Bare metal respray

[ozy]

Hi
I've got myself a project car which I am planning to respray from bare metal. This is my first project, so I'm trying to work things out as I go along (am also teaching myself to weld).
What I'm planning with regards to painting is this:
1 coat self etch primer
2 coats of cellulose primer
2 coats of cellulose colour
1 coat clear lacquer

Is this about right?
Can the cellulose primer be sprayed straight on to the self etch (i.e. it won't cause a reaction or anything) or do I need to do some special prep work?
I will have to treat some areas with 'rust converter' do I then spray these areas with the self etch, or go straight on with the cellulose primer?
I am planning on painting the chassis/underside with hammerite or similar, does this go on bare metal or should I paint with self etch and/or primer first.

I have also been told by a paint shop that I don't need to bother with the self etch?
Sorry about this, but I just want to try and get things right (or not too far wrong) as I can't really afford to be doing the whole thing again in a couple of years because I got it wrong.

Thanks
Oriel

 

[malcolm]

Sounds about right. Do the filler work first and any rust inhibitor, then always start the painting with self etch. Otherwise you risk poor adhesion (I had that once on some wings I bought already primed - very annoying). Cellulose primers will go on top without problems.

Is it metallic or plain colour? I'd put a couple of coats of colour on, wet sand, then a final coat. I've only used lacquer on metallic, and for that a couple of coats and a good polish. Some tips on spraying here: http://www.mig-welding.co.uk/spray-painting.htm

Hammerite would need a primer. I use a zinc-phosphate primer for decent adhesion. Hammerite is brittle. Smooth Hammerite seems better but still chips off easily. I did one in household gloss once, and that has survived better than hammerite, but would react with anything I used to overpaint with so not very sensible.

 

[BillJ]

I'd avoid Hammerite on a car. As Malcolm says, it's very brittle. It'll chip off easily under stone impact. I once made the mistake of using Hammerite Anti-Rust Primer (essentially matt grey Smooth Hammerite) on a windscreen frame, painting over it, then bonding the screen on top - it didn't take a lot of force to rip the screen out again as the Hammerite simply cracked off the frame when pulled.

Hammerite's main virtue is that you can paint it directly over rust. Since you won't have any (untreated) rust, Hammerite loses its advantage.

I'd be more inclined either to spray the underside the same as the rest of the car and then use a good underseal (I like Waxoyl Underbody) or prime, then use a flexible, paintable stone-chip protector and spray the colour over that. The stonechip protector is especially good on cars where the undersides of the doors are visible (like the older Saabs) so you can protect them without having to have them underseal-coloured underneath.

It was Hammerite Stonechip Protector I used, I think, but I've never sprayed cellulose over it so I don't know whether or not it's compatible.

 

[Mr_Caine]

Do you need to bare metal the car. Generally if the existing paint is solid then it's better left on than off. If the car has never been resprayed I would just recommend takibg areas of surface rust back to bare metal and treating but not the whole car. Flat the car back with a DA sander.

 

[jaykay]

taking that is a steel body.do you rust treatment,make use you do as instrutions say.
dont leave any on car or it will wreck your paint.
etch if you want,but not really needed. but does help.
celly primer onto etch is fine.

 

[ozy]

Hi
Thanks for your help. Most of the paint is ok I guess, just very faded. But there are some areas where it has flaked of which will need doing from bare metal, so I'd just assumed it would be best to take everything back to bare metal.
So if I'm just overspraying the old paint do I need to do the primer layers, or do I go straight on with the colour?
Is that waxoyl underbody or stonechip protector stuff also ok for painting the whole (separate) chassis as well as under the body?

Oh and btw its a mk2 Triumph Spitfire.

Oriel

 

[jaykay]

no, primer it first.
if it was me,i'd start a fresh from bare metal.
stone chip and then the waxoyl would be ok.thats what i would do if i was keeping the car.maybe a bit over kill.

 

[m1ecy]

I really cannot see any good reason for a bare metal respray - all the existing paint will make a really good base for your new colour, and is much cheaper than stripping the shell, and puting all the paint and filler back (oh yes, there will be filler!)

Save yourself some money, and invest that on more topcoat

Sean

 

[dopplershift]

Malcolm,

You say you use a Zinc-Phospate primer.... is this also an etch primer? If not, do you put it on before or after an etch primer?

I would think it makes sense to have a zinc primer right on bare metal, but will this deal with invisible rust like an etch will? Would you put etch over a zinc primer for good topcoat adhesion?

:s

 

[malcolm]

An etching primer (self etch) would contain some acid content that acid etches into metal for a really good bond. I don't think they do anything to stabilise rust. Etch always has to be on bare metal not other paints - it can lift existing paint.

Most decent brush on metal primers will be zinc phosphate. Doesn't etch, and doesn't galvanise despite the zinc content, but but sticks very well.

Both are bare metal and neither are fussy about what they are overpainted with.

That's my understanding anyway.

 

[dopplershift]

Ah, ok. Thanks Malcom!

What I meant about rust and etch primer was that even shiny, fresh steel will have microscopic rust (forms instantly). I thought an etch primer was the best way to make sure that this didnt progress into a more serious condition underneath the paint?

Sounds like they both do the job though!

 

[jaykay]

etch is for adhesion,not rust prevention.

 

[h-magic]

What do you class upol acid 8 product as then?
Will that stop rust re-appearing?
Will it eat into rust?

 

[jaykay]

jaykay

its a etch primer

 

[h-magic]

its a etch primer

Can you recomend a product that will stop rust then and can be used on 2k products also.
Thank you.

 

[jaykay]

most of them you have to apply first and then cleaned off
do not put rust remover on any paint,it will react.
i use jenolite,but plenty on the market.just follow instructions fully.

 

[h-magic]

right then let me get this right...

Jenolite then should i use Acid 8 (upol)
or straight to 2k hs build primer?

 

[jaykay]

jenolite,acid 8 then 2k primer.

 

[h-magic]

Excellent thank you very much.

 

[the snooper]

i wouldnt use cellulose paint either its outdated buy yourself a carbon filter mask and use 2 pac paint the results are much better its also better to spray