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Old 2013-01-24, 6:12pm
Talonst Talonst is offline
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Join Date: Sep 11, 2011
Posts: 152
Default Experimenting with Compressed Air - Test Rig

This picture shows my test rig. This has been replaced by a new build which I'll show later but because of it's layout it's easy to see what's going on. There are also a couple of issues I'll point out along the way

Before continuing, some warnings.
- If this looks alien to you - don't do it. You should be familiar with your torch and have plenty of experience with it before you get into this type of thing.
- Introducing air into your torch creates another set of variables and flame types so there is a learning curve
- The compressed air is introduced into your gas line NOT THE O2 line. Compressed air can contain compressor oils and other foreign matter that won't play nice with oxygen. Remember O2 and petroleum (gas, oil, plastics, rubber) = YOU having a VERY bad day
- All of the air connections use teflon tape for sealing or you can solder them. All the gas fittings DO NOT use teflon tape. Gas fittings seal when the male threaded part bottoms out on the back of the hose nipple or fitting. If a gas fitting leaks when tightened it's bad - dispose of it - don't use tape or sealing compounds
- This probably isn't sanctioned by the torch manufacturers
- Only you are responsible for taking on this project and it's results

So now we can move on, starting on the left is the compressed air quick connect and then an in-line regulator. After the regulator is a ball valve and then a transition section from the 1/4" air fittings to the b fittings on the propane y-connector. Air comes in from the left, propane from the bottom and the resulting mix exits to the right out to the propane port on the torch. All inlets and outlets use quick connects

One thing I did wrong with this was the section of clear hose - that needs to be T-grade welding hose since it can come in contact with the propane gas.

I also discovered that the in-line regulator I used (this one is from Lowes) is really just a needle valve and so the pressure reading fluctuates as you adjust the gas valve on your torch. This makes it hard to know how much air you're running through. I also decided that I should have a water/oil trap to catch any contaminants in the air so as not to clog up the ports on the torch over time. These observations led to the next build

(See next post)
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