jpolenek Posted February 4, 2009 Share Posted February 4, 2009 After removing peel ply, is it necessary (or even desirable) to give the area a light sanding (followed by vacuuming, of course), or is the freshly peeled surface ready to make a good bond as is? Joe Polenek Quote Joe Cozy Mk IV #1550 Link to comment Share on other sites More sharing options...
TMann Posted February 4, 2009 Share Posted February 4, 2009 Differenct schools of thought on that. It is considered sufficient to apply new glass over a surface that has been peel ply'd. I usually wait as long as possible before removing the peel ply and then sand to get the best bond. I read somewhere that when they built the Voyager they used peel ply and sand blasted prior to bonding. Quote T Mann - Loooong-EZ/20B Infinity R/G Chpts 18 Velocity/RG N951TM Mann's Airplane Factory We add rocket's to everything! 4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done Link to comment Share on other sites More sharing options...
Big Steve Posted February 4, 2009 Share Posted February 4, 2009 Joe: I rough up all my peel ply before I glass over it. I usually do it just before glassing so it is nice and freshly scratched up. Steve build on Quote Steve Harmon Lovin Life in Idaho Cozy IV Plans #1466 N232CZ http://websites.expercraft.com/bigsteve/ Working on Chapter 19,21 Link to comment Share on other sites More sharing options...
Marc Zeitlin Posted February 4, 2009 Share Posted February 4, 2009 After removing peel ply, is it necessary (or even desirable) to give the area a light sanding (followed by vacuuming, of course), or is the freshly peeled surface ready to make a good bond as is?If you remove the peel ply within a short period of time (where "short" is a function of which epoxy you're using, and I have no idea what it is for any particular epoxy, but is measured in minutes to hours at the most) then the surface energy is high and in theory no further preparation is necessary. It's almost always a good idea to sand as well as peel ply, however, for grandma. The "Abaris" presentation on the cozybuilders web site under OSH presentations has some good info on the matter. Site seems to be down right now, but I assume it'll be up soon (ISP issues, I imagine). Quote Marc J. Zeitlin Burnside Aerospace marc_zeitlin@alum.mit.edu www.cozybuilders.org copyright © 2024 Link to comment Share on other sites More sharing options...
Steve Innova Posted February 4, 2009 Share Posted February 4, 2009 Why take any risks? I peel ply all my parts, then sand them, then wipe them with acetone. Quote Link to comment Share on other sites More sharing options...
Vacabrava Posted February 4, 2009 Share Posted February 4, 2009 ...then wipe them with acetone.I used acetone on polyvinyl esther resin, when fixing some swimming pool chairs.But with epoxy is that good too? Quote Alexandre Souto Cozy Mark IV Ch 09, Go Retracts! Brazil http://www.maddyhome.com/canardpages/pages/voolivrebrasilia/exindex.html Link to comment Share on other sites More sharing options...
Steve Innova Posted February 4, 2009 Share Posted February 4, 2009 This study (conducted by "Orion" from the Homebuilt airplanes forum) compares the effect of surface preparation methods on peel strength: http://www.oriontechnologies.net/Documents/bonding.pdf Quote Link to comment Share on other sites More sharing options...
TMann Posted February 4, 2009 Share Posted February 4, 2009 Why take any risks? I peel ply all my parts, then sand them, then wipe them with acetone. I'm with you right up to the acetone part. I won't be doing that. Quote T Mann - Loooong-EZ/20B Infinity R/G Chpts 18 Velocity/RG N951TM Mann's Airplane Factory We add rocket's to everything! 4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done Link to comment Share on other sites More sharing options...
Steve Innova Posted February 4, 2009 Share Posted February 4, 2009 I'm with you right up to the acetone part. I won't be doing that. Then allways wear gloves while handling your parts. Your hands have dirt and oil on them that can contaminate (to some degree) the bond. Quote Link to comment Share on other sites More sharing options...
argoldman Posted February 4, 2009 Share Posted February 4, 2009 I used acetone on polyvinyl esther resin, when fixing some swimming pool chairs. But with epoxy is that good too? Be really careful with the acetone (spelled don't use it!!!!) Almost all of the lay-ups are over foam of some sort. Although we like to think that all of our lay-ups are impermeable to any outside influences, many are permeable and the small amount of air inclusions will wick any fluid to the foam which underlays. Put a little acetone on some polystyrene and see the results. PVC etc may not react the same way, but if you dissolve the foam from under the layup you have squat!! You may never know it until the part fails, or a careful inspection shows what will seem like a delam. Use clean water after sanding to get the sanding dust off. Peel ply is good. Jeff Russell suggested to always lightly sand the peelply (my guess is to activate the surface electrically. In the dragonfly world, we just wiped it off and bonded to it. I am not aware of any separations that were the result of that. Don't use acetone.... Quote I Canardly contain myself! Rich Link to comment Share on other sites More sharing options...
argoldman Posted February 4, 2009 Share Posted February 4, 2009 Unless I read the research wrong, which is possible as I skimmed it, The testing was on the bond between glass stuff and aluminum. In our birds this type of bond happens, for example in the aileron and elevator control tubes, but unlike many bonds in our aircraft, that bond is over a very large surface area. Perhaps that is why we don't see the tremendous problem which those data may suggest in terms of weak bonding. I seem to remember, that there is a specific anodization process which greatly increases the epoxy-aluminum bonding strength (I'm sure that it is used in many places in the aerospace industry (the Yankee(Grumman) series were totally bonded aluminum. They had some problems with this in the beginning, but that seems to have been solved before they stopped production)) There are few other places in our birds, if any, where we depend on glass to aluminum bond as a primary bond. When we sandwich a layup between a piece of aluminum (or wood) (even though we bond the aluminum (or wood) to the understructure) and a piece that gets bolted to the sandwich, ( ie seatbelt attachment on the seat-back bulkhead) we actually don't depend much on the aluminum (or wood) bond to the substrate as we count on the aluminum (or wood) to serve as a big washer transferring the stresses to the overlying glass (the PB&J of the sandwich) and where it sheds it's load. Is anybody aware of delaminations happening in the control surface/torque tube interface???? Quote I Canardly contain myself! Rich Link to comment Share on other sites More sharing options...
Jason Heath Posted February 4, 2009 Share Posted February 4, 2009 Unless I read the research wrong, which is possible as I skimmed it,.....The testing was on the bond between glass stuff and aluminum. This one is from the FAA and is cited in the Abaris training that Marc pointed to and has more to do with peel ply than peel strength in glass to aluminum bonding. http://www.tc.faa.gov/its/worldpac/techrpt/ar06-28.pdf Quote Regards, Jason T Heath MarkIV #1418 heathjasont@yahoo.com Link to comment Share on other sites More sharing options...
Steve Innova Posted February 4, 2009 Share Posted February 4, 2009 Don't use acetone.... The wing & canard foam is the only material especially susceptible to acetone. Acetone is fine for working on the fuselage. Quote Link to comment Share on other sites More sharing options...
Big Steve Posted February 5, 2009 Share Posted February 5, 2009 Steve_Innova: said The wing & canard foam is the only material especially susceptible to acetone. Acetone is fine for working on the fuselage. Acetone is for cleaning up tools after a layup. It does not get close to anything used in building a flying airplane in my shop. After all the sanding and prep work who the heck has any grease on there fingers? build on STeve Quote Steve Harmon Lovin Life in Idaho Cozy IV Plans #1466 N232CZ http://websites.expercraft.com/bigsteve/ Working on Chapter 19,21 Link to comment Share on other sites More sharing options...
Steve Innova Posted February 5, 2009 Share Posted February 5, 2009 Do you have research to back up the anti-acetone claims w/regards to damaging Divincell foam & fiberglass layups? Quote Link to comment Share on other sites More sharing options...
TMann Posted February 5, 2009 Share Posted February 5, 2009 Do you have research to back up the anti-acetone claims w/regards to damaging Divincell foam & fiberglass layups?Who cares? Our shops have a tendancy to get crowded quick. I don't need to bait my own traps. If it works for you, that's great but advice like that is going to cost another builder ...... guaranteed. Quote T Mann - Loooong-EZ/20B Infinity R/G Chpts 18 Velocity/RG N951TM Mann's Airplane Factory We add rocket's to everything! 4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done Link to comment Share on other sites More sharing options...
Steve Innova Posted February 5, 2009 Share Posted February 5, 2009 Who cares? Our shops have a tendancy to get crowded quick. I don't need to bait my own traps. If it works for you, that's great but advice like that is going to cost another builder ...... guaranteed. Regardless of superstitions, cleaning with acetone is an accepted technique for preparing / repairing fiberglass laminates on PVC foam (e.g. Divincell H45/H100). Here's the Exra 300's tech manual (lots of good info on composites there. Go to Chapt 51, pg 21: http://www.extraaircraft.com/Tech-Manuals/MM300SC/CH51.pdf If builders can't distinguish between their Styrofoam wings and the PVC fuselage, strakes, and spar, then maybe they ought to select a hobby better suited to their lack of attention to detail. That said, it's not bad advice at all, that once the wings are on (or exposed) don't use acetone around them. Quote Link to comment Share on other sites More sharing options...
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