Painting a frame with light surface rust.

Hey guys did a search but nothing really specific to my situation.

Plan on getting my f100 frame sandblasted at a friends next week. Once it is blasted I'm gonna take some time to finish welding some stuff on the frame. Might go from shop to shop. Over this time it could develop some light surface rust.

Should I do...


-Por-15 with their metal prep?

-Some sort of rattlecan tractor paint?

-Rattlecan rustoleum?


I did a search on por-15......
most of it was about applying it to crusty frames and working great OR people said it flaked off on clean metal. I wonder if they actually used the "Metal-Ready" clean metal surface prep at all.

Also sunlight exposure is not a concern, the truck will obviously be full fendered.

Any advice for painting that "in between" metal? Not crusty but not insanely clean either.

I want to do everything nice as possible by myself, because I don't have access to surgical grade, dust-free, low humidity paint rooms or a ton of money either.

THANKS

 

Buy some Phosphoric and brush all over the frame and leave it. When you are ready to paint, give it a light sanding and paint with whatever paint you want to use.

 

Roll brush or spray two coats of good quality epoxy primer on it after the sand blast.
Clear away what you need for welding.
When your ready, come back and scratch it with 180 and hit it all again after spotting in the welds and your finished in my book.

 

Normally, I do all the grinding, welding, cutting, torching first. Then when I am totally satisfied with the frame I then sandblast and prime/paint within a day or so. Maybe it's the wrong way to do it, but it has worked fine for me for years. Why paint over a rusty frame that's going to have metal work done and fight with removed paint in the areas to work?

 

I use PPG 1791/1792 for a shop coat. Very thin transparent film.

 

I would be doing all the welding and grinding first before sandblasting but the frame is so crusty and gunky with junk, it's easy enough to go to the friends, get it sandblasted, and have a nice clean slate to work with.

I like the primer immediately idea then grind away what needs welded.

Anything that is a rattle can or brushable I'm willing to do.

What exactly is epoxy primer and what makes it so special? Is that spray gun only? Sorry I'm not much into paint and no where near a chemist.


What about self-etching primer with tractor paint over it? Will that hold up and bond together?

 

The only thing in rattle can that is much good is self etch. Upol makes a good one. I't will protect the frame well enough while you work on it. Epoxy primer is a two part primer that has very good adhesion and corrosion resistance. It can be rolled if your not looking for a super smooth surface.

 

Well the question is what kind of paint job do you want on the frame when your done?

If I were in your situation I would sandblast, clean metal with paint prep then roll or lightly brush on epoxy primer onto bare metal. Grind away epoxy on areas needing work. Then when all work is done, go back 120-220 grit sand whole frame and put another couple coats of epoxy on.

As for sandblasting then putting por-15 on, its kinda antiproductive. Por-15 is for metals that have been roughly grinded down and still have rust residue on them. If you sandblast then you have a clean slate and really dont need it. Epoxy primer ontop of bare metal is the best.

Good luck!

 

Thanks so far everybody. Everyday's a school day

I was looking into the por-15 I guess because it was a ch***is paint, figured it would mainly be designed chip resistant and be able to flex. Guess it's really designed to go over crusty metal and hold up, heard bad reviews on clean with metalprep now

I'll look into the epoxy if it can do all that then.

 

On my '40 I had the frame sandblasted, then did all the frame work, cutting welding MII even did some mocking up. The frame was always kept inside. Maybe even two years later I metal prepped and brushed on POR 15. As far as I can tell it has worked great and gives a nice heavy top coat, no peeling or flaking.

 

I like to use self etching primer on clean metal that gona stay a long time unpainted, it's real easy to sand off were you're gonna weld, just a scuff pad is enough, hell you can even weld right through it too with a MIG (not a good idea though since you polute your weld).
I also have a frame that got sand blasted and brushed with phosphoric acid some 17 years ago and is sitting in an attic since then, rust still didn't come back, like Jcmarz said just scuff it before painting.

 

I here yah on not wanting to work on a dirty ch***is. Why not just have it re-blasted, touched up after fabrication, then powder coated or painted. That's what we sometimes do. Shouldn't cost much. Powdercoating is sometimes cheaper than painting if you want it nice and durable.

 

Why not have it blasted, do the work and then take it back to have "dusted off" at the blasters before paint?

This way all the new parts and welds get blasted so the primer/paint has the same finish to stick to on the whole frame.

You said it was "easy enough to go to the friends, get it sandblasted" This just seems like the easiest way to go.

 

I've used POR-15 on a lot of pretty nicely done cars. Sandblast the frame, do your welding, then POR and a topcoat of Ch***is Black, from POR, or even regular single stage paint (paint it after 2 coats of POR, while the second is still tacky).
Isn't what I'd use on a show car, but for a "street & show" job, it's real tough stuff and looks pretty good.
In your car, though, if you plan on doing more mods on the ch***is, I wouldn't use it, Too tough to get off, to weld near! And if it burns, it smells terrible and is probably toxic!

 

Sand blast it then work on it, piss on it, let the cat walk on it and when your ready for paint, re-sandblast it (shoulden't cost as much the second time) and then epoxy it.

 

I'm pretty much in agreement with this line of thinking,,you don't want to have to grind primer off to weld.

you will only have light surface rust that will clean up relatively easy. HRP

 

Another point to conciter is ,once it is sandblasted you will find more areas that need repairing and welding. Besides, it is much easier to work on a clean frame and you will tend to do a better job because it looks better.

 

I like Miracle Paint for rusted metal if you cannot get it all by blasting.

http://www.hirschauto.com/products.asp?dept=3

 

KBS coatings.

http://www.jegs.com/p/KBS-Coatings/KBS-Coatings-RustSeal-Rust-Preventive-Coating/1037885/10002/-1

 

I use zinc chromate..........

 

Are some of you guys advocating priming the frame before doing the welding? HRP

 

Epoxy is the way to go straight after blasting.

 

Yes with epoxy to keep the rust at bay, when welding time comes just grind it off and weld then recoat, Personally I would do all the welding & fabrication and then blast and prime, I guess the OP has his reasons.

 

I've been thinking about this since I'm coming up on it too. Decided to blast the frame (stock A frame), shoot inside the channel with weld through primer, box/strengthen it, add brackets and re-blast before painting. More work, but it'll be so much nicer working on a clean surface.

 

FYI Por15 sticks extremely well to blasted metal, as good or better than rust....

 

Weld thru primer is made for bare metal mating flanges only. (for the inside surfaces of a lap joint). It has very poor adheason and will fail in any other application.

 

I'd like to sandblast it once, he's a friend but not a best friend. He's very busy, also if he's kind enough to help me sandblast the frame, use his equipment, etc. I'm not gonna ask to do it again and wear out my welcome.

Again powdercoating is not an option, don't have money for it, don't know any good ones around here, and just don't want to do it. I want something I can do with very limited paint skills/equipment. Plus this will be driven alot so I'd like to have the ability to easily touch up the paint if need be.

I like the epoxy primer idea, take away what I need for welding. All I have to weld is a mid-crossmember and finish the already tacked in boxing plates. I'm not going to weld through primer either.

If I do epoxy primer where can I get it? And what should I put on top of it as a final coat?

Or has anyone used a self etching primer and tractor paint?


Thanks so far fellas

 

Check out masterseries paint and coatings. Brush or spray it on. Their site is http://www.masterseriesct.com/home.html

 

POR15 rocks if you're done working on it - but only put it on freshly sandblasted metal, well scuffed primer or surface rust. See my link here: https://sites.google.com/site/edanneberg/

If you're gonna sandblast, then work on it, you could spray a self-etch on it from a rattle can, but don't really need to. When done your work you can just scuff it with a 3M Scotch pad, clean it well with any Wax + Grease Remover (critical) and put POR15, or Ch***is Black on it. POR15 goes on really nicely with a brush as it's "self-levelling".

I swear by it.

 

I'm getting por-15 is good or bad from what I've found on fresh metal surfaces. Why would in some cases the por-15 peel right off even with the metal prep?