Painting aluminium: zinc chromate primer vs self etching primer

[Scott Bentley]

Originally Posted by Stuart Fedak

Grant/David,
Thanks for the leads. This is all new to me, so I am slowly working my way through the information.

I tried some of the yellow Zinc Phosphate primer and some etching primer for aluminium, on some test pieces. The Zinc Phosphate did not look very good. Not sure if it was because the piece was not warm enough, or clean enough, but it did not adhere well. Then I tried the etching primer, after cleaning with some vinegar, which adhered nicely.

So I did the PRC-77 battery box and the main box with the etching primer, which just happened to be green. Then some rattle can OD green final coat. I do not expect this to be the best job, but the PRC-77 was really ugly before, so anything is an improvement.

I am still cleaning off the front panel of the PRC-77, and should be in a position to prime over the weekend, or next week....

There are a few odds and ends missing on the PRC-77, such as the frequency locking mechanisms on both the right and left frequency knobs, plus I could use a Canadian or US issued PRC-77 data plate. Those can go on afterwards, when I track down the parts.

The PRC-77 receives and transmits well, so no issues from an electrical perspective.

One other step to do is the white lettering on the front panel. I am going to check out The Hobby Centre in Ottawa, which seems to have all sorts of fine brushes for painting. I figure if they service the model crowd in Ottawa, they should be able to point me in the right direction for painting the front panel markings on the PRC-77.

ref: https://hobcen.wordpress.com/


Cheers!

Stuart

For the panel letters I used a pencil eraser dipped in white paint and then daubed on the raised letters. Did this with both my 77 Set and 2060 Tray. Both turned out excellent.

EDIT to add detail: You don't need a lot of paint on the eraser. I actually daubed the eraser lightly on paper first and then touched it to the raised letters. Provided the letters are not damaged badly this works really well. 524 with the sunken in letters would be a different story which is why cleaned mine well and just left it alone.

[Scott Bentley]

Not the greatest pics, but you can see the results of the above method.

[Scott Bentley]

I didn't actually strip the old paint from mine. I did a light scuffing with Scotchbrite pads, wiped down with Acetone, and then sprayed with Gillespie 24087 Semi-Gloss OD. I suppose one could also go with 383 CARC Green, but 90% of the radios I used were still in Semi-Gloss OD by the time the TCCCS started arriving. While I'm happy with the end product, I feel like I should drag them through gravel or something as no radio I ever handled from that era looked this fresh

For sunk in letters there are a couple options. You can spong the paint over the letters, let the paint tack up for a few minutes, and then wipe away the excess with an acetone soaked cloth. Looking at NOS Comms bits, this looks like how it was done at the factory as I could actually see faint smudges from the excess paint being wiped away. Alternatively, you could get a fine point white paint pen from Michaels or similar and go that route.

I'd definitely be curious to see how my installation is working. Everything powers up and receives fine (I used to tune in Range Control when I was in Gagetown), but I have no idea if everything transmits. Aside from confirming that the 524A fan spools up when keying the mic, I've attempted to communicate with anyone.

[Scott Bentley]

The Gillespie paint isn't terribly expensive, but the process of getting it is. I think my rattle cans came from Rapco. I had it shipped to the Ogdensburg NY UPS Store as the UPS fees to have it delivered in Canada were significant enough to justify the 2hr round trip to the border. I used it for all my ancillary equipment like the radios, pioneer tools, etc.

I have a few cans left, but I still need to paint the underside of my hood to match the rest of my engine compartment. If you're willing to wait a little bit, I may be able to help you out. I need to find the case of cans and count how many I have left.