PAINT THREAD

[Rookie]

So you are saying that you spot prime the area and try your best not to sand through when you flatten it? Seems like a bunch more work that etching and then spraying over it.

[Spencer]

You can use etch but as I said it is old technology, if panel beaters are still using it now its because they are old school and won't change, or because its cheap. Epoxy primer is a superior product in pretty much every way

You shouldn't be breaking through fuck all when you are close to colour. The way I do things your car should be blocked out and re-coated in 2k primer before paint. This final coat of primer will be wet sanded with fine paper up to ~600 if you breakthrough it will be fuck all at edges, 2k primer is fine to put over small bare metal patches and I would mix some up in my small gun and touch it up and wet sand again. You can get PPG 1K primer in a can that is a real good quality, it will adhere to the bare metal pretty well for a tiny edge break through, I don't use it myself but it is an accepted option rather than mixing up tiny amounts of 2K primer

In some production line type shops they wont fuck around touching up small break throughs when final sanding. They hit the car with a thin sealer coat of epoxy and then wet coat the colour straight over that. For the amatuer though that is another step in your paint process and another stage to introduce orange peel. Also we don't work on the time frames where we will be block sanding and painting all in one day, usually happens over weeks

I wouldn't touch a car with etch primer these days, I have seen how shit it can be with reactions and bad adhesion to other paints first hand.

[Spencer]

So you are saying that you spot prime the area and try your best not to sand through when you flatten it? Seems like a bunch more work that etching and then spraying over it.

So you top coated wet over the etch? or let it dry and didn't sand it? what did you top coat your car in? single pack acrylic lacquer? seems a backward way to do things if you used 2k paint

[Rookie]

Yea I was only talking about breaking through on the edges. I just went and etched the bare metal, let it tack off, and then hit it with the colour. Like I said I'm no professional, and I was doing it under the instruction of a panel beater. I used Spies Hecker base coat clear coat.

[Spencer]

So wet coated over the etch, sure you weren't using epoxy? you wont find many people who will tell you to use old school single stage etch to spot prime break throughs then wet coat over it. Etch goes on pretty thin, last thing I would want to do is go straight to top coat over it. I can't see why he didnt get you to use epoxy or 2k primer instead? but then again allot of painters do different shit and swear by it as they have done the same thing for x amount of years. You will probably find the tech sheets for your brand of paint will have a specific epoxy primer/sealer which is made for spot (or a full sealer coat) wet coating before colour.

Personally wet coating over spot repairs for a hobby/restoration is a no go for me, as I said its another place to introduce orange peel or an imperfection. Would rather take some time chuck some more 2K primer on and have the whole car smooth as shit when it goes in to shoot colour. Not many home paint jobs here are done in a rush, I keep wet coating over primer to engine bays and firewalls etc

[Spencer]

Actually I dont think you will find a etch primer that will let you paint over it wet because of the acid content?

[Rookie]

I dunno man, but that is what I did.

[Spencer]

So you are 100% that you used single stage acid etch primer though

[Rookie]

Yea, it sits in the gun waiting to be used, if it was a 2k it would go hard wouldn't it?

[Spencer]

You have a pot life of 4-10 hours with most epoxy primers once mixed, depending on temp/humidity and the paint brand, in low temperatures it wont set at all. When doing block work and bogging I will have some sitting in the gun most of the day, urethane 2k primer and paint is the one that goes off quickly in the pot, say 10 min-2 hours again depending on a bunch of things. Maybe the panel guy called it etch but it wasn't? didn't see the tin? mix any yourself?.

[Rookie]

Na, I didn't see the tin, or mix it. He was all like; *thrusts gun at me* puff this on the bits you sanded through. But he definitely referred to it as Etch, and it was heaps different to the 2k stuff I had put on previously.

[Spencer]

Yea so If you are using 2k paint and primers I doubt this guy chucked acid etch primer at you to touch up some edges before paint. Sounds like a terminology thing, I would say it was an epoxy sealer or your paint would probably be falling off

[bubblegoose]

unfortunately spece you are incorrect, 1k etch is used as a wet on wet primer (2 in 1 product) in alot of shops including the one im at and is covered under the manufacturers lifetime guarentee

most can even be tinted to be used as a ground coat for weak covering metallics, its not as old school as you think

[Spencer]

Cool, what brand/system does your shop use out of interest?

[bubblegoose]

we use PPG but the wet on wet etch shit we swapped to standox as it seems to self level better

reason behind sticking with the 1k system for this is all 2k products have a much higher build/fill and always require sanding unless doing a full wet on wet coat ( ie ppg dp40/ 4000) with the standox 1k we can spot prime a rub though, let it flash then paint over it with no visible edges or peel as it drys to thin to make a difference

its also super handy to throw down as a first coat before slapping heaps of 2k primer over a rough old panel

[LS 2 THE DEEE]

Spies hecker does an etch called 4085 its 1k and can be used wet on wet.... its expensive but its good and also comes in an aerosol which is handy as opposed to using/cleaning a gun

Ive used it as stated earlier on edges where theres been a rub through, both wet on wet and given a light rub as it is quite thin but it has amzing ability to kill any fish eyes from contamination and seems to be quite resiliant to fry ups on edges of repairs

Im no professional but keep a can of this stuff about always it can be very handy

[bubblegoose]

ill just throw this up here

this was a weekend rush job on cherrios 740 and after slapping on the second coat of black base coat i noticed that we had rushed too much and 320 sanding marks were visible over the whole car so i let it sit for 15mins and slapped coat of spies wet on wet mixed 50:50 with black base (as seen in the picture) then 2 more coats of black and it fully covered the whole woopsie.

its a fantastic product

[Rookie]

Hey Spence,

I just hit up the panel beater while I was round there and it's definitely a 1k etch primer. He echoed what bubbles said almost exactly.

[Spencer]

Yea cool man, I guess 1K etch has moved along from the shit back in the day, I am yet to look up a MSDS or tech sheet but I'm doubting they have the acid content of the old stuff if you can wet coat them? I learnt what I know off guys doing restorations and its epoxy all day for them, my current paint system doesn't have a 'etch' you can use wet, but there are 1k primers in the range you could use for the same thing. As usual with painting there is different shops/professionals on different systems with different ways of getting it done. Just reiterates to read all your data sheets and learn the paints in your range/system

Still to most of us amateurs painting at home painting primers wet on the day we do colour is probably not the best idea. When your prep etc has taken 6 months why add an extra wet coat on paint day, especially if you will probably be using your topcoat gun to lay it on.

[bubblegoose]

for restoration epoxy is defiantly the way to go, mostly when bare metalworking its perfect for slapping on right after blasting or stripping then you can asses rust and dents without fear of the metal deteriorating while you work on the car.

For panel work a 2k hi build or filler primer is a must as it has many multiple times the build as an epoxy and sands alot easier which is nice

buying a wet on wet capable etch primer that costs not much more than either single product is clearly the way to go if its available at the time

to clarify what a wet on wet primer is for for those who are not so sure, its a thin primer sprayed out of a regular paint gun before you lay down your colour, reason for using it can be to cover up any wayward sanding marks you may have missed (dry guide helps with this), to prime areas that have been rubbed though to bare metal or bog, if you are doing a colour change and have several patched of 2k primer over repairs but dont want to 2k prime the whole car, as a ground coat for colours with poor coverage and a few other reasons but those are the mains

^dry guide, is a colored dust usually black that can be rubbed over bog and primer to check for shape, hi/lo spots and when working down the sanding grades it will show up coarse lines that need attention

imo there are too many products on the market, should just make a self priming black paint and leave it at that