Jay,
You really need to use one of the acids to open the pores/etch the zamac, otherwise the dichromate is really streaky or splotchy. Kinda like the gold bowl how that corner didn't fully take. Probably just some oil that was still in there. Some parts absolutely will not recolor properly. That is one of the reasons I'm upgrading my plating station, I'll just go ahead and replate the whole main body/metering blocks/bowls etc and then go through the whole recoloring process again.
So let it sit in there for 15-60 seconds, pull it out and water wash it. water wash it in another bucket, water wash it in another bucket. blow it off really quick and dip into the dichromate.
This keeps you from contaminating the dichromate and also deactivates the acids.
The acids don't need to be heated, but the convertor/dichromate needs to be either an even temperature or you need to account of cold, like it needs to soak longer.
again, 15-60 seconds, maybe a lil longer. You can pull the piece out and look at the color. When done it needs to be water washed again as it'll keep darkening.
It's a zinc convertor, like ospho is for steel, so treat it in the same manner.
When done with the dip, they need to dry. You can add heat but not much, 120-140 would be the upper limit.
Again, these chemicals are pretty nasty. So wear gloves, don't touch stuff, etc.
I intended to set up a larger plating table for actual electroplating of zinc and do some photos of that operation, but just got called back to work, which sucks.
I worked through half of my time off last time, and it looks like instead of a month off, I only get 8 days off and then gone for the next 7+ weeks.
Got home, got a 302 tuned and running a 32 Ford, did yard cleanup because there was a hurricane a month ago and I got called back to work, so the trees were still there. Just spent the day tuning a 482 in a 63 Galaxie for some nice folks. No time for plating projects. Hopefully I'll get to it next time I'm home.
Either way, it's a weird hobby but a fun one. I doubt there is a ton of profit in it, but it's rewarding in it's own way. I suspect I have 10-20 man hours in each carb, mostly just due to getting everything absolutely perfect, if it isn't perfect, you pretty much have to start over. Plus saving old car parts and refinishing them keeps them out of the scrap pile, I've been less than thrilled with a lot of the new junk out there. Maybe someday I'll get decent enough at this to try proper restoration work, but I'm just messing around right now, I don't think I'm skilled enough to handle precious originals at the time.
