Re: paint color

Posted by Fish'n Jim On 2019/10/16 10:00:22

Another one of "those" issues. "Looks can be deceiving" Today's paint is different than what you got in '46-51, so whom are we kidding that it's restored with original paint?
The paint chemistry changes over the decades, so what's appropriate for one is not necessarily the same in a later.
These type "supplier/OEM" parts are usually painted to some spec from a bulk buy paint. Some are not painted. Some paint chips list the under hood and some do not. As far as I can tell in my limited searching, Packard only listed exterior, didn't list all finishes. (We went through this for faux wood. PAC/Stude archives might have documents but certainly "rosters" do not know.) Why good low miles unmolested originals are used as benchmarks.

Today's rattle cans are fast dry and come in standard hues. Even these are changing to water based.
Automotive mixed paint has 6 finishes, from flat to gloss. All that varies is the amount of "flattener" they mix in. w/ Gloss = 0 flattener, flat = max. I find the mid gloss #3 aka "semi" closely matches GM underhood. For ease, I shoot acrylic enamel for these.
I keep rustoleum semigloss black rattle can on the shelf for touchup/small parts. I prefer "appliance" epoxy for unprimed direct to metal coats. This only comes in gloss (rattle cans) so I only use on certain things like cast where the surface won't be extra glossy or making an unseen mounting bracket, etc. You can actually shoot paints in such a way as to reduce gloss, "haze/dry coat", also. Oppositely, you apply a wet coat (with levelers) to bring up an as-sprayed gloss. Epoxy lasts longer/harder and I don't have a gun to clean or 9/10 qt of paint left over.
Early pre-war would have been nitrocellulose lacquer and then straight lacquer. Lacquer requires a high solvent content, so is inherently dull from flash off until "rubbed" out, same applies for some other finishes, so what appears to be gloss maybe rubbed and/or waxed to gloss, not as applied. Gloss requires a flat surface. Certainly not unreasonable to wax or rub out a big air cleaner in days past. I know I've done it. The cleaners in wax help a tired old paint finish too. Keeps that dirt off and easier to wash/wipe, too!
"Alkyd" is probably post war period what we refer to as "straight" enamel. You can still get, but it takes long to dry w/o an oven, and today most add accelerator or hardener to it. This is what is still used on restoring tractors, etc. Low VOC inherently. Hardener is isocyanate and needs personal protection. Fairly good direct to metal and not many faults in application.https://www.paint.org/article/brief-history-automotive-coatings-technology/