I have no clue. The foam is closed-cell and very firm. There is virtually no cushioning, none is needed, the comfort comes from the sculpted fit. Even in the USA, it's much easier to find the foam in thinner stock or one-foot width. I had to hunt online for 2ftx2ftx3in block to make a seat that measures about 22inWx19inL. BUT, I don't see any reason why you couldn't Goop or contact cement halves together lengthwise, as LeeG suggested, or even to double the thickness.

: This seat looks fantastic. I would like to make one.
: Having said all of that, my next question is about minicel foam.
: The product is not available in australia under that name. It is sold under
: the trade name "softlon" here and may be difficult to obtain in
: the correct thickness. Is there any reason why I should not use
: conventional P.E. closed cell foam in the same manner?

: many thanks

: Nicholas Sheahan
: Mildura Australia