I am assuming you live in Phoenix.

Automotive Refinish Supply
3806 E Superior Ave, Phoenix, AZ
(480) 968-9383

They sell PPG. PPG has an office here. I am not sure if it is distribution or manufacturing but it is basically across the street from ARS. You can walk into ARS and tell them what you want to do. They have done well by me so far. My guess is an epoxy primer. They aren't as porous as typical primers.

I am in sort of the same boat as you.

 

Check out this informative site @ Collision Blast
Donnie has recently filmed some videos explaining everything there is to know about primers.

 

I bought this product from Eastwood and plan on priming my entire outside with it

http://www.eastwood.com/epoxy-primer-and-catalyst-kit-black-gal.html

 

On bare metal, I have always used an epoxy primer. I mail order mine from Southern Polyurethanes (SPI). Shipping is free and their products arrives at my door quickly.

Fred

 

The Epoxy primers are not high build primers and are mostly a sealer. The benefit of epoxy primers is they are nonporous and will resist weather better than urethane (after about 3 days curing). You also have to make sure that the epoxy is a Direct To Metal primer (DP-90 is not). The Eastwood primer suggested above is a DTM primer so that would be ok. To get high build to fill the low spots I would use urethane primer. I am not familiar with the Eastwood urethane primer and so do not know the specifics, but it is my understanding that NO urethane primer will adhere directly to metal. You will need to apply an acid etch primer before the urethane. I just looked, and if you look at the product information sheet for it, it says you need an etch for application. Eastwood sells one for $26.99 Item #16109 ZP. If it was my car, I would use the urethane with the etch primer because you need the high build and you don't expect to have it out in the weather (the urethane does afford some protection provided you don't saturate it). It wont rust because it isn't exposed to the air. Good luck.

 

You also have to make sure that the epoxy is a Direct To Metal primer (DP-90 is not).

...but it is my understanding that NO urethane primer will adhere directly to metal. You will need to apply an acid etch primer before the urethane.

i'm a little confused why you say DP isn't a Direct to Metal Primer. It explicitly says it is. Can you explain why it isn't? I applied the original DP and the available DPLF straight to metal.

DPLF P-Sheet

The PPG K36 is a urethane primer and the P-sheet states it can be applied directly to metal.

PPG K36 2k primer

 

i'm a little confused why you say DP isn't a Direct to Metal Primer. It explicitly says it is. Can you explain why it isn't? I applied the original DP and the available DPLF straight to metal.

DPLF P-Sheet

The PPG K36 is a urethane primer and the P-sheet states it can be applied directly to metal.

PPG K36 2k primer

I used to think it was direct to metal but I was told by the paint supply store that is is not direct to metal unless it is sand blasted. Since they are not open I am unable to call them to have them claify why. I have the p-sheet at home and that was why I thought the same as you. I am sure there is a reason why they told me that. Looking on line I found this:

"There is no need to DP90 over your mud and surrounding bare metal. Ever since the lead was removed from DP ( note: the label now reads DP 90 LF, LF =lead free) PPG calls for 1791 wash primer over bare metal prior to the DP epoxy. The catch is, you can't put the wash primer over filler or adjacent feathered primers. So if you did not wash prime, DP epoxy, then apply your filler over DP which is PPG's recommended best practice you may as well simply sand your mud and bare metal to as clean and contaminate free surface as possible and prime with a DTM."

Whether he is right or not I am uncertain, but there is an addendum on the p-sheet with info. mentioning DX1791/1792. As for the K36, yes, there are some DTM urethanes, but most urethanes (from my experience) are not. I had forgotten K36 since I do not use it. I'm sure you can find exceptions to anything, but that doesn't change the general rule.
I also found this, which confirms my understanding of epoxy under filler:

"OK--Here's the gospel on body filler/bondo over primer. I used to work as a technical/sales rep for the company that makes rage filler. I know the guys (chemists) that developed the resin for rage filler. I've been a bodyman/painter,sales rep and technical rep for 30 years. The resin in rage and other body fillers is fiberglass (polyester) resin. Today's resin technology makes the adhesion of these new resins as good or better than most epoxy adhesives (glue). They are designed to really stick! Also they are somewhat flexible when used properly. Most or probably all filler manufacturers design and reccommend them to be used over clean and prepped (grinding with course-36 grit) and rust free (sandblasted)and dry (free from moisture) BARE metal . They will stick to epoxy primers with mechanical adhesion-they DO NOT chemically bond with epoxies. If you put filler over epoxy primer it has to be fully cured with no solvents (thinner-reducer) left in the primer and still should be sanded with a course grit and cleaned. In other words- It's a wasted step that may or may not cause adhesion problems later on. Most critical is to be clean and moisture free. Body filler resin is a thermal set plastic-it cures with heat." Hope this helps.

 

I used to think it was direct to metal but I was told by the paint supply store that is is not direct to metal unless it is sand blasted. Since they are not open I am unable to call them to have them claify why. I have the p-sheet at home and that was why I thought the same as you. I am sure there is a reason why they told me that.

Whether he is right or not I am uncertain, but there is an addendum on the p-sheet with info. mentioning DX1791/1792. As for the K36, yes, there are some DTM urethanes, but most urethanes (from my experience) are not.

i recommend simply reading the datasheet (if available...).

the P-sheet states the compatible surfaces. the mention of DX1791/1792 is in the DPLF datasheet linked.

you previously wrote "NO" (in capital letters) urethane primer will adhere directly to metal, so i guess i incorrectly interpreted that as none instead of most which is the reason for pointing out the K36 P-sheet. my mistake:shrug:

 

I would recommend epoxy primer on the bare metal. Follow that up with high build urethane primer. The urethane primer will fill very small imperfections, but don't expect to be filling any noticeable impressions - you'll need to use filler or glazing putty for that. I used Eastwood urethane primer over the epoxy and it adheres very well.

 

I would recommend epoxy primer on the bare metal. Follow that up with high build urethane primer. The urethane primer will fill very small imperfections, but don't expect to be filling any noticeable impressions - you'll need to use filler or glazing putty for that. I used Eastwood urethane primer over the epoxy and it adheres very well.

That's too much work for me (plus expense). You can spray the acid etch primer and apply the urethane over it the same day without having to resand in between coats. Why make more work by spraying epoxy and having to resand before applying urethane?

 

I'm going with a couple of thick coats of EP on bare metal because it will be a driver in primer until I can scratch up enough for a top-notch paint job.

 

You don't really have to sand epoxy, just reshoot in the window. After the window has expired you just scuff it, then shoot. It is expensive, but IMHO I want the best rust protection money can buy.

 

x2....

 

I am gonna hit up my local auto body store on this. They and my body guy recommend epoxy on bare metal. In fact I did my truck in dp-90 on bare metal and 5 yrs later shes still good. I use dp 74 on the stang (vert 2 yrs ago, now the coupe). It does need scuffing when you miss the window for adhesion; but scotchbrite is all we have ever done and never had adhesion issues (I know; maybe I got lucky) I have been sanding the dp 74 (due to a gun issue- it was very orange peely)- This is tough ****- using 180 on a block it takes a long time to even scratch it. Will report back what the body shop supplier says.

Had another thought: I almost always sand blast so maybe thats why mine bonds so well to bare metal (I leave the rough texture and paint over it- not even duct tape will lift the epoxy; I use PPG not lesser brands -maybe that accounts for something?

 

DP will stick to sand blasted metal no problem. Most of the cars I do, I mechanically strip and thus cannot use DP over it. Mechanical adhesion is stronger than chemical and so I always sand what I can to ensure everything sticks. I like PPG (expensive though). I have never had any problems with using etch and urethane allowing rusting underneath. Once the clearcoat is on you wouldn't have to worry about weather penetration anyways. If I had to leave a car in the weather, I would definitely Epoxy it though. If you need a high build primer either use a DTM high build directly on the metal or use an etch and urethane. My one qualm about the DTM is I haven't found one that is as high a build as the urethanes I have used. If the original poster needs the high build, then urethane is the way to go. It just seems like a waste to me to use DTM and then spray urethane over it. If I'm going to use DTM I'm going to sand it between it and the urethane to ensure it has the best adhesion as possible (mechanical over chemical). You can use scotchbrite to scuff it and reprime, although I just use 180g or so since I feel better about that over the scotchbrite. I feel for you on the DP74- been there done that. I used a Sherwin Williams poly prime (years ago) that if it sat longer than 48 hrs. you damn near couldn't sand it. I think they changed the formula to remedy that though.

 

SPI epoxy is one of the best for a great price.
Spray 2 coats of epoxy and then a couple of coats of high build primer within the time window. Doing this, you will not have to scuff and shoot another coat of epoxy later.
When you are ready for a top coat all you need to do is block the high build and shoot your Base/Clear Coats.
SPI epoxy is around 175 for 2 gallons of spray-able paint.
Pricing Info
Do a google and read the painting forums if you are in doubt of the high quality of the material.
It can be brushed or sprayed also

 

Lusid Technologies makes a high build epoxy primer called Northstar.

Products

Check to see if their product is available in your area. It's a 1 to 1 mix so you'll have two gallon's sprayable. It's under $200 for a gallon of primer and activator. You can reduce the primer if needed. Even further to make it a sealer. Un-reduced you'll need a 2.0 tip on your gun. Spray directly on to bare metal. No induction time required. It's perfect for blocking out panel's.

The primer work's very well. I've used it for year's.

 

After cleaning the bare metal of any contaminants using a wax & grease remover or naptha, etch the metal (I prefer Picklex20) and then apply an epoxy primer. It can be brushed/rolled on in areas that won't be seen. If you don't apply a high-build right away, you can simply scuff it up with a Scotchbrite before the next step. I have used Eastwood's epoxy primer with very good results.

 

Thanks for all the great information. I am sure glad I made the post, and didn't go straight to my local store without thinking the process through. Since I have been considering Eastwood products, I went back to their website to check the urethane primer. It says "Eastwood’s high-build 2K Urethane primer surfacer is a dream to blocksand, powdering easily after a short cure time. Use over Eastwood Epoxy Primer. Alternatively, used in conjunction with an etching acid pre-treatment, this 2K Urethane Primer may even be applied over bare metal". This pretty well agrees with the advice I have received so far on this post. I plan to call the tech people at Eastwood to make a final choice.

I was wondering if there is any difference for priming the interior versus the exterior. But since I have seen no comments on this, I assume that there is no difference.

One other point - someone said they assume that I am from Phoenix. No, I am from Annapolis MD. My user name relates to the car (hopefully) rising again from the ashes!​

 

Thanks for all the great information. I am sure glad I made the post, and didn't go straight to my local store without thinking the process through. Since I have been considering Eastwood products, I went back to their website to check the urethane primer. It says "Eastwood’s high-build 2K Urethane primer surfacer is a dream to blocksand, powdering easily after a short cure time. Use over Eastwood Epoxy Primer. Alternatively, used in conjunction with an etching acid pre-treatment, this 2K Urethane Primer may even be applied over bare metal". This pretty well agrees with the advice I have received so far on this post. I plan to call the tech people at Eastwood to make a final choice.​

I was wondering if there is any difference for priming the interior versus the exterior. But since I have seen no comments on this, I assume that there is no difference.​

One other point - someone said they assume that I am from Phoenix. No, I am from Annapolis MD. My user name relates to the car (hopefully) rising again from the ashes!​

Going by the p-sheet is sounds like the urethane is recommended be used with their etch primer for bare metal adhesion. My preference is to use the same product line as much as possible to prevent problems and resulting disclaimers that you did not use our products throughout the process (minus the paint portion as sometimes you have to use a different paint to get the color you want). I would ask for recommended flash times for the temp. you are expecting to spray at to give you a better idea, as flash times are calculated a 70'. I also would wait to sand it for longer than recommended (I know you were planning on waiting anyways, but you never know how it goes). It will shrink back and waiting (at least a couple weeks depending on temp.) will allow it to do that before you have sanded it. I've seen a lot of cars where the primer has shrunk back after being sanded and as a result there are sand scratches in the paint. Just my $.02.

 

epoxy primer for sure

 

Epoxy SPI - just shoot it and leave it on. that what I did with mine and then took to body shop and they used the high build etc. Neded to check on bondo work you did - I know is recommneded filler over epxoy not sure about shooting epoxy over filler though.

 

This has been a really useful thread and I know I'll refer back to it when I'm ready to start my bodywork and need to prime.

 

I use polyester high-build over my EP. Text below from autobodystore.com. Yeah, it IS somewhat a beetch to sand, but I think the effort is well worth it.

Polyester is a very specialized primer used in very small amount in most shops across the country. But when it is needed, it does a job like no other. Polyester has a huge solids content and will fill 80 grit scratches in one coat or 36 grit in two or three! Urethane for instance provides about ½ or ¾ mils per coat while polyester can give you as much as 4 to 6! Because of it’s high solids, it shrinks very little. It is basically like spraying polyester putty. Look for a manufacture that has a recommendation to apply etch primer under it. I see NO reason to use polyester on a straight panel. It is for use only when you need some serious filling and surfacing.

Benefits:

- VERY high filling

- Low cost

Disadvantages:

- Very high texture

- Harder to sand than a urethane

- Possible need to purchase a large gun to shoot it.