No secret that clean joints will produce the strongest welds, but I'm just wondering how far some of you guys really go. I usually use a small grinder to blast off the mill scale, and then weld it up. I supose I could go further by wiping the joints down with acetone, but call me lazy I don't do that. Just wonder if you guys go crazy with cleaning the joint, or if you think just removing the mill scale is enough...

For GMAW with mild steel a quick cleaning with a wire wheel on a grinder is more than sufficient as most of the commonly used filler (ER 70S-2/ER 70S-6) will have a high enough deoxidant content to deal with surface contaminants. Filler such as ER70S-3 or S-4 does not have as high of level of deoxidants which makes surface prep more important.

Can't get it too clean...

Most times i prep like it's going to get paint

One thing many people overlook is cleaning the inside of tubing prior to welding.
Cutting oil will hide in there untill the tube starts to get hot, run down and contaminate the weld. I use a rag with a long skinny needle nose pliers for shorter chunks, or shove a rag through the tube with welding rod for longer chunks.

I use a wire wheel on a grinder to prep, if it's critical or really dirty/oily I use acetone to finish up before welding.

brake cleaner is handy or if there is scale i'll hit it with a 36-50 grit (wich ever happens to be on it at the time) 3" rol loc disk.

Yeah, you guys are probably right about the acetone and/or "preping for painting". I was reading a book about welding, and everything in there stressed the need for proper joint preparation. They said to actually clean the welding rod/wire, and warned that fingerprint oils will contaminate welds. I swear after reading this book you would think you need to weld in a vacuum chamber!

whenever i TIG i wipe down my rods. you'll be suprised how much grime is on them that you dont want to get in your weld. As for MIG, i dont see how you could clean the wire, but then again, it isn't as crucial as TIG. you just dont want to skip on a minutes worth of work that can be the difference between a good weld, and one that will fail down the road.

As for MIG, i dont see how you could clean the wire.


run the wire threw a foam ear plug before it runs threw the rollers

run the wire threw a foam ear plug before it runs threw the rollers

That's a great, easy idea. Thanks!

I use a rag with a long skinny needle nose pliers for shorter chunks, or shove a rag through the tube with welding rod for longer chunks.

Rifle cleaning rod. $5.00 at Wal-mart. You'd be amazed how often such a thing comes in handy in the shop.

Peace,
PT

run the wire threw a foam ear plug before it runs threw the rollers

Most welding shops sell a felt wiper that clamps around the wire before the rollers. They are vey cheap. I like the earplug idea.

I wire cup everything

I wash all the full length sticks of tubing with "super duper grease cutting" dish soap and a rag on the outside and use a long rod to shove the rag through the inside to get all the oil off the tubing. Makes fabricating much nicer when your not covered in black oil...

Then I just wire wheel the joints before welding.

I wire bruch and scotchbrite.

I then rub down with acetone and allow to air dry.

I never thought to clean the inside of tube, silly me.

I generally wire brush the trivial. I've never used any chemical cleaner, if it's a critical weld (I don't do many) I'll hit it with a sanding disk until I see "shinny" metal, that's gotta be clean right?

chad

brake cleaner is handy or if there is scale i'll hit it with a 36-50 grit (wich ever happens to be on it at the time) 3" rol loc disk.

IIRC my welding inst. discouraged the use of brake cleaner for weld prep due to the chlorinated solvents. I don't remember the reasoning exactly, but I think it had to do with inhaling the fumes given off by the residue when welding. :confused:

IIRC my welding inst. discouraged the use of brake cleaner for weld prep due to the chlorinated solvents. I don't remember the reasoning exactly, but I think it had to do with inhaling the fumes given off by the residue when welding. :confused:


i likes the fumes :smokin: .j.k. i use non chlorinated brake cleaner if that matters, also it is allowed to dry completly before i weld. i feel brake cleaner is better than the oil that comes on the tube (or cutting oil from holes drilled beforehand on a bracket, ect).brake cleaner is always accesable to me and dries quickly. i am not tig welding air plane fuselages out of 4130, tho :D .

run the wire threw a foam ear plug before it runs threw the rollers



I just put one on after my spool. Thanks for the tip! :smokin:

I was a welder at an aircraft plant. 1/2 my welds went through x ray all done with tig. Here is what I learned.

1. the last mechanical cleaning should be done with a 300 series(no iorn) wire brush.

2. gloves are white cotton and clean.

3. wire and material to be welded wiped with alcohol and clean white rag.

This was my what I did to weld butt weld stainless fuel lines on 50 millon dollar aircraft for about 15 years. A prayer before you strike an arc doesn't hurt. Some of those lines are 20 feet long with 5 welded joints one (butt weld 4 fillets). One f'up and you scrap 10k worth of material!

This might be overkill for welding a trailrig through.

Stuff at home that I MIG I just wire brush it or sand it. Right now I am helping to TIG a chromoly race car chassis at school. All joints get polished to a shine with a prep pad on a 90 deg die grinder. Once they are tacked they get acetone wiped on them and get brushed with a fairly new/clean stainless steel brush. The short length tubes get a rag run through them to clean anything in them, the longer ones get just the ends cleaned. The tubes are also fully purged with argon before welding. Also use clean gloves.

I just bust out the 6011 and go to town then throw a cap of 7014

I just bust out the 6011 and go to town then throw a cap of 7014
That's tellin' them princess':flipoff2:

I have to admit,sometimes I'll throw in a few rounds of grind and glob and regrind just so I don't have to hear their shiat:shaking:

Usually wire wheel, or flap wheel to get shiny metal. But I also weld with Flux Core, instead of MIG...

I can't say I've ever had a weld fail on me, other than small tack jobs. Don't do a ton, but I've built 4 trail rigs in my garage.

When I'm welding parts for other people, my prep work(well, work in general) is better.

I just bust out the 6011 and go to town then throw a cap of 7014


I'm guilty of sort of the same thing. If I am in the shop working on my own projects, I am anal about cleaning the metal. When the kids are there, and I am demonstrating the basics, I just wirebrush the work area, and run either my 7018 or 6010.

If I am helping demonstrate techniques for certification, I clean like an OCD patient, and clean some more in between beads.