Welding Tips and Tricks

Beginner question - do I need to clean steel before welding with MIG? (I've heard you should with TIG) I'm talking about new steel from the metal supplier with that thin coat of protective oil. Obviously I'd need to clean rust or scale, but I wasn't sure if I need to wipe off the metal with acetone or another solvent before welding. Thanks!

Yes you should! Especially the mill scale.

That oil stinks, and not like Mom's cooking. It also creates a lot of smoke in the shop.
ZEP purple brush on, hose off. I think Homer Desperate and Blows sell it.

S6 composition mig wire will be better at Welding over dirty material, but oil is not great.

Just make sure you keep the rags you wipe with agood distance away. Seems like you can set them on fire with a single welding spark from 20 feet away. Heck ive even set a pan of gasoline on fire that someone left on my solvent cleaning sink "by accident" from across the shop. Tho that was with a plasma cutter.

Makes for an interesting day though

JayWal wrote:Just make sure you keep the rags you wipe with agood distance away. Seems like you can set them on fire with a single welding spark from 20 feet away. Heck ive even set a pan of gasoline on fire that someone left on my solvent cleaning sink "by accident" from across the shop. Tho that was with a plasma cutter.

Makes for an interesting day though

"By Accident" I set the grass n stuff outside my garage on fire, Just a spark or two from an angle grinder! Scary few minutes, grass, house wrap, siding, etc burning, melting, welding machines and corvette in garage. Only takes a spark to set a quick fire. Glad it wasn't windy out. Be Careful, it CAN happen.

andyb wrote:Beginner question - do I need to clean steel before welding with MIG? (I've heard you should with TIG) I'm talking about new steel from the metal supplier with that thin coat of protective oil. Obviously I'd need to clean rust or scale, but I wasn't sure if I need to wipe off the metal with acetone or another solvent before welding. Thanks!

its always good practice to clean the metal before welding. it just makes it so much easier to get better welds.
however many people don't.

Hit it lightly with a sanding wheel. Always a good idea.

andyb wrote:Beginner question - do I need to clean steel before welding with MIG? (I've heard you should with TIG) I'm talking about new steel from the metal supplier with that thin coat of protective oil. Obviously I'd need to clean rust or scale, but I wasn't sure if I need to wipe off the metal with acetone or another solvent before welding. Thanks!

Cleaning not need most of time if you use flux core E71T 11, E71T GS or E71T-1
This information is found in the data sheet
I use E71T-1 with CO2 for 30 years
Today I use E71T-11 NO Gas works

Dave

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I also do not use any type of cutting fluid when cutting the steel so do not have to clean the steel for welding and painting

Dave

What kind of saw do you use that doesn't require coolant?

weldin mike 27 wrote:What kind of saw do you use that doesn't require coolant?

I'm guessing he just doesn't use cutting fluid

weldin mike 27 wrote:What kind of saw do you use that doesn't require coolant?

I’m guessing he keeps the bandsaw blade manufactors in business.

Or he uses a dry cut. Like the Evolution ones.

I weld with a flux core mig machine and before anything else, I use a grinder with a flap disk to remove rust and mill scale then pour acetone into a wad of paper towels or a rag and wipe the oil off.

weldin mike 27 wrote:What kind of saw do you use that doesn't require coolant?

Bandsaw
I used 3 bandsaw cutting steel all on low speed and one man running all 3 and using a drill press

Dave

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weldin mike 27 wrote:What kind of saw do you use that doesn't require coolant?

Bandsaw
I used 3 bandsaw cutting steel all on low speed and one man running all 3 and using a drill press

Dave

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smithdoor wrote:Cleaning not need most of time if you use flux core E71T 11, E71T GS or E71T-1

smithdoor wrote:I also do not use any type of cutting fluid when cutting the steel so do not have to clean the steel for welding and painting

Welding is somewhat like painting an automobile; surface preparation guarantees great final results. You can weld through rust and mill scale, but the welds will not be as strong as welding clean metal. You can cut metals without fluid, but you impose more stress on the blades and shorten their lifespan.

Neither of these habits of skipping preparation to save time lend themselves to quality welding or cutting. But its your time and your money...

I worked in structure steel
I used Red oxide or grey primer paint
I look at cost of cleaning over cost of blades
The labor did cost a lot so ever to reduce labor I look at over other costs
By reading sepc on type wire would reduce the over cost that would make or brake the profit it was NOT T & M all quoted type work.
If did T & M I too may clean just for the bottom line

Dave

cj737 wrote:

smithdoor wrote:Cleaning not need most of time if you use flux core E71T 11, E71T GS or E71T-1

smithdoor wrote:I also do not use any type of cutting fluid when cutting the steel so do not have to clean the steel for welding and painting

Welding is somewhat like painting an automobile; surface preparation guarantees great final results. You can weld through rust and mill scale, but the welds will not be as strong as welding clean metal. You can cut metals without fluid, but you impose more stress on the blades and shorten their lifespan.

Neither of these habits of skipping preparation to save time lend themselves to quality welding or cutting. But its your time and your money...

Water is the only contaminate I've found to wreck a mig weld with porosity. I worked as the welder in a machine shop most of last year. I would just wipe the coolant off with a dry rag, but that was spray transfer.