Urethane or Epoxy Primers

[stfinney]

I know they are both great primers, but what are the good and bad points of both? Will be going over bare metal and have read either one can be used, so which do you guys and gals prefer and why?

[CC69Rat]

I use PPG DPLF50 Epoxy and I like it so far. I'm new to the game too, and I'm sure you'll get some other opinions. Coverage, metal protection and a great base build. I shoot it at about 38, with a 1.8 tip. It's pricey but I think they offer an Omni version of the same stuff... about 1/3 the price.

[El Campo]

Im sure hugger will chime in here shortly. Epoxy is the newest technology and has the most sealing properties from what I understand. I used Southern Polyurethanes epoxy primer (after reading LITERALLY nothing but great reviews about it from pros and individuals who have sprayed every kind of primer under the sun) and it was amazing stuff. Great price too with the best customer service you will find anywhere. I sprayed it on May 19 and got some on my feet, it is STILL on my toenails today even though I scrub them all the time and have tried everything to get it off. Your paint is only as good as the foundation under it. I am sure that DuPont and PPG all make good primer too. Here are some pictures of black SPI primer on my frame:

[mcbassin]

I prefer epoxy over bare metal and urethane over the epoxy. I think moisture can get through standard urethane primer. You sure don't want to leave anything outside with just urethane primer coating.

[stfinney]

That's what I was thinking to but wasn't sure if I read it correctly. Eastwood's site mentioned about using both, but thought it might have been a mistype or something. So, from what I read, the Epoxy gives you the seal and the Urethane primer gives you the coverage needed for sanding??

[CC69Rat]

Yep -- I'm going to try some of the SPI stuff too once I run out of what I have. I have never heard anyone say they didn't like it.

But I would suggest Epoxy though. It's kinda like a plastic coating over your bare metal. It just seals out moisture from getting to your bare metal and rusting the truck from underneath the paint.

From bare metal:
Epoxy - 2 or 3 good coats
Let it cure for at least one day, but no more than 7 days. If you go past this window you need to scuff if with 220 and reapply more epoxy.
I usually scuff the cured epoxy with a red scothbrite pad
DX330 was and grease remover about 3x over the whole panel, or until your towels are clean and free of dust and debris.

Any filler work, obviously as thin as you can just to make it really smooth and flat. Then spot the places of filler with more epoxy. This will seal out the bodywork.
Scuff the little spot in places with a red scotchbrite

.. then start your high build. Omni, SPI, etc. If you used the Omni Epoxy, I'd stick with their high build too. I usually like to go start to finish with the same maufacturer's products so they all play nicely together.

good luck man.

[CC69Rat]

You got it .. but you need the Epoxy underneath it. The highbuild is porous and water will penetrate it.

[stfinney]

Just want to be sure when ordering my primer and other supplies. Thanks.

[stfinney]

What paint gun would you recommend for a novice painter? Looking for a HVLP one. Thanks.

Edit: Anyone using the Eastwood Concours HVLP Paint Spray Gun??

[hugger6933]

I'm chiming in cause I am excepeted to but I love the Omni epoxy and high build primer. And my sister has called and I am eating lunch and need to get back to thew shop and lost my thoudgt train. Sorry. Jim

[CC69Rat]

Budget in mind?

[CC69Rat]

http://www.summitracing.com/parts/DVR-802343/?rtype=10

this one is also available at Eastwood, but hey didn't have a price on their site.

This setup is what I have and I really like it. Mine came as a promo and I got a little touchup gun with the kit too, .. but this one will give you two guns actually. a 1.8 tip for primers, and a 1.5 for more of a clear / base gun.

Different people have different styles and opinions about this but in what little bit I know about it, my guns have never failed me or my skill level. And they're cheap enough too.. I'd buy them again, no question about it.

[CC69Rat]

^^ There's the man right there..

[stfinney]

Was looking for one to use with my compressor that I already have. It is 2hp and has 5 cfm @ 90 and 6 cfm at 40. Was hoping to not have to buy a new compressor also. Budget wise is a good good at a low price. The one at summit is good on price, so under $200 would be great. Thanks.

[El Campo]

I live in South Texas and I imagine that our humidity is very similar to yours, very $#!++). So you will definitely NEED a drier of some sort. I built one that is modeled after one theastronaut built on here. Entire thing cost me less than 35 bucks and my devilBiss QC3 that is mounted after it (for insurance) collects virtually no water it cools and separates water vapor so well. I just pour ice (and salt if I am really worried about the humidity) into my 5 gallon pail for now.

[stfinney]

Yes, the humidity sucks here! lol....and yes I plan on having a full setup when I go to start spraying anything. I really don't want water in my primer or paint. Going to use the disposable filter I read about also.

[hugger6933]

I put a water seperator off of a Peterbuilt truck on my air compressor and drain it once and a while,I never have to thinkabout water in my lines anymore it was the best thing I could have ever done as far as water filtration/seperation goes. I love it I had it laying around so it was free but I could not imagine that one would cost hardly anything from a salvage dealer of big truck parts,as they are not a wear item. I would suggest an HVLP gun that is a gravity feed type.and if you are spraying primer with it look for something inthe 2.0 tip size. I used a 2.0 tip for a long time and was very happy with it, but I recently bought a new gun with a 2.3 tip that has not made it first sprays yet, I am curious to see what it does with the little bigger tip. I will give you a hand on the primer with something that I had to learn on my own mix a little reducer with the primer[or base coat stabilizer whatever the case may be] into the primer weather it is epoxy or high build. Somewhere between .5 parts to 2 parts will really smooth out the primer and not only make it slick, it will be easier to sand as well. So for example if the mixing ratio is 4:1to1 mix it 4:1 :1 to1 and see the difference it makes!! Good luck with it .Jim

[sevt_chevelle]

Epoxy and urethane are two different primers with two different intended purposes.

Epoxy is meant to be applied over bare metal, as it has corrosion resistance and adhesion properties not to mention it won't wick water.

Urethane has NO corrosion resistance and NO adhesion properties and not meant to be applied over bare metal. Urethane primer is designed for film build and removing minor surface imperfections. This is the primer you block sand and block sand.

The proper paint job starts with an epoxy primer for corrosion resistance and adherence and then urethane primer for film build.

I use SPI products, the SPI epoxy is second to none. Sorry but that DPLF is junk, good epoxies like those from SPI, Diamont and a few others WON'T wipe clean off with a little bit of lacquer thinner. Hopefully you are at least using the 402 hardener and not the 401...Eric

[MLB57]

I did the same thing jim did about air dryer, used a AD9 air drier off of a truck, only problem is that it is really noisy when you pop it off to drain

[CC69Rat]

Eric, where can I see some of your paint jobs?
Posted via Mobile Device

[hugger6933]

I will try not to over simplifie what Sevt. said eariler. The epoxy we all are know of as epoxy. The urethane primers go by that name or by the action that it does and that is high build primer. That is as common as calling all body filler Bondo when acutally Bondo is a name brand. The same came be said for Saran wrap for cling wrap or Reyenolds wrap for alumniun foil. Also the thing about the water trap off a big truck I have a regular dran cock on the bottom of mine and it is outside with the compressor. I use an old gas tank stnad to hald up a camper shell that I took off a wrecked truck to cover the compressor to hold down shop niose and it helps a bunch! I hope the explaination helps clear up any confusion about the primers, I don't know why I have'nt thought to make all of that clear before now. Jim

[sevt_chevelle]

Originally Posted by CC69Rat

Eric, where can I see some of your paint jobs?
Posted via Mobile Device

Well, I hate painting so I don't go out looking for paint jobs. But I made my living as a body and paint tech, and 2 of my most miserable years were spent as the head painter spraying PPG products. I'd much rather be doing some metal shaping then painting.


Here is a tractor I did for my dad done in PPG products.



My dodge truck done with all SPI stuff other then the PPG DBC base coat.
That's all I have without digging through CDs.

[El Campo]

Sweet paint jobs! Shoot, like has been said here even a NEW separator off of a truck is less than a hundred bucks! I was going to get one and the only reason I didn't is because I could never find a number as to how small of things it filtered or how well it separated water. Good to hear that it does a fine job.

[oldspowered67C10]

I don't use urethane primer but as I see it, usage wise its between epoxy and polyester primer. Denser and harder to sand than polyester but not as dense and easier to sand than epoxy. Offers more protection than polyester but less than epoxy.

Like I said, I don't use urethane but Ive heard from some guys that they like to use it in final block sanding. The logic as I understand it is this; after your last block sanding in polyester primer you spray a light coat of urethane to fill any imperfections like pinholes and air bubbles that polyester primer is prone to have. For me it just seems easier to deal with those types of problems with spot putty or thinned out polyester primer in a detail gun but I can see as it would work.

Primers, just like types of paint can be confusing due to a lack structure in how people(and even manufacturers) refer to different products.

[CC69Rat]

As soon as I run through my PPG stuff I'll try some of the SPI Epoxy / Primer. I'm new at this, I only know what I have tried and what the paint shop guy sold me. Just trying to learn as much as I can.. I don't know good from bad if I have only ever tried one brand.

The paint jobs look great Eric. Thanks for your help.