blue pink foam

[Big-Tex]

I know many have used those to make signs and letters.
Lowes carry 1" blue and its fairly cheap.

Can you briefly explain how well it worked cutting what did you use to glue up to add thickness, finishing process products etc.

Maybe there is someone in Dallas area that I can help in their projects and pick up some knowlege kind like an apprentice.

[Brady Watson]

Blue & Pink extruded foams are about 3# density. They machine best with a 4-flute end mill and 18,000+ RPM, moving as fast as your hold down solution will allow. While theoretically, you could cut the stuff @ 8,000 RPM, the cuts will not be clean. The softer the material, the lighter the chipload to get a good finish - hence the high RPM and 4-flute tool.

You can glue it together with regular wood glue, polyurethane glue (Gorilla) or expanding foam (Foam2Foam or GreatStuff), epoxy resin with microfibers or similar mixture. Polyurethanes tend to expand, so be careful.

Finishing low density foams is an entire subject & art in itself.

-B

[sailfl]

My experience is different. I have not used the Blue foam but the pink foam I have used is polystyrene. I found that regular wood glue, though I know people use it, does not set up. I bought 3M 78 spray glue made for polystyrene. I also found that Onsruds 52-550 series of bits (2 flute) work very well.

[harryball]

I made our "big bat" from blue foam. (found in this gallery http://www.habitatforbats.org/?p=126&album=2&gallery=24) The bat is glued into the large foam backboard. I tried several samples and ended up using the liquid nails quick tack stuff where the neighbor sticks the guys hammer to the ceiling. It has held up well so far. It gets carried around and it flexes a bit because the backer is only 1/4" luan which I also glued on with that same stuff. So far no signs of separating.

On my samples I glued two 6" x 6" blocks of blue foam together, one had been "skinned" so it was foam as if you'd pocketed it.
Regular wood glue - did not dry after 24 hours
Waterproof titebond III - same problems maybe it takes longer?
Gorilla glue - worked but expanded
3M spray adhesive worked but only on the smooth surfaces. For the pocketed areas it does not stick so well.
the black polyurethane adhesive I used worked well enough, but takes 48 hours to cure.
I tried the Great Stuff... I have to say it sticks. Spritz a little water on each piece, put on the foam and squish it together. But I couldn't figure out how to stop the expansion pushing the blocks apart as it cured. Maybe someone can explain how that's done?

/RB

[Brady Watson]

I've found epoxy mixed with microfibers to be the best. ANY polyurethane will expand & the only way to reduce the expansion is to clamp it in between plywood platens.

Foam2Foam is also good with minimal expansion. http://www.shop.hotwiredirect.com/foam2foam-c-36.html

-B

[Big-Tex]

Thanks guys.
My next step I guess will be buy 1 sheet of 3/4 blue foam $13 at brand store
and try to play with it.

[Big-Tex]

can anyone post feeds and speeds including bit you use