Hey there,  I am wanting to experiment with a flexible mouth plate in my next project, but I am having trouble finding it here is Australia.  So I went to ebay and found the following...

http://www.ebay.com.au/itm/2x-Black-EPDM-Rubber-Gasket-Sheet-Material-1-16-x-12-x-12-Weath-Resist-8610K82-/300976635923?pt=LH_DefaultDomain_0&hash=item46139b0013&_uhb=1

http://www.ebay.com.au/itm/FDA-SILICONE-RUBBER-SHEET-1-16-THICK-12-X-12-SQUARE-FOOD-GRADE-HIGH-TEMP-/190861942766?pt=LH_DefaultDomain_0&hash=item2c70421fee&_uhb=1

Is this the right material?  And if so, is that about the right price that I should expect to pay?

As far as I recall, gasket rubber is the stuff used for car floor mats? If so, you could always try Clark Rubber (offcuts, since that makes it cheaper).

The first one looks about right, I think the second one may be less flexible and more like cutting board but I could be wrong. Price on the first one is not bad since you are getting two sheets but it is the postage that is going to put it over the top.

Do you live in a remote area that does not have many stores?  I would think that if not you could find something even if it was not called gasket rubber. In fact if you can't find it can you get leather in your area?  That would work also. The big difference would be that gasket rubber tends to give some spring open action to the mouth that leather would not, but in regards to a durable mouth plate they are both great materials. You are looking for something that is about the thickness of a cardboard box you would mail things in. Somewhere around a 1/16 - 1/4 inch or 1.58 - 6.35mm.  You don't want it to be too difficult to bend in half.  The 1/4 inch or 6.35 mm is getting almost too thick.

This page over at Clark Rubber looks promising. http://www.clarkrubber.com.au/rubber-and-flooring/rubber-strips-sheeting/standard-rubber.html  In fact if you could find one of them that looks like the rolls of tape that was wide enough, that could be useful. http://www.clarkrubber.com.au/natural-strip-insertion-rubber.html

Do you live in a remote area that does not have many stores?

Haha - I live in a capital city with millions of people. Trust me, Aussies really are not good for having big supply stores of materials. I remember a Canberra puppeteer getting all excited about *finally* finding a leather supplier here in Melbourne after years of looking for one. (Don't ask me, I don't know it)

Actually come to think of it, my experience with finding a plastic supplier suggests that it's better to save the shoe leather, do some googling and find a big factory supplier/manufacturer whose shipping costs are not astronomical.

... Anyway, now that you've posted a second time, Clark Rubber is basically the only place outside of industrial manufacturers that you'd easily find in a store nearby. One of the reasons I suggested it.

Well even leather can be hard sometimes to find locally. Used to be you could find a Tandy Leather pretty easy but not even sure there are any left here in KCMO. 

Thank you both for your help.  I live in a city, but as Na said it can be difficult finding some things here.  I had already tried our big hardware stores and the automotive parts stores with no success.  There are a few Clark Rubber stores around (thats actually where I bought the foam to make Praccie) so I will drop in this week and see if I can find something suitable.

Hope you find it!

Like everyone has said, Clark Foam and Rubber have it really cheaply. I bought a role based on what I'd read about building puppets and to be honest, I can't stand the stuff. I'd pocket your cash and find an alternative. Having said that, it does pay to strike a relationship with the Clark guys. I get tonnes of free foam as they bag up their offcuts. It's not all always usable for puppetry purposes but you can often get a utes worth for nothing and the tip fees to ditch the unwanted scraps are far less than even buying off cuts.

Do you guys have a recycle place anywhere near you? I have one specifically for off-cuts that people offer to be recycled. You go in, pick out what you want, pay a low low low price, and walk out with whatever materials you need. Since discovering it, I only go to craft shops when I need something urgently (PT is no fun!) or require more fabrics than they have for sale.

http://www.reversearttruck.com.au

I've seen more rubber and foam in there than in Clark or Spotlight put together.