backpurging how do you set it up?

[Lunar240z]

I want to make my own turbo header eventually and i' a bit curious as how to set up backpurging with a tig machine. anybody have any pics of their set ups?

[OlderThanMe]

well if you want to make a lot of stuff that requires back purgeing:

www.weldhugger.com

 

or since you are doing a header and want to di it cheaper...block off one end of the tube you are welding on and on the other end block it off but put the tube from your flowmeter through the block off. You will need a second argon tank, flowmeter, and tube to backpurge sucessfully.

I had a friend that made a "orange juice container" *cough* out of stainless and just stuck a second tube in there and blocked the rest off to keep it safe to drink out of

[johnc]

You will need a second argon tank, flowmeter, and tube to backpurge sucessfully.

 

Naaahhhh...

 

1. Put a "Y" after the regulator and turn it up to about 30cfh.

2. Use a gas lens on the torch to reduce any turbulence.

3. Seal each end of the tube with bronze wool and insert the purge hose.

4. Purge the tube for about 5 minutes and remember that Argon is heavier then air. Keep that in mind when positioning the tube.

5. After welding in one position, reposition and let the purge run for a couple minutes before welding again.

 

Or:

 

http://www.solarflux.com/

 

Wonderful stuff.

[OlderThanMe]

I was thiking about that but I have never seen a "Y" for a gas line. good idea and then crank up the flowmeter while purging.

[Z-TARD]

As John said, argon is heavier than air so you want to start the purge from the lowest portion of whatever you are welding, and vent it out of the uppermost portion. I normally just stick the end of the purge hose into the part I'm welding and seal the opening around it with duct tape. It works pretty well, but be prepared to clean off some sticky gunk if the taped area gets hot. For the purge outlet, I again use duct tape, this time with a hole cut out of it that is at least as large as the ID of the purge hose. Anything smaller could cause backpressure which could blow out your weld, or create lots of porosity. Along with the Y fitting on the gas line, I also use a small inline ball valve fitting to throttle the flow. For a good purge you should have just enough flow through the workpiece that you can barely feel it on your wrist when you hold it over the purge outlet, probably only around 3 to 5 CFH.

[Lunar240z]

JohnC, How do you set up the tee? would a welding supply store have a fitting for that? or would it go on the soft line?

i'll pick up some of that solar flux and try that out too.

[johnc]

Just go to Home Depot and find the barbed hose fitting plumbing. You should be able to find a brass "Y" fitting or you can use a "T". I just took my regulator down there and found a "Y" that fit the outlet. Then I added two valves off the "Y" so I can shut off and/or regulate the flow to each hose.