a Q for shiny paint spraying types...

damn, this whole "bare metal respray" shit is a bastard! just taking the paint OFF was hard enough, now i'm supposed to put it all back on!!?? crap!

okay, basically i have removed every last skerrick of paint from the car, then cried as i discovered acres of rust hidden by a previous, semi-decent, paint job, and will sometime in the next week weld in the last patch panel of what i would estimate would be about 30...

unfortunately, i come from a school of welding that turns out really good grinders...

okay, so i now wish to take this thing back to a glorious, street-driveable, rain-immunised shiny thing. i have basically everything i need, i think:

- 2mm nozzle primer gun.
- loads of hi-fill primer
- 1.4 mm nozzle HVLP gravity feed top-coat gun.
- enough base-metallic and clear to paint my house. twice.
- more plastic filler than you can poke a stick at, or in.
- a big long straight filler file on a cool holder thingo.
- lots of big long straight flat things to hold sandpaper.
- lots of sandpaper.
- phosphoric acid to burn off any microscopic rust patches that i can't see.
- some metal prep shit that cleans off any oil and other contaminants ready for paint.

i think that's about it. first question - am i missing anything?

oh yeah, other than the compressor, i have one of those!

okay, second question involves the correct procedures for applying all this shit, so that it doesn't all flake, peel, crack, run, rust or just plain suck...

here's my plan:

1. wash panel thoroughly.
2. apply phosphoric acid solution to kill any rust in pits or whatever.
3. dry thoroughly.
4. apply metal prep solution to clean off any hand prints or whatever.
5A. apply plastic filler
5B. sand. repeat until flat. (how do you get rid of all the sanding dust without water? a vaccuum cleaner?)
6. immediately prime filled area to prevent any water touching filler while i'm away, as i understand it (filler) sucks up water like a sponge and fucks everything.
7. repeat for every panel on the car.
8. somehow clean all the primer (which i will no doubt have accidentally touched with the skin at some points by accident.) i was thinking either the metal-prep stuff, or just sand the whole thing with 800 grit. any suggestions here?
9. spray the car with three to five coats of base coat metallic, praying that i've practiced enough to avoid runs! also waiting the apropriate time between coats.
10. three to five coats of clear.
11. 1000 grit.
12. 1200 grit.
13. buffer.
14. collapse.


does this sound okay? any strategies for MAKING SURE i don't let water or any contaminants under ANY LAYER of the work? i've got so much time in this project i DO NOT want to fuck it up!


i guess i'm pretty sure i know what i have to do, but any HAMB experts that can offer advice, dire warnings or "you got it, go do it's" should do so now... i need the reassurance.

thanks.

 

I would strongly suggest using a metal etch primer prior to spraying the primer on.What are you using for the hi-build primer?I always sand my filler with 80 before I sporay a filler primer on.The filler primer is actually thicker than hi-build primer.I liken it to spraying some of the 2 paaart glazing putties.I usually try and give it 3 coats with the filler primer.I'll knock the top off of the filler primer with 80 grit,then 180,then 220.Remember to guide coat before you start sanding.After you've sanded the surfaces with 220,then reprime with your high build.If you have any really low spots,fix them after you sand the filler primer with 80.Easiest way to get rid of the sanding dust is with a vacuum,but you could lay some masking paper on the floor to "catch the dust as it falls,then pick up the paper and throw it in the trash.When your ready to sand yur clear,I'd suggest that you start with 1000,move to 1500,then finish with 2000.It'll actually save time wheeling the car with the buffer.Make sure you spray 1 additional coat of clear over what the paint manufacturer suggests,if your planning to sand the clear really flat.This will insure you end up with adequate film thickness for UV protection after your finished.

 

thanks ccc... i hear you on the number of coats of clear. a good point.

regarding the primers, all these different sorts are getting me slightly confused, i must admit. etch primer is good at "grabbing" bare metal, correct? if so, i understand the importance... i can't remember exactly what the hi-fill i have is, and i'm not going to check just now 'cause it's midnight here and i'm mowing through a bowl of ice-cream!

the guy at the paint shop said it was a good combination primer/filler so that i could lay on a few thick coats, with a guide, to sand nice'n'flat, post-body-filler... seemed a good idea at the time... (?) let me know if this sounds a bit dodgy.

thanks for all the advice.

 

You've got most of the story down pretty good. Etch primer is made primarily for adhesion to bare metal. Use it first (unless using an epoxy primer that's made for bare steel). Then filler primer over your bodywork to fill in imperfections. You 'may' want to use a final coat or 2 of a sealer primer before painting, to keep the paint from reacting with whatever's underneath. In your case, it won't be old paint, but sometimes the bondo can release up chemicals that may stain, or bleach the paint. (I use epoxy exclusively now, so I don't know if this still happens with good uro primers).
I like to block out my first primer coats (3-5) with 100 grit, guide coated, of course, and then reprimer. When that's cured, I go at it with 180 wet, primer again, and then 320 or 400 wet, ALL with guide coats!. You'd be surprised how much you need to correct at each sanding. you are finding smaller and smaller things wiong each time, but even the small stuff shows up in the shiny stuff!
I wash the car down with soap and water after each sanding. Let dry thoroughly, and get it ready for the next step. I always mask it fresh right before painting. You should also use a "Pre Paint Cleaner" right before spraying primer or paint. It is different from your grease and wax remover that you started with. It leaves no residue behind, and removes any contamination, and fingerprints. After Pre-Paint Cleaner, use a fresh tack rag to remove any dust before spraying.

 

You've got most of the story down pretty good. Etch primer is made primarily for adhesion to bare metal. Use it first (unless using an epoxy primer that's made for bare steel). Then filler primer over your bodywork to fill in imperfections. You 'may' want to use a final coat or 2 of a sealer primer before painting, to keep the paint from reacting with whatever's underneath. In your case, it won't be old paint, but sometimes the bondo can release up chemicals that may stain, or bleach the paint. (I use epoxy exclusively now, so I don't know if this still happens with good uro primers).
I like to block out my first primer coats (3-5) with 100 grit, guide coated, of course, and then reprimer. You can skip this step if you started with a straight car, with only little bodywork. When that's cured, I go at it with 180 wet, primer again, and then 320 or 400 wet, ALL with guide coats!. You'd be surprised how much you need to correct at each sanding. you are finding smaller and smaller things wrong each time, but even the small stuff shows up in the shiny stuff!
I wash the car down with soap and water after each sanding. Let dry thoroughly, and get it ready for the next step. I always mask it fresh right before painting. You should also use a "Pre Paint Cleaner" right before spraying primer or paint. It is different from your grease and wax remover that you started with. It leaves no residue behind, and removes any contamination, and fingerprints. After Pre-Paint Cleaner, use a fresh tack rag to remove any dust before spraying.