kaiserbud

Summary: Can I use Deltron DP90LF over Omni MP281 lacquer primer? If so - what are my temperature minimums for applying DP90LF. It is 58 degrees in Houston today.

Details: I will be putting Deltron Epoxy Primer on my C3, but I made a change over the past 2 days of using lacquer primer (Omni MP281) to cover my body work until ready to Epoxy Primer. I ended up coating the whole car as a contiguous primer coast. All looks awesome and I and doing 180 block with 400 to follow for Epoxy.

Well - I figured I should verify the compatability of DP90LF over Omni MP281, but I am getting mixed information from the PPG website. The Omni site says do not mix product lines (Omni and Deltron???) and the Deltrom site says I can overcoat lacquer substrates with DP90LF if I use a certain additional chemical.

REALLY would like to Epoxy primer today, if compatability and temperature issues are put to ease.

porchdog

i would not . imho the lacquer needs to come off. it gave you no protection anyway as it is very porous and will suck up humidity from the air. next time just spot it with epoxy.

crazywelder

I agree. It would be a waste of material and money to put epoxy over your existing primer. One advantage of epoxy primer over bare fiberglass or steel is the excellent adhesion factor that epoxy offers compared to lacquer primers as well as epoxy's sealing ability that blocks moisture. It makes little sense to use epoxy over another primer that has less adhesion ability, you might as well finish your primer work with the same Omni product or remove the Omni and recoat with DP, then switch to the Deltron line.
Omni is a less expensive production shop paint line. Once you start with Omni, you need to use Omni products through to completion. Plus you need a steady 60 degrees minimum day/night to paint. If the temp drops at night, 2k paints won't cure properly. Even if your high is 58, it takes a long time for the body temp to equal the ambient temp.

kaiserbud

Porchdog and Al - thanks for the input.

On the temps - thanks - I waited anyway as I was unsure of the direction I needed to head in

I contacted PPG today and inquired of my issues. Basically, they said they do not guarantee any cross-linked products,,.... in other words, their products are made to work together and if otherwise, voids the warranty. However, the tech said I could indeed put 2k DP90LF over Omni MP281. He said to allow the DP to dry at least 7 days, scuff, re-coat with DP and initiate color and clearcoat after 30mins+. Or - he said I could recoat with DP and initiate basecoat/clearcoat all in the same day. I will do the first suggestion.

Porchdog - I understand what you said about 'next' time... And Al - your comment about using a lower quality primer as a base are noted. That being said, in the past I have done lacquer primer w/ lacquer basecoat clearcoat that has withstood 15 years. The only thing that degraded was the topcoat and the subsurface was solid and strong adhesion. In my current project, I was extremely diligent in properly prepping my primer basecoats. Also, with all due respect, I feel high build primers are a poor substitute for good body work. So although I hear what you are saying and wish I had spotted DP Epoxy, I do not think I am at the stage where I need to strip. The body is blocked very well too

I appreciate the input and will follow up with pics - thanks Gents !

porchdog

i would block as much as possible to remove as much as i could. then no less than 4 coats epoxy. i use nothing but epoxy to resurface corvettes , no 2k primer at all. no offense but calling ppg is a waste of time. they will tell you anything but back up nothing. good luck with it.

wombvette

This is typical of paint companies gooble- de- goop. They always spout this statement. The funny thing is that there is effectively no gurantee any way. It is almost impossible to get anything out of a paint company.

Now you never said what year the car was. If it is the 69, you may be OK, but if it is later, I would remove the lacquer primer and respray with epoxy and urethane. Lacquer primers do not work well with SMC fibrerglass.

crazywelder

"In the past" we all used lacquer primers and they are still the fastest, easiest to use and most economical route to go and their long term performance is quite good for production work. But lacquer primer is your weak link under epoxy. Since you have all your blocking completed, I would not spend the money on the epoxy. Your enemy with fiberglass, is from behind the panels, that's where epoxy shines. I would continue on with Omni sealer and top coats. Don't take me wrong, but product planning is important from the beginning, now is not the time to switch to epoxy in my opinion.

kaiserbud

Thanks guys...

On the warranty, I know - even if you did everything right - what do they gaurantee - the cost of paint... ?? although expensive, the big $$$ is in the work.

Porchdog - 4 coats??? I was thinking one gallon - how does that equate to your coats?

Wombvette - can you explain the theory on the backside issue of the fiberglass?

Al - you are correct. I planned Epoxy, but I was convinced at the last moment to do otherwise... my bad.

I am at a crossroads and will make a decision.

porchdog

normally i use only epoxy . i would get rid of all the lacquer i could . 4 coats of epoxy (with at least 1 hr flash between) will give good protection and some mil thickness to sand on. after the epoxy cures for 24 hrs i would prep with 600 then paint. i have repainted over lacquer in the past by sealing it down with epoxy. i dont like to but have done it with success . good luck with it.

i use spi epoxy. great product and good price. plus it is a 1-1 mix .

kaiserbud

porchdog... thanks....

So maybe rambling, but don't we all paint over lacquer (previous coats) anyway? Or are you concerned about the freshness of it??? Is there a cure period that might make you more comfortable... or do you strip everything (fyi - I did)

Ah - also - you said to coat with epoxy and await 24 hours. I was going to await 7 days and then rescuff and prep for color.....

porchdog

i do not do repaint anymore . i have a media blasting business and strip everything. lacquer is just not a good base .

crazywelder

You primed your bare fiberglass body with a 1k primer, it's not wrong, it's just old school and no longer a preferred process in the restoration world as it once was. It's not a daily driver, it will be sheltered and protected from the sun, so your 1k and prep work should give you several years of good service. You can use the epoxy as a wet on wet sealer, but painting epoxy over your 1k will not extend the life of your new paint job or make it more durable.

There are several products that are popular for use over bare glass, epoxy is just one of them and my favorite as well. Although my priming process differs from dogs, there are 3 major advantages of epoxy compared to 1k; it seals the backside from moisture which will extend the top coat life, you can apply filler directly to epoxy which eliminates the possibility of moisture absorbing into the filler from behind, such as when used over bare glass, and epoxy is tough and sticks like glue. These advantages are even more important on steel bodies for preventing corrosion. You missed out on these points by going with 1k primer first, so the entire quality of your paint job is riding on your 1k, not the epoxy you spray over it. From my experience there is no advantage to spraying epoxy over a 1k primer base.

To strip, reprime, and reblock is a lot of work and added cost. I support the local paint supply so I don't have experience with SPI. Dog does all his blocking with SPI epoxy. PPG DP is expensive, has a 7 day window, it is very hard and does not sand well. You would use a 2k primer over the DP for block sanding. Transtar epoxy sands well and does not have a window time, so it is very user friendly and more economical than DP for the home painter. I use DP or Transtar for epoxy.

I make repair decisions all day long and I base my decisions on quality, cost, and return on investment, usually in that order. Rework is not an option. You need to be a strong person to redo all your work and not lose interest midway. In your case since you have the car blocked and you are confident it's ready for top coats, I would continue with a compatible sealer and your top coats.

porchdog

tuff call huh al . in the past we used featherfill to hold down lacquer on repaints . never know what lacquer will do in a repaint the epoxy does the same. with it being fresh maybe nothing will come up.

al, you gotta try some spi . cost even with shipping is good. i promise you that after using it you will love it. barry sells some of the best clear i've found in 20 years. i cleared the 57 vette in dec and did not buff until march. still looked booth fresh and buffed with ease . a big plus is it is a 1:1 mix .

crazywelder

I will try it. I have one or two an opportunities to try it this coming summer. It's hard to change, you know. Thanks dog.

kaiserbud

you guys are great ... good info and will absord and move forward. Al - I do have the tenacity and a weekend of blocking it off (or close to all) is not the end of the world... as for the expense, since I am not doing for a profit, I will chalk it up to the learning process.. Being a black paint job, I want it to stay flat. will follow up.

kaiserbud

Gents... well, I did it. I removed all the lacquer primer

I had previously done all the bodywork using Fiberglass, Clawplast and Evercoat Filler, so I do not have the opportunity to do so on top of the Epoxy primer.

So off the Omni lacquer primer came off today. I hated to lose all the blocking - it was really nicely done. I DA'ed most of it off and left 'splotches' as to not get too deep into the fillers. I then decided I could use 80 wet to finish it off. I only started the wet sanding on 2 panels, but it seems that the the wet 80 does not have the clean cut that dry 80 would have and the wet 80 may be impeding on the filler more than dry 80. Comments?

I do plan on PPG DP Epoxy. But as Porchdog guided me in other post, I am covering raised fiberglass hairs - I assume I would not want to use a 'sandable' primer ???? Pdog - I know you use SPI

Question - there are some scratches that appear still filled with primer - they are not coming out with the wet 80, soi I assume they are dry 80 scratches and hopefully not 36 remanants from the previous vampire body man

I will re-assess in the morning and go from there... argh ! what a ton of work.

crazywelder

Whenever you sand a porous surface such as 1k primer or body filler, you should sand it dry, because 1k primer and fillers will absorb water and slow down the prep and prime process. I do all of the early body prep and blocking dry.

The epoxy primer will permanently glue down those hairs. That's one of the advantages of epoxy on a Vette, 1k primer can't do that. What it doesn't glue down will sand off.

No problem with the primer filled scratches, those sand scratches are partially filled and you can leave them as is.

I noticed you are going with PPG DP. I use that on almost every job but it's pretty hard and does not sand well, so I would recommend a different 2k primer over the DP for your blocking.

Take a rest, this is a hobby and it needs to be fun.

kaiserbud

Awesome hearing from you guys was hoping to hear from you all tonight. Thanks for the advise- will do as suggested....

Funny you mention that. My fingers are numb, every muscle in my body aches.... headin to bed.

BUT - the thought of that black beast shining with the 427 loping, will have me up early in the morning !!!!!!