Technical PPG 2050 high build epoxy review

Well "Low and Behold", here's the Tech tip for epoxy.
FAQ

PPG Refinish > Products > Tech Tips > Paint Pointers: Technical Tips from PPG > April 2019 > No Etch Primer Under Epoxy!

No Etch Primer Under Epoxy!


When planning to paint bare metal with an epoxy, make sure you are applying the epoxy directly to properly cleaned and sanded bare metal. Do not use an etch primer. Residual acid from the etch primer can interfere with the proper curing of the epoxy. This may lead to extended dry times, potential blistering and even adhesion failure.

I mentioned the effect of the acid on the epoxy catalyst in my "long read" above.
QUOTE:
The acid in etching primers can cause the epoxy primer catalyst/hardner to change chemically and not cure or possibly fail/peel.

This is referring to epoxy over etch primer and not treating the steel with metal conditioner/phosphoric acid.

 

Yep. No etch ever wet on wet with epoxy.
It definitely slows the cure time for polyester as well.
I’ve seen it done and no issues other than cure time.
When I asked a rep about fully cured etch or say you were repairing a car that had etch used at one time and etch was exposed during repairs later, that it had no effect if epoxy was used.
Can I back that up with a tech bulletin? Nope.
Just experience

 

There are 3 or 4 Tech Sheets for the VP2050 primer and this one has the reference:

The PPG Logo and VIBRANCE COLLECTION are registered trademarks of PPG Industries Ohio, Inc.
Date: 8/2013
VP2050
DTM High Build Primer
Product Information:
VP2050 is a gray, two-component 2.1 VOC DTM High Build Primer which provides excellent adhesion and corrosion
resistance to properly cleaned, sanded and treated steel, galvanized steel, and aluminum substrates. VP2050 provides
excellent direct to metal properties important in today’s restoration and custom market.

https://us.ppgrefinish.com/getmedia...ab/201308_vc_VP2050_shop_en.pdf.aspx?ext=.pdf

 

Good call on etch under poly, be it mud or poly primer. Makes a nice "release agent" and I've seen it cause massive heartache in prototype shops. "Hey, don't etch that it needs poly prime." In the corner whispering, "Fuck him, this is my project and..." and a day or 2 later it's peeling off like granny's old shelf paper.

This shit isn't easy, even harder if you don't step back and read tech sheet now and then.

 

We had a rush build in the paint shop. Sanded and cleaned the metal finished body. DP epoxy and a bake cycle. An hour later it had polyester on it. We were blocking it out that evening.
3 days later it was getting scraped off. The epoxy turned to mush. Primer curled up along every body line.
Trapping solvents is bad juju

 

Featherfill G2 is is ok over self etch according to the tech sheet--https://www.evercoat.com/wp-content/uploads/2022/08/TDS_100710_FEATHER-FILL-G2-3.2021-US-ENG.pdf

Evercoat Slick Sand is not, according to the tech sheet----https://www.evercoat.com/wp-content/uploads/2022/08/TDS_100709_SLICK-SAND-10.2022-US-ENG.pdf

But I just found that Evercoat has an on line Training Portal and it appears to be FREE--with online certificates.----https://training.evercoat.com/

 

I used a polly over etch once. Tech sheet stated it would slow the ready to sand time.
Truth.
It bonded just fine and worked out.

 

We were Slik Sand users back then. Featherfill always felt like self abuse. Slik will go over a few prep substrates but the safe play was ususally to treat it like mud, best over metal. Another I will-defeat-you practice, too much mud over some poly primers. I know, I know, sounds counter-intuative. Similar chemical construction. But I had to peel a completely finished Duesy gas tank a few years back because he did not listen, AGAIN, and a few months later a nice slick black tank was being stripped off, mainly with a blo gun! I directed to poly prime after ONLY if it needed it. He did it 1st. He knew more than me because he had maybe 7-8 years in it and few tech classes. WTF did I know, his potential brothers and sisters ended up in his dad's teen age sock when I was slingin paint n mud with youthful enthusiasm.

There are etch products that are ok, as so generously shared above by @overspray . Sometimes you hit that "Nope, not worth it..." point and just avoid a potential fail, or you don't have the luxury of digging up a tech sheet, or are just abivalent to even trying to change established process. And this industry has found ways to market product and tools to a whole new breed of finishers. Do I buy a bunch of blocks of different sizes and colors and put em in their shrine to be used by and for only the best, or stay with a tried and true standby for me, an actual wood paint stick. I'ma stay with the stick. I don't pay $80+ for Rage Gold. I pay about 1/2 or less for USC Chromate Lite. For me? IDENTICAL. Whip it too fast, pinholes. Too much cat, flakes off. Not enuff, gobs up the paper. So what did I get for twice the $$ ? "Gucci" label on the shelf. Perspective. Sometimes it's a bitch, and sometimes no matter what you won't be able to help some folks out. They too stick with their standby and I can't fault em. Not my $$$$ so...

Best of y'all, and thanks for the inputs to those who are in pursuit of this stuff.

 

G2 was specifically designed to go over etch. It was developed when etches started to get popular.

Yes the Evercoat Training portal is free you just need to register. There are a number of video covering topics on fillers, putties, polyester primers, UV products etc.

 

Don’t confuse rattle can etch with a real 2 part etch either.
I’ve used the rattle can on very small sand thru areas or small parts.
But it’s not the same product as a quality 2 component etch.

 

I miss the good old days when you could just spray some lacquer on a car.............

 

The truth of the matter is it's not that difficult if you read the tech sheets of the products you are using BEFORE you start using them. Everything is laid out pretty clearly. In 20 yrs of going into shops to look at problems I can't think of a single time where a product failure due to incompatibility wasn't avoidable by simply reading the tech sheets of the products being used and following them.
A lot of the fear of product incompatibility is created by the paint companies to get shops to stick with their products. I can tell you for a fact that the paint companies will turn on a dime about if products are compatible if it will help them get into shops. We had a paint company that insisted to their shops that if one of our products was used under their paint they wouldn't warranty it, then they wanted to partner with us to kick 3M out of 700 shops in NA and suddenly the exact same product was part of their SOP.

But having said that if it says don't use something or something isn't compatible on the tech sheet FOLLOW that advise it's not worth the risk.

 

Here's a comment from another forum when someone's epoxy primer failed. (cheap product and limited experience)

"But wait! Epoxy is the GOD of primers."
(the epoxy primer was 14 days old and fast lacquer thinner used to remove overspray also softened and removed the epoxy primer.)

Experience, knowledge and training should tell us that good product will work over good preparation. We have excellent products available to us and tons of good information but the less experienced hobbiest is easily swayed by price and claims of ease of use. I see lots of posts regarding primer, to sandblast or strip/sand to bare metal and apply epoxy primer---and that's it. Most of us here are not working with new vehicles in a modern collision repair shop environment. We are trying to rebuild the finish on vehicles degraded and rusted for decades that have long lost the original corrosion protection applied to the original body panels, which, in most instances, started with phosphating the steel bodies. There is more frequently than not, no mention of how rusty the panels are, no recommendation of how to prep the residual rust in the metal before applying primer and when epoxy primer is mentioned hardly ever (not never) is a brand name or type suggested and why.

I'm not a big fan of most epoxy primers for working on old (paint degraded and rusty) cars. If you want it to last, remove the rust chemically (metal conditioner) or use a self etching primer on the bare steel (not both).

Several years ago, I looked at a nice Street Rod with about a 8-10 year old (paint job) build. The owner knew I was a painter and asked me to look at some paint issues he found. I spotted the issue that appeared to be under the paint film. He asked what I thought it was. I asked him if he knew what the car was primed and painted with. Epoxy primer (DP) and base/clear paint. I told him my best evaluation was that the body was not properly prepped to neutralize the rust before the epoxy was applied and a small amount of moisture was causing rust to creep under the primer. (I found out later I was correct). The owner wasn't happy but, I guess you get what you pay for. I had heard from other car guys and painters that he aggressively shopped until he had the cheapest quote for a "paint job". I was surprised the car looked good for an 8-10 year old finish. Had it been a daily driver -- maybe 3 years before the same failure.

 

EXACTLY! Now with almost all the information available on your computer or phone and 1-800 tech lines, every technician should be able to avoid issues like these. 5 minute tech read or phone call can save a 12 hour re-do.

 

Just the way I do it. I have been using evercoat 4:1 polyester direct to metal primer. It is infused with epoxy. It's a high build and I have had real good luck with it. Sands good , you need a 2.0 tip or bigger. It mixes 4 to 1 with catalyst and I usually put 10% urethane reducer with it. I'm doing an O/T AAR 70 cuda and it seems to be pretty nice. Just throwing it out there. Lippy

 

I have been using UPol UP2253 lately.

I just put a half-can from this morning back in the flammables cabinet.

It lays down smooth. It sands maybe a little harder that other brands, but that might just be my arthritis talking.

Two coats seem to do the trick, with my bodywork practices.

I might do a single coat with a little reducer to close up the pores, should anything need to sit before final sanding, and top coat.

 

Used the VP 2050 again this week.
This time shot with a 3m gun with a2.0 tip. Sprayed a lot better than the 1.4 we used last time.
Product seems to have a good bit of texture. But sprayed by first timers as well.

reduced 10%
It’s been raining the past 2 days so we have 100% humidity. Primer has been applied for 24 hours. Sanded well

Was still a little tacky this morning. Not a product for speed. Powdered up well with 220 this evening. I did put a light on it this morning.

Probably still a tad green for sanding. But not bad for epoxy.

edit: teamp have also been between 45 and 65

 

Tip size, maybe a little reducer, flash time between coats, ambient temp-shop temp-cure time. These are critical with the very high solids (thick) material. A good reminder.

 

Very interesting thread Anthony (and all that contributed). Thanks for reporting and following up. Very timely discussion given the state I'm at with my project '38.

 

Shop temp was not optimal at all
2.0 is the largest tip we have
TDS says a 1.8 will work so we’ll try that next.
We did reduce it.
That crap won’t hardly spray without it.

 

I still like DULUX

 

Best served on a "Hot Plate". (Really Old painters will relate)

 

Mixed Thursday. Told the students to set the leftover on a shelf. Watching to see how much it shrinks. So far looks like none

mixed also on Thursday. The wax and grease remover is the same label as the reducer. Ooppps.
Didn’t even really stir it up. Still hardened.

Good learning experience