Is it absolutely necessary to primer resin kits?

[Grayson72]

Hi guys, pondering building one of my resin kits and am wondering about paint steps.

Thanks,

Grayson72

[bsu legato]

I would. The last resin kit I built, I first sprayed with some automotive primer and had no problems. Just make sure you scrub those parts off before you even think of painting. Most, if not all resin kits will have mold release agent all over the parts.

[wm cheng]

Yes, definitely scrub them down with dish detergent (without lotion) and a toothbrush.

I have used a Tamiya spraycan primer (fine) it goes on beautifully smooth.

Lets see the progress shots!

[007-vf1]

Is it recomended?, yes...even if the mold release is taken off completely ( which is always hard to tell) the surface is too smooth in some parts and the paint might peel and scratch off easily. You would have to sand the whole kit a bit to make the paint adhere to it better.

Also by priming you can see imperfections on the surface a lot better.

[Valkyrie]

Here's a trick I like to use on resin kits. Get some Comet bathroom cleaner, put some in an old or disposable cup, and mix in a little water, making a thin paste. Put some of it on an old toothbrush, and scrub away at the resin parts. Not only will it remove the release agents, but it will also smooth out the surface of the parts. It works like liquid sandpaper

This works really well on kits that have a really smooth, glossy finish that paint doesn't want to stick to, and also on kits that have an uneven or 'orange peel' texture to them. And it gets into all those nooks and crannies that sandpaper never could!

[Grayson72]

Oh this is good stuff, I don't think we've had a good discussion topic about resin kits before. Keep it coming the rare resin kits are calling to me.

Any other resin building tips?

[wm cheng]

Since the resin parts are much heavier, I usually drill one or several tiny holes in the connection points (which are always too small of surface area for the epoxy) and epoxy metal pins (I rough them up wth sandpaper, they are usually paper clips) as re-inforcement to help hold everything together.

[David Hingtgen]

Yup, for resin, scrub the h*** out of it. There's many people who literally soak the parts in acetone, rubbing alcohol, even brake fluid. It depends on the kit. Some are as easy to work with as styrene, some are h***. IMHO, the more the part looks like plastic, the better it is. White/grey resin=good. Tan, not as good. Yellow=bad. Just a general rule, plenty of exceptions. And there's always big chunks which have never fully cured, and won't for another 30 years...

Nothing glues resin well, I usually go for a heavy bit of superglue, for I am one of those people who use it as a filler/putty as well, and it saves a step. (Since the superglue will ooze out of the seam already, I just sand it then--and I have a glued, seamless joint after that).

[captain america]

Primer will actually help you do two things on a resin model: allow you to spot tiny imperfections not readily visible on the bare plastic (pinholes, scratches, mold lines, etc) and also act as a barrier-coat that, itself, adheres to the resin, and allows paint to adhere to itself as well, whereas straight paint might not stick well to bare polyurethane (resin.)

Always wash/clean your parts prior to priming though: Valkyrie's suggestion to scrub the parts with Comet or a similar product is best. Alternately, for parts that are too delicate to scrub, you can shoot them with straight lacquer thinner through an airbrush and let air-dry. Do NOT submerge resin of ANY kind in lacquer thinner or acetone, you will attack/dissolve it. A light wet-sanding with 1000-grit on larger, less-detailed surfaces will also work well.