heat treating salts

[Brad Humelsine]

I have finished finished building a new high and low temp heat treating rig.

Now, the problem is finding the salts to fill them. Both Houghton and Heatbath will only sell salts in quanties of 400 pounds. So the the problem becomes what to do with an extra 300 lbs each of high and low temp salts.

I would be willing to either buy salt from another maker who has been in the same spot. If that does not work, I would be willing to order the drums of salt and sell them in small quanties if there is enough interest.

I am open to any all input.

[fitzo]

check reply at BF

[Ed Caffrey]

Give Swain's Spring Service a call. 1-800-378-1246 You'll likely talk with Chris. The last time I checked, they had salts that they were selling by the pound.

[Brad Humelsine]

Ed, Thank you.

I called Chris, and yes they do have salts. Problem is they only had 40 lbs of each type in stock with none on order.

FYI they charge $3.00 per pound.

73 Brad

[TJ Smith]

Having the same Problems.
Check out some of the old threads.
It seems that a 50/50 mix of sodium chloride and calcium chloride works.
Sodium is easy. Can't locate any calcium chloride at a reasonable price.
Have heard that ice melt works.
I'm ready to start building mine. Were you in Spokane?
Maybe we can get together on some ingrediants.
Take Care
TJ

[cramnhoj]

Umm, what is the working temperature of the 50/50 mix of sodium chloride and calcium chloride?

[Ed Caffrey]

Lyle Bronkhorst uses that mixture for his salt heat treating. I was there a couple of weeks ago helping him teach a class...........he buys rock salt from the grocery store, and calcium chloride from a concrete batch plant (calcium chloride is used as an accelerator for curing concrete) He mixed approx. 50/50 in his salt tank and it worked just fine (we didn't go above 1550F)

[Brad Humelsine]

I made the decision that I would homebrew the high temp salts. My sodium chloride was purchased at the grocery store, and the calcium chloride at a swimming pool supply shop. The sodium chloride was $7.00 for 50 pounds and the calcium chloride was $31.00 for 50 pounds.

Both Houghton and Heatbath manufacture heattreating salts to Mil. Spec. 10699. Tomorrow I should receive a copy of that specification which will includes the formulas for the various mixtures covered by the specification.

My desire is to mix my salts to obtain the same melting point as Houghton Liquid Heat 980 which is the product that Swain sells.

I am leaning toward Brownell's bluing salts for the low temp salt bath. The price is identical beween Brownell and Swain, so it really comes down to having additional benifit of being able to blue various parts in addition to just quenching.

I have already purchased from Houghton 5 gallons of Martemp 325 which is marquencing oil that is useable to 400 degrees. I want to run test with quenching both in oil and in salt. I want to try and establish which process produces not only the toughest blade, but which process produces the least amount of distortion.

[fitzo]

I'm glad my initial recommendation was of some accuracy.

[TJ Smith]

Sounds good
How about posting the mix ratio of the hot salt when you get it.
TJ

[Brad Humelsine]

You were right on the money Fitzo...

The primary reason I wanted to buy the salts was I wanted them to be anhydrous, and perfectly neutral.

I am planning on drying the salts in the oven before I put them in the salt pot. I hope I can drive some of the water out before I melt them.

The salt can be tested for neutrality with a double edged razor blade. You heat the blade in the salt and then quench it. If the blade snaps when it is bent the salt is neutral, if the blade takes a bend and holds it, the salts are not neutral.

I will post the Mil. S. as soon as I receive it.

[millironknives]

my experience with my high temp salt pot is it collects moisture while not in use and it cooks it of every time I start it up. I take the lid off to let it escape insteade of dropping back in and making nasty splattering action. So the way I see it is you will not need to pre dry it it will be cooked out way before the mix goes liquid. Just my two cents.

[Joe Walters]

my experience with my high temp salt pot is it collects moisture while not in use and it cooks it of every time I start it up. I take the lid off to let it escape insteade of dropping back in and making nasty splattering action. So the way I see it is you will not need to pre dry it it will be cooked out way before the mix goes liquid. Just my two cents.

That only works once the salts have been melted and all the airspace is gone. You MOST DEFINATELY should pre-dry the salts before adding them to the tube. Adding salts with moisture into the already molten pool in the tube will cause the molten salt to spray out. Bake the salts in your oven or roast them on the BBQ until all moisture is gone. Ask me how I know. The other alternative is to let the molten pool cool and solidify and then re-charge the tube with the unmelted mix, but it will take forever.

Also, Angle your salt pots so that you have a directed blast when moisture does get into the molten salts. It will happen. An added benefit is that longer blades will be easier to insert and withdraw (if you're making a deep salt pot).. The high temp salts are incredibly dangerous and you should take every precaution around them.

Low temp salts are a mix of potassium nitrate and sodium nitrite/nitrate. Low temp salt from Swains will also heat blue, and quite nicely at that--just like nitre blue. The mil. specs. on heat treating salts, low temp and high temp, are online in PDF. I'll try and dig the link out.

Low temp salts work best in horizontal type troughs or in large tubes. They foam and froth and will spill all over if there isn't sufficient surface for the moisture to evaporate. Marquenching a sword into a 4 inch low-temp salt tube was a learning experience to say the least!

Moisture (spiders, sweat, invisible condensation on an un-preheated blade) is the enemy! Remember that and salt pots are a joy to use.

[cramnhoj]

Hi, any luck finding that link for mil specs of heat treating salts? Tried to search for it last night but couldn't find it.

[cramnhoj]

Umm, what happened to the people here, was really waiting for someone to post about the mil spec salts?