what is the best thing (readily available) to prime wood wood wheels ? I will be painting them black
Unlike steel, wood is flexible and expands and contrats with the weather (change in temperature, humidity, etc.), so it cannot be treated like steel, which is much more stable. Because of this, primers that are made for priming steel should not be used on wood.
About the best thing to use to prime bare wood with is an oil based alkyd primer, such as is used on a house. I have gotten superb results from Sherwin Williams A-100 Oil based primer. It is made for exterior use on wood; it is easily applied with a brush, drying to a smooth finish; it sinks into the wood; is flexible and provides maximum protection. It does take at least four days to dry though, so keep the car undercover and do not apply the finish coat until you are sure it is completely dry (when the strong odor of Mineral Spirits disappears). When applying, you need to try and get the primer deep into the end grain of the spokes at both ends to protect the end grain from soaking up water.
Do not paint the steel rim with A-100, or if you do, clean off any that has gotten on the steel. A-100 is made for wood and will not provide the best adhesion for finishes meant for steel. You need metal primer for that. Jim
I had my wheels respoked by Bill Calimer and I painted them black. I did not want the wood grain to show through, so I used a wood filler on the spokes to cover the grain. I know many will say that Henry didn't do it that way, but I like the looks of a grainless spoke as opposed to one where you can see the grain. After I sanded them smooth, I primed them with a gray auto primer. I then painted them with automotive urethane. They came out great and I have had no problems with cracking or peeling.
PS. I meant the A-100 is not a good primer for adhering to steel. It is meant as a wood primer and for providing a good bond between the wood and the finish you choose to apply. You can, apply any car finish you want to the A-100 once it has thoroughly dried. Jim
Filled grain painted spokes are correct. I have seen unmolested original wheels and, although the paint had lost its shine, the finish was smooth.
I painted my wheels with DP90, a flat black epoxy primer. I then followed with K-36, a two part filler coating (might not be available now, and I think the DP is now LFDP or something). Sanded smooth, then followed with a sealing coat of DP90 (sealing coat is thinned more than usual, as per the factory sheet) and finally Concept Black (I don't remember the color number, it's the blue-based black). That was some 6 years ago and they still look wonderful. Now if the car were only finished. . . .
Re sealing/covering the grain, use good quality house primer, water base. Used to be oil base was better, not any more. Spray it on with a cheapo gun from Home Depot. Two coats perhaps. You'll only sand once. Been there done that.