sensei

Hey, it gives me something to do while I am in the middle of our home renovation.

Bob

LesUyeda

So. Back to the original subject.

As I recall History; 3M 77 WAS the gold standard; until they got environmentally friendly, changed their formula, and it turned to poop. Then they came out with two different varieties, one that worked, and one that the EPA was happy with. I don't recall which was was which, but I seem to remember seeing 3M 77 "original" formula. Could easily be wrong, with my memory the way it is these days.

Les

jtotten

Memories of sheeting in the 60's and 70's - Used 3M 77 a lot, but in our club we never trusted it. We applied a criss-cross pattern of a small bead of carpenters glue (Titebond or equivalent) with about 3" spacing, then used the 3M to apply the skins. After skinning, we gave about 1 day per 1/32 inch sheeting for glue drying before finishing. I have several wings for pattern planes built that way in the late 60's, and have never had a skin lift. However, I never trust a spray adhesive alone for wing sheeting.

GREG DOE

Cool comments Bob. I especially like the compliment about being a "leader in advance airplane design", but the comment about being into AMA politics is not true, I'm afraid. I've never campaigned for any AMA office. All of my service has been voluntary. No organization including the AMA is perfect, but it's what we've got, so we need to work to improve it instead of making negative comments, which don't help a thing. It's kind of like what you said about unknowing souls reading this, and taking your predjudice toward the AMA. I can't do the "bla, bla, bla," thing. I think that's too mean spirited, and I wasn't raised that way. I hope we can be friends who just don't always agree? Greg

MTK

Over my 40 some odd years of building, designing and flying crates with sheeted foam wings and stabs, I think I've used all methods. They all work okay, but some work better than others.

The 3M77 spray method worked well
The Southern Sorgum worked well but you had to apply a pretty good amount of it or the sheeting lifted. To me it was a heavier approach
Gorilla works great but you have to work very fast since it begins kicking off in about 30 minutes or so. It could be a bit heavy if not careful since working fast with it tends to force you into shortcuts
Laminating epoxy works even better and with slow hardeners you have an hour plus of working time. This is my method of choice because I want the lightest and strongest wings. Epoxy allows laminating other types of reinforcement (glass and carbon) in judicious places at thetime of lamination

No matter what, skin prep and core prep are absolutes for successful skinning that will last 1000's of flights. Wood sealing is a good idea. I usually use hair spray or nitrate dope.

The most important thing about the skins and the foam is using a tack rag to remove as much sanding dust as possible. It can make a difference between good adhesion and lifted sheets.

Since discovering vacuum packing in the mid 80's I don't build any laminated balsa-foam wing without the technique. Is it necessary for success? NO! But the eveness of applied pressure over every square millimeter makes it worthwhile

sensei

Hello Greg,

I have no prejudice against the AMA, never have, I have just never had much use for politicians, especially ones that boast and toot their own horns. You may not have campaigned for office but you were quick to pull out your titles and accomplishment when I pointed out a little factual tidbits about adhesive... It's kind of like building airplanes, there are builder's and then again, there are builder's....

Bob

ovationdave

My Feedback: (16)

I have only used z-poxy finishing resin and it works great for me. Everybody has an opinion, however I would never use the current 3M 77 product to attach a skin, it stays pliable for way too long and doesn't harden well, you can test this yourself easy enough........I also use it for removable applications only.

FYI, the trick to using an epoxy finishing resin is to add it to the wood side only and only after you have vacuumed the core well to eliminate the dust from sanding off the sheen from the core. I then use a playing card to squeegee off the excess and use whatever method you feel comfortable with (Vacuum bag it or sandwich it using the original core shucks with about 5 years worth of RCM stacked on top on a flat table, whatever) to attached the skin.

Good luck, whichever method you choose,

Dave

speedracerntrixie

My Feedback: (29)

I have sheeted foam wings with Gorilla glue and the results were acceptable but not as light or strong as epoxy. I'm not doubting that you have seen an epoxy sheeted wing fail but either will fail if not done correctly. Contact area will be the same if the core is sanded correctly prior to sheeting. A good cleaning is nesesary with both methods as well. If the GGpenetrated the foam 1/4" then way too much was used. On my models, I just can't afford that much weight. BTW, if one vacuum bags with GG it will not expand nearly as much, vacuum pulls moisture.

colmo-RCU

HOW DARE YOU CONTRDICT ME!!!!!!!!

I was voted most likely to succed by my highschool and was miss teen USA 4 years in a row. I obviously know everything there is to know and my method is definitely better that yours, just because Ive been using it since the early 1820's.

I also help some kids with some indoor tissue planes that by the way don't use sheeting, but somehow that is also relevant. Have some respect to the GG (gorilla gods)


Ok, I've had my laugh, now seriously. You're right about the ammount of glue, I actually scrape most of it, which I didnt in the trial i cut to see, so I guess it doesn't penetrate quite that much. However, the results for me are as light as epoxy, and the fact that it does penetrate into the pores of both balsa and foam as it grows, gives me a lot of peace of mind. That is the problem with epoxy, it sticks the hardest, but only to the foam balls on the top of the core. When I've seen delaminated cores, the balsa always has foam balls stuck to it. Clearly, what failed was not the glue, but the foam.

We all try whatever we want, and choose whatever works best, and it's fine. If I'm asked for advise I'll give it based on my experience but I wont get upset it someone thinks different, or the suggestion is not used in the end. Good luck

GREG DOE

Colmo, I like your latest post. You have a way with words. I hope you were being funny? We all need to not take ourselves too seriously. By the way, is English your first language? If English is your second language you certainly have an excellent command of the Kings tongue. I've been away from this forum for several days. Here in the states it's TAX TIME, and I had to attend to that distasteful chore. In a previous post you commented that even double sided tape could be used to skin wings. Were you aware that at one time, Sonic Tronics sold a tape for that purpose, and modelers used it successfully? I still have some. I have skinned wings with every glue mentioned here, and some that haven't been mentioned. However I have not used Gorilla Glue. Does anyone remember when we used Formula II Hobby Poxy. That was a long time ago. I have used Z Poxy, but I now prefer West Systems 105 and 206. Sorry if I bored you with the brief paragraph about Science Olympiad. It's been rewarding for me. Maybe there isn't anything like it in Columbia? Greg

Avaiojet

I read this entire Thread and still don't know what method to use.

C

CK1

My Feedback: (60)

Who knew a subject could be so subjective ?

Avaiojet

Really.

I did experiment with a can of 3M 45 spray adhesive on a test piece.

Anyone ever use this product/

Charles

box car

iron the skins on, 2 coats of white glue on the foam and skin, let dry then iron the skin to the foam , don;t get the iron to hot. Play around with some scrap. I iron my skins to wood also.

Pylonracr

Simple. use epoxy laminating resin. Scrape excess off with a playing card and vacuum bag. This gives the lightest and strongest wings possible. If people say epoxy is too heavy they are using too much.

Scott

RCFlyerDan

My Feedback: (54)

I am glad that this forum has become active again. First guys where here in 2013 discussing their methods.

Box Car, I am building a jet that I have to sheet the fuselage. I am going to use the laminating epoxy for the wings, so that I can add carbon fiber between the foam and balsa sheeting. The fuselage, they recommend ironing the sheeting onto the cylindrical fuse. I am glad that you said to let white glue dry first then iron. Does the heat reactivate the white glue? If so, how does it hold up on a hot paved ramp sitting for the afternoon? Seems like heat would reactivate it then too? And the balsa would come off or warp? Of course, the whole thing will be fiber glassed on the outside of the balsa.

F4 Phantom blue angles

I always used M77 adhesive, You can use it,BUT you don't want to let it pool,or get soggy anywhere. It will eat the Styrofoam quicker than ****.. Just a fine coat,let it set,and your good to go. I never had a problem,just be carefull when spraying.

aspeed

Back in 2013 PU glue was a fairly new idea. I think if it is spread very thin it would be light and strong. My feelings are PU and foam rubber with plywood on top, and then a couple batteries for weight. Interesting that the Glidden primer had been used. No one does that any more? I never heard of it for wings, but I bought some for a trailer project that I never did. It seems like it could be heavy. The Home Depot foam paint , or whatever, sounds interesting too. I wonder if that is used as a glue or just a smoothing paint for a hard surface. That may be a good thing. Likely the guys are not on the forum any more.