[Oilman]

Ok so I'm going to weld up a stainless steel tank for a home built tig cooler. I'm looking at the process and wondering about a few things. I could just put 2 sides, bottom and top and end pieces together to form the box with little overlap at the edges and do a lot of tacks to attempt to minimize distortion. I got to wondering on how to back purge something like this and it seems like it would be problematic with all the cracks and so forth. I expect it would leak argon like a sieve.

Another idea is to overlap all the joints by break bending the sheets. This way with proper clamping might eliminate some of the sugaring, and allow for better back purging.

Or I could just punt the stainless and weld an aluminum tank.

What???

[MosquitoMoto]

Hey there.

I've seen good results using a piece of copper of thick aluminium angle placed against the backside of the weld. This can work nicely provided your fit up is decent. Or you could make a square/rectangular purge box and just place it behind the weld area as you go...



Kym

[Rick_H]

Make it so the seams fit tight, no overlap. tack every 1/2" or so use a small hammer to tap it together when hot slightly. Purge away then weld....

After I get some tacks on if my seam is a little off I will take my grinder and sand the seam so they are nice and flush. Then purge away or I have found some setting that allow me to get about 90% through with out sugaring the backside, not full penetration needed in all cases.

How thick is the material?

[Poland308]

I'm with Rick fit it up nice and purge. If your an Ausey and paranoid about the 300$ an once they charge you for your Argon then you could always use painters tape to seal up the seams. You just peel it back a little at a time as you weld. I only know this works cause I'm a semi parinoid non Ausey who's also a cheap ass.

[exnailpounder]

All great suggestions. I am with everybody else on purging or at least backing up a weld so you don't have to purge. The fun part of purging is having to get creative about it sometimes. If it's worth doing then it's worth doing right. Then again aluminum is fun to weld too.

[MosquitoMoto]

All great suggestions. I am with everybody else on purging or at least backing up a weld so you don't have to purge. The fun part of purging is having to get creative about it sometimes. If it's worth doing then it's worth doing right. Then again aluminum is fun to weld too.

Aluminium is fun to weld, too, but every time I see someone on here discussing an aluminium tank for a cooler, one or two people chime in with talk of a (cathodic>) reaction with aluminium, coolant and torch components that supposedly rots out torches.

One of the most interesting I've seen on these boards is the guy who made his tank from copper.


Kym

[exnailpounder]

All great suggestions. I am with everybody else on purging or at least backing up a weld so you don't have to purge. The fun part of purging is having to get creative about it sometimes. If it's worth doing then it's worth doing right. Then again aluminum is fun to weld too.

Aluminium is fun to weld, too, but every time I see someone on here discussing an aluminium tank for a cooler, one or two people chime in with talk of a (cathodic>) reaction with aluminium, coolant and torch components that supposedly rots out torches.

One of the most interesting I've seen on these boards is the guy who made his tank from copper.


Kym

Welding copper is alot of fun too.

[Oilman]

I'm not really sure of the gauge of the steel. It's somewhere around .060....or at least I have some that thick. It may be as light as .045. I haven't gotten around to grabbing a mic and checking.

I appreciate the tape Idea. That just sounds too easy. I am also a do-it-yourselfer.....Cheap is relative to quality, however, I'm not much convinced that buying one is a guarantee of longevity and if I build it I at least understand what it took, and how it works. I find myself re-designing and or rebuilding equipment because either functionality is poor or quality of components or construction is poor.

I have seen some profound electrolysis/erosion of aluminum in the welding environment. There is something about electrical fields generated around welders that plays hell with aluminum and water combinations. True, our weld water was treated with copper compounds to control biological contamination. Copper will rob aluminum of electrons all day long. This is why I steered away from building the tank out of aluminum.

It sure has been fun relearning to tig aluminum. (why I need the cooler) The air in the shop is considerably less smokey blue the last few weeks. I can actually weld for some time without sticking the tungsten in the puddle.

[Oilman]

Youse guys got me thinking about a copper tank. It immediately comes to mind that a soldered joint copper tank would work work well for a coolant tank....but what potential reactions might there be to the solder. I think most modern solders are a silver/tin mix?

You could always colorize the outside of the tank with some judicious heat application. That would look right cool.

[exnailpounder]

Youse guys got me thinking about a copper tank. It immediately comes to mind that a soldered joint copper tank would work work well for a coolant tank....but what potential reactions might there be to the solder. I think most modern solders are a silver/tin mix?

You could always colorize the outside of the tank with some judicious heat application. That would look right cool.

Soldering is for girls Weld that baby. I have only tigged copper once but it welds suprisingly well, you just have to pour the heat to it to keep a puddle. Very challenging. I wish Jody would do a video about it.

[motox]

well get me a dress
I've soldered miles of copper flashing
and gutters.
not wearing a mini.....
craig

[exnailpounder]

well get me a dress
I've soldered miles of copper flashing
and gutters.
not wearing a mini.....
craig

Never too late there big guy

[entity-unknown]

I'm hoping I didn't read it wrong but I do have to say aluminum should be fine for a cooler since aluminum is what we all use in every radiator for a vehicles. Copper handles water well since that's what we use in our homes excluding PEX which is the "new thing" however copper or stainless steel fittings are still used at the outlets. Why not copper? Price.

When there is corrosion in the water, no metal will stand up to it so this is why you're supposed to use ethylene glycol based coolant, not propylene and always with a mix of distilled water. Also you're not supposed to use automotive coolant (usually propylene) because there are coagulants (hole clotters) which I believe the propylene (thick substance used in many things such as hydraulic fluid, food stuff, sexual lubricants, eCigs) itself assists with. Using ethylene glycol which would be ethyl (alcohol) based would be thinner and be a better inhibitor or nasties since biological growth can occur within propylene but not ethylene. They also use ethylene glycol mostly these days for RVs with the idea that the RV will be stored, vs. driven most of their life. The key thought there is there is no movement, and when any type of water sits without flow (think of water features) bad things happen.

[Poland308]

They are referring to the galvanic corrosion that comes from discimilar metals exposed to the flowing fluid and an induced electrical current.

[motox]

Never too late there big guy

lol

[entity-unknown]

Interesting Josh I did not know about dis-similar metals and it playing a part with electrolysis. And that's why I will probably cruise this forum for the rest of my life since there's always something to learn Thank you again, again, again!

[Oilman]

What Poland said. I am not sure what Hi-freq fields do to dis-similar metals with water flowing through them. There are a lot of factors that I just can't quantify. All I know is that we had a monster problem with severe erosion in aluminum cooling blocks in hi-freq environments with induction welders. We were adding copper (?sulfates) to the weld water coolant system as a biocide. Coolant lines in all the welders were copper. The only metal erosion issues we had were with aluminum components. Ate through 1/2" of aluminum wall thickness in about 2 years. Not good to have water leaking on top of a high voltage SCR in a weld controller cabinet. I got the call to investigate after the electrical engineers were stumped as to the cause after arguing for a few hours. It too all of 2-3 seconds to say, "you guys ever hear of electrolysis?" The copper compounds added to the weld water was probably the main culprit. Most of the other plants who had similar equipment/systems did not use biocides and had to deal with lots of gunk build-up and plugged coolant lines. We on the other hand had to go through and replace all the coolant blocks on a scheduled maintenance schedule.

As much as I will be welding, an aluminum tank might be OK, but I tend to err to the side of caution. Besides I need to learn the "stuff" about stainless welding.

[Poland308]

If your looking for in depth info just google Galvanic corrosion. There are lots of college level papers and studies to explain it in any depth you want.

[maker of things]

If you tack every 1/2 to 1 inch, before welding you shouldn't have too much distortion. As stated, if there are any gaps, just tap them shut with a hammer and you shouldn't be very porous. But, is there a reason you need to back purge? It's not like the backside of the weld will be visible and I assume you are not welding the inside of the tank?