Fabrication questions. EXPERIENCED Welders Step in

[Gamble97]

I'm looking to make myself an 02housing/downpipe

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I have a lincoln 140hd (115v) mig welder and this 120* pipe is stainless. I also bought a 3" stainless vband flange. Should I go with a 98% argon/2%oxygen mix of gas?
What size stainless wire?

And I keep finding different answers on the web. Do you or do you not setup back purging for MIG? Do I need a second tank for back purging or should I just use solar flux?
Looking to do this the most inexpensive way possible with gas, back purging, wire etc.

 

[Imback]

When you weld SS with mig you use a tri mix. As for wire you can use .035. Since that's the 02 housing/Downpipe it is not necessary for back purging. You can use solar flux if you want but it's not needed. I've made a few o2 housings as well as exhaust systems with out back purging and there holding up just fine.

Also the wire i mentioned is SS wire of course.

 

[KT_McHan]

^^^+100


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[rollover-tsi]

When you weld SS with mig you use a tri mix. As for wire you can use .035. Since that's the 02 housing/Downpipe it is not necessary for back purging. You can use solar flux if you want but it's not needed. I've made a few o2 housings as well as exhaust systems with out back purging and there holding up just fine.

Also the wire i mentioned is SS wire of course.

+1,000 couldn't have said it better

 

[Gamble97]

When you weld SS with mig you use a tri mix. As for wire you can use .035. Since that's the 02 housing/Downpipe it is not necessary for back purging. You can use solar flux if you want but it's not needed. I've made a few o2 housings as well as exhaust systems with out back purging and there holding up just fine.

Also the wire i mentioned is SS wire of course.

Why does it matter if it's an 02 housing or not for back purging?
Also I heard the tri mix is really expensive and the 98/2 is the way to go. Why is tri mix better?
I use .030 wire currently and I was wondering if I should step up to larger wire or not that is what I was wondering. Thank you for that, I'll have to make sure i Have the rollers for .035.

 

[phatTSi]

I've honestly never heard of anyone backpurging when MIG welding. As stated when welding SS I've always used a tri mix and .035 308ss wire

 

[ontario AWD]

The most inexpensive way would be to just weld it with the steel wire thats on your machine.If you want to get the stainless wire for your machine go .30 beacause i don't think your little guy is designed for bigger.At work we also use the 98/2 mix for stainless.

 

[Gamble97]

I'll price out the trimix and the 98/2 mix and see what the local place can do for me.

Can you weld satin steel? Or is there prep work that needs to be done?

And this is a dump question, but I was walking around home depot and saw some chrome plated brass in the plumbing section. Would that work for a dump tube you think?

 

[BeatupVR4]

I have only TIG'd but make sure everything is CLEAN CLEAN CLEAN!

 

[KT_McHan]

Make sure no carbon contamination...
Wire brush b4 every weld...
If u cant weld a seem in one pass..run into your welds...make one weld end where others start...that way u dont have a cold lap...

Thats for mig...

Ive been on govt fuel/water tank project for the last 4 years...200ft of weld per tank..mig outside...tig inside...plus tig couplings ...6 tank per week...plus all associated pipes...

I got a little exp

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[bigjdog84]

Tri mix will work just fine for this. 98/2 would work fine as well. I would suggest practicing on scrap tubing and doing some fillet welds on tubing to steel plate.

I wouldn't back purge it. Be sure to bolt your V-band to the exhaust housing and clamp it down while welding it--they will warp a bit if you sit on it too long with the mig.

Be sure to keep in mind your t-case clearance also.

Practice, practice, practice, or you will not be happy with the results and will be kicking yourself in the end for not bringing it to a fabricator.

Tri mix is not expensive.

.035 wire would work just fine for this. Thinner wire will work well for the tubing as thicker wire will want to push through the tubing if you do not move quickly. I would suggest pulling your puddle on the tubing--anyone who says you must push on a mig is misinformed (to put it gently)


KT, he's not doing piping... But yes, make sure the tubing is prepped properly. Remove all burrs, wire brush/flap wheel it whatever you find to work well. Use some acetone to make sure all oil is cleaned off the pipe. Do not use brake cleaner or carb cleaner--it's toxic.

Good luck.

 

[bastarddsm]

I'll price out the trimix and the 98/2 mix and see what the local place can do for me.

Can you weld satin steel? Or is there prep work that needs to be done?

And this is a dump question, but I was walking around home depot and saw some chrome plated brass in the plumbing section. Would that work for a dump tube you think?

No brass will not work.

Also, weld in little stitches. apart from each other to keep the heat down in any one area.

Like zzzzzt move zzzzzt move zzzzzt move....ect.