welding ports in pressurized storage tank

wrightk20 said:

I'm looking at rounding up some propane tanks to use as storage and a buffer. I'm looking to buy a welder that is capable of welding ports in the tanks without them leaking. I'm just wondering what any of you have used as far as the welding process required for asme grade welding. I would like to buy a good sized mig welder. I have heard that dual shield welding can be used. Maybe the same as intershield welding? Also where would i go to get the ports to weld into the tanks? Kevin

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Most of my welding I did with stick welder with e-7018 rod and nse black pipe fittings NOT cast iron type but steel fittings. A mig welder would be ok too, with argon gas and right size wire would be ok.
Clean tanks out good run air into them also,,

Try mscdirect.com for one easy source. I used some of their "class 3000 forged steel threaded pipe fittings" (extra thick wall makes easier welding). Also their "standard heavy flanges" (female fittings with weld flange).
Using a coupling rather than a flange fitting allows you to cut one end at an angle to you can let the water enter the tank horizontally at any point on the tank's curved surface. May help reduce mixing in the tank.

most any size welder is capable of welding bungs into a tank with the proper prep work and welding practice. i wouldn't use shielded wire unless it was an emergency repair to get me home. im just not a fan of it especially when your making a leak proof weld. just my two cents.i believe "GRAINGER" sells weld in bungs as well

As stated above, make sure you don't get cast fittings. Aside from that, regular black iron fittings will do - but some places seem to mix cast with iron in their parts bins. That happened to me and I had to get my welder to make a house call to me to fix a couple leaks.

I'm pretty sure he just used a stick welder - he did for sure when he was here doing the fix up. It was just a little thing that plugged into a 110 outlet, and I think he used 7018 rods as mentioned above. So you don't need anything fancy.

I think if it was a buy just for welding some tank fittings in, I'd just get someone else to do it for way less that the cost of a new welder. If you'd be buying for other things - well, it likely won't matter much what we say - just buy it.

I got weld-o-lets from McMaster-Carr. I have had bad luck welding waterproof in the past. So I had a local welder do four ports for my tank. It was less than an hour work. They used a plasma cutter to make holes and wire feed gas shielded 7018 equivalent wire. I was happy, and I'm pretty good at welding, other than waterproof and pressure.
If you don't weld, waterproof welding is not a good place to start. If you do weld and are comfortable with your skills, most any welder will be OK, amps depending. I'm sure everyone has bought nifty tools to get the project done.

Best place to buy weld-in tank flanges is Burdens Surplus Center that I've seen. Most of the common sizes are $2 to $3. They are a hobbyists' dream catalog.

lotawood said:

If you don't weld, waterproof welding is not a good place to start.

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I second this. I'm fine for working on my farm equipment. I had a pro do it.. even at that it took him several tries to fix a weep using top of the line equipment.

JP

700renegade said:

Best place to buy weld-in tank flanges is Burdens Surplus Center that I've seen. Most of the common sizes are $2 to $3. They are a hobbyists' dream catalog.

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The problem is the fittings you reference I believe are not rated for pressure tanks. They are for hydraulic reservoirs. #3000 class fittings are the way to go and they are not that cheap.