2k urethane or epoxy primer?

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daredevil

daredevil

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Whats the pros and cons of each? Looking at Summits line of paints and they dont provide enough info.Going to be painting the wifes bcuda and will be scuffing the paint in places not requiring any body work and doing 1/4 patches. Not a painter so considering just a single stage paint. Will be happy with a driver quality job.Opinions and advice welcome.
 
I have used summits epoxy and 2k. For bare metal you will want to shoot epoxy first for rust prevention. If you just scuff the rest you can shoot 2k over the entire car and wet sand to 600 grit before you shoot your single stage. I would not sand epoxy.
 
I would go to a local paint supplier and talk to them. I would be scared to use summits paint for some reason. I would spend a little more a get a better paint.
 
I dont understand. the 2k is an epoxy primer and the urethane primer is a 2k.
 
http://www.autobodystore.com/ms7.shtml


“1K” This is a product that uses no hardener, catalyst, activator, etc. It may have an added solvent, but no hardener or activating reducer. 1K products like RTS dry with the evaporation of solvents and are soluble, meaning that they are could be wiped off with a rag soaked with lacquer thinner. They could in THEORY be scraped off and put in a can with solvent and stirred back to a sprayable condition. Of course ALL RTS products are 1K. Examples: All lacquer products, some synthetic enamel products, and some acrylic enamel products. Because of the low VOC regulations the 1K product options are getting scarce, with most limited to “specialty products” like adhesion promoters.

“2K” or “Two component” is any product that uses a hardener, activator, catalyst, etc. It may or may not use a third component in the form of a solvent. 2K products don’t “dry” like a 1K. The 2K product “cures” by molecules linking together to form a whole new compound. Most high quality 2Ks are insoluble after a full cure and will not soften when exposed to solvents like thinners or gas. Examples are urethane under coats and top coats. Epoxies, ISO free products that use a hardener, etc.

Basic tip, ALL 2K products should be mixed as accurately as possible. As a rule 2K products need a minimum of 55 degrees to cure with an ideal minimum of 65 degrees. MIX THEM AS DESCRIBED BY THE MANUFACTURE. They have spent hundreds of thousands, possibly millions of dollars developing the product, they WANT it to work as BEST it can. Do as they say, don’t become a “Junior Chemist”.
 
Badart said:
I have used summits epoxy and 2k. For bare metal you will want to shoot epoxy first for rust prevention. If you just scuff the rest you can shoot 2k over the entire car and wet sand to 600 grit before you shoot your single stage. I would not sand epoxy.
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I've used them as well and agree that the epoxy is for bare metal.
One thing I would add is that you do have to sand the epoxy if you do not topcoat within 4 days.

Here's the instructions for the epoxy.
http://static.summitracing.com/global/images/instructions/epoxy-1.pdf

Here's the instructions for the 2K urethane primer surfacer.
http://static.summitracing.com/global/images/instructions/2k primers.pdf
 
Epoxy sticks, use that first, urethane is a finish primer that you use over the epoxy and under the finish coat. Make sure you paint over the epoxy within in the critical recoat window.
 
efriedrich said:
Epoxy sticks, use that first, urethane is a finish primer that you use over the epoxy and under the finish coat. Make sure you paint over the epoxy within the recoat window,usualy about two weeks.
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That's what I was trying to get across daredevil. Like he said, just make sure you shoot within the recoat window.
 
Agree with what others are saying. Epoxy is a good foundation to build upon. Then lay your poly or urethane primer over that. If you miss the recoat window on epoxy (or anything for that matter) you scuff it before laying more over the top. Not a big deal. It's not uncommon to lay epoxy when the car will be sitting for along time while you work on other areas. I believe the stuff Summit sells is relabeled Sherwin Williams. Others sell relabeled Kirker.
 

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Yep i agree with others too, Epoxy is to cover bare metal it's not a rust preventor !!it's for stick, most primers are not DTM products ( direct to metal) so any areas that are bare must be spayed with epoxy first then your primer top coat.
 
So ,excuse me for being frugal but could I use a spray can of epoxy primer over the bare metal for adhesion and then buy a gallon of urethane to spray the whole car,? Hate to buy 2 gallons of primer.
 
daredevil said:
So ,excuse me for being frugal but could I use a spray can of epoxy primer over the bare metal for adhesion and then buy a gallon of urethane to spray the whole car,? Hate to buy 2 gallons of primer.
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Keep in mind that a spray can is a primer with a little epoxy resin added to it not a true automotive grade two part epoxy. I'm not saying it won't work, I'm just saying.
 
daredevil said:
So ,excuse me for being frugal but could I use a spray can of epoxy primer over the bare metal for adhesion and then buy a gallon of urethane to spray the whole car,? Hate to buy 2 gallons of primer.
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You really want something that is catalyzed (a hardener). You can buy two part paints in aerosols but it's not real common. They have a button on the bottom that punctures and releases hardener into the remaining contents. Here's an example: http://www.spraymax.com/index.php?id=149&L=1
 
daredevil said:
So ,excuse me for being frugal but could I use a spray can of epoxy primer over the bare metal for adhesion and then buy a gallon of urethane to spray the whole car,? Hate to buy 2 gallons of primer.
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Ah man i don't mean to sound like a know it all but i have been doing it since
the late 70's LOL, And yes Dominion sure seal sell a spaybomb of self etching which you can use as a base coat in small areas before prime.
:burnout:
 
I'd consider base coat clear coat. I'm not a bodyman but have done both. Single stage seems simpler but bc/cc is actually more forgiving and I think the end result is much nicer.
 
I have been painting cars for 20 years now and have used this combination on most of my restoration jobs. From start to finish: bare metal car. First either epoxy or etching primer, then polyester primer (blocked) then, 2K urethane primer (blocked) then, 1K sealer or a base coat for coverage (mainly white, grey, red, black, etc depending on the color you are shooting. Example, if painting sassy grass start out by basing the car in white) then, the base color then, clearcoat (block), then clearcoat again (block). if painting a single stage, insert that where it says base color.
I know it's alot but hope this helps.
 
green1 said:
Etching primer will work on the bare metal.
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Etching primer does work ok, but it's 80's technology, nothing beats a good epoxy for adhesion.


And you can sand epoxy, but it will clog the sand paper fairly quick if you don't do it correctly, I've blocked it down and even feather edged it without any problems.
 
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