Welding Question

[bobodu]

Torches,brake cleaner,preheating,grinding,different wires,gases....$900???


Arc welder!!

 

[Reg]

I don't get it.
Are you saying that you get a crappy root pass and then just wash weld over it to make it LOOK pretty ?
If not I apologize for my misunderstanding.

We do ALL KNOW that gouging it out and starting over is the right thing to do, right ?
Anything else is just about certain to fail - assuming.... well, all kinds of things that are normal practice, such as it needs to be a however many pass weld.

 

[Egon]

such as it needs to be a however many pass weld.

Pictures would be excessivelly expensive for this type of situation.

 

[nunyabinis]

I don't get it.
Are you saying that you get a crappy root pass and then just wash weld over it to make it LOOK pretty ?
If not I apologize for my misunderstanding.

We do ALL KNOW that gouging it out and starting over is the right thing to do, right ?
Anything else is just about certain to fail - assuming.... well, all kinds of things that are normal practice, such as it needs to be a however many pass weld.

Basically you are correct. Crappy root pass using either a Z pattern or a circular pattern with the torch.

I can then clean the slag off and weld right back over the top of the root weld (as if it wasn't there) with either a Z pattern or a circular pattern and it "cleans it up" as you say, has no porosity and leaves a very nice looking deep weld.


Words don't do justice to just how "crappy" the root weld is on this new 1/4" thick metal. I'll post some pics when I get the chance.


And yes, I know the correct procedure is to gouge out the original weld but I was "experimenting" and the item I was welding, a rifle bench, really isn't going to be under any appreciable load. But I plan to build a road scraper like a GradeMaster and I'd really like to figure out the problem before I start welding on something that WILL have a big load applied.

 

[nunyabinis]

Here's a picture of the finished rifle bench I was doing the welding on. You can see the old wobbly wooden bench in the background. The metal bench does NOT wobble.


I know it has nothing to do with tractors but variety is the spice of life and I wanted to practice on this metal with an easy project before I jumped into the road scraper project.


Unfortunately, I don't have any photos of the "crappy" root passes. I'll have to make more crappy welds and take pics.

 

[sizzami]

actually sandblasting is what drives impurities into metal ,well more into the crack or joint you are trying to weld, sandblasting should be used as a last resort , especially if you are repairing a crack.

 

[ben2go]

Here's a picture of the finished rifle bench I was doing the welding on. You can see the old wobbly wooden bench in the background. The metal bench does NOT wobble.


I know it has nothing to do with tractors but variety is the spice of life and I wanted to practice on this metal with an easy project before I jumped into the road scraper project.


Unfortunately, I don't have any photos of the "crappy" root passes. I'll have to make more crappy welds and take pics.

That's a great looking set up you made.I can't add anymore than others have already added about the welding issue.

 

[nunyabinis]

That's a great looking set up you made.

Thanks. I designed it so that when you sit in a regular height chair the butt of the rifle stock fits right into your shoulder pocket. The rear of the bench top is beveled on both sides so that a righty or lefty can use the bench with ease. The legs are buried two feet deep. Makes for a darn solid rest.

 

[swines]

Use a flap wheel along the weld pass area to clean it if you're using hot rolled steel or tubing. Then use acetone to clean the metal. You'll be surprised at the dirt + oil the acetone will pull off the metal. The acetone will flash off the surface rapidly and leave a residue-free, clean, surface to weld.

 

[esimmons]

A while back I purchased a Millermatic 251 MIG welder that I run .045 flux-core wire through. I always grind/polish the area I intend to weld before laying a bead, however, I've noticed that on some brand new 1/4 inch steel I bought that the first bead always looks terrible with open "bubbles" that form once the weld hardens. I can go back over the same area a second time and the weld looks perfect. It's almost as if the first bead evaporates some sort of contamination and "prepares" the metal for the second pass.

Is there some sort of contamination on the surface of the metal that I'm not completely removing when I grind/polish the metal? The metal has some sort of think oily coating on it that I assume is supposed to keep it from rusting. What's the best way to clean that off before I lay a bead?


Thoughts?

Most new steel is coated with a cosmoline-type material at the factory to prevent rust.
One of my first jobs at a welding shop was to soak a rag in laquer thinner and wipe down all the material we were about use for a particular job. You need to wipe it down before grinding. Otherwise the grinder just smears it around, as well as produce heat, which opens the pores and drives the oil into the steel. Laquer thinner in 5 gal. cans is pretty cheap compared to grinding discs and welding wire.