Salt pot thermocouple ?

[4horn]

Ed.
I've read your page about saltpots on your bits of steel web page and have found it very helpfull. After looking into the thermocouple website I'm having a hard time deciding which one is the best for the application ? Is there no worry of breaking them when you bend them?
Also a very basic question , what type wire or rod do you use to dip your blades
into the tank ?
Thank you for your help
Mike

[Ed Caffrey]

Hi Mike!

Here's a link to the thermocouples I recommend for salt pots, as well as forges: http://www.omega.com/pptst/JTIN.html if you go down the page, near the bottom there is an area called "Part Number Builder". Here's what I put in each box:
(1) K
(2) SS
(3) 14
(4) U
(5) 12

You can basically build your own, and they will send it to you. I choose the SS sheath because it keeps the price down, and because I have not found any durability advantage using the more expensive "IN" or "XL" sheaths in the salt pot application. The "XL" sheaths last considerably longer in a forge application, but I'm not sure its enough to justify the cost.
I've never had a problem bending any of the sheathed thermocouples...just do it by hand and be gentle.
Honestly, I use old bailing wire for my dipping wires in the salts (the super heavy wire that is used for clotheslines...approx 1/8" in diameter) If your using a neutral salts in your pot(s), the type of wire you use should make any difference, just as long as its heavy enough not to break due to the high heat. (small gauge wire will sometimes give way when you allow a blade to soak for any length of time.)

One more thing that I have found over the years using salt pots.... some of the neutral salts will, for lack of a better way to explain it, become carbon deficient. Meaning that after prolonged use, the salts will "suck" the carbon out of a carbon steel blade when you let it soak. The way to fix this is to purchase a box of 1/4" carbon arc rods from a welding store. Break them up 3-4 of the rods into very small pieces and put them in the melted salts. They will float on top, and will bit by bit be absorbed by the salts. The way I found out about this problem was when I tried to harden a 1084 blade, using the salts, and it simply would not harden... after some research I found the problem, got the carbon rods, and not I constantly have a small pile of carbon floating atop my salts. About once every 3-4 months I have to add a few more pieces, but have never had the issue since.

Hope thats helpful!