what steps do you do when painting new rust free steel

[rjrobin2002]

What steps do you prefer to get your primer to adhere to new steel, or do you just degrease and spray an etch primer?

 

[lowpressure]

I used a thinner that doesn't leave a film behind and then an acid etching primer. I got it from ashleys paint by the downtown airport. (about ten minutes from your house lol)

 

[Rolltide]

I por-15 all my metal first then primer...
Seems to work very well.

 

[allenfahey]

Does it need primed? If so finish sanding with 180, degrease, and then prime with etching followed by a high solids (HS) primer. If you have an epoxy primer you can skip the etching and go straight to primer. If you don't need to prime then the best way is to finish sanding with 320 and scuff with a scuff pad. Degrease, then apply etching and then sealer, let flash and then paint. Or if you have an epoxy sealer skip the etching.
Check the primer TDS (technical data sheet) for the substrates and mix ratios to see if you can use the primer as a sealer.

Another thing.... I wouldn't get in the habit of using lacquer thinner as a final degreaser for painting. It can react to primer and paint. It will/can lift the edges and you will get a ring around it, especially enamel and lacquer. Use a dedicated degreaser for automotive painting. If you have a Keystone Automotive (aftermarket distributor) they sell a inexpensive degreaser that works great.

 

[rjrobin2002]

It is new unprimed steel tubing, i thought all bare metal had to be primed. So 180 sand, clean with a dedicated auto paint degreaser, then i can spray regular epoxy primer. No need to ise a special etch primer?

 

[bflippinw]

are you painting a roll cage? might want to degrease before you start sanding so you dont inbed stuff in the metal. metal is porous.

 

[bknbronco]

like allen said id just scuff it and epoxy prime it but mix it as a sealer.

 

[allenfahey]

I would do as bflippinw said and degrease first. Good advise there! Scuff with 320 and a red scuff pad. Seal it if your sealer is epoxy. If it isn't epoxy then etch it, let flash, seal it, let flash then paint. No need to prime it unless there are major scratches and bodywork.
Doing it with sealer is no sanding needed. If you mix it as a primer you must sand the primer prior to paint. Nothing wrong with that way it just takes longer.
A tip for sanding tube is to use a scuff pad as an interface pad. It will give you a more uniform sand scratch on the tube.

 

[bax]

I just primed up a roll cage. After reading Allan's instructions I may have done an extra step but I am all about overdoing stuff. I had a welded up cage. I degreased it first a good auto paint degreaser. This took a bunch of rags because there was lots of oil on the steel from the bender and dirt from everything sticking to the oil. I then took a wire wheel to the welds and coarse scuffy pads to the tubing. Then I degreased again and sprayed etching primer. I then went after it again with a finer scuffy pad. because me paint tubing sucks. I always get dry spots or overspray doing tubing. That stuff is hard to paint, for me anyway. After I got it all smooth again, I cleaned it again and sprayed an epoxy primer / sealer. I sealed it because I was not ready to finish paint it. It needed to be sealed because stuff in fla rusts overnight. Its sitting in the corner of the shop waiting for more paint. I guess I did not need the etching primer but more is better, right?

 

[allenfahey]

Then I degreased again and sprayed etching primer. I then went after it again with a finer scuffy pad. because me paint tubing sucks. I always get dry spots or overspray doing tubing. That stuff is hard to paint, for me anyway. After I got it all smooth again, I cleaned it again and sprayed an epoxy primer / sealer. I sealed it because I was not ready to finish paint it. It needed to be sealed because stuff in fla rusts overnight. Its sitting in the corner of the shop waiting for more paint. I guess I did not need the etching primer but more is better, right?

No matter what product you use please read the TDS (technical data sheet). That will tell everything you need to know about the product. In the TDS sheet you will find what substrates you can apply the said product on. It would have said you didn't have to scuff the etching. It's not wrong to do it that way, just not needed.
The way I would have done your cage Bax is to degrease it. Wipe it down with a wet lint free rag with degreaser and completely dry it with 2-3 more rags. Never let the degreaser (prep-solvent) dry on the panel you are working on. I would have followed that with a rag with POR's Metal Ready or other zinc phosphate coating like Dupont 5717S. Wipe it on wet and let dry. Then just let that sit till you were ready to paint. I too live in a humid climate and I did a friends VW bug and it sat in my garage for over a year in bare metal with zinc phosphate coating (same as Metal Ready) on it while I slowly worked on it. It never flash rusted. Again your way wasn't wrong by any means but not really the easiest.

You stated that you get dry spots when painting a cage... For me it's both, If it's not dry spots it's runs! They are pretty hard to paint even for an experienced painter since they are complex and you can't see the whole thing all at once like a flat panel. Then there is alot of jumping around to try to keep a wet edge. I would suggest to slow the reducer and hardener down a bit. That will leave the wet edge open a tad longer and avoid the dry spots. You should start with the front and work your way to the back. Spray in the morning while it's still cooler out too. Also don't go for appearance on the first coat, it might be dry here and there, that is a medium wet coat. The second coat you can put on wetter than the first coat.

 

[bax]

Thanks for the tips on the paint. Tubing is hard to paint.

 

[NicksTrix]

allen, sometime if you ever get the chance try shooting a cage with an electrostatic gun.
it's a pretty cool set up.