Detailing undercarriages & mechanical parts

I usually prime the whole sprue.  Whether I cut the parts off of the sprue depends on how hard it will be to hold the part. If there are holes or stubs that can be grabbed with a clothespin, I will cut it off the sprue to paint.  I usually paint these parts with a rattlecan. If the part is very small I might use a brush.   I certainly build up sub-assemblies, and if the parts are all the same color I will paint as a subassembly.  If I paint while on the sprue, then I accept the necessity to touch up the point where I cut it from the sprue with a small brush or toothpick.

Rather than flat black, Testors makes, in the Model Master line, a Black Chrome, which to me makes a better chassis/frame paint than flat black. It is a semi-gloss black.

Thank you for the feedback!

As for the sort of color-monotony of the undercarriage though, how do you spice it up a bit?  Just with weathering, or do you paint small details (bolt-heads and what-not), or is it pretty much common practice to just paint just about everything down there the same color and call it a day?

Thanks!

I've primed small parts both on and off the sprue. You can prime them on the sprue and then remove and finish each part. Reprime as required. I have a clothes hanger with adjustable clamps for hanging pants. I use the clamps to hold a strip of masking tape, which in turn holds my small parts. The hanger can be held in one hand while you paint with the other, or the hook can be straightened and slipped into a homemade sleel/aluminum tube mount.

In the automotive world, you have to decide whether to paint the chassis clean and bright (suitable for the Barrett-Jackson chassis cam, or worn and weathered as it would appear if street driven. In either case, black primer makes a good base color. Dust over the black with Bragdon powders in shades of gray and brown, then follow up with dry brushing in gunmetal gray to bring out the bolts and other details.

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For added interest, silver can be used for the fuel tank and in rare cases (newer Corvettes as an example), suspension arms. Bright colors can be used for shock absorbers and swaybars, coil springs if you're feeling spunky. Aluminum drive shafts are rare, but some competition cars and late model vehicles use them. The underside of the engine will also add some color and detail.

dan o'war

Thank you for the feedback!

As for the sort of color-monotony of the undercarriage though, how do you spice it up a bit?  Just with weathering, or do you paint small details (bolt-heads and what-not), or is it pretty much common practice to just paint just about everything down there the same color and call it a day?

Thanks!

Springs are frequently different colors than the frame.  Coils are painted, sometimes a gloss black.  Leaf springs are usually a treated steel color.  There may be lines and hoses under there, usually unique colors.  Exhausts need to be painted with a "burned" patina.

Leaf springs will also tend to have a little coarser surface than other chassis parts, so they'll grab more dirt.  Also, since the spring leafs will rub against one another as the chassis moves, they may also have a slight patina of rust or dirty rust along the leaf joining points.  A wash of thinned rust will do well here. 

Don't forget there are aftermarket coatings you can use to spice things up a bit.  Undercoatings are almost always a flat, while any factory coating will tend to be a semi-gloss.  And depending on the manufacturer, certain parts, or the while chassis won't even be painted.

Gene Beaird,
Pearland, Texas