I hate asking stupid questions: primer removal

[purzell]

But I do seem to feel like alot of them are stupid...

Anyhow I read the forum for several hours today getting side tracked on other folks' builds, trying to find the answer to my question....

I am cleaning up the truck getting ready for a body guy to sand blast some of the more rusty areas to patch some holes.

I tried the CLR method on the paint to see what would happen. My truck is mostly in white primer. Some areas the white primer thinned out with multiple attacks with CLR and a scrubby sponge. Mostly the white primer held up.

So my question is: besides sand blast any way to get through that primer stage? I think I found some painted on numbers and lettering underneath part of it and I really want to know what it says without loosing it all. My truck was supposed to be a Forest Service or gov't truck and it would be cool to find some markings under that primer.

[markeb01]

If you just want to be able to read the letters, I'd suggest wet sanding the area with 600 or 800 grit paper. This will take some time because it won't remove much material quickly, but it will allow good control to remove just enough of the top coat to see what's underneath.

Sandblasting really isn't a very good way to strip paint off sheet metal, but can be effective in rust repair areas. Flat surfaces can be easily damaged by a careless operator using too much air pressure.

[rendus]

What kind of primer? The PO of our 914 rattle-can primed the whole car and then left it out in the elements to rust. A bunch of rags and a can of Lacquer thinner took it all off cleanly.

Epoxy primer? fuggedaboutit!

[BR3W CITY]

oooh oooh is it that weird green color? Mine was supposed to be a DNR truck, but only half of it looks to have been

Rattle can or sandable primers should come off with mineral spirits, reducer or naptha. Epoxy primer.....ya ur calling the sand blaster.

I had overspray epoxy primer on a machine screw that was an old ground...I can't even back the screw out with a drill. That stuff is hardcore.

[Captainfab]

If you just want to uncover a layer of paint at a time, you can try wet sanding with Scotchbrite pads. The maroon ones are semi agressive. The gray ones are a bit finer.

[ChiefRocka]

Hey ....

I am going thru this as we speak.

I started using standard scotchbrite pads....with just soap/water.

It works great. What I am doing is removing the rattle can primer, and exposing the OG white paint.

Some areas even had two to three different colors, besides the primer, and its all coming off.
Posted via Mobile Device

[purzell]

Well, I'm going to try the next step...a lil bit of lacquer thinner. Also the wet sanding in another area. I have a whole lot of truck to experiment on.

It's forest green under some of it.

The scotch brite equivalent is what I am using, with CLR and water, but it didn't cut through the white primer too much. Like I said, a couple areas thinned out. Not sure if it's green all under the white but it seems to have been all green including the steps on the bed.

[63burban4x4]

this may or may not help anyone, but here it is for what it's worth.
I have not used the scotchbrite pads everybody talks about, so this may not be a fair comparison.

As a home builder, we use a roof ridge vent material, comes in a roll, and is a "woven", or "spun" poly of some kind, that lets air through but provides a baffle designed to keep water out, some of you may be familiar with this. (one brand is "Cobra Vent" I think) One day while cleaning up some parts for painting, I ran low on sandpaper, spotted some scrap of this lying about, so I cut a small square, and lo and behold, it worked pretty good as a replacement. I think it may be somewhat like the scotchbrite stuff, but like I said, I'm not that familiar with them. What I do know is that any job we use this on, there's always going to be some unusable scraps left, so the price can be REALLY right.....like, save it from the trash barrel!
I'm pretty sure those pads you buy at the local harware will really add up when you do a whole lot of sanding, but a 4' scrap of this would yield probably 25 (2 sided) pieces 6"x4" or so (easy to cut with decent scissors or a box cutter)

I've used it especially between coats on smaller stuff I've painted, with good results. If you are on a budget (who ain't?) it might be worth checking with yer builder buds for some scraps of this stuff! I can't guarantee it'll work for you, but........... -Ed

I'll get a picture of some up a little later.

oh, and I also used it when I put a pcv baffle in my old 283 "script" valve covers.......I think I should have a pic of that, too

[63burban4x4]

a couple pics of the material.......how many palm-size pieces ya think I could get from this leftover roll? LOL

[63burban4x4]

hre's how I used it in my valve cover....untested, but I'm hopeful!

[BR3W CITY]

hmmmm thats fairly interesting. Probably similar to the red or green scotch pads.

As long as it isn't oil or fuel reactive I guess its fine to use in an engine. Its a plastic tho isn't it? I'd be curious about degradation.

[DesertCat]

If the primer is uncatalized, you can remove it by leaving a very wet rag saturated with laquer thinner in one place at at time for a few minutes. Mineral spriits will only work on rattle can stuff.

I would try that, and/or laquer thinner with a scotchbrite red pad until you start breaking through to the original paint. Once you get to that point I would go carefully with little to no abrasives.

Wet sanding would also be a good choice, for ease start with 220 and stop as soon as you see another color underneath, then go to 400, and on up from there.

Another way to get there would be a heavy wool pad and buffing compound.

[DesertCat]

Originally Posted by BR3W CITY

hmmmm thats fairly interesting. Probably similar to the red or green scotch pads.

As long as it isn't oil or fuel reactive I guess its fine to use in an engine. Its a plastic tho isn't it? I'd be curious about degradation.

I'd spend the few bucks for the correct mesh. I have waaaay too much money in my engine to have some unknown substance in the crankcase/oil. Yikes!

[63burban4x4]

Hey, don't get me wrong, I don't recommend the baffle thing to anyone!
you'd be crazy to use it. I shouldn't be taking the chance myself, of course. I could lose the whole almost $300 I got in this motor, all at once!

yeah, Ive used 'em for gleaning parts in gasoline, as well as purple degreaser. even leaving em in the stuff seems to have no effect.
don't blame you for thinking it's a bad idea. This seems to be off topic however, and I only added this to the discussion as an interesting sidenote, it does'n't belong here it in the first place when the thread is about removing primer, and it doesn't seem very risky to use the material to do that. -Ed