This stuff, Perfect brand Gasket material is great for model engine gaskets. I've used it for ETA 29 head gaskets and it hasn't failed yet.
I got mine from this lot on ebay:
http://www.ebay.co.uk/itm/1709245958...84.m1423.l2649
Yes the international postage is excessive but it's much cheaper if you're in the US. It's also available from a whole lot of other dealers.