I've done bulkheads a half dozen different ways over the years (even TIG). The cleanest and easiest way I've found to do it;
a 13/16 greenlee punch, brewhardware pull through fittings and silver solder.
https://www.brewhardware.com/product_p/ptbulkheadmf.htm
There is very little chance of messing one up this way. Once you have the punch and pull through tool, you can install bulkheads quickly and easily on anything you want.
Uh..... Ok.
Are you implying that I'm mistaken or lying? Keep in mind that I offer this as a service at my shop and end up pulling 1/2" NPT fittings and 1.5" TC ferrules at least 15 holes a week for the last 3 years. I think my sample size is bigger than most. When I drill the holes with a Unibit or Tungsen hole saw, zero rips. When I do it with a vessel that has been radio punched, about 20% have torn.
You can imagine how terrible I feel when someone messes up their pot so this warning is important.
fwiw, I for one would certainly defer to that experience if I was considering the pull-through bulkheads. I'd be crazy not to respect the numbers.
As to why the sawed holes are resistant to pull-through induced fracture, it's likely the heat from the hole saw is annealing the hole perimeter, increasing its ductility; whereas the punch is a virtually cold process, leaving the original metal character unchanged...
Cheers!
God. The level of sensitivity on this forum is astounding.....
I shouldn't respond, but I will. Stainless steel is not going to be cold work hardened by one pass of a punch. Stainless steel does not get "annealed" by the heat from a drill bit (it gets work hardenend).
Sorry if this hurts your feelings.
Just a word of warning, using the pull through process on PUNCHED holes is a risky move. We have had some reports of the hole splitting. I'm generally convinced that the shearing force of a punch creates a micro perforated and work hardened edge.
They may have been punched. Sandpaper the inside edges to smooth the micro tears and it should be fine.So, I just spent a "free shipping" amount of money on, among other things, pull-through fittings from brewhardware.com. I plan to install them in my Megapot 1.2s. Based on this, I ordered a couple drill bits from you as well and will save my punches for another project.
Here's my concern, how will I know if the original holes in the kettles were punched (prone to tearing) or not? I'm already a little anxious about pulling because of the thick walls on these pots. Can I sleep or should I stay up worrying?