Painting engine parts

[Hws5283]

Im building my first model car and wanted to know how you should go about painting the engine of the model. Personally, I was going to first prime all the pieces and then paint them with an airbrush before using glue (Tamiya plastic cement) to attach any of the pieces. So to clarify have zero assembly of the engine done until all the pieces are primed and painted so If pieces of the engine are different colors I wouldnt have to mask anything. Is this the right way to go ? 

Also would plastic cement not work as well on two pieces of plastic if they already have paint on them ? 

[GeeBee]

I tend to build the engine up with parts that need to be painted the same colour, all the other parts I prime at the same time, then airbrush in the colour they need to be painted,  plastic cement doesn't work well on painted parts, I use epoxy resin. 

[Casey]

30 minutes ago, Hws5283 said:

Im building my first model car and wanted to know how you should go about painting the engine of the model. Personally, I was going to first prime all the pieces and then paint them with an airbrush before using glue (Tamiya plastic cement) to attach any of the pieces. So to clarify have zero assembly of the engine done until all the pieces are primed and painted so If pieces of the engine are different colors I wouldnt have to mask anything. Is this the right way to go ? 

Also would plastic cement not work as well on two pieces of plastic if they already have paint on them ? 

It depends upon the order of assembly. Some parts need to be assembled before painting, and other are best done after.

Any two surfaces to be glued together must be free of paint and/or chrome plating. Always glue bare plastic to bare plastic.

Which kit are you building? A typical V-8 engine could have the block halves, cylinder heads, water pump, and intake manifold glued together first, then painted as one unit. Then add valve covers, the fan and pulleys, etc.

 

[Hws5283]

Heres the complete engine assembly directions for a 1967 Shelby gt350 

 

Edited January 6, 2021 by Hws5283

[Casey]

Got it. I would recommend gluing the block halves, cylinder heads, water pump, oil pan, and intake manifold (unless the intake manifold is supposed to be aluminum) together, then painting it as one unit. 

Tamiya cement works great for bare plastic parts, so just make sure you follow the instructions, and give the cement some time to soften the mating surfaces. Then, let dry for 24 hours, clean up any excess glue squeeze out, and prep for primer, then paint. Detail painting the smaller parts is a matter of preference. I think it's best to carefully cut all parts free from the runners, clean up any remnants of the gate (that little bit of plastic which connects the part to the runner), then prep and paint each part individually. 

If you are hand painting/brush painting the smaller parts, you will have better control over the areas you want to keep paint off of, such as the four flanges where the exhaust manifold mate to the engine block, the underside of the carburetor where it mates to the intake manifold, and so on.

When you can glue together and paint parts as assemblies (such as the transmission halves in your kit), I would always try to do that, then assemble the smaller assemblies into the complete engine and transmission, and so on. Follow the instructions as best you can, too, as the kit was designed to be assembled in a particular way. You may discover a shortcut or alternate order as you go, but generally, the instructions are designed to make assembly easy and building the kit a success.

[Hws5283]

Thanks a lot ?

[Fat Brian]

Some kits have the oil pan molded to the block halves instead of being a separate piece as in your kit. In those cases the engine halves need to be joined and the seem sanded down before painting. As you build more kits you'll get a feel for the order of operations for things like this.

[espo]

An additional thought would be kits where the engine and transmission are done in halves running length wise. I suggest gluing those together before any painting since you may need to use a little filler to hide the seem between the two parts. Depending on the engine and the types of metal or alloy materials you're trying to represent many of the parts would have to be painted before assembly. Often a cast metal block will have a flat finish and the oil pan or valve covers and timing chain cover will have a semi-gloss to a gloss finish. Even engines that are all aluminum will often have a slightly different finish or color shade even. 

[R. Thorne]

If you have to glue painted parts together you can scrape the paint off and use cement, but I got tired of cleaning off the paint and now use the small tubes of super glue on painted surfaces.