When tig welding certain alloys such as stainless, 9 chrome, inconel etc.. you will need to purge your pipe with argon before attempting to put a root in. This can be done very easy on a weld test or fabricating pipe on jack stands. Situations will arise that will be very difficult to achieve a good purge such as tie ends, tube welding and other field welds you will some time not have the full control over. I will discuss a few simple steps to get a good purge below. Example given is for a 6″ pipe.
- First step would be to use masking tape to seal up all holes
- After the pipe is sealed with masking tape you will need to poke some weep holes in one end. Simply use some 1/8 wire and poke 4 or 5 holes in the tape. This will allow the argon to push the oxygen out and over take the pipe.
- You will need to make sure you have a diffuser on the end of your argon hose. You can use a gas lens or some steel wool and tape one of them to your argon hose. I have seen welders try to purge with a open ended argon hose. This does not work to well.
- After you insert the diffuser in the pipe and tape back up you are ready to set your flow meter. Crank it up high for a minute or longer. If you have a bigger volume of pipe you can leave it on longer. After initial flush you can turn it down. On a 6″ pipe 10′ft long i would set it around 20-30 on your flow meter. You can check it with a cigarette lighter. Pull a few inches of tape back from the bevel and engage the lighter and put the flame in the gap. If it goes out usually your purge is good enough. You do need to make sure that the pressure of the argon is not blowing out the flame.
- Stay tuned for a video on this subject
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