do i have to primer?

[hellonwheelz3]

I a building an engine and will be painting lacquer for the first time. I know from past experience (and this forum) that you probably should primer a large part, like a body or frame, but what about an engine. Is it small enough that I can just shoot it straight without the primer?

[JamesW]

You should always prime any part before paint.

[Zoom Zoom]

I almost never prime engines unless the plastic is not white and is painted in a light color; depending on the paint you are shooting it should cover fairly well. Testors lacquers are especially pigment-rich, and should cover nicely. What color are you painting? What paint are you using?

[Guest Gramps-xrds]

Everything should be primed. It gives the paint something to bond to. If you paint lacquer directly on plastic it will etch or craze the plastic and show up in the finish and every time you strip it it'll still be there.

[Steve Keck]

In my opinion there are three reasons to primer:

To highlight flaws in the bodywork. Find Mark Taylor's excellent tutorial and read it all.

To promote paint adhiesion ESPECIALLY if there will be any masking required.

And, as a barrier between the paint and the body(work)when hot paints are used.

I do not use primer under Alclad other than the chrome and stainless steel.

Steve

[Steve Keck]

If you paint lacquer directly on plastic it will etch or craze the plastic and show up in the finish and every time you strip it it'll still be there.

Gramps I disagree with you. Model lacquers are formulated for plastic and safe. If you mean automotive lacquers then specify automotive primer.

Steve

[Longbox55]

Gramps I disagree with you. Model lacquers are formulated for plastic and safe. If you mean automotive lacquers then specify automotive primer.

Steve

I agree with that as well. Even then, I have sprayed automotive laquer directly onto plastic with no primer at all, never got the first bit of crazing, not even where I had removed the side emblems. In this case, the kit is an AMT '60 Chevy pickup, the paint is PPG Delstar Skyline Blue, which was leftover from sprying my 1:1 '55 Chevy (didn't want to waste the paint left in the gun).

[hellonwheelz3]

I will be spraying (or shooting, i haven't chosen) testors auto lacquer in hemi orange

[highway]

I will be spraying (or shooting, i haven't chosen) testors auto lacquer in hemi orange

I used the Testor Custom Lacquer System Hemi Orange on this 09 Dodge Challenger.

Here's where I probably will confuse everybody, or at least hear "You shouldn't have done that" and such, but the body IS primed, using the Testors Lacquer White Primer. The orange in these next two pictures, the engine and engine bay, WERE NOT primed, just sprayed on the bare plastic.

If it were not hobby grade lacquer, I would never have sprayed the bare plastic without primer, as a few of the others have said. I have used Krylon lacquers before on bare plastic many moons ago, and they crazed the plastic like, well, crazy. Even if I use auto grade enamels like DupliColor, I always prime under them first.

[diymirage]

i would suggest primering the engine and here is why : the engine will get handled more then just about any other part of the build because of detailing and mock ups

i find with my build a lot of times the paint of the engine will wear off where i hold it (the oilpan and tranny mostly)

primering will cause the paint to adhere better and rub off less

[Guest Gramps-xrds]

Gramps I disagree with you. Model lacquers are formulated for plastic and safe. If you mean automotive lacquers then specify automotive primer.

Steve

I would say that if it's formulated for styrene plastic. It's probably not really a lacquer, but an acrylic. Since I don't use model paints I can't say without seeing what solvents they use. But you go ahead and do whatever it is you're doing. I'll prime.

[Guest Gramps-xrds]

I agree with that as well. Even then, I have sprayed automotive laquer directly onto plastic with no primer at all, never got the first bit of crazing, not even where I had removed the side emblems. In this case, the kit is an AMT '60 Chevy pickup, the paint is PPG Delstar Skyline Blue, which was leftover from sprying my 1:1 '55 Chevy (didn't want to waste the paint left in the gun).

The Delstar I used to use on 1:1s wasn't a lacquer base. It's an acrylic enamel. They act like lacquers in that they dry fast and can be polished, but their still enamels. I personally never liked PPG paints. Dupont was far superior in my opinion, but like I told the other guy. You do whatever you like. I'll prime and have less trouble and better paint jobs.

[Longbox55]

No need to be snippy. I was only relating a personal experience. This one truck was the only one I did that way, and it turned out very nice. I have double checked the can, and it does say acrylic enamel, but I also read the reducer, and it has all of the same nasty stuff in it as laquer thinner, which from what I understand is the real issue.

Personally, I don't care for DuPont, seen far too many failures of their products, including 2 vehicles owned by my family. I have never had a problem with PPG.

Having said all that, I will agree to disagree. Now lets just build something!

[Guest Gramps-xrds]

No need to be snippy. I was only relating a personal experience. This one truck was the only one I did that way, and it turned out very nice. I have double checked the can, and it does say acrylic enamel, but I also read the reducer, and it has all of the same nasty stuff in it as laquer thinner, which from what I understand is the real issue.

Personally, I don't care for DuPont, seen far too many failures of their products, including 2 vehicles owned by my family. I have never had a problem with PPG.

Having said all that, I will agree to disagree. Now lets just build something!

I'm not being snippy, just stating facts. Being the son-in-law of an old auto body shop manager / body man and a painter myself. I can speak from yrs of experience. The reason they put labels on the cans is to tell you what thinner or reducer to use. Using anything else can cause the binding agent to break down or change the flow out or other problems. If it doesn't cause problems immediately, it can cause them down the road. Most common is a dead finish or paint lifting. PPG paint was to oily for my tastes. But every shop has their preferences though. Now you can go build something: .

[Longbox55]

Too late, been working on adapting a Racers Wedge to an L700!

I appologize for the "snippy" remark, it was uncalled for.

For the most part, I do prime my bodies and chassis, Dupli Color has been my primer of choice, but I do use Valspar and BPS primers, too. I generally do not use 1:1 automotive paints, however.

[Guest Gramps-xrds]

Too late, been working on adapting a Racers Wedge to an L700!

I appologize for the "snippy" remark, it was uncalled for.

For the most part, I do prime my bodies and chassis, Dupli Color has been my primer of choice, but I do use Valspar and BPS primers, too. I generally do not use 1:1 automotive paints, however.

No need to apologize Bill. If I came off as being a bit snippy, it wasn't intentional. I'm sure sometimes I can appear that way. And for that I'm sorry too. I know from experience and what I read on here that a lot of ppl give advice from personal and sometimes very limited knowledge. A great deal of the time it's incorrect, or may have worked once for them. I've been building and painting models among other things for almost 60 yrs and I sure as heck have done a lot of things the wrong way. Sometimes I got away with it and sometimes I didn't. I guess that's how ya learn.

Ben, I'm sorry if this post got out of hand. The bottom line is, all paint manufacturers recommend their products be used on a primed surface. The reasoning behind this is, it makes their product perform and look better and if you're happy, you'll buy more.

Edited May 27, 2010 by Gramps-xrds