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Old May 31, 2012, 03:10 PM
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Spray foam sealant?

I searched for this, but could find any relevant threads. Has anyone ever tried using spray foam sealant in their pod/fuse/boom? I'm referring to the type used to seal gaps during residential and commercial construction. My thought is using it to hold components, like pushrods (rod and tube) in the boom, or making molds for the receiver/battery to sit in inside the pod. The stuff sticks to anything, it's lightweight, and it carves easily with a sharp blade. Thoughts?
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Old May 31, 2012, 03:38 PM
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http://www.rcgroups.com/forums/showt...+foam+dlg+tail
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Old May 31, 2012, 05:25 PM
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I've used it for years to hold pushrods in place inside booms, provide a bit of buckling resistance on older 3m fins, etc. It's very handy stuff in some situations.

I've used it inside clown balloons to apply pressure like a bladder inside a fuselage under repair as well.

Be careful not to use too much. Expansion can ruin stuff quickly if confined.

On a side note, gorilla glue is urethane as well and has similar properties when applied to a wet surface. I've used it similarly.
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Old May 31, 2012, 07:49 PM
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If you mix Gorilla or other, similar polyurethane glue with a little bit of water (1 part in 10 or 20????) you can get a nice, flexible foam out of it. Recently used this when the foam under a spar cap got too crunchy. It's thin so you can inject it with a syringe, but doesn't have gobs of working time. Much slower than the stuff from the can or the two part mix, though.

A friend of mine used to use the spray stuff (or maybe it was the two part stuff?) in the fuselages of his Dodgson gliders. They had a taco shell style fuselage, so he could leave one side open and carve the overflow to shape afterwards. Worked for him.

However, it is possible to run into trouble with continuing expansion. I read an article by Stan Hall about a bad experience he had filling in surfaces on a full sized sailplane using the two part stuff.

If you have pushrods and tubes in the tailboom, you can also just stuff in moderately flexible foam plugs at intervals.
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Old May 31, 2012, 10:17 PM
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Wow, I must suck at searching threads! Thanks for the great insight.
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