Painting the underside and inner arches.

[gaf2]

Hi guys, getting near the point in my project where i will be painting the underside. I have wired wheeled it back to pretty much all bare metal, any rust has been cut out and replaced. Looks like this.



Now i have been reading various threads on here and other sites, am after some clarification. Should i firstly spray with rust converter (I use Vactan), then etch primer followed by upol Gravitex. Do i then need to paint over the Gravitex with high build primer or a top coat?? Or what have you boys done in the past?

Cheers for any input.
Grant

[Southie]

Nick J could be someone worth pm'ing as he's pretty knowledgeable regarding spraying, also Benn is worth a try as well as he's also done plenty of titaviting.

[paul james]

The more layers the better in my opinion. On mine I gave another blast with wire wheel/polycarbide disc then panel wipe just before any painting. I used a bit of rust converter in places, but mostly applied several coats of acid etch/zinc primer. Covered that in a rubbery paint on stuff I can't remember the name of now, then a whole load of brushed on hammerite paint on top, which I can easily just fix with a few brush strokes if it ever gets chipped.

[Iain]

Sounds good, I think Gravitex is a sealed coat in itself but I covered my stonechip with a very light dusting of primer and 2k mixed up without thinners and brushed on. Has stood up to the test of time very well.

[gaf2]

Cheers for the info boys, i think am gonna go with: vactan, etch, gravitex with 5% thinners see how that goes then possibly 2k on top as iain has done.

[Iain]

I painted my whole chassis in por15 before the gravitex too

[ledpen]

Degrease and apply a coat of etch primer, if you wish you can apply a coat of high build or ordinary primer as a sealing type coat, then apply gravitex, if using white gravitex you can add a cup full of colour paint the same paint code as your body and mix it up an apply, this way you won't need to over paint anymore and it can be just left, however I sprayed black gravitex then a thinned down coat of high build( as it's hard to get the correct shading if spraying over black), then I sprayed base coat and 2k clear coat, came out well


Black gravitex



Thin high build coat



Finished result

[Benn]

I'll be honest and say i don't think Gravtex is that good. Used it for covering welding at the bodyshop. Never found it lasts long.

As Ledpen said, get it in a coat of etch primer.Are you re sealing the seams? (i would to cover the welding marks) If so do that next.
Then for me you want a good under body sealant. 3M make fantastic sealants, as do the people that make the por15 stuff.

If you do use Gravtex stuff, do a full thickish coat, leave it to fully dry for a few days/week then do anything coat.
Then etch it and paint it.
2K paint works well. 4 coats of lacquer is enough. As if you use to much it can weaning the clear when dry.

When its all dry. Give it a good wax and you'll be smiling.

[Edd]

Don't use Gravitex it's utter crap

Mine is all flaking off, probably need to scrape it all off soon

Use a rubberised overpaintable product, 3M for example

[Iain]

I used 3m paintable stonechip and its been great for years.