Technical challenge

Here’s a question for all those engineering types and people who like to make a mess experimenting with materials.

I’m looking for a way to put a non-absorbant skin-like surface onto open-cell foam. I want the surface to be non-porous, able to be painted (with or without latex), and to remain flexible.

Have recently tried melting the surface with heat, but it just singes the foam and the burnt material then rubs off, leaving the normal open-cell surface exposed. I tried both direct heat with a soldering iron and indirect heat from a flame. No luck.

In the past I’ve tried painting with liquid latex, but open-cell foam absorbs a lot of liquid making this an extremely expensive operation. Also it doesn’t produce a smooth skin, you can still see the bubbles of the foam.

I’m wondering if putting on a coating of contact adhesive might work, perhaps followed by liquid latex. Has any one got some contact adhesive and can try this?

Any other ideas?

Perhaps some other substance to coat the foam with.

Or a different way of melting it. I can’t melt the surface with heat, but maybe there’s some way to melt it chemically. Anyone know a substance that will melt soft foam leaving a smooth skin?

Depending on the shapes you want to get, you could look at gluing on fabric. In particular, look at thermal drapes. They have a thin white rubber coating on one side which could be your outside.

I’m not sure of the best adhesive to use for this. I receintly tried to glue lycra to open cell foam and it didn’t work.

That reminds me, I did consider making flat sheets of latex and then gluing them on.

The difficulty with gluing on sheets of material would be making the sheet stretchy enough to go around tricky curves in the foam. We’re talking about body-suit stuff, so going around things like shoulders and even monster faces. I guess it would require either sewing of the material to be 3D curved or glueing it on in pieces.

With latex you could make casts of the skin in the correct shapes and then glue them on. I’m trying to stay away from molds and casting to keep things simple, but that’s another option.

I believe if you make up the latext forms shapes first and they’re dry, gluing the foam in the back will be easier.

Probably true.

Anyone have any other ideas that don’t involve molds? Especially interested in ways of treating the open-cell foam surface so that it closes up and becomes non-porous and smooth. There must be some gunk out there that’ll do it.

What about that PVC glue that melts hard plastic? I had some of that, it might be at Mikes. Wonder if that would melt open-cell foam… although it’s a bit expensive I think.

What about underbody sealer? Do you have any left?

Might have some. Not sure what result it would give, could be worth the experiment.

But underbody sealant is heinously expensive, $20 a can or something and a can runs out really fast. My intent is to find a cheap fast way to make bulky monster costumes. Open-cell foam is an excellent base because you can scavenge it for free, and it’s easy to carve. But if you have to pay $20/sqm to spray it with a surface that would kind of undo the cheapness.

Yeah, it does work but it’s quite expensive and also quite HEAVY. Some still gets soaked in by the porous foam. It’s the solution I’d suggest to anyone reading this who wants to make one costume NOW - but hopefully we can find another way that suits repeatition…

What do the pro’s use? Norman Cates did creature prosthetics for LOTR, and he’ll be talking in Auckland at Conclave in early June. $35 for a day-pass though.

The pros use foam latex, cast into molds. That’s the ideal long-term solution that I’d like to move towards, but it could be expensive/messy/difficult.

In the mean time looking at cheap fast methods.

Marc and I are looking at this stuff for Warhammer purposes at the moment, but it’s relevant to any kind of larp creature-making.

I’ve run a parallel topic on Pagga, and had an interesting suggestion:

He goes on to suggest that a 1mm thick sheet could be formed around difficult shapes by using heat.

From previous experience, the closed-cell foam could then take latex or even just spray paint to colour it. And the closed-cell foam could be grey, which is a better base for colouring over.

I wonder if Dunlop Foam will supply such thin sheets. Should be very cheap if they do. Then we could use a heat gun (paint stripper) to heat-form the foam skin layer.

sigh I wasn’t really going to give away many of the new build idea’s, but I hate seeing costume idea’s hindered.

Ok first off the suggestion of a thin layer of foam is a good one, something I’ve been playing with myself as seen at entropyhouse.com/penwiper/costum … sdeep.html you can shape the foam to a degree, the $2 shop for a while was selling craft foam, which basically is a closed cell layer of foam not much more than a mm thick, the cost was $2 for 4 sheets of reasonable size. look around, I’m sure there is craft foam about for that price in Auckland just got to search for it.

However there is another approach which you just about revealed yourself with the glueing on the latex trick.

Get yourself a large sheet of glass or a clear sheet of plastic, paint a few coats of Latex (colour of your choice) onto the sheets and permit each layer to dry. Peel latex off the the sheet of glass / Plastic and you have yourself a skin, the skin of course being rubber is stretchy, using Ados F2 or the spray can version apply a bit of glue to one part, apply the first bit of latex and allow to dry, then proceed to glue / spray other parts of the area with the the ados and stretch the latex over the shapes you require, however you may need to pin or peg the latex in some parts to allow the glue time to dry, the pin holes are not very obvious in the end product.

Another trick is to use a thick layer of PVC glue it drys clear and should fill in the gaps quite nicely and Latex loves sticking to PVC glue.
I’ve been using a similar trick on some of the bigger shields I’m building, along with a piece of fabric to allow less coats of latex with the same strength of 7 layers, basically the latex soaks into the fabric which is held on by the pvc glue, the latex also makes contact with the Corflute underneath reinforcing the bond between corflute and fabric. Using this technique I’ve slashed the usual 7 layers of latex down to about 3 or 4 depending on the amount of PVC that was applied in the beggining, surprisingly the shields are quite robust, while taking the usual damage from tree’s etc, they don’t seem to get through the latex soaked fabric and shields tend to preserve their look.

Those are my suggestions.

Infact you may just find your answer in that url.

Cheers Scottie.

So, craft foam.

craftdirect.co.nz/index.php?cPath=25_602 - 9x12 sheets for $1.90 each. Can get in black which would be a pretty perfect general base colour. Or that Xmas green for greenskins. Wonder if 9x12 is in cm or inches. Best case in inches that would be around $18/sqm which could be a bit too pricey.

Can’t see it elsewhere online in NZ. Internationally this looks like better value (larger sheets and cheaper per sheet), although having every colour in the rainbow probably wouldn’t be an advantage. Or here is even cheaper, and can get in black.

Never assume that the only products people have are on their website!
ultralon.co.nz/
rubbermark.co.nz/product_vie … D=75.00000

From Pagga:

[quote=“Calus”]thin layer of impact adhesive works great.

Then latex over, looks just like the closed cell foam untill you prod it [/quote]

Which was my original idea. I hope this guy is right, that’d be the easiest method by far.

And Plastidip comes recommended. Advantage of that is that it sprays on and you might not need to use glue first.

I’ve considered getting tooldip for stuff but while it costs $6 for a can in the USA it’ll rob you of $25-$30 here in NZ.

I’m keen to use the black stuff to plastic coap some pole weapon heads for SCA combat.

PVA glue is cheap, Kmart does wood strength stuff for $20 for two liters, you can easily water that down a bit and it still works great.

Will try PVA too then. Will find out if it has the same effect. I assume it’d be flexible enough.