Help me work with green high density foam

October 18, 2012 9:15 AM

I am at the "what have I gotten myself into THIS year?" portion of the costume making season and am struggling with my material choice - 1 inch thick green high density foam.

This is the stuff you get at Joann (etc etc etc - this stuff). It cuts beautifully, and I've been using hot glue to glue it together, but that makes for ugly seams. I could, I think, use a different glue for it, but there's no good way to clamp the pieces while the glue sets.

I don't think my sewing machine has enough spunk to sew it together, but I suppose it wouldn't hurt to try.

Any advice would be appreciated, whether that is a method of construction that I haven't thought of, or a method of finishing to make the seams a bit less ugly. Caulk?

posted by dirtdirt to sports, hobbies, & recreation (13 answers total)

What are you doing to the exterior once it's assembled? If you're painting it, maybe you could glue the seams, cover them over with tape, and then paint over everything to blend and conceal.
posted by Faint of Butt at 9:18 AM on October 18, 2012 [1 favorite]

I think I saw on mythbusters that they used some sort of spray glue/adhesive and that it worked beautifully.
posted by PuppetMcSockerson at 9:19 AM on October 18, 2012

Oh! I should have mentioned: I am painting the exterior when I am done. I have thought about, but am going to avoid, covering it with sewn fabric.
posted by dirtdirt at 9:21 AM on October 18, 2012

Seconding spray adhesive, it's the best one I found for working with such things.
posted by Nimmie Amee at 9:22 AM on October 18, 2012

Yup, spray adhesive. Sandwich between pieces of plywood (or a hard surface and plywood) and put a bunch of books on top.
posted by phunniemee at 10:06 AM on October 18, 2012

If you're dealing will small pieces, just use tape instead of clamps.
posted by jon1270 at 10:08 AM on October 18, 2012

Alas, I threadsit: the work I am doing is edge to edge construction along non-regular lines. Seams. If it was fabric it would be sewn together. There is no good way to immobilize for anything like the amount of time it would take for it to cure. A spray contact cement might work (77?) , but the overspray issues seem pretty insurmountable. Hm.
posted by dirtdirt at 10:17 AM on October 18, 2012

How much joinery is there? Would it be manageable to sew with a big upholstery needle, some yarn, and a chunky hand-sewn baseball stitch or other butt join seam?
posted by peachfuzz at 10:23 AM on October 18, 2012 [2 favorites]

When you say that the seams from hot glue are ugly--is it because the glue doesn't go all the way to the edges of the foam? I've found that hot glue-ing gets alot neater if you use a Popsicle stick to spread it around quickly. If you decide to use this method, make sure you use an old-school glue gun that gets really hot, and not one of those new-fangled "cool temperature" ones.
posted by tinymegalo at 10:26 AM on October 18, 2012

Tape might be your best bet.

Get some decent double sided tape and use that for your initial edge-to-edge join. Then put some 2" tape down over the seams. Given that you are cutting, your edges may not be flush anyways. I'd suggest the upholstery needle/baseball stitch as well. You can then tape over the stitching.

Or you can do as the cosplayers do and use stuff like wonderflex or fosshape to make your costume.
posted by robocop is bleeding at 10:42 AM on October 18, 2012 [2 favorites]

If it were me, I'd find some small, flat, plastic pieces, a couple inches in diameter. Maybe cut them out of some milk jugs or something. Then cut some evenly-spaced slits in the middle of each edge, fill them with am appropriate adhesive, and slide a disc halfway in, and repeat for the other half of the joint. Basically a biscuit joint, made of foam and plastic.
posted by jferg at 12:01 PM on October 18, 2012 [2 favorites]

I'm not sure I have a great mental picture of what you're creating, but I think an upholstery needle and thread (like this) might work. After sewing the pieces together, I'd glue down a strip of muslin to cover the seam and then paint over the whole bit.
posted by Flamingo at 12:28 PM on October 18, 2012 [1 favorite]

I also think tape is a good idea. I recently bought some Gorilla Tape and was surprised by the strength of the adhesive.
posted by orme at 8:59 AM on October 19, 2012