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Building Tips and technical articles. => Building techniques => Topic started by: James Mills on November 15, 2006, 09:22:41 PM
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What's the best way of sheeting a foam wing? In the past I've used contact cement (came out heavy), 3M 77 spray, and epoxy. I have some West Systems epoxy but have never used it for sheeting.
Thanks,
James
Thanks for all the help.
James
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James
I have done 1000s of foam wings. I have tried all ways.
Best I have ever found is to paint the inside wood with full thick dope, sand it with 400 paper then use thin epoxy.
Lightest best method I have seen.
It also gives you time to keep the wings perfectly straight, and recheck them
Regards
Randy
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What type of Epoxy are you using Randy?
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What type of Epoxy are you using Randy?
I use several types, The one I am using now, is hard to buy, however, you can use Smooth N easy , or most any Finish resin. these are very thin epoxys and spread out very well.
Zap makes one also, as well as BOB Smith. which most Hobby shops carry.
I have used all of these with excellent results
The epoxy you want is thin, do not use any acetone or alcohol to thinn thicker slow cure epoxies.
Most all finishing resins are pretty thin out of the bottle
If you can't find any I do sell thin finishing resin, just ask
Regards
Randy
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James,
A couple of us also answered your question over on the SSW board.
I agree with Randy: I have used a lot of methods to bond the skins (Sorgum, contact cement, etc.) and epoxy is the best method.
I have used Hobby Poxy 2 (no longer made) and Enviro Tex, but now I use the thin 20-minute Finishing Epoxy from Bob Smith Industries. It's sold at your LHS (usually with their label) and works fine. CAVEAT: It says 20 minutes, but I've never had any set that fast. It really takes a few hours for the stuff to cure. I vacuum bag my wing panels and let them cure overnight.
Take care,
Ron
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I've used West System with great success.
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Hello James, dont know if your going to sheet the whole wing. If you are you might consider doing the Tom Dixon method which only sheets the leading and trailing edges then puting strips where the ribs would be. Works very well and is much lighter. I like the 3M spray glue. Hope this helps. Regards, Jim
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When I was into RC gliders we did wings like Dixon but the used a hot wire an cut out the foam bettween the "rib caps" looked like a built up but lighter than a foam. Used it on many hand lanched gliders.
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Thats a good idea also, but you have to leave enough foam to keep its integrity.
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James,
(snip)
I vacuum bag my wing panels and let them cure overnight.
Take care,
Ron
Geez, Louise!!!!! Vacuum bagging! Doesn't that get a lot of dust, and dog or cat hairs, on them?? Or do you use a new bag?? We have a Rainbow Vacuum, it doesn't have a bag..........
**) **) **) n~ n~
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When I was into RC gliders we did wings like Dixon but the used a hot wire an cut out the foam bettween the "rib caps" looked like a built up but lighter than a foam. Used it on many hand lanched gliders.
Todd Lee used that system on his Opus III which was a Sig Magnum built to look like a "B" Model P-51. After several years, and countless flights, the area between the "spar" and the trailing edge began to collapse. It really took on a "Pollywog" rib shape! (but it still flew mighty darn good!)
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Geez, Louise!!!!! Vacuum bagging! Doesn't that get a lot of dust, and dog or cat hairs, on them?? Or do you use a new bag?? We have a Rainbow Vacuum, it doesn't have a bag..........
Hook it up to a Hefty bag. **) **)
How about I do a USA-1 with a foam wing? Would that give you a heart attack or what? f~
Ron
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Todd Lee used that system on his Opus III which was a Sig Magnum built to look like a "B" Model P-51. After several years, and countless flights, the area between the "spar" and the trailing edge began to collapse. It really took on a "Pollywog" rib shape! (but it still flew mighty darn good!)
Mike Stott and his dad did something like that but replaced the "ribs" in the cut out area with balsa ribs cut using the cut out part as a templet. Similar to lost foam.(wished I payed more attention in typing class back in highschool **) **))
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Hook it up to a Hefty bag. **) **)
"How about I do a USA-1 with a foam wing? Would that give you a heart attack or what?" f~
Ron
You wouldn't DARE commit such blasphemy!!!!!!!!! Them's serious fightin' words!!!!!
**)
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does this look like the right stuff to stick the skins on the wing?
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Frank: It says on the can do not use on polystyrene foam. What kind of foam are the wings ?
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Frank: It says on the can do not use on polystyrene foam. What kind of foam are the wings ?
DOH!! HB~>
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Lost foam wings!!
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Lost foam wings!!
DOH! HB~>
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Hey all, the last four stunters I have built were using the tom Dixon "kept foam" method and I tried taking the foam out between the ribs, weighed that foam and found I'd eliminated a whole one quarter of an ounce! Not worth the effort OR the bit of structural integrity loss involved. My shipd were all of the tTivial Pursuit design as far as aerodynamics and weighed in at a very consistant 61 to 64 ounces with PA65's aboard. They all flew GREAT! I still have the last two, sold the other and mean old mister gravity got one. I will campaign the last one again next year as my main stunt, it's fourth year.
Blessings,
Will :## y1
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Just to set the record straight on the sheet/capstrip foam wing. My buddy Dave Noel built the first one of these about 1978, long before anyone else tried it. He campaigned several different planes over the next 10 years using this construction method before it caught on with anyone else. He really showed that it was simple and quick, and could support a very nice finish.
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Oh,, oh,, you sayin' somebody else did it?
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Just to set the record straight on the sheet/capstrip foam wing. My buddy Dave Noel built the first one of these about 1978, long before anyone else tried it. He campaigned several different planes over the next 10 years using this construction method before it caught on with anyone else. He really showed that it was simple and quick, and could support a very nice finish.
It really goes back even farther than that, around 1972 or 3 was the first one I saw with cap strips
Be careful not to use 3M spray. I have personally seen many of these pop loose and even come loose a year or so later. 3M spray hates high heat..as in sunshine.
and some of the 3M spray will attack foam
Randy
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Randy, Phil, etc.,
There is more history to that method....
The first GSCB OTS meet was October 1970, I was one of the entrants.. ( 1st.. Bob Hunt, Veco Mustang; 2nd John D'Ottavio, All American Sr; 3rd yours truly, Barnstormer) That is one of the few trophies that I have kept over the years.
I CD'd the second OTS contest in the country the summer of 1971 at Buder Park, St, Louis.
****John Davis quick built an All American Sr for the St. Louis contest and took 1st.
His All American Sr had a foam wing with the "kept foam" method that was "created" many years later! ****
I am sure that only two of us saw that airplane before it was covered. At that time, any entry for the brand new event was most welcome, as long as dimensions were true.
I would not be surprised to hear that somepne might have even done it before then.