I'm getting into a habit of spilling info on my prototypes way before I'm ready for mass production. I figure now is the better time for feedback than ever so why not?
Basically the story is that people that refuse to use weldless anything but can't find a competent TIG welding professional only have silver soldering as a last resort. The typical process involves making a dimpling tool, basically a tapered mandrel and backing die, to flare out the holes where fittings will be installed. This helps add surface area and physical strength. Commercially available tooling for this process is relatively rare and expensive so everyone has been making the tool from various off the shelf pipe fittings (concentric butt weld reducing couplings) and other makeshift objects.
Long story short, here's what I'm working on. A single fitting that has 1/2" male NPT threads on one side and Female threads on the back. It has a machined in taper on the fitting itself so it can act as its own flaring mandrel as it's pulled through a 13/16" hole. That way you can grab any number of bulkhead fittings and buy or rent the die and pulling bolt hardware. Let's say the tool costs $12 and if you send it back, you get a refund in store credit.
Why male threads on the outside? You thread a ball valve on anyway and this takes away the need for a close or hex nipple. One less place to leak.
I don't have a picture handy, but the back of the fittings shown in the two pictures is already soldered to the pot. There's a thin shoulder on the fitting to keep it from being pulled all the way through and even provide additional contact area for solder above and beyond the flare in the vessel wall. This shoulder only sticks into the pot by about 1/8".
Video coming...
Basically the story is that people that refuse to use weldless anything but can't find a competent TIG welding professional only have silver soldering as a last resort. The typical process involves making a dimpling tool, basically a tapered mandrel and backing die, to flare out the holes where fittings will be installed. This helps add surface area and physical strength. Commercially available tooling for this process is relatively rare and expensive so everyone has been making the tool from various off the shelf pipe fittings (concentric butt weld reducing couplings) and other makeshift objects.
Long story short, here's what I'm working on. A single fitting that has 1/2" male NPT threads on one side and Female threads on the back. It has a machined in taper on the fitting itself so it can act as its own flaring mandrel as it's pulled through a 13/16" hole. That way you can grab any number of bulkhead fittings and buy or rent the die and pulling bolt hardware. Let's say the tool costs $12 and if you send it back, you get a refund in store credit.
Why male threads on the outside? You thread a ball valve on anyway and this takes away the need for a close or hex nipple. One less place to leak.
I don't have a picture handy, but the back of the fittings shown in the two pictures is already soldered to the pot. There's a thin shoulder on the fitting to keep it from being pulled all the way through and even provide additional contact area for solder above and beyond the flare in the vessel wall. This shoulder only sticks into the pot by about 1/8".
Video coming...
nestar:
