As far as high temperature salts go, I understand that Nu-Sal is the most popular for bladesmiths. It seems that having a little lower temp in the working range would be nice for heat cycling, but is there something negative about the "Uni-Hard IR" that I'm missing? Perhaps it's more corrosive?
From Heatbath:
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Type / Melting Temp / Working Range
Uni-Hard® IR / 1020°F / 1100-1700°F
Nu-Sal / 1230°F / 1300-1650°F
NU-SAL This barium-free salt is the most economical and most commonly used neutral salt for heat treating performed within its working range. It is non-hygroscopic and relatively non-corrosive to metal and fixtures.
UNI-HARD® IR Frequently used as a preheat for tool hardening or as a heating medium for continuous production hardening. Dragout is minimal because of high fluidity. Uni-Hard IR is water soluble and non-hygroscopic. Non-ferrous and precious metals as well as ferrous alloys can be treated in Uni-Hard IR.
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Any advice is welcome.
Also, is it possible to acquire either of these salts in smaller quantities than the 400# barrel?
Thanks.
hightemptools.com has high temp salts in small quantities. I know the business was having some problems but since switched owners. I haven't heard of problems since.
Another option is mixing your own. Somewhere the milspec recipes are floating around in a pdf but I can't seem to find them right now, they were on the Don Fogg forum. I know one smith using a 50/50 mix of sodium chloride and calcium chloride with good success. Given the dangers involved though I would do some research on the subject first.
Got in touch with Heatbath, and they tell me that they don't sell to knifemakers, no matter what the quantity. They wouldn't tell me why.
Apparently, the Uni-Hard IR uses barium, which is toxic, and one needs permitting to dispose of it. So, it makes sense that folks are using the NuSal which doesn't require the paperwork.
|quoted:
hightemptools.com has high temp salts in small quantities. I know the business was having some problems but since switched owners. I haven't heard of problems since.
Another option is mixing your own. Somewhere the milspec recipes are floating around in a pdf but I can't seem to find them right now, they were on the Don Fogg forum. I know one smith using a 50/50 mix of sodium chloride and calcium chloride with good success. Given the dangers involved though I would do some research on the subject first.
As per Bob Kramer's suggestion at an NWBA demo, I use a 50/50 mix of sodium chloride/calcium chloride. Both of these are easily/inexpensively obtained at Ace Hardware.
John Emmerling
