Smooth paint finish over hot-zinc spray?

[hot_anvil]

Hi,
Some of my (steel fab) work is blasted, hot-zinc sprayed and then wet painted (100% gloss normally).
I contract out the hot-zinc spray work, but apply the wet paint myself.
I find the painted finish is not as smooth compared to painting on steel without hot-zinc spray. In fact it looks a bit like I've oversprayed the items as the finish is quite rough and matty. The hot-zinc spray is not a smooth finish so that explains why this happens - I think.
Or at least I have to coat it a million times before it even approaches the same smoothness as bare steel.
Does anyone else have a similar experience please?
I guess my main questions are:
1. Is my hot-zinc sprayer doing a bad job and I shouldn't be getting this roughness?
2. Or should I be specifying a 'smoother finish' option?
3. Is there a clever/special way of painting these, or a special paint?
(I'm guessing the answers to 1 and 2 are no.)
Any help/tips much appreciated.
Thanks.

 

[awemawson]

In my experience zinc spraying with my Metco gun you always get a matt finish. Remember what is happening: The individual small droplets of molten zinc fly through the air and splat onto your work, generally bonding by mechanical locking onto the roughness of the blasting. Each droplet flattens into a microscopic cushion shape overlapping adjacent ones hence the surface finish.

If you want a fine surface you may be better with hot dip galvanising, but that won't be perfect either.

 

[blacksmithstris]

I've had stuff powdercoated after zinc spraying which has produced a good finish, as far as I can remember!! (Was about a year ago the last time I had that done, so maybe my memory is clouded!!)

Stuff that is hot dipped has to be well fettled after, as the zinc can create all sorts of drips and scabs and rough bits, but otherwise is a good smooth finish. I always have to go over everything that's come back from galvanizers, before it goes on to be powdercoated, as they do a bit of the fettling, but it's never what you would be happy enough with to pass along to customers!