I have one March and two Chugger Center Input Pumps that have long had tri-clamp connectors screwed on with PTFE tape. I finally got tired of unwinding, cleaning and re-winding the connectors, so I bit the bullet and tried silver soldering the connectors onto the pump head threads.

 

I carefully cleaned the threads on the heads and connectors. using a bronze bristle rotary brush on my Dremel tool. I then lightly sanded the threads, cleaned them with acetone, applied a copious amount of flux to the threads, then I assembled and soldered the heads one port at a time.

 

The result came out pretty well if I do say so myself:

 

I’ve hooked up and run all the pumps and leak tested them, and everything was copacetic.

 

If you’re going to try this yourself, and don’t already have the tri-clamp fittings, I recommend you use Bobby’s Low Profile NPT adapters.