High temperature SAND?

Sam Salvati

Sam Salvati

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Aug 6, 2007
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Any problem with bringing plain old sand box sand up to 1550F? What temperature does sand go and turn into glass? A customer of mine who used to be a diemaker had mentioned they had used sand when heat treating punches and stuff to get a more even heat. Thanks!
 
quartz would be fine, over 3000 degrees, calcium carbonate would melt right around that 1550
 
I always thought sand was used for doing differential tempering.

You can bury a blade edge down in the sand for the fancy high performance knives that are ductile and hard as glass at the same time :D That is what were supposed to be making , right.

Kidding. It can be used as a thermally stable medium and as a diff tempering medium, depending on how you use it.
 
The sand used for doing sand casting will take the temps you need.You can get it dry from some companies which is what you will want as if you buy the canned stuff it has oil in it and works almost like a clay.

Bruce
 
They also used sand as a tempering medium. Put the box of sand on the forge and heat it up. After quenching the blade but it into the hot sand. Blacksmiths oven...

Chuck
 
I guess i should've tagged this post onto the "heat treating forge/furnace" thread. Thinking about using sand as a way to even out the temperature in the tube in a tube design for hardening temperature 1550F.
 
Mark Williams said:
I always thought sand was used for doing differential tempering.

You can bury a blade edge down in the sand for the fancy high performance knives that are ductile and hard as glass at the same time :D That is what were supposed to be making , right.
Click to expand...

And people have always been telling me to "pound sand"
Would that be . . . sand-vik steel? :D

-Page
 
I wonder how much less efficient silica or some other high temp tolerant solid would be compared to the salts in a saltbath type furnace ?
 
I would imagine that it would take a lot longer to even out, as there is no convection in powdered packed solids and since the sand is solid any deflection encountered in the process of removing the blade would bend the blade, for the equivalent of the low temp salt trying to push a red-hot blade into sand would probably warp the blade more than the mythical "plunge into the body of XXX" of legend, and once the layer immediately in contact with the blade had absorbed heat it would act as an insulator, since there is no convection to provide fresh quenchant

Just my impression

-Page
 
I really do not think they used sand for the high temp heating. All the old books i have only refer to it being used as a tempering medium. As the term tempering has been Misused in the past it has been used to describe the hardening process. I think this may have been the case as the old-timer remembers someone tempering with sand and he thinks they used it to harden the tools.

Chuck
 
I would say Page you are right it would take a little longer to come up to heat and even out. DEFINATELY not for low temp salt-style applications, but it might work for the higher temp for hardening. I don't think you would meet much resisitance pulling the blade from the hot sand but definately if you tried to quench into sand there would be problems. Over the next couple days i think i will throw together a small size version as a prototype, with the JTH7.
 
Sam Salvati said:
Any problem with bringing plain old sand box sand up to 1550F? What temperature does sand go and turn into glass? A customer of mine who used to be a diemaker had mentioned they had used sand when heat treating punches and stuff to get a more even heat. Thanks!
Click to expand...

I have what they call green casting sand and as it drys out in use you add good ole 30 weight oil to it to bring it back..
but I'm thinking it has to be a white sand and very very sand dry before the oil is added.. if not the steam may cause you problem,, I buy mine... :) but I use mine to cast with
 
Sam Salvati said:
I would say Page you are right it would take a little longer to come up to heat and even out. DEFINATELY not for low temp salt-style applications, but it might work for the higher temp for hardening. I don't think you would meet much resisitance pulling the blade from the hot sand but definately if you tried to quench into sand there would be problems. Over the next couple days i think i will throw together a small size version as a prototype, with the JTH7.
Click to expand...

Sam, what will be interesting is if you have a thermocouple measuring different spots as it heats to see how evenly it comes up to temperature, and how fast, then when you take away the heat source how it holds temp.
My concern in withdrawing the blade from the sand is that there is likely to be some deflection from your tongs that would bend the blade against the sand resistance. I am very interested in your results, after all there is no proof without experimentation.

-Page
 
sunshadow said:
Sam, what will be interesting is if you have a thermocouple measuring different spots as it heats to see how evenly it comes up to temperature, and how fast, then when you take away the heat source how it holds temp.
My concern in withdrawing the blade from the sand is that there is likely to be some deflection from your tongs that would bend the blade against the sand resistance. I am very interested in your results, after all there is no proof without experimentation.

-Page
Click to expand...

Yeah the thermocouple will have to have a few spots to make sure it runs evenly. I will be building a small prototype in knife size within the next couple weeks, as soon as i can get the refractory for the furnace tube, i have everything else(picked up the sand today). I'll test for sand tube size, depth and how fast it heats up and holds temperature, and how even it is. You wouldn't happen to have a thermocouple i could borrow would you Page?
 
Thanks that would be awesome, i'll let you know when i am ready, working on a no money budget sucks sometimes.....another good reason for an AMPLE scrap pile.
 
Sam Salvati said:
Thanks that would be awesome, i'll let you know when i am ready, working on a no money budget sucks sometimes.....another good reason for an AMPLE scrap pile.
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You're not saying anything I haven't been experiencing! No money budget sucks all the time! It's taken me 20 years to build up my tooling to what I've got. Fortunately I married someone who is cool with what I do (most chicks see the shop as competing for time and attention, and a waste of time and money. As for the money thing, once I showed my wife that there was no tool purchase that had not paid for itself at least twofold, if I can pay for a tool she doesn't ever bitch about the money spent)

Keep the fire lit!

-Page
 
You can get silicon carbide powder in a number of grits, course to fine. The course grits have a sandy texture. They sell it in lapidary supply shops as tumbling charges.
 
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