Need help with salt pots...

[Phillip Patton]

A couple months ago I was starting up my salt pot, and checked it every few minutes while it was warming up. The last time I checked it, there was white fumes coming out of the chimney. So, I shut it down immediately, and let it cool down a minute, then pulled the pot out to take a look. There was a stream of salt jetting out of a small leak that had formed. Also, the bottom of the pot, which had once been flat, was now bowed out significantly. Apparently, the tapered rod trick did not work in this case, and some significant pressure built up.

If I hadn't caught it, I would probably have an unwanted skylight in my barn.

So, my question is, once I fix the pot, how do I prevent this from happening again? I was thinking this morning that I could put another burner port near the top of the pot, and once it melts, move the burner to the bottom port. Make sense?

Also, how much taper do you guys put on your rods?

This experience took away my desire to use salt pots for awhile, but I want to get it going again.

Thanks,

 

[Dan Zawacki]

Take this with a grain of... well.. salt. Mostly because I don't have a set of pots.\

However, the top burner / bottom burner is exactly the soloution I have seen others talk about to solve this problem. As near as I can tell, the tapered rod only needs to be tapered enough that you can remove it (meaning not bulbed so it gets locked into the solidified salts.).

Normally, it had been the impression that I was under that the top burner / lower burner arrangement was only really needed with longer pots. How tall is your setup?

 

[Stacy E. Apelt - Bladesmith]

The best way to avoid any possibility of trapped liquid salts under solid salt is to heat the pot slowly. Set the PID to start at a temperature below the salt's melting point, and slowly increase it until the salt melts. This way all the salt melts at about the same time.
Stacy

 

[NickWheeler]

Phillip-


My tapered rod is 7/8" and tapers down to about 3/8" over a length of about 18. The whole thing is about 28" long.

What's the wall thickness of your pipe? Mine is 5/16" wall, with a cap on the bottom that's pretty close to the same. It was beveled and TIG welded by Kelly Cupples.

My first one was stick welded by a guy that wasn't really competent for the job, and it leaked. I had that same foggy cloud coming from the exhaust tube. Four days later I had rust on EVERYTHING in my shop that was ferrous and didn't have paint or heavy oil on it. What a major f'ing PITA! :grumpy: :grumpy: :grumpy:

Hope you don't have the same!!!

How long is your salt vessel? Mine is only about 20" long, with about 17" of salt in it... so one burner works fine. If mine was much longer, I'd probably go with two burners.

 

[SteelSlaver]

I have seen Nicks pot and watched it in action. Very nice setup. I will say you can do a decent job of stick welding something like this. Use the the right rod. 309 will do most stainless welds well and do stainless to carbon also. Make sure everything is clean, start your arc a bit away from where you want thee puddle to start, make sure you get both pieces with your puddle all the way around, deslag and clean or grind your restarts and tie ins very well (many welds fail because of not doing this). If you are not an experienced welder this is not a good starting project. We stick weld many socket weld fittings of stainless for high pressure piping, but, it must be done right. A bad tig weld will fail too.