Rubicon Owners Forum banner

1 - 18 of 18 Posts

·
Premium Member
Joined
·
5,182 Posts
Discussion Starter #1
Question for the welders out there. Seems like if I clean up an area for welding using a wire wheel. I have trouble holding a bead. Am I correct in assuming the brush (power driven, not hand) is leaving a film of metal and the shiny look is not just clean base metal?
 

·
Registered
Joined
·
153 Posts
You got a picture of what you're getting? I've found that sometimes I get better results when I use a grinding wheel or flap disk as opposed to a wire wheel, but it should still provide decent results if you play with the settings a bit. You're right though, my experience is that on millscaled material the wire wheel doesn't have enough oomph to get down to good, clean metal.
 

·
Administrator
Joined
·
10,765 Posts
Try more amperage Frank. I'm just a shade tree welder but so far I've only found aluminum to be picky about surface prep. If your surface is bright and shiny you should be good to go.
 

·
Premium Member
Joined
·
1,709 Posts
Question for the welders out there. Seems like if I clean up an area for welding using a wire wheel. I have trouble holding a bead. Am I correct in assuming the brush (power driven, not hand) is leaving a film of metal and the shiny look is not just clean base metal?
Question is too vague. What metal specifically are we dealing with?
 

·
Premium Member
Joined
·
1,709 Posts
Try more amperage Frank. I'm just a shade tree welder but so far I've only found aluminum to be picky about surface prep. If your surface is bright and shiny you should be good to go.
If he is messing with painted sheet metal, a lot of it has a zinc type coating under the primer and when the paint is gone, the metal looks shiny but because the zinc is still present, the bead looks bad and it will pop holes in the metal when the zinc interacts with molten electrode.


You are correct about aluminum and you should keep aluminum specific stainless steel wire brushes handy for cleaning while you weld and a set of discs, grinding wheels and sanding discs that are only used for aluminum. That and aluminum oxidizes very quickly so you need to prep as close to weld time as possible.
 

·
Administrator
Joined
·
10,765 Posts
If he is messing with painted sheet metal, a lot of it has a zinc type coating under the primer and when the paint is gone, the metal looks shiny but because the zinc is still present, the bead looks bad and it will pop holes in the metal when the zinc interacts with molten electrode. ....
Frank is welding sheet metal patches in a Jeep body he's restoring. Hadn't thought about zinc but I've never worked with body panels before.

I've done a bit of experimenting with aluminum surface prep. The recommended prep is as you say use only a dedicated stainless steel brush and followed up with an acetone wipe. I've tried welding Al with and without both of those steps and I don't recall much of a difference but then again I'm just a backyard hack.

If I'm welding steel with mill scale and don't care about cosmetics (and in a hurry), I'll weld right over it. Once the steel gets hot enough, you can make a good weld.
 

·
Premium Member
Joined
·
5,182 Posts
Discussion Starter #7
If he is messing with painted sheet metal, a lot of it has a zinc type coating under the primer and when the paint is gone, the metal looks shiny but because the zinc is still present, the bead looks bad and it will pop holes in the metal when the zinc interacts with molten electrode.


You are correct about aluminum and you should keep aluminum specific stainless steel wire brushes handy for cleaning while you weld and a set of discs, grinding wheels and sanding discs that are only used for aluminum. That and aluminum oxidizes very quickly so you need to prep as close to weld time as possible.

Blaine the parent metal (acid dipped 1970 j2500 truck cab) is 16 gauge that has been through the caustic/acid dip cleaning process. The patch material is 16 gauge sheet. No paint involved. The parent metal has been rusted badly needed some spots are not 16 anymore. That part I understand and am becoming proficient at fixing blow holes. The specific question concerns the wire wheels. Although the wheeled surface looks shiny and clean I am concerned the shiny us actually metal being deposited in a film from the bristles of the wire wheel. Possible? I have dedicate SS hand brushes that I use on welding project but they some times don't allow me to access rough areas.
 

·
Premium Member
Joined
·
1,709 Posts
Blaine the parent metal (acid dipped 1970 j2500 truck cab) is 16 gauge that has been through the caustic/acid dip cleaning process. The patch material is 16 gauge sheet. No paint involved. The parent metal has been rusted badly needed some spots are not 16 anymore. That part I understand and am becoming proficient at fixing blow holes. The specific question concerns the wire wheels. Although the wheeled surface looks shiny and clean I am concerned the shiny us actually metal being deposited in a film from the bristles of the wire wheel. Possible? I have dedicate SS hand brushes that I use on welding project but they some times don't allow me to access rough areas.
It sounds more like you have a welding wire problem. Check the spool of wire for rust spots. I can't think of anything that would be on a wire wheel that is being deposited on the metal that you couldn't see that would cause an issue unless you are leaving small pockets of rust in the pits when you brush it.


What wire size are you running for the sheet metal work?
 

·
Premium Member
Joined
·
5,182 Posts
Discussion Starter #9
It sounds more like you have a welding wire problem. Check the spool of wire for rust spots. I can't think of anything that would be on a wire wheel that is being deposited on the metal that you couldn't see that would cause an issue unless you are leaving small pockets of rust in the pits when you brush it.


What wire size are you running for the sheet metal work?
I was running .035 then switched to .024 until I ran out. The 35 seems to actually work better than 24. Go figure.
 

·
Administrator
Joined
·
10,765 Posts
Is your wire fairly fresh?

My first MIG was a used Sears two heat variable wire speed box. Try as I might I never could make a decent weld with it. Bought the Hobart IronMan 250 and holy cow what a difference - I was making decent welds right out of the box!

I hated stick welding, it was difficult to strike and hold an arc with my AC-only Lincoln arc welder. I needed to repair a gate and had to weld on a fence post (steel pipe) so I bought a small Esab MiniArc 161LTS DC arc welder and again WOW, what a difference. I was actually making fairly good welds right out of the box again. With DC it was child's play to strike an arc and hold it. BTW, the MiniArc is a fantastic little box, it will run off 120V or 220V and easily ran off my 3500VA generator.

I'm not bragging about my stuff, I just wanted to point that having the right equipment can make a humongous difference in getting a task completed while avoiding a bunch of frustration.
 

·
Premium Member
Joined
·
5,182 Posts
Discussion Starter #12
Put a new contact tip in the gun and see if that makes a difference. Do you run a wiper on the wire before it enters the drive rolls?

No I don't--didn't thanks for the suggestion. :grin2:

I had never given much thought to the wire being an issue. :surprise: Had always though parent metal because of the horrible shape its in.
 

·
Premium Member
Joined
·
1,709 Posts
No I don't--didn't thanks for the suggestion. :grin2:

I had never given much thought to the wire being an issue. :surprise: Had always though parent metal because of the horrible shape its in.
Rust on metal is a lot more forgiving than rust on wire. This was done with no prep because I knew I could and the black flecks are slag on top, not defects in the weld.


 

·
Premium Member
Joined
·
1,709 Posts
The debate on how clean and shiny has been around a long time. I have a friend who used to work at Cat welding together large chunks of steel to turn them into machinery and I called him up one day and asked him how they prep their steel for welds. He said that as long as the rust wasn't big flaky chunks, they pulled it in out of the yard, fixtured it up and went to welding.


I do however suspect the difference is the weld process. He was running a dual shield process with gas shield AND flux core. Most of us don't have the horsepower in our machines to do that and get it dialed in.


Anyway, the point is, when you are having an issue with poor weld quality and the material isn't the obvious culprit, then ignore it and look at the rest of your set-up.


I struggled for almost a whole day once trying to fix a bad weld issue and all I did was swap on another correctly labeled bottle of gas. The only way I figured it out was to put the bottle of what turned out to be straight argon on the Tig welder and try it there. It welded perfectly so the only conclusion was they labeled it wrong x 2 tanks.
 

·
Premium Member
Joined
·
5,182 Posts
Discussion Starter #16
Pretty sure it is not the gas. New bottle and fairly fresh wire--within the past 6 months. I can got several welds with no trouble at all then it starts to sputter. That is what lead me to believe contamination. I will try all the suggestions and see what happens.


Thanks
 

·
Premium Member
Joined
·
1,709 Posts
Pretty sure it is not the gas. New bottle and fairly fresh wire--within the past 6 months. I can got several welds with no trouble at all then it starts to sputter. That is what lead me to believe contamination. I will try all the suggestions and see what happens.


Thanks
Pay attention to how your lead is coiled on the floor. If you are welding and then tilt the gun so the tip is vertical and it starts welding poorly, the liner is probably full of crap and the tighter radius on the bend is causing the wire to slow down and it won't weld the same as it did with the lead straighter.


Also check the tension on the drive rolls. If you are getting intermittent wire speed changes, the rolls may need more tension.
 

·
Premium Member
Joined
·
5,182 Posts
Discussion Starter #18
Pay attention to how your lead is coiled on the floor. If you are welding and then tilt the gun so the tip is vertical and it starts welding poorly, the liner is probably full of crap and the tighter radius on the bend is causing the wire to slow down and it won't weld the same as it did with the lead straighter.


Also check the tension on the drive rolls. If you are getting intermittent wire speed changes, the rolls may need more tension.
Appreciate it!
 
1 - 18 of 18 Posts
Top