[Vettezuki]

Originally Posted by enkeivette

Look above the saw.

Is there a reason to get that since my brother left his gun?

[enkeivette]

If your brothers gun is nice, and you intend to use it for paint, then yes. Best not to get our paint gun clogged up with epoxy. Some even use a different gun for clear and color.

[enkeivette]

But if you don't want one, don't worry about it. I think I'll pick one up today.

[Vettezuki]

Say, since we need to cover some bare metal bits, which is best? My brother mentioned to use self etching primer, you've suggested PPG epoxy. Please to edumacate.

[kameleongt]

let me know what you guys want ill try to find it for you guys We carry only are own brand paint "northstar coatings" they make a great surfacer or epoxy primer. I can drop some off if you would like to try it I can try getting other stuff its just more difficult.

[Vettezuki]

Originally Posted by kameleongt

let me know what you guys want ill try to find it for you guys We carry only are own brand paint "northstar coatings" they make a great surfacer or epoxy primer. I can drop some off if you would like to try it I can try getting other stuff its just more difficult.

Is the epoxy primer appropriate for bare metal? This is what I'm a lil confused about. Most of the car is just scuffed, but in several places it went down to metal and has begun to flash rust. Not a big deal, just want to clean it up and primer it to avoid repeating unnecessary work.

[enkeivette]

Epoxy is best for creating a barrier between the old and the new. It's... epoxy. According to the pros on the autobody forum it is best for shooting over rust (can lock it down and prevent it from spreading) or old paint (will lock it down and keep it from interacting with the new paint. Epoxy is not the best for sanding, possibly the worst, and it's too thin to use as a surfacer. But it does what it does well, lock down the old shit and provide practically a clean slate for your new coats. Also it sticks very well to bare metal, better than anything else.

Self-etching primer... don't know what it is, nor have I ever heard it recommended other than at Maaco. Your bro will need to inform about that.

[Vettezuki]

Originally Posted by enkeivette

Epoxy is best for creating a barrier between the old and the new. It's... epoxy. According to the pros on the autobody forum it is best for shooting over rust (can lock it down and prevent it from spreading) or old paint (will lock it down and keep it from interacting with the new paint. Epoxy is not the best for sanding, possibly the worst, and it's too thin to use as a surfacer. But it does what it does well, lock down the old shit and provide practically a clean slate for your new coats. Also it sticks very well to bare metal, better than anything else.

Self-etching primer... don't know what it is, nor have I ever heard it recommended other than at Maaco. Your bro will need to inform about that.

The etching I understood better than the epoxy. I get the application of epoxy now and it seems appropriate to our task.

Etching
Paint does not stick to bare metal as it comes out of a die. The surface needs to be scored. This is done with a chemical process known as etching. My understanding is that at the OEM level this is done as its own process. The self etching primer is what is used with bare metal at the non-factory level.

Update
Did a little googling. Seems that it's really only needed for new metal, not even sanded bare metal. It seems the hard core way is to use a dedicated etcher, or better yet, to media blast, then epoxy. But epoxy by itself will not stick to brand, bare, un-"etched" metal.

If you ask the manufacturer like I did you can get the correct answer.

Self etch primer is for metal that has not been etched by some other means. So if you are building a something and weld up some brand new sheets of the steel and do not want to sand them you use the self etch primer. The job of self etch primer is to make a good surface for putting the next layer of paint on to the metal. If the metal is already a good surface for a direct to metal paint then you do not need (and do not want) an etching primer.

The etch primer has been improperly thought of as a way to prevent corrosion. I had the local dupont paint store guy try to sell it to me for that purpose.

For most of what we are doing the better solution is to etch the metal. Either with various chemical methods such as Pickle X or metal pre-treats the paint companies sell. We can also sand the metal or even better sandblast. Then put down a nice layer of epoxy to seal the metal from moisture.

Of course do not forget to use a proper wax/ grease remover before painting.

http://www.hotrodders.com/forum/when...er-133847.html

[Vettezuki]

So, epoxy is correct for our use. However, if most of the car is going to have a white base, a black epoxy seems . . .

[enkeivette]

Makes sense, so self-etching has a chemical sanding agent in it for adhesion purposes. Since were not using the section of Ben's garage for pouring and stamping new sheet metal, guess we should go with epoxy.

Yes, white over black would suck, fortunately it also comes in gray. But since the epoxy will go under the surfacer, it's not a big deal. Here's the preferred order.

Sand, fill, sand, etc.

Epoxy prime. (Some say to epoxy prime before filling, I've seen tests that suggest otherwise.)

Poly primer surface. (If this is not done after 24 hours, we'll need to sand again. But you can't cover the epoxy the same day or it might not cure.)

Guide coat.

Block Sand.

Glaze, sand, etc.

Spot prime. (We can use whatever for this, I think urethane at this point is ideal.)

Sealer (Reduced epoxy.)

Coat.



But! If you want to be cheap and quick, if you care less about the long term and more about cost and your time, you can skip the epoxy, and even the urethane. Just shoot the surfacer, use it as spot primer, and finish with at least 400 grit.

Here's what I did on the Vette: Sand, fill, glaze, primer surfacer, sand, glaze, spot prime with epoxy, sand, full coat of epoxy, wet sand, sealer, coat.

Notice, I didn't lay out epoxy first because I took it down the bare substrate, but we're not doing that here. Also, my body is SMC and the poly surfacer has a hard on for SMC. Like epoxy has a hard on fo metal.

I decided to do the full coat of epoxy last min because I wasn't pleased with the way the car looked in the booth, saw too many waves and sanding scratches. Decided to do another 10 hours of block sanding.