Thanks ,Actually the pellet in the left,, where it contacts the alox plunger is smaller in diameter than the plunger itself.. The pellet on the right is an example of the pellet filling the whole plunger chamber during the press.
Whenever I was using the alox plungers I would at times (or all the time, I forget) get the bottom that would get goofy like you show, even chip away at the bottom during sandblasting, leaving it beveled looking like yours. That cleared up in using the disposable plungers, and in my case, the Zubler seem more consistent for me.
I was once told to hold the alox plunger top with the tong part you use to grab the ingots with, after it comes out of the press will help draw heat out of the plunger to help it cool more evenly. Maybe that's why I would get the little chip edge as seen below, but it did resolve the cracks I would get once in awhile that would run partially up the sprues. Others here can confirm or deny if that idea is valid. I also think it a good idea to run a dummy sprue (same length as the sprued unit) on a base that would normally have just a single unit on it, to help diffuse the pressure. Again, maybe that needs to be shot down or acknowledged as valid or not.
And last but not least, free, at no charge, I've found another useful way (maybe I posted this before?) to use the Ivoclar cooling tray. It works great for holding syringe opaques and stains.
