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whats the best way to prep a chassis for painting?
MikeR - 10/7/08 at 08:03 AM

In the next couple of weeks i'm going to paint my chassis.

I'm curious what the best way to prep the metal is before painting.

Do i use marine clean / detergent to wash the chassis, once dry use a wire brush in an angle grinder to clean?

Perhaps the other way round, get the rust off then detergent?

What about using a chemical to clean it like white spirits?

Is there an issue with using a water based detergent and the chassis rusting afterwards?

I've spent 8 years getting this far, i don't want to mess it up now.

richardh - 10/7/08 at 08:07 AM

dont forget about a suitable primer
(zinc oxide or similar)

tegwin - 10/7/08 at 08:09 AM

I used a selection of drill mounted rotary wire brushes to get the entire chassis back to shiny bare metal...... took a while and is fiddly...but worth it!

Then I scrubbed the chassis with liquid degreacer....cant remeber what the name of it is...but it came from halfords in a big red bottle.... (Swarfega or something similar)...

Then I hosed the chassis down with a lot of pressure to remove the degreecer and bits of old paint etc...

Dried the entire thing with a towel....
then started painting

Andy W - 10/7/08 at 08:09 AM

After 8 years I wouldn't want to mess it up either. I'd go for powder coating. Painting the chassis is right pig of a job, I know you don't see much when it's finished but I think it's worth the cost to save all the grief

Andy

Mr Whippy - 10/7/08 at 08:27 AM

powder coat it in a nice bright colour, always looks the best

nick205 - 10/7/08 at 08:46 AM

quote:
Originally posted by Andy W
After 8 years I wouldn't want to mess it up either. I'd go for powder coating. Painting the chassis is right pig of a job, I know you don't see much when it's finished but I think it's worth the cost to save all the grief

Andy



Amen to that!

I must have spent 2 weeks in total cleaning, prepping and brush painting my Indy chassis on the belief that I was saving money on powder coating. IMHO I did a reasonable job of the prep, 2 coats of red oxide primer and 2 coats of chassis black paint (Jenolite?). Aside from the physical effort and mental torture involved in painting all four sides of every chassis rail 4 times, the finish (no matter how good you are) will never be great and TBH it's the one element of my build which really gripes me. Particularly as you can't rectify it once the car's built. The only thing in favour of paiting over coating is the ability to be able to touch it up if you chip or scratch it. But then powder coating should be more resistant to that anyway.

tomblyth - 10/7/08 at 09:15 AM

buy a cheap paddling pool and some soda crystals use electrolisis to remove all traces of rust! ,scotchbright it ,etch primer it and twinpack paint it your chosen colour! "thats what i'll do next time, this time ! this time I got it powder coated and I regret it each timei drill a hole or add a bracket!" although I might look at galvinising depending on price!

mikeb - 10/7/08 at 09:18 AM

I've got to do mine soon.

I was planning on a flap disk in the angle grinder and the wire wheel followed by the scotch pad, I have some spray on degreaser that's alcohol based so evaporates off (or use thinners), then a couple of coats of acid etch weld through primer followed by a top coat of some kind of enamel paint (hammeright etc) i have painted a couple of wishbones and uprights like this and the finish is good.
Not sure of the total cost saving to powder coating but I like stuff I can do at home rather than arranging and transporting the chassis etc.

You'd still have to prep the chassis prior to powder coating I would assume?

big_wasa - 10/7/08 at 10:32 AM

Its on my to do list very soon

Powder coating is out as I have already bonded the floor on.

As said its going to be a pain in the arse getting it taken any where. So it looks like I am stuck with the job.

A year or two ago I gave it a clean with the tool a spayed it with primer.

So I think I will give it a rub down and etch prime bits that I have modified ect. I will then give it a couple of coats of primer and a couple of coats of chassis black.

job done

indykid - 10/7/08 at 10:46 AM

shotblast then powdercoat.

by far the best finish and most durable. MK's powdercoat only chips so easily because of the wee poor prep.

powdercoat can be touched up with brushpaint or aerosol and still looks better on the whole.

expect to pay £250-300 for it doing but if you're looking at marine clean etc, you're still going to be over £100 by the time you're done and have devalued your car in the process.

just my view on it anyway
tom

CaptainJosh - 10/7/08 at 03:38 PM

Fingers crossed i'll be doing my chassis next week- im going to get a few mates together and sand it down with 240 sand paper ( goes right through surface rust ), then i'll spray it with zinc oxide primer with the compressor.

I'll get a about 3 coats on, then leave it a few days to dry then, with what mates i have left, im going to paint the chassis a few times with cheap satin black spray paint.