The Spray Painting Thread

["Z" UTE]

After applying your rust converter, there should be no need to use etch primer, as the rust converters have an acrylic barrier on top, or they use phosphate to coat the metal.

Realistically if you think the area will not be seen, and you can live with a few brush strokes, by all means brush the primer and paint on.

A mate of mine in the windscreen replacement repair industry uses "Wattyl killrust rust-eeter". Steve uses it to prep any rusty areas that are visible once the screen has been removed. Applied with a brush, or a fibre swap such as plumbers use for glueing pvc pipe together. Works a treat for all rust repairs.

cheers Chuck.

[Z2TT]

Thanks, will do that then.

Is it the rust converter that makes a layer that prevents the metal rusting, or does the etch primer do that too? Or does the etch primer only help the normal primer stick onto the metal?

So I'm just wondering if I sand all the rust away, will the etch primer help seal the rust away, or will I still need to use rust converter to kill all the microscopic bits of rust.

Like say if I had a rusted door or bootlid and i sanded it away to the metal, can I coat it with etch primer, then acrillic primer then paint + clear.

Or do I have to use rust converter, and the rust converters that I know of are ones that are meant to be applied by brush, so cant be sprayed?

[derekjay]

Anyone dealt with these guys before? http://www.detroitcustom.com.au/

They seem to have some good rep on the web.

[Z2TT]

Got a few questions regarding fixing the rust.

1. I was thinking of sanding the rusted bit and spraying over with k@h etch primer :

http://www.khst.com.au/index_autoretail.html

But won't it fry the surrounding paint, So how can i get around this?

2. Do I need to then use normal primer, as the K@H stuff says "Etches and Primes", or do I still need to use normal primer over the etch primer before applying the color, or does etch primer simply just make the bare metal "sticky", so you can apply normal primer onto it?

3. This etch primer, can it be easily sanded with normal wet/dry ?

4. What sort of safety equipment and mask should I use when working with the etch primer i've read it's very dangerous to inhale.?

5. Does the etch primer act as a rust converter too, as in stops further rusting of the surface?

[kremsra28]

i too am wondering bout the rust converter, we have nearly a whole car which is covered in surface rust, we are using septone rust converter, was told ny the paint shop guy that it would still need to be etch primed so we bought some wattyl superetch, but i also want to use spray poly to fill the pitted areas left by the surface rust, but was told that the etch primer and the spray poly aint good mates so to speak, so wat would be the best option??

cheers in advance for any help given.

krem

[Steve M]

It depends on what etch primer you use and how you use it.

I initially used Protec metal conditioner and degreaser (phosphoric acid treatment) to remove the surface rust / grease (that stuff works really well but you have to rinse it off again very thoroughly or the paint doesn't stick well).

Using etch primer as an etch primer it is only applied very thinly, purely to prepare the metal for the primer surfacer. Please correct me if I a wrong here.

I used a vinyl etch primer and found that if it is applied too thick it is not sandable. Where it has sanded it swells at the edges when other wet coats (acrylic) are applied over it. Spray pack etch primer often does this too. (Motospray spraypack etch certaily does).

The manurfacturer of my stuff (Protec) recommends light use of etch followed by coats of primer surfacer, then spray putty /sand where required. Primer surfacer is then used again before colour and top clear coats are applied. I don't recommend sanding through to the etch level. It is better to apply more primer surfacer before sanding too deep and havign issues with the etch.

I am not a trained painter and so others are welcome to tell me I am wrong. I have found that good results can be achieved this way.

I want to get my hands on whatever Toyota used as their primer (the red stuff from the 1970s) That shit was amazing. One good coat and it doesn't rust up for thirty years!

Does anyone know what they used?

["Z" UTE]

Steve M, the red stuff is "red lead", so I guess there is no chance of getting that again.

The absolute best bet with surface rust, is to mechanically remove the rust, with sand paper or a graffiti removal disc. (These things are about $12.00 from bunnings, work on your small angle grinder.) The graffiti removal disc is like a plastic birds nest, removes paint and rust, with lttle removal of metal. Mind you, you can generate some heat with these, to avoid panel warpage, best to limit work on bootlids, bonnets and turrets to a square foot, then move to the other panel, just switch between the panels allowing cool down time.

I use PPG products, as that is what I am familiar with, used to be called Dulux. The following procedure is taken from the Dulux handbook I picked up back in the sixties

Next step after buzzing the rust off, is to use "Deoxidine" which you apply, then wash off with running water. Some etch products leave a heavy sticky residue, as can this stuff if you try to work too large an area at one time.

Dry off with an air gun, wash with prepwash/prepsol, and then give the panel a light translucent coat of "Port Etch Primer", then primer, then highfill. (Steve M, the "Port Etch is damn tough to remove, so almost as good as Toyota's red lead.)

Epoxy CT etch can be used if you have it. This is quite good at covering and would probably be the best bet if you are not planning on priming and finish coating till some time later.

If you happen to blow through the etch coating while doing repairs or sanding, there is no need to reapply the etch primer, just apply a good coat of primer.

Highfill, is the best for filling all the little pocks in the metal after you have etch primed.
I had to highfill and sand one TA22 three times to get a decent flat surface, the owner had got to it with a 9" angle grinder with grit about the size of road base!

Any painting should be done with a decent respirator, and please change the cartridges regularly. If you happen to be using a little bit of 2pac please use an organic cartridge, the same as you would use when spraying insecticides.

cheers Chuck.

[Steve M]

Ah, red lead. Yeah, like you said not much chance of finding that now.

One thing I liked about Protec's etch is that it is very resistant to welding head.
Other paints bubble up a long way from where your welding, the vinyl etch doesn't burn and doesn't really loosen from the metal much, any bits that came unstuck are easily removed but the damage is minimal compared to other primers I've used.


Protec's metal conditioner sounds very similar to deoxidine. I sand the surface rust flat and then use the conditioner to remove the pitted bits. I've had totally red bits of metal come up looking lie they were brand new after about 5-10 minutes work with a scotch bright and the conditioner. I love that stuff.
It must be very well rinsed before it dries otherwide it leaves to much photphate on the surface.

It also ruins your fingerprints for a couple of weeks if you don't dilute it and use gloves!


It s a good idea to wear full body coverings with 2 pac, it stung the shit out of my brother in law's eyes adn skin when he was spraying his boat. (He changed his mind and went shopping for a chemical suit, correct face mask and then sprayed it on a farm to avoid killing his neighbours).

the owner had got to it with a 9" angle grinder with grit about the size of road base!

Haha, you wrote that very well !

I found some patches on my car that were similar to that.

[Z2TT]

Is Metal conditioner basically another name of rust converter? So this one can be applied by spray gun instead of brush like septone ones that are meant for like shovels and stuff?

What's the difference between metal conditioner and etch primer, I thought the Etch primer was what treats the rust.

Is Highfill primer only needed when your spraying over etch primer? can you spray basecoat straight over highfill or do you have to then use normal primer, and why so?

["Z" UTE]

Ok, a rust converter will contain phosphoric acid, which chemically converts the oxisdized metal.

An etch primer may contain a small amount of acid, which becomes inert very quickly when applied to the metal.

Depending on the product, you can etch prime an area that has seen "rust converter", but many of the rust converters leave a plastic film when cured, etch priming that would be useless, because you have a physical barrier between the metal and the acid in the etch primer..

Other rust converters, after converting the oxidisation, leave a film of phosphate on the metal surface, to protect against further oxidisation.

Metal conditioners are basically a coating of very mild phosphate, used when metal has been worked, but not oxidised.

I have used many different brands of rust converter, and I would not trust the ones that leave a plastic layer, if I were to use that product, I would remove that coating before etching and priming.

Etch primer is applied to give a bond between the metal and subsequent layers of primer. This is also why there is only a very thin translucent coat required.

High fill primer is effectively primer with loads more solids in it, designed to build a thick sandable coat. You would only use hi fill after doing all your repair work. The hifill is then quickly knocked back using 120-240 on large boards, then a guidecoat is applied, then you commence your final sanding with 320 moving up to 800. Base coat or any colour can be applied to the high fill without needing to be coated with primer.

I use a PPG product called one shot primer filler, unthinned it is high fill, thinned it is primer.

cheers Chuck.

[1JZ-Rolla]

Good explanation Chuck, cheers.

[Z2TT]

I take it most metal conditioners you have to spray on then wash off with water? or wax/grease remover, right?

Which conditioner do you recommend chuck that is available today?

So now the way I understand it, highfill primer is good for filling in irregular surfaces so you can get a flat surface to paint on?, but wouldn't you apply bog to irregular surfaces instead of highfill. Or have i got it all wrong, is Highfill meant to fill in little micro gaps in the bare metal and is necessary when doing a bare metal respray?

[kremsra28]

i thought that after you treated the metal with rust converter that you could sand the film off thats left by the converter then go bout the panel prep as normal?? as the converter has already done its job.

or is this wrong??

Z2TT, high fill is only good to fill very small imperfections, pin holes in bog or bridging the gap where your filler may not be feathered off properly, i too have used ppg 1shot and found it to be very good, but then tried spray polyester, which i found to be much much better, you can apply bog over it if need be as its made from the same stuff, with the high fill, you would need to take the area you not happy wit back to bare metal and start over again,

also spray poly is a bit more expensive, but it also covers more than the 1shot. altho it is very very smelly and toxic, so a respirator is a definate must.

as for the red lead, is that similiar to the galv paint you can use to protect the metal or is it different??

i will be doing the ra28 soon so will post pics up of before and after, you will see how bad the surface rust is, the whole shell and tailgate is covered in it, its been like it for around 8yrs that i know of but the actual rust holes are very minimal, my last 28 was painted but had 100 times the rust holes than this shell!!

krem

["Z" UTE]

Z2TT, I simply use Deoxidine for all my metal prep, it is applied via cotton cloth, agiated where necessary with the "painters red scotchbrite" then rinsed off with water, prepwashed then primed.

As krem has said Hi fill is used to fill small impefections after you have used body filler. However crem is a little off the mark, as you can "bog" over Oneshot, with PPG Galvaplast filler. This is a microfine filler, and is able to fill pin holes and deep scratches. Very handy instead of using blade putty, which is just paint solids with a litte thinners. Blade putty can shrink back big time, whereas the Galvaplast being a catalyst cured plastic will not.

krem it depends on the brand of rust converter, but yes you can generally sand it off after it has done the conversion job, however if it is the phosporic acid type like deoxidine, you would leave the phosphate coat alone, and apply your etch prime, primer or poly straight on top.

Red lead is not the same as the cold galvanising paints. These paints contain zinc in solution not lead.

High fill is normally used as an all over last coat prior to sanding, as it will fill all the featherd bog edges and rough sanding marks left from repairs etc. You may have to apply a couple of coats to fill large depressions.

cheers Chuck.

[DrNick]

Is PPG Galvaplast similar to K&K Pedigree fine filler?

I was thinking of trying the latter one out but never got around to it and have used blade putty instead, but the shrinking is terrible. I would prefer to use K&H if it is similar as I use the K&H bog as well and I try to keep the same brands together as theres less chance that they will react strangely.