how to paint

[jveik]

ok i am doing a frame up restoration on my 73 chevy truck and i will soon be done with filler work and stuff so i have a few questions.

-should i use self-etching primer on filler or will it eat away the filler?

-how should i go about painting the interior of the cab and then the exterior? should i completely finish the interior even with clearcoat and all and then just sand the edge of that finish and do the exterior finish over lapping the interior one a little? or should i just mask it off as well as i can?

-do i have to let the primer completely cure before sanding and topcoating it or should i do it within 24 hours or whatever? some people were even telling me to topcoat when the primer is still somewhat tacky and some say let it sit for a week then topcoat it so im really confused.

-do i need to sand the topcoat at all before applying the clearcoat layers and do i need to sand each clearcoat layer before applying another layer or can i just spray it all on while tacky and skip the sanding process?

thanks for all your time reading this huge post. im just really confused lol

[rollin_on13s]

All of the questions that you are asking about depend upon the same basic factor- the type of material that you are using.

I personally would avoid putting self-etching primer over bondo.
only because there’s really no need for it!

I don’t know what brand of products you are using (It sounds like Dupont maybe)
But generally, this is the procedure;
After stripping, fabrication & welding- on bare metal mostly- Self etching primer is used to re-establish a chemical bond between the metal and paint/primer topcoats.
A mechanical bond may work just as well- done with sandblasting and/or rough grit DA sanding- but it's significantly more work.

Then, bodywork is performed using plastic fillers/ bondo. (Sounds like you've got this whipped)

After the bodywork, you may use a sprayable polyester leveling primer.
(It's cheap, reliable, and the whip for ending up with a straight car if you've got alot of bodywork)

After this is block sanded, seal it all up with an EPOXY primer (Sprayable polyester is no different than Bondo interms of being porous).
Over the epoxy you may spray "wet-on-wet" (as you mentioned), a catalyzed urethane primer (for even more blocksanding).
Or you can rest assured that all of your work is sealed up, and take a break for awhile. If you allow the epoxy primer to dry, you will need to lightly sand the surface before you spray anything else over it.

After all final sanding- and right before paint- you will definitely want to seal the entire truck again. There are a number of different types of sealers (keep in mind that some are designed for convenience within a production painting environment), but epoxy primer with a little bit of reducer added will work as well as anything for an all-over. Only a couple thin coats are needed- enough to create a uniform color over the entire painting surface.

Modern Basecoat/Clearcoat systems don't require any sanding between coats.
You may spray wet-on-wet:
1) Sealer
2) 3-4 coats of basecoat
3) 3-4 Coats of Clearcoat

...with no problems.

Keep in mind- epoxy and self-etching primers are designed to allow wet-on-wet topcoating- but will need sanded before recoating if allowed to dry.

All other kinds of primers (mostly filler primers) are designed to dry completely, and need thorugh sanding, before topcoating.
This includes polyester and urethane, and (Eiyyh!) Laquer.

[jveik]

thanks for the good information. heres an update. last night i tried the epoxy but im not a good painter and it gummed up my gun really bad and i didnt even manage to get any on the cab. It was only about 4 in the afternoon, so i headed down to the paintshop, on my neighbors advice, and picked up some laquer and some laquer thinner. It worked really well, although the gun seemed to have issues with spraying large amounts of product (i borrowed my neighbor's cause mine was still soaking in thinner) i covered it all eventually and am now waiting until a few days because i have to work tonight. ill scuff and tack it, then apply another couple coats. The paint shop told me not to worry about sealer since its not going to be getting wet while it sits in the garage all winter. he sed just to scuff it up really well in the spring and put another coat on before doing the topcoat. So far it looks sweet tho, even tho u can see thru it in some spots. The cab corners and floorboards look almost original except for a few imperfections i need to glaze over. I think it will be ok tho lol. thanks again for the advice