A drilled hole, what cleaner to use to weld it.

[Mr Fixit]

Hi Group,

I have this project that I want to put a spacer between the sides of a 2x3" tube so it does not crush when a bolt is put through it. I drilled the holes and wiped it down to remove the oil but when I weld it I get contamination craters so I'm not clean enough I'm guessing.. I am MIG welding with 75-25% gas and all settings are fine per other welding on the same material.

So, what do you use to pre-clean a weld spot that has been machined, drilled, or sawn, that has cutting fluid residue left behind...

PS. I tried brake cleaner and it improved but still few craters. Do I need to grind it all out 100%?

TX
Mr fixit for the family
Chris

[ImFred]

Heat it red with a torch.

[flathead4]

I have good luck with acetone.

[oxford]

Acetone. Also clean the mill scale off the tube and get the inside of the tube as clean as you can, it’s usually as dirty as the outside.

[The Metal Butcher]

I welded some oily stuff, and many more have welded far grosser (leaking transmissions for example.) I don't think that's your issue. If it is, drill without oil.

[BCRider]

I believe that it's most forms of brake cleaner that you want to keep away from welding. At least be sure it's totally dry. Something about when heated that the brake cleaner gives off fumes that are very toxic.

Or is that for the old styles of brake cleaner? All the reading I've done where solvents to degrease before welding are mentioned warn of this and say to use acetone instead.

[Joel]

I usually just clean with carb cleaner, but it seems less likely that this is the problem (assuming the metal is otherwise 'clean').
Check/verify good gas flow. Perhaps it was windy, or the other welds were in corner joints? Just guessing here.

[oxford]

I believe that it's most forms of brake cleaner that you want to keep away from welding. At least be sure it's totally dry. Something about when heated that the brake cleaner gives off fumes that are very toxic.

Or is that for the old styles of brake cleaner? All the reading I've done where solvents to degrease before welding are mentioned warn of this and say to use acetone instead.

Chlorinated brake clean is bad news for welding. It’s fine if it is completely dry but it can get into crevices and stay wet where you don’t see it. Heat from welding turns it into phosgene gas iirc. It will kill you and it doesn’t take much.

[Jim Stewart]

Chlorinated brake clean is bad news for welding. It’s fine if it is completely dry but it can get into crevices and stay wet where you don’t see it. Heat from welding turns it into phosgene gas iirc. It will kill you and it doesn’t take much.

I once used it when my sandblaster was down. Wiped it down thoroughly and let it dry for at least five minutes. Didn't matter.

When I started the arc I was suddenly overcome by fumes - yes, phosgene. Staggered out of the shop nearly puking. Nasty stuff.

-js

[Doozer]

I have had a BAD bottle of argon before,
right from the welding supply. I got a new
bottle and all was fine. I swear it was just
compressed air they gave me, or nitrogen
by mistake.

-D

[darryl]

I used to think brake clean was the cats meow. Not so much anymore. Lacquer thinner works better for the cleaning I do, and it doesn't seem to affect paint adhesion like brake cleaner sometimes does.

[SLK001]

You can't weld a hole - there's nothing there!

[Superbowl]

Can you stick weld it? That usually works even with very dirty stuff.

[Willy]

Have you tried cleaning the mill scale off of the joint with an aggressive wire wheel or a flap disc?
Cleaning to a white shiny surface is a prerequisite for tig of course but it's always amazing to see the improvement it makes when mig welding.

Acetone is my standard for cleaning the surface of anything I suspect of being contaminated with oil or grease.
Never brake clean as mentioned.They should put a sticker on welding supplies to get this message out.

[Mr Fixit]

HI Group,

I had some time in the shop today. The craters went away when I used the grinder to cut out the old weld and I used acetone to clean with. So, the moral of this story is use what is recommended and clean, clean, and clean again, for a good weld is all I can say..

Thanks to all who contributed...

TX
Mr fixit for the family
Chris