Table Top Kiln for Heat Treating Simple Steels?

Great video IT. Is there any way if you get time you could draw up a schematic? That would be damn near sticky worthy if you did.
Would this work for a propane forge as well?
 
all the controller can do is turn a relay on or off, unless you want to get into a 4-20ma analog output to drive a motor(how we regulated steam flow to keep drying room at constant heat and humidity) not sure how you could incorporate that in a gas forge
 
Scott - As far as running a forge, wouldn't you just need to wire it to a solenoid valve to regulate the propane input?
 
weo said:
Scott - As far as running a forge, wouldn't you just need to wire it to a solenoid valve to regulate the propane input?
Click to expand...
sure, it shuts off the gas. but unless you have an igniter of some sort or a pilot light, what happens when the temperature goes down and the valve opens? are you sure it will re-light 100% of the time?
 
scott.livesey said:
sure, it shuts off the gas. but unless you have an igniter of some sort or a pilot light, what happens when the temperature goes down and the valve opens? are you sure it will re-light 100% of the time?
Click to expand...

Scott, a smith I know has this set-up for forge welding and it works fine. I've done a similar thing at below forge welding temps when I've shut off the gas, thinking I was finished for the day, then realizing I forgot something and turned the gas back on and it's fired right up, and I was below welding temps. I always have the blower on before the gas (which is how the forge should be lit anyway).

Years ago, when I first started blacksmithing, I did this, but I turned the gas on with the blower off, and as I walked around the forge to turn it back on the gas did build up in the ribbon burner before igniting and the forge lit with a loud POP and although there was no significant damage, it did scare the heck out of me. If I remember correctly, the forge was in the red-ish heat range or dull orange at the highest, but that was quite a number of years ago.
 
This setup you saw in the video actually started its life as a forge controller. I have tweaked how it was configured a handful of times over many many years. Once I built my oven I moved it to the quench tank and removed the forge control part. I will do another video explaining what I have found to be the best configuration. But in a nut shell yes you wire a red hat solonoide valve to the SSR. My first configuration had the blower also connected to the SSR and a speed controller. I know a few other knife makers that run a system like this. I found I did not like how it preforumed and started tweaking it. Basically I ended up with the blower hard wired to the speed controller. Then the solonoide connected to the SSR. The gas coming in would split at a T befor the solonoide and one line would go through the solonoide and the other would bypass it. Then both these lines would run into 2 separate needle valves. I would then come out of the valves and go into another T and into the main line to the burner.

What I found was the on and off of the blower was not long enough for the fan to slow enough and the pulsing power was causing it to heat up more then normal. Also when the fan would slow down it would take a sec or two to come up to speed but the gas was already on. This would create a large wosh out of the forge. So I ran the blower at the set speed all the time and just pulse the gas on and off. The forge is plenty hot to re ignite the gas. You use the main needle valve that's connected to the solonoide to set the high burn when the SSR is on. Then the other needle valve to set the idle. I adjust the idle valve just enough to keep the flame burning but under my set temp. So what happens is the solonoide switches the forge burner from hi to low and the blower just stays running. You can do away with the idle part of the gas and it still works fine. but depending on the temp your at it might not be a smooth on/off/on transition and you will get pops as it lights back up.
 
using a furnace, gas or electric, to heat treat high carbon steel, you need it to get to 1500F and hold. unless you are heat treating thick stock, say 3/16" or more, the blades are going to be inside for 10 to 15 minutes. what is the controller going to do that you can't with a simple adjust of the gas valve or the electric power control? for the simple kiln shown that started the thread, the first thing I did was get a good digital display and monitor the temperature. I found after setting power control to max and getting the heat to 1500F, putting blade in, temp down now to 1450F, start timing, temp close to 1500F, power control to 4, steady at 1500F, 10 minutes is done, blade out and quench.
 
You must log in or register to reply here.
Back
Top