Diy spray prep/paint/polish guide

[goosiegander]

I know there are a few professionals on here as well as gifted amateurs, and was just wondering if anybody would care to share their insight as my diy efforts are average at best,

A proper step by step guide for proper prep work and spraying using both rattlecan and gun, plus the rubbing down/polish and sealing of fresh paint...

Mods if this gets a decent response maybe make it a sticky?

Thanks and best regards, Goosie

[aceraf]

I gave a quick guide on the following thread:-
http://www.e30zone.net/modules.php?name ... 27&start=0

(M-Tech 2 Kit Respray(at home)UPDATE @ 11/10/07)

Just put the few replies together and you'll have a short guide to start with. Will try and write up a better one for the Zone's benefit as soon as i can.

[goosiegander]

cool dude, saw the advice on shaz's thread definatly good to be going on with

[goosiegander]

bump?

[Andyboy]

Tips;

Forget trying to do silver or light metallics with a rattlecan, it never works. The BMW cans are rarely the right colour, always a shade wrong although the solid colours are generally bang on.
The secret is prepping. Let's say you've repaired a scab on the bottom of a door. That means grinding it clean or even better, using a spot sandblaster. Filler is easy enough to get right on a flat surface but there's an art to doing things like arches. I use 40 grit for initial shaping, 180 for finishing and then brush on some cellulose primer, leaving it a day to fully harden. Then you can rub it down with 240 grit wet and dry. From here I spray on some standard primer - grey for light colours, red oxide for dark colours. If you use red oxide under a bright red it will always show through. Halfords do about the best primer.
When the primer is dry, just dust a coat of your body colour on. This is the guide coat and as you flat it down with 800 grit it will show up every scratch in the primer and filler. This is what takes the time to get it perfect.
Once it is, T Cut the whole area. T Cut has no silicon so it's fine to use as it polishes it to a good shine and cleans off all the crap. Then paint on top, use about 4-5 light coats. There will be a shiny area around the repair and make sure you overlap onto the shiny area bu about 3 inches. This will prevent the 'ring' you see on some repairs when the sprayer has painted onto a matt rubbed down surface. You will never get rid of this ring.
Leave the paint for a day or so and then rub is down with soapy water and 1500 grit - 1200 is too coarse. You're just looking to take the top microns off to make a perfect surface. After that you can T Cut and polish it back. I've done some amazing aerosol jobs but be aware you'll never get a good finish with metallics - the rubbing down doesn't do it any good. The clear aerosol laquers rarely work and give a dreadful blotchy finish, especially the BMW ones. Try heating them up in hot water first. But overall, an aerosol metallic job will be average at best.

As for spraying with a gun, Cellulose paint is just about gone now so you're into single pack acrylics. My advice would be to do the prep yourself, take it to a proper paint shop and get them to do the final prep (always do this, otherwise everything will be your fault) and paint it. I've had self prepped cars painted for £250 with some very good results. Forget using 2 pack paint unless you want to die horribly. No, you cannot get away with a face mask and 2 pack paints contain all kinds of nasties like Cyanide.

Don't be tempted by Synthetic paints like ICI Permobel. A gifted sprayer can paint it and it gives an incredible gloss from the gun but you cannot flat and polish it so if you get a run, you're bolloxed. Great for giving an old shitter it's last paint job but that's it. It's oil based and really pretty horrid. You cannot paint on top of it with any other kind of paint.

EEC regs are slowly outlawing all forms of home spraying and even rattle cans could be a thing of the past in 2 years.

[goosiegander]

Andy thats awesome!

Thankyou

[Andyboy]

Pleasure mate.

Final tip for all you Henna red folk - Halfords will not mix the colour due to lead content in one of the pigments and BMW do not supply it anymore. BUT.....BL Cinnabar red is virtually identical and motor factors can mix cans.

[E30BeemerLad]

I am seeing the merits in a lazy matt black rattle can job on the touring already

[Rkive]

Excellent advice write-up Andy,

It willl help me a lot when I come round the spraying my tech 1 spoiler.

[abelai]

I do all my spraying with 2 pack paints, I use a full face mask with filters for organic vapours really you should use a fresh air feed and if I did it often I would. 2 pack paints are very hard wearing and give a very good finish. Spraying with a gun has alot to do with how well you thin the paint down, too think and its orange peel to thin and it'll run all over the place. Spraying panels on a car is also much harder than off the car so if its a wing door bonnet or boot you might be better off removing it to spray it.

A little 25l compressor can used for single panels no problem and are as cheap as £60-£80 a nice HVLP top feed gun £100 ish and a cheapo starter kit for £35 will give you some hoses and a gun to use for primer a condensor/pressure reg would be nice.

Once you start doing a little spraying you realise why a good spray job costs so much, what with all the time and effort that goes into it.

[goosiegander]

Thanks for the imput abelai!
I am seeing the case for the compressor approach especially with windy tools in mind...
Would anybody be able to throw in a clay bar decontamination post as well in the interest of completeness, sounds like it could be quite important...