What kind of paint for sidecar frame.

What about  either  Rustoleum, or Krylon, in a gloss black, that is meant for  metal, such as outdoor  furniture,  etc. ?

Readily available  at any Home  Depot,  Lowes, or ACE hardware. 

When I try to do it right.  

1/ rust treatment by whatever means. Tick that box.

2/ etch prime it for bite. 

3/ zinc rich paint. Grey or black. 

4/ top coat a couple of times.

Of course for sidecar frames it's all out of a rattle can .

At least with rattle cans it's easy to touch up though not as durable as 2 pack.

Ideally I'd just hot dip galvanise the thing.

And on that note, here is yet another simple tip.....specifically for sidecars:

Almost every sidecar has a manufacturers plate, and ID plate, screwed in, or riveted in to the frame, to identify that sidecar frame, much the same as a VIN plate on a motorcycle or automobile or truck.

How many of YOU have looked at that ID/VIN plate and found it marred, scratched over by road debris, painted over, dented, etc ?????

What I have done is to place a piece of seriously heavy duty Duct Tape over the face surface of each of the ID plates, the VIN plates, on each of my sidecars, simply to protect that ID/VIN plate, so that 10 years from now...or 30 years from now, that ID/VIN plate is still legible and readable.

It takes all of 30 seconds to tear a piece of seriously heavy duty duct tape from a roll, then place in over the face of the ID/VIN plate, make sure it is firmly in place, then...forgetaboutit.

The beauty of this 30 seconds exercise is that 10 to 30 years from now, the 3rd or 4th owner of this rig can easily remove that seriously heavy duty duct tape, and clearly read that ID/VIN plate, and know exactly what it reads...clean and clear numbers and letters.

Have to try that on my fiat.  

I mean I'm only the 4th owner.