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3M77 vs Krylon

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3M77 vs Krylon

Old 08-14-2002, 10:54 PM
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Default 3M77 vs Krylon

I found some spray adhesive by Krylon in the local craft store. It is half the price of 3M77. Has anyone had any experience with this product for sheeting foam wings? I brought home a can and it doesn't list foam on it's recommended uses, but it doesn't say you can't. I tried it on some white foam from my last radio box. A light even dusting didn't seam to bother it but a heavy wet coat ate at it a little. I don't know much about foam but it looks close to what a foam core would be. Does 3M77 eat at the foam if it gets too wet?
Old 08-14-2002, 11:24 PM
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Default spray glue

I use Elmers, 3M77, Duro they all work well but then I only use them for temp glueing plans and plan protector down or for templates but would never use it for sheeting cores. I have seen and heard a lot of warstories abt it delaminating especially after setting in the sun for a while. If you going to sheet foam core wings the best is Elmers probond but there are other things out there to use too but I would stear away from spray glues for sheeting.

Old 08-15-2002, 10:24 AM
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Default 3M77 vs Krylon

Ditto the no spray contact adhesives for sheeting, it's a no no IMO.

Old 08-22-2002, 02:28 AM
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Default 3M77 vs Krylon

I have been using the 3Msuper77 spray for years and have never had any problems with skins peeling off foam cores. Stuff works great. I have used it on prop, ducted fan and turbine powerd kits!! Just sand the cores lightly to smooth them out, and give both the skins and foam ONE light even coat. Let the skins and foam get bone dry and apply the skins!! Presto a sheeted wing!!!

Old 08-22-2002, 09:54 AM
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Default 3M77 vs Krylon

edh13, I noticed you live in Az. I live in Southeast Texas and the heat is pretty bad down here, lots worse in Az though. It is a known problem (personal experience) that spray contact adhesive will debond in high heat. The bond between wing sheeting and foam core is far too critical to trust to contact adhesive. Use either ProBond or slow cure epoxy, neither will let go.

Old 08-22-2002, 06:34 PM
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Default 3M77 vs Krylon

Be careful with the new formulation of 3M77, I understand that 3M reformulated 3M77 to meet IPA requirements and the new formulation eats foam. I got this info from a Zagi site so don't know if it is a fact but looking at the ingredients should tell, that or a test on some scrap.
Old 08-25-2002, 01:15 AM
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Default 3m77's new formula

Please do not use the new formula 3m77 on your cores!!!! It's got a higher amount of acetone in it,,,,,,,, ever see what happens to foam when you put acetone on it? Can you say "melt"?,,,,

Anyways,,, the new version is in a purple can,,, the old one is all black,,,,if you see any of the older stuff at Lowe's,, Home Depot, etc,, pick yourelf up a few cans, as it's by far the best stuff out there ofr sheeting wing cores,, or building Zagies!!!! ( I've built about 65 of them!!!!)

aka "Murphy"
Old 08-27-2002, 03:05 PM
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Default 3M77 vs Krylon

If you are worried about the contact eating the foam
There are great water based contact cement formulas out there
I'm a Cabinetmaker,
I use them all the time in my work you can get them at Home Depot, Etc. they donít come in a spray cans but you can spray them through a spray gun. Wet cleans up with water; dry-cleans up with lacquer thinner.
also allot cheaper than the spray acetone based products
and the biggest thing is there is no bad smell or odors
the only down side is they take a lot longer to dry before application can be made

All this being said
I still prefer to use Carpenters glue, Ya thatís right.
everyone says I'm crazy and it can't work, but it does.
I thin it down about 30% and spread a thin even layer over the foam with a squeegee, none to the balsa. then let it set up in the saddle over night. with about 50 lbs. of weight on it
The next day it's ready to go
and your not going to find a cheaper product than that

The plane in my avatar was built this way and has been flying for 7 years now, you couldn't get that balsa off if you had to

Good luck

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