Removing paint to bare metal??

[villageidiot]

OK, while I used to be an adjuster and write basic auto estimates using a computer, I never did anything on the restoration side with refinishing. Most of the repairs where basic sand, refinish and blend. I want to prep my truck as much as possible before refinish. Very little rust as this was an AZ truck all its life.

What are the suggestions on prep? Remove paint to bare metal? If so, what do I use? Or do I sand everything down to a point, clean it up with solvent then primer and refinish?

I have seen suggestions all over about removing rust with sandblasters, etc. but not simple paint prep.

Thanks.

[48Dodger]

Paint shrinks when it drys. if the substrate is weak (old paint not gripping to the metal) it will either bubble up, make "spiders", or pop off as a flake. If you sand with 80 grit and feel that the paint is gripping good, you should be fine. If the paint is powdering up, or checkered, etc....take it to metal. Feather the edges, but don't get to carried away, you'll heat the metal, cause a dent or dig into the metal. The exposed metal should be conditioned (metal prep). There's a reason you had to go down to metal, it might have been the enviorment of the metal. The whole vehicle should then be primered with a good filler primer. I like to put on at least 3 to 4 coats of primer. Primer gets sanded, resanded , and sanded again, so there better be primer on it!! Some primers can act as a sealer as well...depends on the brand. The point is, primer is when you can take a break from the project you started. The dents and body work that need to be done can be sanded, metal preped, primered, and saved for later. If you take it to metal and walk away, its like pushing a truck up a hill and letting it roll back down where you found it. You can push it up again, but why not get it to the top and park it.

1. sand (start with 80 and end with at least 220)

2. condition the exposed metal

3. clean the whole thing (blow it off, wash it with slighty soapy water or windex)

4. clean the surface with wax and grease (bug and tar remover works too)

5. tack rag

6. primer it

"Rattle can" primer(sandable) can go on very thin, but will help hold the project until real primer can be used.

48D

[coW52Dodge]

On stripping, I've used commercially available stripper but that stuff can be nasty. Aircraft stripper in particular is quite toxic. Oven cleaner works but that's nasty stuff too.

Depending on what you're trying to remove, "Dawn Power Dissolver" may work quite well for you. It being a household cleaner, it is available at home depot and some supermarkets. It is quite inexpensive ($3/bottle) and no more caustic than windex. It washes right off.

It works well on the cheaper coats (Schreib, Maaco, etc). Original paint may take several coats.

Spray it on, cover it with plastic wrap and let it sit overnight. The plastic wrap causes it not to dry out too quickly.

After I removed the wrap, most of my aftermarket paint fell off or could be scraped off with a putty knife.

[buds truck]

I prefer to remove my paint with a "D/A" orbital sander with a 6 inch disc. It does not gouge into the metal and you can get it in all the grit sizes that you need. Its slower than a grinder, but much more forgiving. Chemicals are too messy and burn the skin if you are not careful.

[Dave72dt]

I use a sandable epoxy primer exclusively. It costs more than other primers but it also seals. Rattle can primers and most other primers are "breathable" which means moisture can get through it and create rust under the primer. Body work and/or plastic can be applied over it as long as it is scuffed first and can be recoated as needed. A final wet sand before color goes on.

There are some epoxy primers now available in a rattle can but I don't know how good they are. The best bet is to figure out what type and brand of paint you intend to use first and follow prep directions from that manufacturer using only their product.

[grey beard]

If you are sanding a good finish of old paint down to refinish, please DO NOT start out with 80 grit, as was suggested earlier in this thread. Eighty grit paper is very coarse, and is used only for body lwork and rust repair.

Contrary to the beliefs of many, I have foudnd that old paint, if still adhering well, makes a good base for refinishing. I agree with Bud that you will need a DA sander - $19.95 at Horreible Freight - and begin with 180 grit or 220. When you use a DA, the finish is much more forgiving and will usually become well feathereedged at those points where bare metal has been uncovered, like around body work. You need only concern yourself with primer issues on those spots where bare metal is showing. Good old paint finishes need no primer underneath, unless you are going to refinish with some transparant type of paint, in which case a sealer of a compatible color is needed.

For anyone contemplating body/paint work who has little or no experience, I highly recommend this web site. www.autobody101.com.

It is a forum much like this one where questions may be floated past the noses of experts. Unlike this forum, the auto body forum is divided into subject segments - welding - primers and sealers - paint - spray guns, etc. Each segment is moderated by a body expert who will give professional and correct answers, unlike some forums where you will get lots of opinions and local wisdom sprinkled with old wives' tales and malarky. If you truly want to learn body work and paint procedures, read over these forum questions and answers. They go back over many years, and have become an excellent resource for me in the past. The men who answer your questions on that forum are in the business every day and are totally up-to-date in their approach to problem solving. They have first-hand knowledge of which they speak from fluently. Give it a try. JMHO

Good Luck

[48Dodger]

As I suggested, some primers act as sealers. I use PCL's 901 polyprimer which states can be used without a sealer. If your doing a color change I would use a sealer anyway. If you are doing a complete on a car or truck that has a paint job older than say, 15 years, a grit higher than 80, you may hide weak paint. If you want to leave paint that is adhering well, you better prove it's doing just that. If you finish with 220, as I suggested, the 80 scratches will be resloved. A good filler primer will fill the 220 and up scrtaches, and will block out. 40 grit is for body repair and scale rust.

48D

This my most recent complete for a customer. 1966 Ford F-100

To save him money, I did it in stages without a spray booth.

Most jobs I finish in town at my buddy's body shop, renting his 60,000 dollar spray booth.