Prep metal for paint

[wbrian63]

I'm building some frames for adjustable shelves out of 3/4" square tube.

What's the best way to clean the oily film off the metal prior to priming and painting?

On small projects, I've used lots and lots of paper towels with paint thinner or acetone. PITA, frankly.

I don't have access to a sandblaster, so that's not an option.

Suggestions are appreciated.

Regards

 

[BobKovacs]

I've used spray-on products like PRE from Eastwood, and have also used non-chlorinated brake cleaner. They clean the oily off, and evaporate quickly without leaving a residue. You can also use wax and grease remover in a spray bottle, but it needs to be wiped off.

 

[astroracer]

Yea, it's a PITA but it needs to be done. I use a wax and grease remover with ScotchBrite pads to remove the residue AND prep for primer at the same time. Once you are done with the ScotchBrite wipe the tubes down with fresh wax and grease remover and a couple of the blue paper towels. They are ready for paint at this time.
Mark

 

[kazlx]

For bigger things that don't need to be super clean, I will scrub with diluted simple green, then use the O/A torch to heat up a little to dry.

 

[phy6]

Non chlorinated brake cleaner ( I think Chlorinated is ok if you're not going to weld it any time after) or acetone.

I've used simple green or purple power in a pinch, but you have to let it dry first.

If you heat the metal with a torch some (to where it's hot to the touch, not too hot) then spray on your paint, the paint will flash quicker and have a nice bond.

 

[Jack Olsen]

I use a household cleaner like Formula 409 or Fantastic. Then prime. Then paint.

If there's previous paint on it, I clean up the dirt and grease, then scuff it with sandpaper or Scotchbrite pad, then an acetone wipe, primer and paint.

 

[wbrian63]

Thanks to all for the suggestions.

I'll post pics once I'm done with the deed.

Regards

 

[kwb]

Clean material before welding it up -- much easier to get it clean when it is still sticks.

After it is all done I usually wipe with lac. thinner/acetone then scuff, then wax & grease.

Big jobs I will go with the water/soap solutions and a nylon brush.

 

[GYPSY400]

At work we use what's called "silicone wash".. It doesn't leave any residue. Brake clean works in a pinch, but you'll find it leaves a white residue. Scotch brite any welded area as I find this is the first place rust develops - especially with flux core wire.

 

[AMCguy]

On larger items, I hit them with the pressure washer to get the initial oil off them. Then take a scrub brush to them with dish soap. Then a final rinse with the pressure washer. If you do this in the sun light it will dry fast. Sometimes I have to blow dry the nooks and crannies.

 

[astroracer]

You are getting a lot of advice here. All I will tell you is, the "right" way to do this is to use a good wax and grease remover, scuff it well, re-clean with the W/G remover and prime. That is the tried and true body shop/custom paint way to do it. You won't get fish eyes and the paint won't peel off after a year. Just my .02 cents...
Mark

 

[Steroblan]

Get some "metal prep" from the auto paint supply house and follow directions.

 

[kwb]

You are getting a lot of advice here. All I will tell you is, the "right" way to do this is to use a good wax and grease remover, scuff it well, re-clean with the W/G remover and prime. That is the tried and true body shop/custom paint way to do it. You won't get fish eyes and the paint won't peel off after a year. Just my .02 cents...
Mark

I won't disagree that is the way a body shop does it .... but there are lots of other things being prepped & painted every day and aren't seeing paint failures and use many of the methods suggested above.

Water based cleaning is standard in industrial painting. Usually with a base type solution of cleaner and surfactant.

 

[astroracer]

I won't disagree that is the way a body shop does it .... but there are lots of other things being prepped & painted every day and aren't seeing paint failures and use many of the methods suggested above.

Water based cleaning is standard in industrial painting. Usually with a base type solution of cleaner and surfactant.

And I will agree with you, that is true. I use TSP in hot water to clean stuff that I know has been covered in ArmorAll. (And I always wipe it down with w/g remover before painting...) This step is not necessary on bare metal. If he does as suggested he will have no issues with paint quality or adhesion. I will only recommend what I know as the correct way to prep the surface. I know of no paint manufacturer that would recommend anything other then a wax and grease remover for this step.
Mark

 

[tarbellb]

Ive been using denatured alcohol and scotchbrite pads for a while, but my paint quality leaves a little to be desired. Is there any negative effects from this process?

Can anybody recommend a economical (cheap/bulk) Wax & Degreaser formula?

 

[astroracer]

Any automotive store that carries paint will have a selection of w/g removers. I know it is cheaper by the gallon then buying any of the other other stuff by the spray bottle.
Mark

 

[KMinAF]

I usually clean the tubing before any fabrication using a hydrocarbon based solvent. Then after all is done, wire brush the welds and wipe everything down with lacquer thinner. Not the "professional " way but has worked well for me. Just an aside note, I do all my cleaning outside. Fumes and sparks don't mix.