Ian, thanks for the tip, but I already have the rod tubs and the while they do yield the same end results I like the old style tube much better. I already have one and would really like to find a second one because I have a tempering bath that will hold two 8x19 tubes perfectly. Actually a couple more would be nice but I know that I'm pushing my luck.
John, thanks for the offer. I made 5x7 tubes from 2" PVC pipe and ABS slip-on caps and couplers and am pleased with them. My concerns with making 8x10 was getting the caps off when the processing was done and with them leaking. I hadn't though about using threaded fitting. Still the problem is that I spoiled by the one original tube that I already own. The thing that is nice with it is that the threads are three lead, so the cap comes off in about one turn making it very fast to open the tube and get it in the stop.
Roger