Can i use Etch primer on old paint

[Funkatronic]

Im in the process of prepping a clutch cover for re-painting

i have sanded back the rough bits of the cover with 600 grade wet and dry this has exposed a few bits of bare metal

should i spray the whole cover inc the painted bits with the etch primer then rub down it down again before painting? Will the old paint and laquer blister under the etch primer?

if so, am i better off carefully touching in the exposed bits of metal with etch primer and a paint brush, rubbing the whole thing down again and then applying the paint?

or should i get the old cover soda blasted to remove everything then etch prime then paint the lot?

thanks

ali

[analogue_rogue]

Yes mate as long as its keyed properly just prime the lot. But make sure you.sand back through the laquer. It worked great on mine.

[slipperyweeguy]

Yes. You can use etch primer on old paint - but - if it is an aerosol can then use thin coats (in order to reduce the chance of it reacting with the edges of the old paint) and as little as possible, followed by a proper coats of grey primer to build it up, then rub with the finest wet/dry paper you have, (used very wet) to get the surface you will put your final finish on.

Allow time for drying and shrinkage before recoating - patience has its own rewards.
Hope this helps.

[dunlop0_1]

Due you mean primer or etching primer? These are two very different things. Regular acrylic primer in an aerosol won't be a problem (unless you apply to much in one go) however, etching primer is a 2 part acid based paint designed mainly for use on new metal particularly aluminium and will most certainly react with the edges of the original paint.

I was a commercial vehicle painter for 22 years. ;)

[Funkatronic]

Tanks dunlop, so your def the man who knows best

i have both acid etch primer and acrylic primer

whats my best plan then? just use normal arcylic primer all over, even on the on the little bits of bare metal? will the paint stick to these or is ot likely not to bond?
or should i very carefully touch in the exposed bits of metal with etch primer and small paint bruch, sand back any uneveness/reaction blistering, then acrylic prime, then paint
or get the whole thing media blasted back to bare metal then etch prime, sand, then paint?

[dunlop0_1]

The ideal thing is back to bare metal and start a fresh. However, I would patch prime (acrylic) the bare spots being careful not to overload with paint to avoid any reaction. The following day I would key the whole casing with a scotchbrite pad or 1000 grit paper (and soapy water). Recoat with primer and use some colour on the last two coats. Again the following day key the same way and add the colour coats until your happy and lastly two laquer coats. Finally the next day another key with 1200 grit and laquer until happy.
It's a long winded process but patience really does pay off, do not be tempted to "give it one more coat for luck".

The engine and all the bodywork on Louise's M600 were done with aerosols but it took me nearly two weeks to finish, but worth it.

http://i139.photobucket.com/albums/q289/dunlop0_1/IM002247.jpg

[jerry]

Thats a classy paint jobby on the m750

[analogue_rogue]

How do you get a Matt finish with laquer? And van you get good finishes without baking? I have always sucked at spraying.....

[dunlop0_1]

Thanks but its actually Louise's 1994 M600.
Satin finish is acheived with plastikote satin laquer, but you really have to be patient as the flash off time between coats is way more than the acrylic aerosols.