickening without much bulk, and some added bonding strength.Hope this helpful, and not preachy. Gordon > --- I believe you are suggesting fumed silica versus regular silica filler which wouldn't help at all. Fumed silica - for those wondering what the heck it is, one trade name is Cab-O-Sil - looks a lot like little "burrs", with very high surface area to weight ratio, and rocks as a thixotroping agent and structural filler all in one. Regular silica filler takes a lot to add viscosity, and then is quite prone to settling unless stabilized with fumed silica. When thixotroping small mixes I use fumed silica. Do we really want to add microballoons to a structural airframe adhesive though? I worry some folks will go nuts with it is all. -------- Piet-builder-who-hopes-to-be-flying-next-summer Read this topic online here: http://forums.matronics.com/viewtopic.php?p=148057#148057 ________________________________ Message 3 _____________________________________ Time: 07:29:05 AM PST US Subject: Pietenpol-List: Re: Adhesive comparison test results From: "MikeD" [quote="Glenn Thomas"]I guess the redeeming value in the article (although I will read it more closely later) is while there is not an advantage to using slowset epoxy, there is also no disadvantage (for those of us who used T-88). Is the article written with moisture and common aircraft application in mind? Thanks for sharing the info. It's interesting to read about things like this. Glenn W. Thomas Storrs, CT There is little reason in theory that faster curing epoxies should offer poorer mechanical properties than slower cure. This notion comes from the typical properties of consumer adhesive systems, which may use a variety of curative chemistries to make them do what the label says. Consumer adhesives also tend to be formulated so that they have a fairly high tolerance for mismatched ratio mixing, which can result in tempering the overall properties in favor of user-friendliness. I have formulated and used epoxy systems with extremely fast cure times that have equivalent properties to slower set systems. There are a host of curative chemistries available to the formulater - aromatic amine, aliphatic amine, polyamide, boron trifluoride complexes, yada yada - all with different "raison d'etre" (i.e. better and mechanical properties, reactivity, toxicityand odor considerations, bla bla), and the system can be slowed or hastened by the selection of more or less reactive curatives within a family and by the use of curative blends and/or catalysts. Likewise, there are different additives used in the resin side to achieve certain properties, such as reactive and non-reactive diluents, rubber-modifiers to increase toughness, structural fillers and thixotroping agents, UV stabilizers, bla bla. Resins straight out of the drum (like common resins such as Epon 828, Dow 362, others) are okay for laminating applications as they are, but for structural adhesives the properties are usually improved by intelligent use of various additives. -------- Piet-builder-who-hopes-to-be-flying-next-summer Read this topic online here: http://forums.matronics.com/viewtopic.php?p=148060#148060 ________________________________ Message 4 _____________________________________ Time: 07:50:13 AM PST US From: Tim Willis Subject: Re: Pietenpol-List: Re: elevator control question-- do not archive Thanks to all for your replies. After tinkering just a bit I am now getting 3 inches of elevator cable travel, so according to Oscar's geometry, I should be fine, with over 20 degrees of elevator angle each way. Since I am slightly changing a few more things, per my talks with Corky, I will leave some flexibility to change connections and be able to achieve either more or less travel, or to change control sensitivity. Having a ballpark is very handy right now. Your ideas and input have been very helpful. Alan, thanks for the control stops discussion, too. Tim in central TX do not archive -----Original Message----- >From: catdesigns@att.net >Sent: Nov 22, 2007 12:58 PM >To: pietenpol-list@matronics.com >Subject: Pietenpol-List: Re: elevator control question > > >>From my notes: > >Alan James in the UK Recommends > >Elevators: >20 degrees up/15-20 degrees down. I've run out of elevator before now > in a machine with something less than 20 degrees up and found myself >almost bending the stick trying to get a decent break during a stall test. >Don't be tempted to add any more - 20 degrees up is perfect. > >Rudder: >I have fitted stops to retain 1" clearance between rudder and elevator >at full deflection on G-BUCO. This works fine for me. > >Ailerons: >You don't want the down-going aileron spar to clout against the wing. I've >fitted blocks to the fuselage floor under the ends of the aileron bellcrank >to >act as stops. They allow a gap of about (?)" between the wing and the bottom >edge of a closed aileron. And whilst we are talking ailerons, tape over the >gap on the upper surface during covering - it lightens the stick load >considerably. > >AJ. > >Chris Tracy >Sacramento, Ca >Website at http://www.WestCoastPiet.com > >----- Original Message ----- >From: "Tim Willis" >To: >Sent: Wednesday, November 21, 2007 4:57 AM >Subject: Re: Pietenpol-List: Re: elevator control question > > >> >> >> Dan, >> Thanks. I will begin tinkering with adjustments for that full range in >> mind. BTW, Corky put Vi Kapler hinges on this plane. >> Tim in central TX >> do not archive >> >> -----Original Message----- >>>From: dwilson >>>Sent: Nov 20, 2007 10:12 PM >>>To: pietenpol-list@matronics.com >>>Subject: Pietenpol-List: Re: elevator control question >>> >>> >>>I asked this very question of Vi Kapler. Vi stated that the elevator >>>deflection should be at least 20 degrees down and 20 degrees up. He also >>>stated that the elevator deflection should never exceed 30 degrees. I >>>consider Vi one of the most knowledgeable experts with regard to the >>>Aircamper. >>> >>>Dan >>> >>> >>> >>> >>>Read this topic online here: >>> >>>http://forums.matronics.com/viewtopic.php?p=147635#147635 >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >> >> >> >> >> > > ________________________________ Message 5 _____________________________________ Time: 08:26:37 AM PST US From: "Rick Holland" Subject: Re: Pietenpol-List: Lengthened control tube Built mine to the plans on my long fuse and it fits fine (along with all other control components). Have fun Rick On Nov 22, 2007 6:07 PM, Ryan Michals wrote: > Quick question to the list, > > Does the control torque tube get lengthened in the longer > fuselage? I couldn't find this mentioned in the archives. > > Have a happy Thanksgiving, > > Ryan > > ------------------------------ > Be a better sports nut! Let your teams follow you ">Try it now. > > * > > * > > -- Rick Holland ObjectAge Ltd. Castle Rock, Colorado ________________________________ Message 6 _____________________________________ Time: 08:42:50 AM PST US Subject: Pietenpol-List: Re: View The Video From: "MikeD" [quote="brian.kraut(at)engalt.com"]I normally don't pass on emails like this, but this is just about the wildest thing I have ever seen in aviation. Hmmm, where is the closest mountain? Brian Kraut Engineering Alternatives, Inc. www.engalt.com Subject: View The Video quote] Why not go the next step?... http://www.youtube.com/watch?v=bEXxkWXncuo -------- Piet-builder-who-hopes-to-be-flying-next-summer Read this topic online here: http://forums.matronics.com/viewtopic.php?p=148073#148073 ________________________________ Message 7 _____________________________________ Time: 08:44:46 AM PST US Subject: RE: Pietenpol-List: Re: The Pietenpol is a Chick Magnet! From: If your wife catch's you,pleed insanity.I didn't know what I was doing,I got caught up in the moment!!!!!!!!!!!!! -----Original Message----- From: owner-pietenpol-list-server@matronics.com [mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of MikeD Sent: November 23, 2007 10:01 AM Subject: Pietenpol-List: Re: The Pietenpol is a Chick Magnet! kmordecai001(at)comcast.n wrote: > Fellow Pieters, > Pulled the throttle back to idle, and tried to explain to the attractive-lady-about-my-age-or-younger that I had 96 lbs fuel onboard and we would be over gross weight, not to mention that the front cockpit headset was back home in the hanger and a step-stool is needed to get in. > Dave Mordecai > Panacea, FL > NX520SF 1. Don't put so much fuel in next time. 2. Always have the other headset with you. 3. A girl that say she doesn't need to talk (before or after) is worth investigating. 4. If your wife catches you, tell her that the passenger's husband bought her a ride. Carry $50 cash in your pocket at all times. 5. Good luck! Now I can't wait until mine is done. MJD -------- Piet-builder-who-hopes-to-be-flying-next-summer Read this topic online here: http://forums.matronics.com/viewtopic.php?p=148055#148055 ________________________________ Message 8 _____________________________________ Time: 10:08:31 AM PST US From: "Gordon Bowen" Subject: Re: Pietenpol-List: Re: Adhesives article Yep, Cab-o-sil is the brand name for fumed silica and what I was recommending as a thixo agent. The canard-pusher composites folks have been using cotton flox or cabosil for about 35 years making any of the Rutan type designs. Anytime you have an adhesive not holding on a vertical bond, just a pinch of cabosil or cotton flox really adds holding power without too much bulking. The standard procedure for composites "gluing" applications is to bulk-up (the glass ballons weight a heck of a lot less than pure epoxy adhesive) with glass microballons then add just a pinch of thixo to get it to hold in place. There's also some reinforcing additives like short chopped fiberglass, or kevlar flox that is used to improve the strength of the adhesive. All these additives are available in the composites materials section of the AirSpruce catalog. Gordon ----- Original Message ----- From: "MikeD" Sent: Friday, November 23, 2007 6:13 AM Subject: Pietenpol-List: Re: Adhesives article > > [quote="gbowen(at)ptialaska.net"] > 2) if you have problems with gap filling and/or runouts of the glue, use > microballons to "bulk-up" and then a pinch of cotton flox or silica to > eliminate sag of the glue before curing. The flox and silica are > thixotropes, kinda like long fibers under a microscope, this gives > thickening without much bulk, and some added bonding strength.Hope this > helpful, and not preachy. > Gordon > >> --- > > > I believe you are suggesting fumed silica versus regular silica filler > which wouldn't help at all. Fumed silica - for those wondering what the > heck it is, one trade name is Cab-O-Sil - looks a lot like little "burrs", > with very high surface area to weight ratio, and rocks as a thixotroping > agent and structural filler all in one. Regular silica filler takes a lot > to add viscosity, and then is quite prone to settling unless stabilized > with fumed silica. When thixotroping small mixes I use fumed silica. Do we > really want to add microballoons to a structural airframe adhesive though? > I worry some folks will go nuts with it is all. > > -------- > Piet-builder-who-hopes-to-be-flying-next-summer > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=148057#148057 > > > ________________________________ Message 9 _____________________________________ Time: 10:46:52 AM PST US Subject: Pietenpol-List: Re: Adhesives article From: "MikeD" gbowen(at)ptialaska.net wrote: > Yep, Cab-o-sil is the brand name for fumed silica and what I was > recommending as a thixo agent. The standard procedure for composites "gluing" applications is to > bulk-up (the glass ballons weight a heck of a lot less than pure epoxy > adhesive) with glass microballons then add just a pinch of thixo to get it > to hold in place. There's also some reinforcing additives like short > chopped fiberglass, or kevlar flox that is used to improve the strength of > the adhesive. > Gordon > --- For Canucks, they are also available at compositescanada.com, a place I am guilty of impulse buying with now and again.. Yeah, I guess when you are gluing wood or plywood, a sensible percentage of microballoons isn't going to mess up the tensile or shear properties relative to the substrates. All the structural adhesives I used to make used fine silica as structural filler (obviously where density was less of a concern for the applications at hand) with fumed silica as thixotoping agent, or in lower percentages as anti-settling agent for the fillers. Plus rubber modifers and reactive diluents. We generally used aliphatic amine curatives, but the average homebuilder isn't weighing adhesives on a digital scale, or wanting to put up with the ammonia blast when you open the curative container (a good way to wake up fast in the middle of a long day)! But these were killer adhesive systems. -------- Piet-builder-who-hopes-to-be-flying-next-summer Read this topic online here: http://forums.matronics.com/viewtopic.php?p=148092#148092 ________________________________ Message 10 ____________________________________ Time: 10:56:18 AM PST US From: "Gordon Bowen" Subject: Re: Pietenpol-List: Re: Adhesive comparison test results Having been involved early in my career with the Rutan folks developing suitable laminating epoxies for composite homebuilts, I can tell you a lot of thought went into development of resins for composites homebuilts. Hexcel being the largest worldwide supplier of composite materials for commerical/military aircraft, we had a lot of testing equipment, proven aircraft applicable epoxy formula data bases and wet formulas at our disposal to use developing resins systems for Rutan's hand laminating needs. Have often wondered how much trial and error went into development of epoxies for wood aircraft pre-dating Rutan's demands. Suspect the epoxies used by the early wood builders were simply based on what was available off the shelf, they either worked or didn't. T-88 seemed to be one of those systems that functioned well even if not optimized for the application. As to the question about slow vs fast epoxies, the "5 min. epoxy", used by composite Longeze or Varieze or Cozy homebuilders, this system was never recommened for structural applications, where failure of the bond could compromise the safety of the airplane. All early plans for Rutan designs used our epoxies from Hexcel and only our resins, fast, slow and in the middle gel times . Rutan/Mike Melvil were very picky about their early requirements, they knew we had the testing equipment necessary to do the tests in the lab, saving them trial and error in their workshop or airborne testing by Melvil (world's first private astronaut and maniac test pilot). Testing on fiberglass laminates of "fast"(gel time 30 min or less) vs "slow" (gel times approx. 1 hr-1 1/2 hrs.) formulations always gave poorer mechanical properties with the faster resin systems, using fiberglass as the reinforcment. Heck we still had testing laminate coupons soaking in Avgas for testing 20 years after developing Saf-t-poxy or RAE for Rutan, once per year we'd pull a coupon and do mechanicals to make sure the fuel wasn't destroying the laminate. For the wood homebuilder not sure all this crap this makes a heck of a lot of diff. The structural failure will always be the intra-wood fibers not the bond between the wood fibers and the adhesive. Bulking agents like glass balloons will decrease some mechanical properties of the adhesive layer but the bond would always be stronger than the intra-wood fiber bonds. IF wood homebuilders get good wet-out of the wood and the epoxy formula is not sensitive to the oil/moisture in the wood, their biggest worry won't be bond failure of the wood parts, it' gonna be that big metal bug chopper hanging on the front firewall or the nut behind the control stick. Gordon ----- Original Message ----- From: "MikeD" Sent: Friday, November 23, 2007 6:28 AM Subject: Pietenpol-List: Re: Adhesive comparison test results > > [quote="Glenn Thomas"]I guess the redeeming value in the article (although > I will read it more closely later) is while there is not an advantage to > using slowset epoxy, there is also no disadvantage (for those of us who > used T-88). Is the article written with moisture and common aircraft > application in mind? Thanks for sharing the info. It's interesting to > read about things like this. > > Glenn W. Thomas > Storrs, CT > > There is little reason in theory that faster curing epoxies should offer > poorer mechanical properties than slower cure. This notion comes from the > typical properties of consumer adhesive systems, which may use a variety > of curative chemistries to make them do what the label says. Consumer > adhesives also tend to be formulated so that they have a fairly high > tolerance for mismatched ratio mixing, which can result in tempering the > overall properties in favor of user-friendliness. I have formulated and > used epoxy systems with extremely fast cure times that have equivalent > properties to slower set systems. There are a host of curative chemistries > available to the formulater - aromatic amine, aliphatic amine, polyamide, > boron trifluoride complexes, yada yada - all with different "raison > d'etre" (i.e. better and mechanical properties, reactivity, toxicityand > odor considerations, bla bla), and the system can be slowed or hastened by > the selection of more or less reactive curatives w! > ithin a family and by the use of curative blends and/or catalysts. > Likewise, there are different additives used in the resin side to achieve > certain properties, such as reactive and non-reactive diluents, > rubber-modifiers to increase toughness, structural fillers and > thixotroping agents, UV stabilizers, bla bla. Resins straight out of the > drum (like common resins such as Epon 828, Dow 362, others) are okay for > laminating applications as they are, but for structural adhesives the > properties are usually improved by intelligent use of various additives. > > -------- > Piet-builder-who-hopes-to-be-flying-next-summer > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=148060#148060 > > > ________________________________ Message 11 ____________________________________ Time: 11:04:53 AM PST US From: "Brian Kraut" Subject: RE: Pietenpol-List: Re: Adhesives article Never use micro for a structural bond. Flox or Cabosil is structural, but not micro. Brian Kraut Engineering Alternatives, Inc. www.engalt.com -----Original Message----- From: owner-pietenpol-list-server@matronics.com [mailto:owner-pietenpol-list-server@matronics.com]On Behalf Of Gordon Bowen Sent: Friday, November 23, 2007 1:08 PM Subject: Re: Pietenpol-List: Re: Adhesives article Yep, Cab-o-sil is the brand name for fumed silica and what I was recommending as a thixo agent. The canard-pusher composites folks have been using cotton flox or cabosil for about 35 years making any of the Rutan type designs. Anytime you have an adhesive not holding on a vertical bond, just a pinch of cabosil or cotton flox really adds holding power without too much bulking. The standard procedure for composites "gluing" applications is to bulk-up (the glass ballons weight a heck of a lot less than pure epoxy adhesive) with glass microballons then add just a pinch of thixo to get it to hold in place. There's also some reinforcing additives like short chopped fiberglass, or kevlar flox that is used to improve the strength of the adhesive. All these additives are available in the composites materials section of the AirSpruce catalog. Gordon ----- Original Message ----- From: "MikeD" Sent: Friday, November 23, 2007 6:13 AM Subject: Pietenpol-List: Re: Adhesives article > > [quote="gbowen(at)ptialaska.net"] > 2) if you have problems with gap filling and/or runouts of the glue, use > microballons to "bulk-up" and then a pinch of cotton flox or silica to > eliminate sag of the glue before curing. The flox and silica are > thixotropes, kinda like long fibers under a microscope, this gives > thickening without much bulk, and some added bonding strength.Hope this > helpful, and not preachy. > Gordon > >> --- > > > I believe you are suggesting fumed silica versus regular silica filler > which wouldn't help at all. Fumed silica - for those wondering what the > heck it is, one trade name is Cab-O-Sil - looks a lot like little "burrs", > with very high surface area to weight ratio, and rocks as a thixotroping > agent and structural filler all in one. Regular silica filler takes a lot > to add viscosity, and then is quite prone to settling unless stabilized > with fumed silica. When thixotroping small mixes I use fumed silica. Do we > really want to add microballoons to a structural airframe adhesive though? > I worry some folks will go nuts with it is all. > > -------- > Piet-builder-who-hopes-to-be-flying-next-summer > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=148057#148057 > > ________________________________ Message 12 ____________________________________ Time: 11:50:50 AM PST US From: del magsam Subject: Re: Pietenpol-List: Re: elevator control question I have his plans as well. It consists of a little different jack shaft behind the seat to adjust the geometry to keep the top and bottom cable distances the same no matter what the elevator angle is. Del catdesigns@att.net wrote: Dan, How did Mr. Perkins build the control horns? And how does he get rid of the slack in the cables? Chris Tracy Sacramento, Ca Website at http://www.WestCoastPiet.com ----- Original Message ----- From: "dwilson" Sent: Wednesday, November 21, 2007 4:16 PM Subject: Pietenpol-List: Re: elevator control question > > During the Broadhead Pietenpol Fly-in last summer Ken Perkins presented a > fantastic demonstration on his method for constructing elevator, aileron, > and rudder horns. He has also devised a method for removing the slack in > the elevator cables. Del-New Richmond, Wi "farmerdel@rocketmail.com" --------------------------------- Be a better sports nut! Let your teams follow you with Yahoo Mobile. Try it now. ________________________________ Message 13 ____________________________________ Time: 07:33:15 PM PST US Subject: Pietenpol-List: Re: Adhesives article From: "MikeD" brian.kraut(at)engalt.com wrote: > Never use micro for a structural bond. Flox or Cabosil is structural, but > not micro. > > Brian Kraut > Engineering Alternatives, Inc. > www.engalt.com > > -- Elastomeric microballoons can be considered structural to a degree as they increase toughness thus reducing possibility of fracture under shock loads, plus they also act similarly though not as effectively afaik as rubber modifiers as crack terminators (akin to drilling small holes a the end of a crack in sheet materials). Regular microballoons can be used if the percentage is in check - this of course is limited to cases where the mechanicals still exceed that of the substrate, and since that is unknown to the average fellow building an airframe, this use of them is an iffy idea as far as the home builder goes. I agree that the best rule of thumb is no to use them except in fillers versus structural apps. -------- Piet-builder-who-hopes-to-be-flying-next-summer Read this topic online here: http://forums.matronics.com/viewtopic.php?p=148132#148132 ________________________________ Message 14 ____________________________________ Time: 07:38:22 PM PST US Subject: Pietenpol-List: Re: Adhesive comparison test results From: "MikeD" gbowen(at)ptialaska.net wrote: > > > T-88 seemed to be one of those > systems that functioned well even if not optimized for the application. As > to the question about slow vs fast epoxies, the "5 min. epoxy", used by > composite Longeze or Varieze or Cozy homebuilders, this system was never > recommened for structural applications, where failure of the bond could > compromise the safety of the airplane. All early plans for Rutan designs > used our epoxies from Hexcel and only our resins, fast, slow and in the > middle gel times . Rutan/Mike Melvil were very picky about their early > requirements, they knew we had the testing equipment necessary to do the > tests in the lab, saving them trial and error in their workshop or airborne > testing by Melvil (world's first private astronaut and maniac test pilot). > Testing on fiberglass laminates of "fast"(gel time 30 min or less) vs "slow" > (gel times approx. 1 hr-1 1/2 hrs.) formulations always gave poorer > mechanical properties with the faster resin systems, using fiberglass as the > reinforcment. Heck we still had testing laminate coupons soaking in Avgas > for testing 20 years after developing Saf-t-poxy or RAE for Rutan, once per > year we'd pull a coupon and do mechanicals to make sure the fuel wasn't > destroying the laminate. For the wood homebuilder not sure all this crap > this makes a heck of a lot of diff. The structural failure will always be > the intra-wood fibers not the bond between the wood fibers and the adhesive. > Bulking agents like glass balloons will decrease some mechanical properties > of the adhesive layer but the bond would always be stronger than the > intra-wood fiber bonds. IF wood homebuilders get good wet-out of the wood > and the epoxy formula is not sensitive to the oil/moisture in the wood, > their biggest worry won't be bond failure of the wood parts, it' gonna be > that big metal bug chopper hanging on the front firewall or the nut behind > the control stick. > Gordon > --- Bingo. It is substrate failure, not bondline failure that is the issue - or perhaps it would be better to say "should be the issue". As you say, assuming the bond is done right with a sensible choice of epoxy system. -------- Piet-builder-who-hopes-to-be-flying-next-summer Read this topic online here: http://forums.matronics.com/viewtopic.php?p=148135#148135 ________________________________ Message 15 ____________________________________ Time: 08:16:35 PM PST US From: "Gordon Bowen" Subject: Re: Pietenpol-List: Re: Adhesive comparison test results Mike, little off topic for wood laminations and Pietenpols but if you'd like to try a rubber modified laminating resin system (off the shelf), that has some of the best properties for handlaminates try Hexcel's (now HBFuller) 2315. Think Epoxical (now Endurance in St.Paul) making same formula. First it's based on a bis-F epoxy but this epoxy is pre-adducted with Hycar rubber. The liquid rubber precips out when cured and makes a two phase laminate. Our test, before HB Fuller bought-out the Resins group, indicated this was one of our best systems. I used it on my Cozy IV, 60 min gel time, kinda hot exotherm when floxed too thick, but best stuff for laminates that need to resist flex cracking. Scaled Composites used a bunch of it for their contract drones work. Gordon ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message pietenpol-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Pietenpol-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/pietenpol-list Browse Digests http://www.matronics.com/digest/pietenpol-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.