Replace Rubber bottom of Corny Keg

I posted this in the Bottling/Kegging forum but have gotten much of a response. I just received 2 corny kegs that need the rubber on the bottom replaced. One just doesn't have any, and the other has about half, which makes it so it won't stand up on it's own. Does anyone have any ideas on what I could do to replace the bottoms?

You could use a simple mold (circular foil pan) and liquid truck bed liner. Lowes and Home Depot sell it.

Good luck with that. Those things are injection molded to the bottom.
Might be easier to just build a wood frame to sit around it so that at least that way, they'll stand up.
I thought of the truck bed liner also, but given the price of that stuff and how much it would take, you'd likely be approaching the cost of another corney.

I don't think they are injection molded. there is a glue type substance on them...still looking for a source for the bottoms....

Haven't seen just the bottoms but like the bed liner thing you could use that expanding foam spray, just make a simple mold like stated above, coat it with a non stick substance and spray a few separate layers of expanding foam.

I believe it's stiff enough to work and would take some banging around.

Just glue or screw a couple of two-by 10's together to get the needed thickness. Then use a bandsaw or jigsaw to cut out the required profile and shape. (Think large donut)
Clean the bottom of the keg with soap and water and a Scotchbrite pad. Apply a good quality construction adhesive and let it sit until the glue is cured.
I'd advice sealing all sides of the new wood base with either varnish or even cheap rattle can paint to prevent mold and rot.

See if you can find a round concrete form to fit the bottom, if the kegs sits on it and doesn't go through it would be perfect. Cut it to 3" - 4" and fill with expanding foam. It won't be perfect but it will hold.

Another option is to find someone with a wood lathe that can cut bowls, Have him cut a bowl the shape of the bottom of the keg and leave the bottom square. It will take some maintenance to keep it looking good but if you glued a rubber mat to the bottom it would work great.