October 22, 201213 yr Hi, Does anyone have experience with salt pots? I just built one and am getting ready to load it. At the NWBA conference, Bob Kramer recommended using a 50/50 mix of sodium chloride with calcium chloride. Both are readily available at little cost thru Ace hardware. Any suggestions greatly appreciated. Thanks, John
October 23, 201213 yr It looks like salts number 5 in the Milspec will get the job done. I find that own-brand low sodium salt from my local supermarket does the job nicely; basically, it's half Sodium Chloride, half Potassium Chloride. I'm in the UK, so things may be different where you are. From a quick Google, it looks like Morton "Lite Salt" is pretty similar, though it does contain anti-caking agents. It might be worth checking out own-brand equivalents.
October 24, 201213 yr I would use commercial heat treating salt. I got mine from Parker Heatbath, but they do not sell to "us" any longer. I suggest looking into the products by Houghtonhttp://www.houghtoni.../Locations.aspx Ask them about the specific salts they sell. Some stuff on liquid bath quenchinghttp://www.dfoggkniv...n_Quenching.pdf Ric
October 27, 201213 yr Author Some observations on my salt pot: I am using a 50/50 mix of sodium chloride/calcium chloride as suggested by Bob Kramer. Both were purchased from Ace Hardware for a very reasonable price. They can be ordered online with local pickup for no extra shipping charge. A 40lb bag of each goes a long way. Share with a friend and the cost is a couple of beers. A little research online is time well worth spent. Having built a temp controlled forge, this project was pretty much the same...solenoid, thermocouple and controller. My controller is a Watlow with a manual dial...easy for old guys :) My last one was a PID that only my kids could figure out. For $ 110. I'm in control. The next pot will be built using a vertical ribbon burner with Kaowool as a refractory. The cast refractory on this pot absorbs too much heat as it takes a single venturi burner 30-45 min to heat a 4"id x 18"stainless pipe. It works and the heat is even as advertised. Ultimate controll and the beginning for me of many experiments. It's messy as salt is hydroscopic and seems to get everywhere. Living in a rainy climate does not help. I wish I had an out building to do the heating/quenching. It's dangerous as anything damp or oily does not do well in molten salt @ 1500 deg. I bought a new face shield. Salt baths do not eliminate warping. Despite thermal cycling and annealing, I still experience some warping. I was hoping for a magic bullet. Oh well... It's clean other than salt on the steel...no scale. That's a major positive. I am interested to hear what others have to say. Thanks, John
October 27, 201213 yr I would second Ric's suggestion of getting proper salts, as they are meant for heat treating, and you can get test materials and other supplies for keeping a neutral environment at the same time. You might be able to work out a purchase at a local heat treat facility. I purchased my high temp salts from a heat treater in Milwaukee rather than try to get them straight from Parks. I also was able to buy 5 gal of Parks 50 from them at the same time. If you can find someone there to help, have them show you their set-up, and how they maintain their salts and safety, while you will probably need to scale it down, a day watching, talking, and learning from them may be worth more than a month's worth of Googling. A quick way to help make sure your blades have no moisture on them when going into the salt pot, is to have a oven set to 300+, and bake the blades for at least 15 minutes to make sure the water has evaporated. Or hold them next to the salt pot in the heating chamber to do the same. Best of luck, I know I love my salt pots. Oh, and make sure that the welds on your pot are top quality, you don't want a crack starting there and have 1500 deg molten salt running into your heating chamber.
November 6, 201213 yr Author I phoned/emailed Houghton. 500lbs minimum order at $1. + per lb. Not happening for me. Any other suggestions appreciated. Thanks, John
November 17, 201213 yr John - I, too listened to Bob Kramer, and I asked him a similar question, and I understood him to say that all of the above are viable options. The best one is the one that YOU learn to use with YOUR equipment and YOUR technique, and remember that each time you make a blade with a new/different batch of steel, you may have to adjust your temps/times to get consistent results due to the vairable alloy contents in each different batch of steel.
November 17, 201213 yr Author billyO, George House and I recently split the cost of a Rockwell tester to improve methodology. Bob Thomas, another friend has one and we just compared the 2 on a blade. They were within a half a point. My only wish is that I had more time to spend blade smithing. :) John
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