Hi All,
In my Indy rebuilds I've come across some rusty PSUs...not overly rusty, mind you. But brown rust forming on the vent perforations, edges, corners, and loss of platting on the underside. I've been racking my brain with what to do about this for a couple years and I wanted to re-establish the galvanized protection for long term use.
Painting the entire PSUs would be a hassle as prepping the surface would be hard to get right (inside and out) and we are really talking about "spots" and "touch-up" here now several manufacturers make a "cold galvanizing spray" product that contains zinc to fix up fences, posts, building materials, boat trailers, etc..
There is a spray and a pint of paint forms of these products. While some people claim the spray is fine...there are enough reviews of ALL these products to say the sprays have big issues (especially if you want to stop and use the can again later). These sprays have a lot of zinc which separates very easily over time. To make the spray really work you have to mix it VERY WELL and then spray, shaking is very frequently...most of the time the mixing isn't good enough and the spray is uneven or clumps or wastes the gas in the spray can.
A few of these products are sold as pints of paint. Based on reviews and such I choose this one (sold through Amazon by a merchant):
ZRC Galvilite Galvanizing Compound 95%, in a pint can.
This stuff was FULLY separated when I opened it..with thick zinc sludge at the bottom. I had to use a drill for a good 10 minutes to mix it nearly 100% smooth. Don't try this without a drill, it will kill you swirling by hand (perhaps use a paint store shaker...but be quick about it).
I don't have a before picture (I was moving too fast and didn't think about it...plus the end result is really what we care about).
These pictures show a single coat, with a brush (so you see brush marks...yeah I know). I used a dremel with a steel wire-wheel (bowl form) to remove all the rust and give the general underside a light sanding, I also cleaned it with acetone too to make sure.
I mixed the pint a lot and the color is not too dissimilar from the Indy PSU. After 24 hours I tested the surface by rubbing it hard with my hand, nothing came off...so adherence is good!.
While some PSUs have a shiny appearance, I think the Indys will be OK with it. I didn't apply it to the rear vent grill (didn't need it anyway). All the moisture damage was at the bottom. I didn't paint the inside of the PSU either (outside of a few bottom grate lines that got coated on both sides due to gravity.
I think this looks pretty good (I didn't do the entire bottom...I still might, but I was trying for touch up). I can do another coat if I need to, but I think it's fine as-is. This SHOULD give it a fairly good future protection from rusting (just as the original coating was trying to do). It's as simple as painting (after exhaustive mixing). So not too bad.
I'm posting this for A - Opinions and B - for other people looking to arrest rust on the cheaper metal parts of an SGI, this can be a good solution that can establish a galvanic protection (unlike simple paint).
Cheers!
NEED -> 