Watertight welding

Date 04-23-2007 22:38

Can't help too much as far as what to change on welding, but to find and repair leaks before water is put in it, do a liquid penetrant test. This should find any possible problem areas.

By LandM Rad (*)

Date 04-24-2007 02:12

Would it be better to use an Argon/CO2 mix due to the fact that the bead will wet out with no need of oscolation? That way a 1/4 stringer fillet weld would not need any manipulation and, in turn, would be easier to watch the puddle fuse the joint pieces

By new tito (***)

Date 04-24-2007 15:26

It would definately help if you detailed exactly what you are building; i.e. - product, thickness, material type, etc.

Just by your short description, im assuming some box type (cube) product, that is made from thin material. It seem sensible considering you are talking about "corners" and in between weld ripples. As mentioned, it does sound like a technique issue. Corners can be a toublesome spot for many welders. As far as in between the ripples, is this where possibly the welder started and stopped his beads? Lack of penetration or lack of fusion, maybe?

If you are having problems with leaks, why not try to implement an inspection plan prior to the testing?

By 803056

Date 04-24-2007 03:55

Hello LandM Rad;

You didn't say how thick the metal is, so I will assume it is thick enough to consider using the spray mode of transfer. Switch to an argon rich (80% or more) and CO2 mixed shielding gas. Increase the voltage and wire feed to develop a nice spray. It's hot, deep penetrating, and the argon carbon dioxide mix should perform nicely without weaving (oscillating) the weld bead.

If the material is too thin for spray mode transfer, consider buying a machine with pulsing capability. They are expensive, but less costly than making repairs in the long run.

Good luck.

By js55

Date 04-24-2007 14:46

You didn't say what your weld joint is.
I don't see anything inherent in CO2 gas, or any particular transfer, that would cause leaks. In fact, the broader penetration pattern of CO2 will help ensure a wide fusion. Tons of pipe joints are welded everyday using 100% CO2. Ask the Japanese, where argon is prohibitively expensive. They are the kings of CO2. And smooth stringers on pipe circumferentials are very possible.
Leaks are almost exclusively a technique problem. Make sure your welding parameters are in balance.
Since you're hydroing I'm assuming its a pressure pipe application. If its sockets try more than one pass. At least until your welders achieve a little higher level of competence.

By LandM Rad (*)

Date 04-25-2007 00:44 Edited 04-25-2007 00:47

Most of our watertight welding is done on 1/8 inch-5/16 inch mild steel material. Most of the jobs are either radiator tanks or welding 10 ga. tubing to the tanks or welding ends onto the tanks. Most, if not all, the leaks happen at the corners of the radiator tank. These are also the radiators for industrial equipment from Hitachi to Komatsu, Caterpillar to Metro Transit, etc.

By Sourdough (****)

Date 04-26-2007 15:25

Turn your heat up, and your wire speed down. Move out of your puddle enough to keep from burning through, but cherry hot in your puddle.

Works for me.

By LandM Rad (*)

Date 04-27-2007 00:41

Do you "grind back" your welds when you start and stop?

By Milton Gravitt (***)

Date 04-30-2007 14:12

It wouldn't hurt to grind your start and stops and use a 75/25 argon and co2 mixture for welding gas and go to a smaller wire like .023, but when you start welding don't start on the stop drop down and start your puddle and go back up sometimes this works for me.