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View Full Version : Quick and dirty (and cheap) heat treat oven?



adatesman
12-24-2010, 09:54 AM
Howdy All,

I don't suppose anyone has thoughts on a quick and dirty (and cheap) way to build a heat treat oven? I've got a couple small parts made from 17-4PH stainless (~7/8" dia x 4" long) that I need to bring to ~H900 condition, which means heat soak at 1900 +/- 15 deg F for an hour and then air cool. This is most likely a one-off, so I'd rather go quick, cheap and close enough rather than putting much (any) money into this (e.g.- I have a nice thermocouple, so some stainless wrap followed by babysitting it on the burner from the turkey fryer is fine with me).

Thoughts?

-aric.

Toolguy
12-24-2010, 11:42 AM
See if you can find someone that does pottery. The kiln for that works good. I bought a small one at an auction for $50. That's what I use for tool steels.
Some day I will get a computer controlled heat treat furnace, but for now, the kiln gets the job done.

Liger Zero
12-24-2010, 12:10 PM
I have a friend at a local heat-treating company. I heat-treated exactly one item through him. All the other "side jobs" he does are for friends who need something done.

Check the yellow-pages, see if there is a shop around. Often times shops are willing to do a small item or two during startups or shutdowns for free.

Weston Bye
12-24-2010, 01:52 PM
I had to harden an O-1 punch for a staking process.

I purchased a dozen firebricks from the local masonry yard. About $20. Stacked them together into a box and fired with a propane torch through a notch cut with a tile saw. A thermocouple in another notch verified the temperature.

the box was held together with a couple of very long SS hose clamps.

The propane torch had no trouble bringing up the part to temperature in the little box and holding it there for an hour. After quenching, I was able to draw the temper back down to the desired hardness in the box with a lower flame and careful monitoring of the thremocouple.

Tait
12-24-2010, 02:58 PM
If you want to pay shipping to and from So Cal, I'd be willing to throw them in my heat treat oven. PM if you're interested.

SGW
12-24-2010, 03:43 PM
To expand a bit on what Liger Zero said:

A friend of mine once asked about getting a small part done at a local heat-treating place. They told him that as long as he didn't want it in a hurry and could wait until they had a batch of something that required the same heat treatment going through, they would do it quite cheaply for him.

adatesman
12-26-2010, 03:07 PM
Sorry for the delayed thanks, Guys (holiday got in the way of my Internet addiction... :eek: ). Your help is very, very much appreciated.

And thanks to Tait; that's a very generous offer and I may take you up on it if I end up not being able to sneak the firebrick into the house (wife thinks I have too many toys as it is...) :confused: :D

-aric.

vincemulhollon
12-27-2010, 02:17 PM
+/- 15 deg F for an hour ... some stainless wrap followed by babysitting it on the burner from the turkey fryer is fine with me

Those two things are not going to go together. You'll get at best +/- 100 out of that plan, and its not going to be uniform which means some exciting warping. Which may none the less be good enough, or maybe not.

Tait
12-27-2010, 07:23 PM
"Those two things are not going to go together. You'll get at best +/- 100 out of that plan, and its not going to be uniform which means some exciting warping. Which may none the less be good enough, or maybe not."

My concerns exactly - you don't want to do all the work, then lost it because of bad heat treating.