Painting & Rust Protecting Underside & Fuel Tank

[skillz 0]

Before i refit my beam i thought it would be a good time to sort out the few bits of rust and cracked underseal under the car and in arches. I'm gonna drop fuel tank off aswell .

Now ive read plenty of threads on the subject but im still trying to work out best method.

I'm going to strip right back with power tool attatchments and want to end up with a body coloured belly and arches obviously. (Miami Blue car) which i'm sure i can manage but paint is something i've no experience in. ill be wanting to do most of it with cans although i've got a small diy type compressor at work i can borrow if needs be

 

Would i be right in thinking

 

1. Strip Back

2. Some sort of etch primer or zinc? what's best?

3. Brush on seam sealer

4. Primer again?

5. Stone chip

6. Body Colour

 

if anyone has recomendations on brands also would be good. preferably for ease of use due to my lack of skill but also for durability as dont want to do this again soon.

 

also on the fuel tank can it be painted if so what to use or will it clean up well enough?

 

cheers

[Leon 24]

Personally:

 

Strip back

Bilt Hamber Hydrate80 on corroded areas

Bilt Hamber Electrox primer (this is my favourite primer ever, it weighs a tonne)

Seam seal (I normally use Grey Stripe)

Epoxy Mastic

Stonechip (Masterguard is my favourite, Gravitex is good too)

Body colour

Lacquer

 

Everyone has a slightly different method though

 

EDIT - I wouldn't bother with painting the fuel tank, it's made of plastic so if you did want to tidy it up you could plastic prime it and then shoot it with some satin black.

Edited September 23, 2012 by Leon

[SurGie 54]

This is how i did mine, a lot easier and will last at least ten years before rust comes back if ever. Rust converters are troublesome to get right and no need with the paint ive used either.

 

http://forum.205gtidrivers.com/index.php?showtopic=143870

[skillz 0]

thanks Leon any pics of your method?

 

just had a read of your build SurGie and looks interesting. did you not use seam sealer or primer then and paint straight onto metal? have you had any signs of cracking/shrinkage?.

also where did you get it from as ive found a few of their products online that come in colours which would save time but not the specific product you used.

[SurGie 54]

This jotamastic 87 is a primer on bare steel, do you want the tech sheet so you can check its benefits etc?

 

Its flexible and surface tolerant which seals any remaining small buts of rust etc. Its for sea boats that cant get sandblasted only wire brush grinded. The 87 is the amount of solids in it, which helped fill in rust pits and gets into panel seams, not used any sealant with this stuff but did on the front panel wings etc. I didnt find this paint till i started the floor and back chassis, wish i did as i had already done the front with zinc primer.

 

No signs of cracking or nothing, i have spoke to a few that has used it and ten years later its still not rusted. I rollered it on then applied another 2k paint rollering it on then top coat body colour.

 

Read the tech sheet fully and you will see how well it is for cars chassis being abrasion risistant etc. It sticks like glue to almost anything. Google in paints for trade and they sell it, it also comes in 90 now which sounds even better than the 87.

[skillz 0]

some good info there cheers, how much did you use on yours?

still cannot work out from the data if it can be over painted or not as it is not available in blue.

[SurGie 54]

Best thing is too spend half an hour reading the full tech sheet and jot a few notes down on things that you need to know or remember. Once read and got your head round it you wont go far wrong, its quite an easy product to use, even drips on the garage floor that was full of dust and bits etc wont come off using my fingers.

 

Look on the surface preparation section, it talks about bare steel prep, always best to key grit it with 40/60 grade for much better adhesion.

 

 

Not the best looking but you can see the finish, any top coat can be sprayed on after at least one day, 24 hours, its quite versatile. Any sooner and you risk going into the flash off period which like any paint can cause bubbling due to the solvent trying to escape etc. There are two types of hardener, one for low temp curing ie winter or the other which is for 20 degrees temps. I would say i used up about 4 litres but mine has 3 coats all under from floor to inside boot seating area. Just make sure you apply 'good coverage' because mine still had the tiny bit of steel showing after a good thick first coat. This stuff can be applied in any thickness, i cured a good jug full that i made too much off, all solid yet durable.

 

 

This one is just the primer then top coat using two good coats rollered on, the lower floor has another 2k coat of paint using two coats off which makes it look at bit rough. It looks like stonechip using just the primer but you can apply 2k stonechip rollering it on with a good face mask. Notice the panel gaps are full of this stuff, filling in making sure there is no room for any water air to get in and makes it look neat too. Edges always get rusty as does weld areas first, this thick primer covers them well, it can be thinned using quality 2k thinners like what i did, for a better smoother finish but takes longer to flash off and cure. The 24 hours gave me some lead time to finish off the next night etc.

 

 

All 2k paints have very good adhesion and durability, especially epoxy, but cant be sprayed without air fed mask.

[skillz 0]

so you painted three coats of the jotamastic and then another coat of 2k on top? spraying with compressor is something i don't want to get into due to my pathetic little compressor and lack of mask so im after something i can brush or roller on ideally

 

could i use a highbuild primer ontop of the jotamastic then spray a miami blue top coat and lacquer to make it look pretty?

 

wanna get this done right and by the sound of it it'll be a bug*er to get back off if i naff it up

[SurGie 54]

Yes it will be very hard to remove, if you want it really pretty then get a good compressor, another one for air fed mask, all the filters pipes etc etc, pretty isnt cheap, mine wasnt but still looks good compared. I applied it thick around the spare wheel area because that seemed to get most of the damage and rust. Fuel tank area just had 3 coats of 87 with no stones or damage in the area.

 

I used a compressor, it will cost you loads using spray cans compared to buying a compressor. Always check the tech data of any other paint on top whether or not it can be rollered on. You dont want to use high build though because it might be too thick as Jotun has a lot of solids in it, heavy paint. It will always look like stonechip using roller.

 

You wont be able to make it look 'pretty' using 1k clear laquer it will go off and look rubbish. 2k clear maybe ok but you dont have an air fed mask, not sure how it would look using roller with 2k clear. Mine being a dark colour doesnt show the stonechip roughness with the amount of shadow there is on the chassis pan, but the Miami will, all i care about more than looks is durability, adhesion and long lasting.

 

 

 

[SurGie 54]

Oh and jotun could be sprayed for a nice finish without an air fed mask as it does not contain any iso's which are bad, but air fed is the safe thing to do tbh.

 

While i remember it says its compatable with most other paints.

Edited September 24, 2012 by SurGie

[skillz 0]

Hi, thanks for the info ill be posting pics of my progress once i get started and try to source a compressor. Any excuse to get new tools

[SurGie 54]

Your welcome mate, its not an easy job and any advice you need let me know, good luck with it all.

[CosKev 16]

One of the most important jobs is removing the old sealer/stone chip/rust to start with.

 

Back to bare metal is the the best starting surface by far.

 

Once its back to bare metal I use Metal Blast,a acid based rust remover/surface prep liquid spray,

 

Then paint with Rust Bullet Automotive,this paint is very good,but expensive,

 

I then seal all seams with Tiger Seal,

 

Then I use non-drip gloss as a top coat,as many coats as required.

 

I don't use stone chip as its harder to keep the areas clean after due to the horrible dimpled finish!

 

http://www.rustbulletuk.com/categories.php

 

My Rallye underside is showing no signs of rust or lifting paint at all,its a daily driver and has done 20k miles now since doing the underside and two winters.

 

 

 

And heres my Evo,as you can see I quite like scratting about under my cars!!!

 

 

[harryskid 193]

With a bottom finish like that the top must be stunning!

[SurGie 54]

The few things that put me of rust bullet is mainly the price and second the flexibility which is doesnt have.

 

Not sure which product you are using because i have no problems cleaning stonechip surfaces, tops are meant to be smooth the floor pans never were.

[CosKev 16]

, tops are meant to be smooth the floor pans never were.

 

But do look alot better smooth.........

 

Stone chip is used to cover rough/poorly repaired/prepped surfaces IMO

[BenC 6]

I know it's a bit late but here's my preferred method:

• Degrease with Bilt Hamber Surfex HD to remove all old dirt and road crud
  
• Remove old underseal & as much loose surface rust with an electric drill and wire wheels.
  
• Then remove all rust with Bilt Hamber Deox-C Gel. Really good stuff, Brush it on thick, cover with cling film so it doesn't dry out and leave it for a few hours. Come back to it and scrub the gel with some wire wool. Rinse the goo off and inspect. Repeat as many times as necessary to get back to clean steel.
  
• Prime surface with Bilt Hamber Electrox. Great primer with a very high zinc content for future protection.
  
• 2-3 coats of Por-15 - do not get this stuff on bare skin, nothing removes it and it takes weeks to get off!
  
• Top coat if you like with some POR-15 chassis black.
  

[SurGie 54]

Yeah it does with light coloured cars like white and red but dark cars are harder to see the finish underneith. I suppose its which you like, i prefer the slight stonechip finish my primer gives by rollering it on, it does seem to be smoother than actual stonechip. I like the textured finish rather than flat, it is much harder and more work trying to get the pitted rust spots filled in and smooth, its hard enough reconditioning an old cars floor as it is.

 

The Jotun 87 does it all in one job if sprayed, filling in rust Pitts etc due to the 87 % solid contents.

 

Did you spray the rust bullet ?

 

I found when spraying underneath it does miss the odd nook and cranny, this is another reason for me to roller/brush it on so every last bit is covered.

[CosKev 16]

 

Did you spray the rust bullet ?

 

 

 

No,brushed on.

 

Not got the patience to spray paint,end up rushing the coats and getting crap finish!

[SurGie 54]

Oh right, it looks quite smooth being brushed on but then pictures dont always show everything clearly.

[CosKev 16]

Oh right, it looks quite smooth being brushed on but then pictures dont always show everything clearly.

 

Good quality brush

[Kevin s 0 1 Cars]

I did the following;

Removed underseal and rust etc with a wire wheel and heat gun.

Patched and welded as required (it was like I had bought a Ford!)

Painted with a marine grade aluminium primer (2 x coats).

Covered with an 2 part epoxy resin used for lining the beds of pickup trucks, once mixed it goes on with an underseal gun.

Painted black (2 x coats) as the resin came in white with no dye as it should have.

 

I haven't got the car on the road yet, but assume it will last forever, as it's hard as hell once it's cured.