Painting
- Thread starter Ceedawg
- Start date
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doug 371
Well-Known Member
what brand and type of sealer? Some are epoxy, some are dtm (direct to metal) some need to be at minimum etched first
ESP47
Well-Known Member
Always go off of what the TDS sheet for your paint/primer says.
Right off of PPG's site " MP170 Epoxy Primer. Primary use: bare metal adhesion and corrosion protection." "Can be applied over: Properly cleaned, sanded, bare or primed steel, galvanized and aluminum." So yes, it can be applied to bare metal.
Yep! The paint tech sheet!!!
ESP47
Well-Known Member
DesertRat
Leading edge boomer
That is the same product I used on my current build after taking the entire car down to bare metal. I followed with urethane primer and will use the PPG sealer just before spraying the color.
Or thin the epoxy primer and use as a sealer.
Talking about tach sheets. I notied othr day when Iorderd more SPI epoxy their thech sheet said to NOT apply over etch primer! NO way they said. I fabbed some patchs other day and had some etch primer handy and shot that over it to al it for now. better sand that off when my epoy primer get here! They scared me!!! I should call them and ask WHY. I have read before that epoxy primers vary and has something to do with acid in some of them. Don't know just curious.
kdbunn
Well-Known Member
Some self etching primers are harsh and may wrinkle certain primers. If the etch primer is old or aged, there should be no problem. Sealers are generally made to go over any substrate to promote adhesion and block any reaction to whatever it's going over to the top coat.
ESP47
Well-Known Member
Good thing is that an email, phone call or post on the forum and the owner will give you a detailed description for why they say no go. Some of the best customer service in the business.
Surprising that the epoxy doesn't jive with it. I figured you could shoot epoxy over oil and it would be fine.
kdbunn
Well-Known Member
Epoxy is really just a straight resin type primer. Generally speaking, It's main purpose, besides rust prevention, is to promote adhesion between bare metal and whatever is going over top of the epoxy. @DesertRat is doing it right. Epoxy (or any DTM) primer, then the high build.
Now that you say that, when I bought the E primer I have now I told him I wanted ‘sealer’ to go over the primer that’s on it now. Bad communication I guess, reason I asked the question, and was supposed to be black too. Now I have to go but sealer!
kdbunn
Well-Known Member
Actually some primers you can also use as a sealer. You need to read the tech bulletin for the product you are using but many of them simply need additional reducing. Sort of like "sandwiching" the products.
Yea I will call Monday and ask for sure. Yes I agree, SPI has the vry best customer service outhere!
You can add some reducer to that to spray a little nicer as a sealer. Omni is Ppgs cheaper sister that is a copy of the old Dp epoxy that is now DPLF.
To spray as a sealer 2:1:1/2
It is slow though. Remember most PPG epoxy have a 72 hour windown where it stays open. Too early of an application of paint "basecoat or single stage" can result in solvent die back.
To spray as a sealer 2:1:1/2
It is slow though. Remember most PPG epoxy have a 72 hour windown where it stays open. Too early of an application of paint "basecoat or single stage" can result in solvent die back.
So wait 72 hours, if I understand you right?
kdbunn
Well-Known Member
With Omni, I generally wait until it tacks off. I have never had solvent popping doing it that way. If you can touch it without transfer or smearing, you are good to go. The 72 hours is a time frame that allows you to topcoat up to that time. between 2 and 24 hours is a generally workable time.
72 is the maximum re-coat window for this product. If this is a large job and you are using it for sealer on a complete paint job I would wait 24 hours before painting it. Small jobs don't need that much time. Epoxy in general cures very slowly.
Die back and solvent popping are two completely different scenarios.
kdbunn
Well-Known Member
^^^^^ Yes. Solvent popping can occur when you recoat or topcoat too soon. If the undercoat is still gassing out, spraying over it too soon can prevent the undercoat from releasing. We are talking about using sealers here.
Very informative guys, appreciate the info. I’ve been painting lacquer’s for 40 years with sanding sealers and catalyzed lacquers so these procedures are a little new. About 20 years ago I painted the race car, (all DuPont paints) base, pearl and clear. Turned out great then. This was over the epoxy primer that had been on awhile but I sanded with 320 then shot the covers. If it’s over 72 hours it can be scuffed up?
Yes it can be scuffed. Ppg and Omni epoxy primers are " non" sanding though. They generally sand like bubble gum.
Always READ that company's tech sheet! And just about every company's epoxy has different windows for everything!! IT is always there to read just go to the PUTER!!!!!
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