Paint prep work questions. big ones.

[mrsleeve]

Stay away from stripping it to bare, unless the car has been painted 3 or 4 times it's not needed. As you are pressed for time just skuff up the current paint with 220 on a DA then put a good heavy coat of epoxy filler primer (I like PPG's K36). Wet sand till flat like I told you in the other thread wipe it down with a tack rag an squirt 1 more coat of K36 wet sand it down with 500 agin an you are ready for color.

This is how I have done several cars and have always had very good results others have other ways that are just as good but the devil is always in the details so take you time an dont cheap out or resort to short cuts, you wont like the results.

Because that's where I'm at right now....And what would happen if I were to just thin ALL the paint off untill bare metal, and just primer that?..would that worK? (I know it seems im looking for a shortcut, and I understand that short cuts lead to problems, but...I really like shortcuts, and am pressed to about 2 hours per week on time.).

going down to bare metal is another challenge, as you need a specific type of primer to seal the metal, then you will need the "filler" primer unless your panel is already perfect. It also depends on some systems, the bare metal primers (generally epoxy) want to be topcoated with a primer and a certain window of time. You need go do more research on your own.

[cactusjacks1]

Read the recent posts "gas filler door smoothing" & "why you shouldn't wet sand in cold temps". While these don't fully relate to your situation, they do talk about the time & quality (or lack of in the case of rolling on paint) you get when you start the painting project. The gas door has 12 hours labor in it alone. At that rate, you would have 6 weeks in only the gas door.

Maybe you could take it to a local high school or JC that has an autoshop class & offer it as a project car they could use for car painting class. You might have to pay for the paint & materials but you would be able to get the job done at a minimum cost & a lot quicker (vs. the 2 hrs./week you can put towards it).

[apexede30]

Oh no...Why can't this be as easy as finger paints.....

Anyhow, in all seriousness, primering seems quite difficult. And then theres the sanding.

What would happen if I just sprayed some primer on, and then sanded it down, without any of the sanding of the previous paint, or..."filling"?

Because that's where I'm at right now....And what would happen if I were to just thin ALL the paint off untill bare metal, and just primer that?..would that worK? (I know it seems im looking for a shortcut, and I understand that short cuts lead to problems, but...I really like shortcuts, and am pressed to about 2 hours per week on time.)

Thanks to the great replies and discussions...If you ever need help on...basic things, I'll try to repay the favor.

[mrsleeve]

I have always used 500 as has 2 of the best painters I have ever met.

[EWAustin]

If you're using a paint system, follow the directions. When I am mixing and matching or something, I never go above 400 grit in prep. Especially on something like neat epoxy or polyester resin that will get very smooth as I sand it. Wetsanding after the fact is the way to get perfection in the surface coat, IMO.

This is the KEY to good paint. The chemical engineers that designed the paint know more about the physical structure of the paint than you or I do.

[matt]

I disagree.

I have always been advised to hit about 600-800 for perfection on high build.

If you're using a paint system, follow the directions. When I am mixing and matching or something, I never go above 400 grit in prep. Especially on something like neat epoxy or polyester resin that will get very smooth as I sand it. Wetsanding after the fact is the way to get perfection in the surface coat, IMO.

[backtrail69]

I usually hit it with 400 wet then sealer, base and clear after you have it in primer. Sometimes 600.

True.

I disagree.

I have always been advised to hit about 600-800 for perfection on high build.

[EWAustin]

Congrats and good luck. I'm an autobody student and I'm just starting on my 325is, As of now I've got the bumpers, sidemolding, and chrome strips off and about a 4x8" hole in the jack well where I had to grind away rust. I'll be welding some metal back in soon. I've also got a bunch more grinding to do. Today I'll be getting some pics and starting a project thread.

[ivo316]

Man, I started my paintjob without knowing what I was getting into, my arm has grown bigger, any money a shop asks for a paintjob is well deserved, it's truckloads of work and dedication to get it right, plust getting to spray correctly is also an art, I decided to do it myself, and once I finish it I'll be very proud, but i bow in front of professional painters (or other amateurs in this forum) because even with an orbital, it's hard work and needs lots of knowledge.

[cactusjacks1]

I was advised not to sand finer than 400, there is a chance that the paint will not stick to the primer.

Many of todays basecoat/clearcoat paints call for a minimum of 400, then 600 - 800 wet/dry, then a sealer coat, before the base goes on. Almost all basecoats can be wet sanded with 1000-1500 before clear is applied. Clear can go 1000, 1200,1500, then 2000 before buffing with compound, swirl remover, machine glaze, hand glaze & a high quality wax. You can see why a good body shop gets big bucks for a real nice paint job.

[matt]

I was advised not to sand finer than 400, there is a chance that the paint will not stick to the primer.

True.

GO here, and ask questions to professionals, this is the BEST body shop forum I have seen yet..

http://autobodystore.com/forum/index.php

[ivo316]

I was advised not to sand finer than 400, there is a chance that the paint will not stick to the primer.