Welding Tips and Tricks

Hello everybody,
I am building a 1000 ltr tank which has an unusual shape. there is approximately 26 meters of tig welding. material is 2mm 304 stainless steel.
The problem i have is that there is no access to inside of tank, so i have to purge it if possible, but i have heard that there always has to be flow of argon when purging.
How can I achieve this without going through numerous bottles of argon?

Cheers,

Ben

Welcome, Ben,

As the "new guy", I'll only tease you a bit for posting in the wrong sub-forum, and fix that shortly.

For purging large volumes, use nitrogen. In bulk, it's 10% or less than the cost of argon. I deal with 15K gallon vessels quite often, and when I don't have access to the inside, I purge the vessel to N2 until there is well under 1% O2 present.

Steve S

Argon will fill a void like water. Put a candle in a bucket fill the bucket with argon. The candle will go out and stay out till you pour out the argon. I know some of you may be laughing right now but it's a goon lesson for new people to see. Point is for you fill the tank with argon and start at the bottom you only have to add as much argon as what leaks out. I like to use painters masking tape to cover over open weld joints on large items. You just peal back the tape as you go. Then you minimize how much you have to use.

Poland308 wrote: I like to use painters masking tape to cover over open weld joints on large items. You just peal back the tape as you go. Then you minimize how much you have to use.

Ooh this is a good tip...thanks!

I'm about to weld up a stainless motorcycle muffler and while the fit up is pretty neat, my concern has been that the thing will leak purge gas constantly and waste a heap of gas as I weld.

Tell me, does aluminium tape have any benefits in uses like this?


Kym

I use painters tape cause it's cheap and the glue doesn't leave a film.

MosquitoMoto wrote:

Poland308 wrote: I like to use painters masking tape to cover over open weld joints on large items. You just peal back the tape as you go. Then you minimize how much you have to use.

Ooh this is a good tip...thanks!

I'm about to weld up a stainless motorcycle muffler and while the fit up is pretty neat, my concern has been that the thing will leak purge gas constantly and waste a heap of gas as I weld.

Tell me, does aluminium tape have any benefits in uses like this?

Kym

I believe it will stand up to a little more heat, not a lot though. It may also leave a residue, however for a muffler it may not be a concern. Suggest trying on a test piece first. Not sure what you have is the same as I, but it probably is...

Okay, we apparently don't agree on the definition of "bigger volumes".

With the volumes I work with, I don't consider any exhaust system you can imagine to be a "bigger volume".

That said, nitrogen is a dandy pack-purge for exhaust work, and dirt-cheap by comparison.

However, the OP has yet to comment back, so I don't yet know his intended use.

Steve S

Yeah, my apologies Steve, I totally thread jacked that one.

Just got a bit too excited about that tip regarding the painter's tape.


Kym

Hi everybody, thank you for your suggestions!
I have a couple more questions.
What gas flow rate in L/min would be the one to use for a 100 liter tank when filling and then while welding?
And if I don't want to invest in a purge meter, is there another safe way to calculate for how long I have to fill before starting welding?
Many thanks in advance

Ben