Alternative to spray-on cold galvanizing

Trying to make an assembly & weld cell that currently uses a rattle-can galvanizing compound. Would like to replace this with a dip tank and blower/heater. This is on the end of what's basically a custom turn-buckle. It has 3/4" all-thread, some nuts tack-welded, a laser-cut 1/4" steel plate at the end (about 2" x 6" long). The whole assembly is around 12" to 18" long (varies) from the end of the 2" tube it's welded to (the tube makes a good dipping handle, doesn't need to be coated). Only this end has to be dipped. Aesthetics aren't important, just can't "gum up" the all-thread.

The current process is cumbersome, wasteful (over-spray) and bad fumes. I'm envisioning that after welding, maybe a minute cooling period, dip the end in a small tank, an air flow to blow off excess and then a heat lamp maybe slight air flow to speed up the drying process.

Any recommendations on a good coating material? Lower viscosity is critical, can't be so thick that it will dry and mess up the adjustment process (about the only good thing on the current process). Doesn't even have to look like cold-galvanized since it's only seen when working inside an enclosed structure.

Thanks,
The Dude

Use hot dipped all thread and nuts, use gal-viz on any welds, do not do much cleaning of existing galv coating. Cut the 2x6 piece from hot dip flatbar or better redesign to use 2" flatbar.
Better yet make all from stainless and dont worry about the coating.

Any process using zinc powder paint is problematic.......the stuff ,settles ,clumps,blocks , and scores pump barrels.You also got the choice of "inorganic binder"...zinc ethyl silicate,or organic ....zinc paint.

Plating - electroless or electroplating - is a clean and easy process to protect parts. And one can use a wide range of coatings including zinc.

The Dude said:

...Any recommendations on a good coating material? Lower viscosity is critical, can't be so thick that it will dry and mess up the adjustment process (about the only good thing on the current process). Doesn't even have to look like cold-galvanized since it's only seen when working inside an enclosed structure.

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If you have enough to hit the minimums, call TFC Plating. They can do a zinc chromate clear that isn't real heavy. I do a handle with 6x 10-32's that get tapped before plating. and the fasteners still go fine.

How about just a bucket of oil or grease or Boeshield?

I asked one trucker how his chain binders stay free. He says he keeps them in a bucket of oil.

Also, they do make zinc rich primer in a liquid form. We sometimes buy it from GME Supply:
Cold Galvanizing Compound by Crown, Sprayon, and ZRC - Zinc Corrosion Coating Primers and Paints | GME Supply

Thanks guys, I may not have made a few points clear. Farm-out is definitely not an option, it would be too lengthy (time) and handling to send out. What I'm looking for is, ideally, when the part is taken out of the weld fixture, or after 1-2 minute cool-down (the total weld on the size of the part is fairly small, heat will dissipate quickly)they are dipped and then just set aside in a blow/heat chamber.

Question about hot galvanzied: is that a "complicated" process to set up (i.e. several tanks)? I'll do some searching on it, maybe my assumptions are bad.

Starting to see why the current process is just pick up a can, spray a few seconds, set it aside.

Thanks,
The Dude

I use a tin plating solution that is sold in a bottle. Pour it into a tray and dip copper circuit boards for 3-5 min. Not bad as long as I don't inhale the fumes and wear gloves.
Cleans up with water and I reuse the liquid.

This is a step above that but have no experience with it. It appears to be geared for small parts, but it probably can be modified for larger pieces.
Electroplating System Tin Zinc - Tin Electroplating System Kit - Zinc Plating Polish

kb0thn said:

Also, they do make zinc rich primer in a liquid form. We sometimes buy it from GME Supply:
Cold Galvanizing Compound by Crown, Sprayon, and ZRC - Zinc Corrosion Coating Primers and Paints | GME Supply

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I will check into this. My assumption is that these will be difficult to thin or, by the time they are made thin enough that they won't offer enough protection but it's worth checking out (the instructions don't include "dip", just spray/brush/roller).

Oiling definitely not an option, has to stay clean, there's an assembly process that involves some cosmetics.

Thanks,
The Dude

The Dude said:

Question about hot galvanzied: is that a "complicated" process to set up (i.e. several tanks)? I'll do some searching on it, maybe my assumptions are bad.

Click to expand...

You don't want to go there. Acid dip and tanks of molten zinc.

Hot dip is way too complicated to bring in house. First, you caustic dip, then rinse in water, then acid dip, then rinse again, then, often, flux spray or dip, then dip in 840 degree molten zinc, then rinse again. 5 to 7 tanks, caustics and acids, and 840 degree heaters. Usually done in open sheds, due to fumes.

Liquid zinc paint is probably your best bet, but dip tanks are always a pain, no matter what paint. They get dirty, the skim over, they need stirring, often need temp controls, (heat) they are messy, and, unless you are running parts all day every day, are expensive and wasteful.

Make a booth, get some tyvek suits and forced air respirators, and put a guy in there with a big paint brush, and just paint em wet with cold galv paint. It will drip and make a mess- but its the cheapest easiest, fastest in house solution.

or, as mentioned above, switch to stainless. Higher material cost, but no coatings.

Since its a threaded connection, stainless will require anti-seize. If strength is an issue, it will either need to be oversized or a heat-treated stainless.

There are several manufacturers that make coatings that have a zinc dust additive where hot dip can't be used.