Were some, or all, of the black painted metal brackets, such as engine mounting brackets and muffler brackets dip painted by the factory? Some of mine appear to have been dip painted. This would have saved a lot of time at the factory. I may want to replicate the dip painting when restoring my bike.
Has anyone tried the dip-painting method? Too sloppy and messy, or otherwise, vs. spray painting with the hobbyist rattle-can of paint?

Thx

Yes, dipped in black enamel while hung from wires, allowed to drain and then run through an oven to cure enamel.

if you want ABSOLUTE authenticity, then dip-painting is the way.
The trick is determining HOW each part was hung when it went into the dip tank. You want the dried dipped paint run-off drop in the proper place.

HINT: In parts that do not have a mounting hole, look for a small drilled hole somewhere on the part, to allow a hanging wire to be used.

I've seen a technique that is very similar. You have a pot of paint and a dipper. Hold the part over the pot, use the dipper to pour paint on the part until every inch is covered. Then hang and bake.
Helps when you don't really have enough paint to dip larger parts.
Cheers,
Bill

read up about Ford model T production on how they dip painted frames with large tank of water , the paint floats on top of water part goes in gets coated completely using less paint.

For me, dipping and baking might give a better result in:

1. paint smoothness
2. paint gloss
3. paint thickness
4. fairly easy to do
5. more originality to factory original

Getting a good result with a rattle-can is difficult for me.

Is baking the parts to cure the paint absolutely necessary? This, to me, would be the sloppiest part of the job. Also I'd have to build a small hanging jig to place in my wife's oven; while she's away, of course...….lol

I've done a fair bit of stove enamel work on mostly antique electric fans, not motorcycle parts. I've always powdercoated those. But, I've found that if you bake the enamel, first, it's ready for use much sooner, and second, the finish can be cut back and polished if you like, making for a very attractive and glass smooth finish with a soft glow, instead of a harsh mirror shine like automotive paints. Once baked, it's also solvent and gas proof.
It's a matter of tastes at the end of the day.
I use One Shot lettering enamel because the price isn't too high, the quality is very good and it comes in smaller cans. Shelf life isn't so long with these types of paints.

It can be costly. When the wife smells what you've done, it will likely cost you a night out at an expensive restaurant.

Cheers,
Bill

I'm trying to figure out how to dip parts in a big tub. Isn't there a ton of waste?

Depends. If you're doing high volume, then you'll use the paint before it goes off. If low volume, you would need to store it somehow until you need it again.
I can't tell you how many cans of enamel I've tossed because it goes off in the can. Changes in barometric pressure causes them to lift the lid just enough to let air out, then it lets air in and starts the process of "skinning". That's when a hard skin forms on the top of the remaining paint. That's about the end of the paint as far as I can see. It's never the same after that.
So, yes, there can be a huge waste of paint and it can be very costly.
Using the pot and dipper process is a lot more efficient.
Cheers,
Bill

When I did a lot of bike parts painting (40 years ago) I would prepare as many parts as possible in advance, then spend four or six hours spraying them, or spray until I ran out of the amount of paint I had mixed. I was spraying urethanes with hardeners. My goal was to waste as little of the expensive mixed paint as possible.
The paint was a lot cheaper then, but money is money. Today's paint is a LOT more expensive, so cut the waste as much as possible.