Mig tip has leaks on forge burners

[John bones jones]

My mig tip that’s tapped in to pipe on forge burners has a tiny leak where it screws in. is this safe to use?

[Irondragon Forge ClayWorks]

Depends, pictures will help the burner folks figure it out for you. Did you use propane pipe dope on it?

[John bones jones]

No I used yellow tape for propane. I sprayed soapy water on the part where the mig tip screws into the pipe and it forms very small bubbles indicating a leak.

 

[Mikey98118]

Basically, the gas ends up going the same way, with leaks or not. Some burner designs (like mine) cannot tolerate the slightest leak, and will continuasly back fire; others don't. If the leak is creating a problem, you will not instantly. If not; well, silence is golden

[John bones jones]

Yeah my burners are working great and the leak is very small. So It should be ok safety wise?

Edited March 28, 2021 by Mod30
Excessive quoting

[Mikey98118]

Yes; you don't have a problem.

[John bones jones]

Why do your burners not tolerate leaks? 

Edited March 29, 2021 by Mod30
Excessive quoting

[Mikey98118]

It is true to say it's a matter of flow. It is false to say I actually know why that is.

I knows what I knows, but that's all that I knows

[John bones jones]

Well thanks for all the help. If you don’t mind I had 2 other question. Do you think pipe dope would be better then yellow tape for sealing the mig tip threads? Also what is a good pipe dope people use for forge burners? 

Edited March 29, 2021 by Mod30
Excessive quoting

[Mikey98118]

I think any of the other choices beat the tape. My preferred solution is non-hardening thread sealant; it is simply less trouble and expense than the alternatives.

[John bones jones]

Do you think RectorSeal No. 5 Pipe Thread Sealant Sealant would be good? Or do you have any brand preferences or suggestions?

Edited March 29, 2021 by Mod30
Excessive quoting

[John bones jones]

18 minutes ago, John bones jones said:

 I think I might know why it’s leaking. The pipe I tapped for the mig tip is schedule 40 black pipe. Can you use schedule 40 or should you always go with schedule 80? Because with schedule 80 being thicker you can put more threads in for a better seal.

Am I able to get away with schedule 40 if I can seal the leak or should I go with schedule 80?

[Frosty]

I just responded to your PM so I won't repeat myself.

Whatever you use with propane make SURE  it's rated for use with Propane. Apply it to the male threads and hold back a little from the end so none gets pushed into the flow path.

You asked about whether you should've threaded schd 80 rather than 40 for the mig tips. That depends how did you mount the mig tips, in the END or SIDE of the pipe? If you tapped the ID of the pipe you'd know schd 40 doesn't work the mig tip would wiggle.

However drilling and tapping through the side is probably the origin for the leak. The OD of the pipe is round and the shoulder where the threads end on a mig tip isn't square it's angles to improve electrical contact in the mig torch. Not that I think a leak there is an issue. 

Frosty The Lucky.

[John bones jones]

I tapped it on the side of the pipe. Would it be better to go up to schedule 80 or would it not matter so much?

I see what you mean with the pipe being curved and not being ideal for threads but I was thinking if I go to schedule 80 it might be a better seal? 

[John bones jones]

Here are some photos as well. 

[Mikey98118]

Changing to schedule #80 pipe would help, but upgrading the sealant will help much more.

[John bones jones]

Looking at the pictures would changing the 1/8” x 4” nipples to schedule 80 cause any concerns for how the forge operates? And would it be safe to switch to schedule 80?

Edited March 29, 2021 by Mod30
Excessive quoting

[Mikey98118]

No concerns; yes it's safe.

[John bones jones]

Ok one last question if I keep it schedule 40 and just get a better seal would that be fine and safe as well?

[Mikey98118]

Yes. The reason we suggest that the 1/8" pipe be schedule #80 instead of schedule #40 is that the thicker wall makes MIG tip thread in the end of the pipe match well, making gas tubes more effective and less effort. But those are in axially parallel gas pipe. Not in cross pipes.