glueing foam
09-15-2002, 06:36 PM
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glueing foam
For foam, use some epoxy. It sticks well, and wont eat through it. I'm not sure what you mean by cutting the glue. Do you mean like sanding off the excess?
09-15-2002, 09:49 PM
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glueing foam
For joining foam wing cores, I've shifted to using 50% Polyurethant glue and 50% yellow Elmer's Carpenter's glue. The result is as good as epoxy, lighter and sandable. (remember.. for foam... don't replace epoxy with this when joining built-up wings!)
The mix will expand and force itself into the styro somewhat. If you wrap the joint with clear packing tape, this prevents excess expansion from getting all over the exterior of the cores, or sheeting. It doesn't eat foam. It sets up in 20 to 30 min and cures in a couple of hours.
The yellow glue enhances the sandability of the polyurethane, and since polyurethane glue needs water to cure, and yellow needs water to evaporate. They accelerate each other's setting. In a way... its an accelerated foaming yellow glue.
I discoverd this mix by accident... glue bottles tipped over and I kind of mixed the glues cleaning it up. Resulting foam seemed neat... so I played with it.
You can use yellow glue or poyurethane glue on practically any foam and get good results. Lighter and cheaper than epoxy, which should be reserved for places needing fuelproofing and extreme strength such as firewall installation. Yellow or polyurethane will be stronger than the foam...
May as well fill gaps between foam cores with a foaming glue instead of epoxy.
Electric foamies, such as the Wingo recommend white school glue and clear packing tape for repairs... (yellow carpenter's glue is closely related to the white stuff...)
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If you have to cut the foam... use a SHARP razor knife, and go slowly. Several passes are better than one deep cutting stroke. You'll tear less foam up.
If you're talking about cutting through glues... the epoxy is very hard to cut through. The poly or yellow is much easier, but still tough enough that you have to be careful or you'll rip the glue off the foam, taking a lot of foam chunks with it.
The mix will expand and force itself into the styro somewhat. If you wrap the joint with clear packing tape, this prevents excess expansion from getting all over the exterior of the cores, or sheeting. It doesn't eat foam. It sets up in 20 to 30 min and cures in a couple of hours.
The yellow glue enhances the sandability of the polyurethane, and since polyurethane glue needs water to cure, and yellow needs water to evaporate. They accelerate each other's setting. In a way... its an accelerated foaming yellow glue.
I discoverd this mix by accident... glue bottles tipped over and I kind of mixed the glues cleaning it up. Resulting foam seemed neat... so I played with it.
You can use yellow glue or poyurethane glue on practically any foam and get good results. Lighter and cheaper than epoxy, which should be reserved for places needing fuelproofing and extreme strength such as firewall installation. Yellow or polyurethane will be stronger than the foam...
May as well fill gaps between foam cores with a foaming glue instead of epoxy.
Electric foamies, such as the Wingo recommend white school glue and clear packing tape for repairs... (yellow carpenter's glue is closely related to the white stuff...)
********
If you have to cut the foam... use a SHARP razor knife, and go slowly. Several passes are better than one deep cutting stroke. You'll tear less foam up.
If you're talking about cutting through glues... the epoxy is very hard to cut through. The poly or yellow is much easier, but still tough enough that you have to be careful or you'll rip the glue off the foam, taking a lot of foam chunks with it.
11-09-2002, 05:23 PM
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Magic Glue?
Wow,, yellow carpenters glue and gorilla grip poly,, Is this the combo,, did it work? I understand the chemistry and it would seem a good mix.. Did you make rubber also as Charles Goodyear.? Jim
11-09-2002, 11:45 PM
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Magic Glue?
I've tried the 50-50 yellow/polyurethane with 'Gorrilla Glue" and "Pro Bond" (Poly version... there's 3 versions of Pro Bond.) Both had the exact same results. (I have also tried TiteBond II and Elmers Carpenter's glues for the yellow glues in the mixes... same results with both)
It makes a hard foam. Consideraly stiffer than white styro. Not fuel proof because its porous. The glue itself doesn't seem to be affected by the fuel, but the bond with other materials can fail due to the fuel getting at the other material.
Its good stuff for repairing broken foam wings, and for joning foam cores. It works fine for repairs of an aircraft's woden structure. (but there's better things to use... like just the yellow glue.) It is good for installing bulkheads in fiberglass fuselages. (the only advantage here vs just the poly is the quicker setup... It is better than using CA though, and lighter than using epoxy.)
As I said... found the mix by accident. Accidents that result in discoveries of somethig useful do occasionally happen.
It makes a hard foam. Consideraly stiffer than white styro. Not fuel proof because its porous. The glue itself doesn't seem to be affected by the fuel, but the bond with other materials can fail due to the fuel getting at the other material.
Its good stuff for repairing broken foam wings, and for joning foam cores. It works fine for repairs of an aircraft's woden structure. (but there's better things to use... like just the yellow glue.) It is good for installing bulkheads in fiberglass fuselages. (the only advantage here vs just the poly is the quicker setup... It is better than using CA though, and lighter than using epoxy.)
As I said... found the mix by accident. Accidents that result in discoveries of somethig useful do occasionally happen.
11-11-2002, 02:51 PM
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glueing foam
Pro bond by LePaGE (I beleive..) It's a poly based glue, activated by water, and foams up like mad! Great stuff! easy to use, and holds really tight!
11-13-2002, 12:41 AM
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glueing foam
I would NOT use the poly/yellow mix for sheeting foam cores. It has higher expansion than just the poly, doesn't (easilly) spread as thin and evenly and is more likely to give an airfoil shape deviation. If just using poly (with a bit of water sprayed on the wood to kick it off) I'd be vacuum bagging or using some very tall stacks of books on the board on top of the shucks to prevent the expansion from deforming the airfoil.
Its a mix that has some limited uses. Filling voids in foam is where its really the most useful. (repairing a broken foam core wing, oversize slots for dihedral braces, and the normal gaps at the wing dihedral/polyhedral joints... stuff like that.)
Its a mix that has some limited uses. Filling voids in foam is where its really the most useful. (repairing a broken foam core wing, oversize slots for dihedral braces, and the normal gaps at the wing dihedral/polyhedral joints... stuff like that.)
