I asked my local vehicle repair/body shop if they new anybody that welds aluminum. They gave me a name. I called him and asked him to supply that sheet. He will bring it in for $80.00 a sheet painted white, which is what I want for our Argosy interior panels.
Just another avenue to try perhaps?
There is also metalsupermarkets.com but call them because the pricing on the website is out of date and they have nobody on staff that knows how to change it!
A wise man once told me he wanted to stay fit enough to run a marathon on his hundredth birthday. Another said he wanted to be shot by a jealous husband on his, I'm with the latter. God bless you Richard.
Carpet Cleaning is what I do, it's not who I am.