Adding Argon to a paragon kiln ?

[SVanderkolff]

Ray
We were told you were the man to ask about adding argon to a paragon kiln. What is your advice. I am not sure what all I need to buy and how to hook it up and even whether it is worth doing. I am getting really tired of using the foil and have a bit of excess cash so figured this was a good project.
Thanks
Steve

[Ray Rogers]

You need a flow meter that will be mounted on the side of the oven and a gauge rated for argon that will be on the argon tank. The gauge looks like the ones you see on acetylene tanks.

The flow meter is mostly a glass tube with a steel ball in it. Gas flowing through the tube raises the ball to some height to show how many cubic feet of gas are moving per unit of time. There is a fitting on the flow meter for a hose from the argon tank (input) and another fitting for a copper line (output). Run the copper line to the rear of the oven and stick it in a hole that you drill in the casing. You don't need to drill through the brick, just through the metal. The gas will find its way.

The flow meter also has a solenoid on it. This solenoid can be wired into the oven's controller so that it feeds gas whenever the heating element is on. If you don't feel comfortable making that connection you can use a different power source to simply hold the flow meter open all the time and adjust your flow accordingly.

As for whether or not its worth doing that's up to the individual. Its the only way I've ever done it so I don't have a broad perspective on that subject. It works for me because I have a surface grinder and the fine powdery scale left by the argon is easily removed when I surface my profiled blade (I grind post HT).

You need to be able to ventilate the room very well. Argon is not poisonous but it does displace oxygen (that's the point of using it) and it will displace it in your lungs if you let it. But, even as poor as I am I find argon affordable and easy to get and effective enough for my needs ...

[SVanderkolff]

Ray
Thanks for the help. Is the flow meter that Paragon sells the one that I need or is there a better source? This sounds like the way I want to go but being the totally non mechanical type I need to make sure I fully understand what I am doing ahead of time. If I am inserting the copper line through a hole in the casing of the kiln, what stops the copper line from melting when the kiln is hot? DO you know if the flow meter comes with instructions on hooking it up to the controller?
Thanks Again
Steve

[Ray Rogers]

If Paragon sells one, that one will surely work. If you were the mechanical type then I would say you'd probably find a cheaper one on eBay but a meter from Paragon would surely be a safer choice. As for instructions on how to connect the meter, you'd have to ask Paragon - it seems reasonable that they would provide some instruction but I ordered my oven with that feature already installed. And, as I said earlier, if you can't make the connection then just stick a power supply on the solenoid to force it to stay open and set your flow rate a little lower to compensate for that.

The copper doesn't melt because it doesn't go into the interior of the oven. Don't drill through the brick, only poke a hole in the thin metal shell of the oven. The gas will flow around and between the bricks and get to the interior. It will also leak out through the seams in the metal case and through the door but that will happen any time you squirt gas into a box that isn't air tight. You will want to seal the joint where the copper tube passes through the metal wall to make sure that all of the gas goes through the oven body before it leaks out again....

[SVanderkolff]

I talked t our local gas supplier and he can get me a 55 cf tank for $250 and he has a flow meter that attaches to the top of the tank. Will a tank top flow meter work or do you need some sort of separate unit? Is there some reason that the hole to insert the gas needs to be on the back wall. I would think that through the top or side would work easier?
BTW thanks for all the help.
Steve

[Ray Rogers]

That's a lot higher than I paid for my tanks but that was 20 years ago. You should be able to rent the tanks very cheaply.

I never saw a flow meter that would mount to the tank and I'm doubtful that's what he has (of course, I have been wrong before). There is a gauge that mounts to the top of the tank similar to the gauges on an acetylene rig. That gauge reduces the 4000 psi pressure in the tank down to a manageable 30 psi or so that you would want to feed into the flow meter. The flow meter - which mounts on the oven - will manage that 30 psi but sending it into the oven at the rate you set the meter for (I use about 7 cu ft/hr) whenever power is applied to the solenoid by the controller on your oven.

As for the location, I said back because that's where Paragon put mine. Putting it through the top would be a bad idea since the top is the part that must be removed when the heating coil needs replacing.....

[SVanderkolff]

Here you go Ray. A flow meter attached to the top of the tank. I got it all hooked up today but first run says I need to increase my flow. I had it at roughly 5 cubic feet per hour. I will try 10 next time and then see which way to go. The tank I have is a 55 cubic foot tank. Does that mean I am only going to get about 10 heat treats per tank?

[Ray Rogers]

Cool, nifty arrangement. That method doesn't allow the oven's controller to meter the gas but I don't think that's a big deal.

At 10 cu ft per hour I would think that you'd get about 5 hours of gas feed from that tank. How many heat treats that is will depend on the times required to reach temp for whatever steels you're using ...

[SVanderkolff]

Ray
Back again with this thread. What do your blades look like when they come out of the oven when you use the argon. Mine are coming out very black. It is not hard to remove but also not what I expected. Can you attach a couple of pictures please.
Thanks
Steve

[Ray Rogers]

Pictures not necessary as mine look just like yours. Soft black covering easy to remove, shallow with no significant pitting. Since I grind after HT its no issue for me ....