TLH101

My Feedback: (90)

I have an old Wescraft B-17 kit that has no shucks for the foam wing cores. Looking for the best way to sheet them. I have done this in the past without shucks, using contact cement, but don't remember what brand I used, that does not attack the foam. Any advice?
What about vacuum bagging? Is that a viable option, if I don't already have the needed equipment?

d_bodary

My Feedback: (85)

I used 3M 77 spray before. It's to bad now the new formula contains acetone. I want to say 3M has another Spray contact cement that may work but i haven't tried it.

Also Dave Brown has a contact cement sorgum or something like that. I haven't used that either but have known a couple of people that have used it and liked it.

DavidAgar

My Feedback: (108)

You can use old magazines to help keep the sheeting in place as the glue dry's. I also have used the 3M 77 with great success, however I have heard they changed the formula which now attacks the foam. Good Luck, Dave

bear 57

Terry, I have had good success with LePages latex contact cement. No odor and it does not eat foam.
Lorne

wahoo

My Feedback: (59)

3M makes a foam safe spray adhesive #78.

http://solutions.3m.com/wps/portal/3...beSC2785KN7Pgl

I had one he11 of a time finding it though, and its a bit pricey too. If memory serves me right I think I paid almost $20 for a 17.9 oz can, and that was a while ago.

The only place I found around here that could carry it was Fastenal and they had to ship it from a different store location.

John

Ed Smith

Vacuum bagging is the only way, with or without "Shucks". For example, With a 500 sq" wing. An easy vacuum to pull is 5lb/sq in.
The bag would apply 2500 lb on the top of the wing and 2500 lb on the bottom of the wing. Total 5,000 lb. How many books, toolboxes, cement blocks, etc, etc, would have to be lifted up to the bench to apply that much pressure?

There is usually somebody around with a bagging set-up.

Ed S

WhiteRook

My Feedback: (38)

I Wouldn't try it without the shucks , because your wing will warp . if its a flat bottom wing
you may have no problem , but a symet wing , i dont know how youd keep the right amount of washout in it , a tapered wing would be even more scary. if you know what the correct amount of washout is, from root to tip ,you'll have to make a jig , and set the wing on it .

TLH101

My Feedback: (90)

Ok, I have done this before without shucks. There is no problem getting the wing straight, because it a 10ft wing that will be done in 4 sections. The 2 center sections will be joined with spars, and the outer tips will be removable. I just need to find some good contact cement that will not eat the foam. In the past I have Dave Brown sorghum, however it would require many small bottles. I also did a NWHT Gee Bee several years ago, with the contact cement provided by the kit maker, but he was unwilling to tell me where the cement came from. Did not want to give away his business secrets.

42etus

My Feedback: (2)

I've use Space Bags ( https://www.spacebag.com/spacebag/901715/ ) as a poor mans vacuum bag. It worked great. Everyone has a vacuum cleaner.
Paul

TLH101

My Feedback: (90)

Hmmmmm........I ve got a vacuum cleaner.
May have to try that.

Deadstik

My Feedback: (8)

Terry,

Keeping that wing "straight" may be a bit harder than you think. All foam, once cut, always seems to expand/contract or in general have a mind of its own. I see this every time I cut a run of wings. What I would suggest, and this would be simple to do, is to simply use your cores to make templates and then cut another set of wings. Yes, you are looking at making templates and then cutting the wings, but you actually solve two problems. You get your "shucks" and you get a spare wing... plus.. you could make others if folks wanted them. I would also bet you that a new set of wings, cut from 1 lb per cubic foot closed cell foam would be 8 to 10 ounces lighter than the foam your original wings are cut from.

Just a thought, but it is what I would do. I can't think of doing a B-17 of that caliber guessing if the wing is straight.

Dan
Carolina Custom Aircraft

TLH101

My Feedback: (90)

Like I said, I have done it before without the shucks. It's no problem to keep them straight. Last one I did was a 96" 2 piece wing. Came out dead nuts straight, without shucks. Cores for that one were actually cut with a "droop" in the leading edge, so I had to throw the shucks away and use the sheeting process to straighten the cores.

Starfighter

My Feedback: (78)

Hi Terry, name's Ken Wilson (Starfighter).

I too can sheet a foam wing w/o shucks or vacum bagging by using contact cement and a separating wax paper. Then you carefully roll the core into the skin while exerting pressure, and 'Voila'. Sheeted, and extremely strong wing. For a reliable contact cement, I always use Sorghum by Dave Brown. It is still the best for this purpose, and will not fail(and cause delamination of the balsa skin from the foam) in the heat of a hot sunny day as some of the others will. I will not claim that any particular brand of contact cement does not withstand the heat, but Sorghum from Dave Brown when properly applied will not fail in service.

Just my opinion.

Ken (Starfighter)