best glue to use for sealing foam?

Hey all,

I have a question, what glue do you guys find is best for sealing your foam. I have used elmers white glue, and elmers wood glue and find that they crack horribly after. Is there a glue that you guys use that is more flexible.

As an example, I did my neck piece about a month ago and haven't plasti-dipped it yet. It looks terrible and has cracks and crevices in it from me taking it on and off. I know those will be covered up with plasti-dip and paint but am wondering if anyone has found a good solution that isn't so rigid.

also I have the same question regarding paint. I used rust-oleum metalic paint in silver, gold, and red, but found that the red has cracked as well when i flexed it.

thanks for your assistance.

Are you heat sealing the foam before you seal it with a glue type substance? You may be experiencing something like a freezing water effect, where the glue is still curing (since it's practically sealed in a small void within the foam, especially if you're using heavier coats of undiluted PVA for your first coat on untreated foam) and as the glue dries out, it's expanding upwards (towards free air) and stretching the under layer enough to crack it.

I've gotten into the habit now of running a heat gun over brand new sheets of foam before I even cut anything out of them. If the pores of the foam are still open, they soak up a lot of the glue and it takes forever for it to completely cure.

I use a mixture of 1 part Modge Podge to 3 parts water for my first pass (of heat sealed foam), then a 1-1 for the next coat. If I want it super smooth, I'll go with a direct application (undiluted) for the last coat, and run a hairdryer set on low over it while it dries to help "level" it out. If a texture is required, I go with Plastidip instead of the last coat of glue, then primer and paint.

It could also just be the paint you're using. If it's not rated for plastic, and depending on the humidity level when you applied it vs. humidity level where it's worn/stored, the paint itself could be slightly uncured and would do the same thing you're describing.

Just my 2cents. YMMV.

I dilute the glue for all coats, but maybe I'm not doing enough water? So after you have apply several coats of glue to your suit and it's totally dry, if flexed and bent will the surface crack, or does it maintain a solid coat? on my better pieces the best I've gotten was a crinkle. Is there a substance or different glue that is more flexible?

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oh and no for some reason I'm being dumb and not heat sealing it. I will do what you said though and put heat to the whole piece before using it. That's a good idea.

I like Aileens tacky glue

parkplace06 said:

I dilute the glue for all coats, but maybe I'm not doing enough water? So after you have apply several coats of glue to your suit and it's totally dry, if flexed and bent will the surface crack, or does it maintain a solid coat? on my better pieces the best I've gotten was a crinkle. Is there a substance or different glue that is more flexible?

- - - Updated - - -

oh and no for some reason I'm being dumb and not heat sealing it. I will do what you said though and put heat to the whole piece before using it. That's a good idea.

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Mine cracked pretty easily before I started heat treating it (I can't take credit for that technique, I learned it through You-Tube), and before I started getting the Modge Podge really thin for the first coat. I also let it cure overnight (±12 hours) before doing any more. You shouldn't have to wait that long, but the foam is still a porous material even after heat treating, and there is no way you can ensure it's completely dry throughout just because it's gotten hard on top. The overnight method practically guarantees that the first layer has completely kicked and isn't going to cure any more.

Your best bet is to take a couple of scrap pieces of foam and try a few different techniques with them to see what works for you and where you're building it at. Just because my method works here in SoCal, doesn't mean it will be fool-proof in, say, Boston.

If you've got a piece that has to flex a lot, it may be worth while to redesign it so it has some flex built into it. Using the right techniques, you can hide elastic webbing really easily. Then your piece will flex against that instead of against itself.

I bought some Gorilla Glue tonite to repair the foam indoor hull of my Parrot AR Drone after a hard landing.It was broken in four pieces.I love GG already: Only an hour after application,it has mended the foam and seems as strong as new.The only thing is there is glue foam extruded at the glue joint,which cures white.The instructions say you can wipe off the excess,or cut it off later.Make sure to follow the simple instructions: moisten the pieces being glued,and clamp the piece until it cures,about one hour.