---------------------------------------------------------- Europa-List Digest Archive --- Total Messages Posted Tue 11/21/06: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:45 AM - Re: To Those That Have Sanded Before Me... :) (Jack Hilditch) 2. 05:01 AM - Re: To Those That Have Sanded Before Me... :) (Jack Hilditch) 3. 05:45 AM - Re: Help Needed (Paul McAllister) 4. 05:54 AM - Re: To Those That Have Sanded Before Me... :) (Jack Hilditch) 5. 06:18 AM - Re: To Those That Have Sanded Before Me... :) (Rob Neils, Ph.D.) 6. 09:32 AM - Re: To Those That Have Sanded Before Me... :) (Graham Singleton) 7. 11:15 AM - Re: To Those That Have Sanded Before Me... :) (NevEyre@aol.com) 8. 11:52 AM - Re: To Those That Have Sanded Before Me... :) (Jack Hilditch) 9. 02:52 PM - Re: To Those That Have Sanded Before Me... :) (Graham Singleton) 10. 03:06 PM - Re: To Those That Have Sanded Before Me... :) (Graham Singleton) ________________________________ Message 1 _____________________________________ Time: 04:45:01 AM PST US From: "Jack Hilditch" Subject: RE: Europa-List: To Those That Have Sanded Before Me... :) Brian, If the low area is still quite visible (greater than 3" radius is a good rule of thumb to start with), with well defined stripes, I would suggest continuing with the serrated trowel. Typically, a flat trowel is only used for the final skim coat. You might want to try a finer toothed trowel, as the depression is filled with succeeding coats, but the striping (or lack thereof) is really what tells the tale. Regards, Jack _____ From: owner-europa-list-server@matronics.com [mailto:owner-europa-list-server@matronics.com] On Behalf Of EuropaXSA276@aol.com Sent: Monday, November 20, 2006 10:19 AM Subject: Re: Europa-List: To Those That Have Sanded Before Me... :) This is a very interesting technique Jack. I am assuming that a flat trowel is used on the second pass to fill the valleys? Brian Skelly Europa XS TriGear #A276 North Texas USA You can see my build photos at: http://www.europaowners.org/BrianS ________________________________ Message 2 _____________________________________ Time: 05:01:16 AM PST US From: "Jack Hilditch" Subject: RE: Europa-List: To Those That Have Sanded Before Me... :) Fred, The serration direction is immaterial as it will eventually be faired in by a thin, flat, surfacing coat. This resin/filler application technique is used to visually identify low areas during initial filling and sanding steps. As I mentioned, it also provide a better keying surface for succeeding coats. Using a 'long board', rather than a block sander, for initial fairing helps to prevent the creation of additional low areas through spot sanding. It spans existing low spots by resting on higher surfaces around the depression thereby bringing the low spot into fair. Regards, Jack -----Original Message----- From: owner-europa-list-server@matronics.com [mailto:owner-europa-list-server@matronics.com] On Behalf Of Fred Klein Sent: Monday, November 20, 2006 3:19 PM Subject: Re: Europa-List: To Those That Have Sanded Before Me... :) Jack, As I visualize this technique, I take it that the strokes of the serrated screed are chordwise (rather than spanwise) in order to facilitate the maintaining of the airfoil. Please confirm. Fred A194 > Jack Hilditch wrote: > >> Composite racing sailboat builders use a technique that produces a >> fair surface, without bumps or valleys, while minimizing weight or >> extra filler. They screed the filler/resin mix onto the surface using >> a small-toothed, serrated plastic trowel (the same kind used to apply >> ceramic tile cement to walls). -- 9:20 PM ________________________________ Message 3 _____________________________________ Time: 05:45:55 AM PST US From: "Paul McAllister" Subject: RE: Europa-List: Help Needed Hi all, Just a quick note to everyone who answered my question off forum. The thread turned out to be M8 x 1.0 mm pitch. I couldn't find it in stainless steel (on a Sunday afternoon) but AutoZone were able to sell me a steel one, along with some graphite based anti seize. So, I was able to remove the EGT, tie it out of the way and blank off the port and be on my way. Just imagine my chances of doing all of this in a small town on a Sunday with a certified aircraft.... I'll still be there trying to figure it out.... I just love my Europa Paul 550 hours and still grinning do not archive -----Original Message----- Subject: Europa-List: Help Needed Hi All, I am currently on the road in Northern Florida and I have a small problem that I need to deal with. The thread has stripped on the nipple that holds the EGT probe in on the rear exhaust pipe (914 Turbo) and its letting exhaust gas out. My current thought is to remove it, try and find a stainless steel bolt to screw into the fitting on the exhaust pipe to blank it off. So, the question to the forum is, does any one know the size and pitch of the thread on on the exhaust pipe port ? Thanks, Paul ________________________________ Message 4 _____________________________________ Time: 05:54:38 AM PST US From: "Jack Hilditch" Subject: RE: Europa-List: To Those That Have Sanded Before Me... :) Graham, Agreed. All builders would be well advised to watch the mix consistency carefully so as to prevent differing moduli of elasticity and (possible) future problems during any lamination process. However, the step currently under discussion is non-structural and really only about fairing reasonably small areas. Filler depth should be quite thin (1/8" or less) so, while sanding a catalyst-rich filler mix may be a bit more time consuming, it really shouldn't be too bad. If the areas requiring filler are large or deep, other considerations may apply. For all lamination processes it would be prudent to: 1.) Use a standard pump system to manage resin to catalyst ratio. 2.) Mix the two thoroughly before adding fillers. 3.) Measure any additives carefully. 4.) Thoroughly mix the additives into the resin matrix. 5.) Conduct all resin application operations within temperature and humidity conditions specified by the resin manufacturer. Assuming those steps are followed, the fairing layers should be nearly identical in hardness. The only time I ever saw hardness become a factor was when the mixing process did not adhere to the proper ratio between resin and catalyst or if the additive was sloppily blended into resin matrix. Regards, Jack -----Original Message----- From: owner-europa-list-server@matronics.com [mailto:owner-europa-list-server@matronics.com] On Behalf Of Graham Singleton Sent: Monday, November 20, 2006 10:41 AM Subject: Re: Europa-List: To Those That Have Sanded Before Me... :) Jack This does work but it is vital to be certain that the resin/microballoon mix is identical otherwise you will get hard and soft stripes, I got that tea shirt once! It would be good with Superfil. Graham Jack Hilditch wrote: > Composite racing sailboat builders use a technique that produces a > fair surface, without bumps or valleys, while minimizing weight or > extra filler. They screed the filler/resin mix onto the surface using > a small-toothed, serrated plastic trowel (the same kind used to apply > ceramic tile cement to walls). After it cures they use a 'long board' > to sand it down. The 'long board' is not a fixed size. It can be 2" x > 24" , 4" x 48" or any other size, depending on the surface area to be > sanded. Most of them are made up in the shop using a piece of planking > with a couple of hand made handles screwed to it and the sand paper > glued or clamped to that. The long board rasps off the high areas, but > leaves the valleys clearly identified by the serrated 'stripes' of > resin/filler. On the next pass you only need apply the mix to areas > that remain 'striped'. It saves work because the actual surface area > to be sanded is reduced to the high points or 'lands' left by the > serrated trowel rather than a raised patch left by a smooth trowel. It > also saves on expensive resin. You get an additional bonus using the > technique in that the serrations also leave a greater surface area, > and irregular surface, for the next coat to bind with or key to. Hope > this helps. I spent plenty of time working on racing sailboats in the > US and UK so I know the technique works with resins from both sides of > 'the pond'. Hope this helps. > > Regards, > > Jack Hilditch > >* >* > -- 9:20 PM ________________________________ Message 5 _____________________________________ Time: 06:18:37 AM PST US From: "Rob Neils, Ph.D." Subject: RE: Europa-List: To Those That Have Sanded Before Me... :) I have near perfect, "suberb" glider wings. Lots of time and a unique tool, a snow picket, made it possible. Snow pickets are extruded aluminum "T" bars either 2 or 3 feet in length. They are pounded into snow to protect snow and ice climbers so they're light-weight and extremely sturdy because climbers trust their life to them. Snow pickets are also perfectly straight, making them the perfect sanding block. I glued ever finer sanding paper to the bottoms. I used the three-foot T-bar mostly so I'd get not waves. When I got done there were no imperfections. I checked the wings often in the dark using a flashlight or a laser beam to determine the "light-rise" was consistent. As you lift the light source up over an edge, the light-to-shadow line will show all imperfections. The laser lifted over an edge will give the final inspection. It takes lots of time and patience. Watch the "spindrift" (let's keep the snow picket comfortable with a compatible vocabulary because you've got to make friends with this tool because you'll be using it a lot) as you work the snow picket. You'll see where the low points are by the absence of "spindrift" as the snow picket slides back and forth going from front to back of the wing sweeping at a 45 degree angle. Move your grip from edge to middle to other edge on the snow fence as you sand. This will allow the power of random numbers "float" the snow picket making the surface superbly smooth. Hours of concentration watching the "spindrift" was the most challenging task I had in the entire build. I took it as a challenge to mental discipline to keep full, alert attention without lapses for hour upon hour. It's hard to believe but once you get clear into it it becomes very satisfying to see such a suburb finish produced by hand. I had trouble not seeking perfection on my build. I sometimes put a "moustache on the Mona Lisa" by trying to make the "excellent" into "perfect." Perfection is nearly always demonic. I finally settled on "superb" and operationally defined it as every station on N128HW has to be within 1/2 of a centimeter of where it theoretically belonged or I'd rebuild or modify. But when it came to the wing surface I went all out: The three-foot snow picket and lots of elbow-grease will give you a finish that is beyond what you could even hope for...damn near perfection. Snow pickets can be bought at http://store.thebackcountry.net/cart/product.php?productid=18174 for $18 or $20 US for the two or three footer respectively. -----Original Message----- From: owner-europa-list-server@matronics.com [mailto:owner-europa-list-server@matronics.com] On Behalf Of Jack Hilditch Sent: Tuesday, November 21, 2006 5:01 AM Subject: RE: Europa-List: To Those That Have Sanded Before Me... :) Fred, The serration direction is immaterial as it will eventually be faired in by a thin, flat, surfacing coat. This resin/filler application technique is used to visually identify low areas during initial filling and sanding steps. As I mentioned, it also provide a better keying surface for succeeding coats. Using a 'long board', rather than a block sander, for initial fairing helps to prevent the creation of additional low areas through spot sanding. It spans existing low spots by resting on higher surfaces around the depression thereby bringing the low spot into fair. Regards, Jack -----Original Message----- From: owner-europa-list-server@matronics.com [mailto:owner-europa-list-server@matronics.com] On Behalf Of Fred Klein Sent: Monday, November 20, 2006 3:19 PM Subject: Re: Europa-List: To Those That Have Sanded Before Me... :) Jack, As I visualize this technique, I take it that the strokes of the serrated screed are chordwise (rather than spanwise) in order to facilitate the maintaining of the airfoil. Please confirm. Fred A194 > Jack Hilditch wrote: > >> Composite racing sailboat builders use a technique that produces a >> fair surface, without bumps or valleys, while minimizing weight or >> extra filler. They screed the filler/resin mix onto the surface using >> a small-toothed, serrated plastic trowel (the same kind used to apply >> ceramic tile cement to walls). -- 9:20 PM ________________________________ Message 6 _____________________________________ Time: 09:32:29 AM PST US From: Graham Singleton Subject: Re: Europa-List: To Those That Have Sanded Before Me... :) Jack Boat people tend to use polyester materials we use epoxy so it isn't catalyst it's reagent. Any variation in hardener /resin ratio will be disastrous, it won't cure properly and unreacted resin or hardener will prevent adhesion of the next layer, paint or whatever. Graham Jack Hilditch wrote: > >Graham, > >Agreed. A Filler depth should be quite thin (1/8" or less) so, while >sanding a catalyst-rich filler mix >Jack > > > > > ________________________________ Message 7 _____________________________________ Time: 11:15:37 AM PST US From: NevEyre@aol.com Subject: Re: Europa-List: To Those That Have Sanded Before Me... :) Hi Jack / All, Filling with a ''comb'' works well on large surfaces like boats [ I was doing that with Polyester resin / Phenolic spheres on 25 '+ boats back in the ' 70's] where the weight is not that critical, but of no real use on our planes. If the Expancell / Epoxy is mixed runny enough to be combed on, it will be too heavy, and much harder to sand.The Expancell mix should be almost like bread dough to put on.... a real bugger to put on.... and impossible to get on smoothly / thin. As mentioned before on here, fill too proud ONCE, it will sand like dense balsa.... if you have to go back for a second fill you may end up with different densities... which as Graham mentioned, will sand away at different rates. If you managed to comb it on, you will end up with stripes, if you have to fill an area, you will get a ''tide mark''. Those of you useing Superfil may get it on OK, because that is runnier / heavier / more difficult to sand than correctly mixed Expancell / Epoxy.[ Why oh why do people insist on useing that ?] Other problems [ with Epoxy] is that all the ''valleys'' that did not get sanded during the profiling, will have to be scuff sanded, to remove the top surface [in preparation for adhesion] before a second fill can be applied,probably have to scrape it all with an Xacto blade, rather negates the point of only sanding the '' hills''? No short cuts in this world I'm afraid ? Cheers, Nev. ________________________________ Message 8 _____________________________________ Time: 11:52:41 AM PST US From: "Jack Hilditch" Subject: RE: Europa-List: To Those That Have Sanded Before Me... :) Grahame, Years ago, polyester resin was the matrix of choice when wet lay-ups were the typical building method. However, 'poly' was way too soft. Hulls would flex considerably, thereby ruining the airfoil shape of the sails as the rigging sagged. 'Poly' was also prone to wicking salt water into the laminate structure causing structural delamination and blisters on the hulls that sometimes reached the size of dinner plates. Those blisters were very expensive to repair and not a great favorite of anyone charged with keeping the hulls looking good. 'Poly' also ex-gasifies under the paint causing bubbles to be trapped lifting the paint membrane. Hulls were/are commonly treated with an epoxy undercoat before painting, even if the topcoat was/is Imron or Awlgrip. Epoxies such as the West System http://www.westsystem.com/webpages/userinfo/moreinfo/composite.htm and the SP lines http://www3.gurit.com/pdfs/adhesive/PSG_Epoxy_Adhesive.pdf have been more commonly used for building over the past 25 years. They produce a better and more durable laminate structure. They are used almost exclusively when constructing a matrix with carbon. In fact, I can't remember when I last used 'poly' on a boat. The catalytic component in any resin mix has always been colloquially referred to as the 'catalyst' or 'hardener' in boat building yards. Mea culpa, mea culpa, mea maxima culpa. I'm old enough to have gotten into the habit of using the word 'catalyst' when referring to any hardener. Be that as it may, the process remains the same. 1.) Mix the resin thoroughly before blending in the filler material. 2.) Once the filler is thoroughly incorporated into the (reacting) resin, it has a pot life determined by several factors. 3.) Screed the resin/filler mix onto the surface to be faired before the resin/filler mix hardens in the pot. As to the mix ratio being critical, I couldn't agree more. That is why I suggested using a calibrated metering pump system supplied by the resin manufacturer. (Our discussion might be over-engineering a simple fairing job. I was just lurking on the list and thought I'd share a tip that made our lives a bit easier when sanding in various boatyards over the years.) Regards, Jack ----Original Message----- From: owner-europa-list-server@matronics.com [mailto:owner-europa-list-server@matronics.com] On Behalf Of Graham Singleton Sent: Tuesday, November 21, 2006 12:35 PM Subject: Re: Europa-List: To Those That Have Sanded Before Me... :) Jack Boat people tend to use polyester materials we use epoxy so it isn't catalyst it's reagent. Any variation in hardener /resin ratio will be disastrous, it won't cure properly and unreacted resin or hardener will prevent adhesion of the next layer, paint or whatever. Graham Jack Hilditch wrote: > >Graham, > >Agreed. A Filler depth should be quite thin (1/8" or less) so, while >sanding a catalyst-rich filler mix >Jack > > > > > -- 9:20 PM ________________________________ Message 9 _____________________________________ Time: 02:52:57 PM PST US From: Graham Singleton Subject: Re: Europa-List: To Those That Have Sanded Before Me... :) Jack I quite agree, I just thought I'd share my experience too, I did it on my Long EZ 20 years ago. (the stripes) unfortunately Superfil wasn't around then and I still have hard and soft stripes to try and hide, thankfully only on one wing underside. At least the stripes are chordwise. Incidentally, spanwise waviness which can be noticed won't hurt laminar flow but any more than .002 inch per 2 inches cordwise (which won't show) will. I use a springy flexible spline that follows the curve of the section and just knocks of the high areas, not a rigid spline. Don't believe in rigid splines. Graham Jack Hilditch wrote: >(Our discussion might be over-engineering a simple fairing job. I was just >lurking on the list and thought I'd share a tip that made our lives a bit >easier when sanding in various boatyards over the years.) > >Regards, > >Jack > > > > ________________________________ Message 10 ____________________________________ Time: 03:06:26 PM PST US From: Graham Singleton Subject: Re: Europa-List: To Those That Have Sanded Before Me... :) Nev I have another trick which works for me. I mix in colloidal silica. Try this, mix up the Expancell then add a little Cabosil..Then you can add another pile of Expancell to get back to the same consistency. The Cabosil makes it spread easier. It does NOT affect the sandability. Then I spread it on over a pair of strimmer lines, remove the strimmer lines and after 15 minutes careful spread again to flatten the tramlines and its done. Controled thickness, and thick enough to not need any more filling. The Cabosil seems to lubricate the Expancell so it spreads easy. Probably the reason my stripes were hard and soft is that the sanded surfaces absorbed resin from the next ;layer of filler and went hard. Superfil doesn't do that for some reason, maybe it has talc in it? Graham NevEyre@aol.com wrote: > Hi Jack / All, > > If the Expancell / Epoxy is mixed runny enough to be combed on, it > will be too heavy, and much harder to sand.The Expancell mix should be > almost like bread dough to put on.... a real bugger to put on.... and > impossible to get on smoothly / thin. As mentioned before on here, > fill too proud ONCE, it will sand like dense balsa.... if you have to > go back for a second fill you may end up with different densities... > which as Graham mentioned, will sand away at different rates. If you > managed to comb it on, you will end up with stripes, if you have to > fill an area, you will get a ''tide mark''. > > Nev. > >* >* > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message europa-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Europa-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/europa-list Browse Digests http://www.matronics.com/digest/europa-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.