Calculator restoration: repairing paint loss

[mfleming]

Hi all,

I thought I'd tap into collective experience to see what advice I might get for restoring paint loss on old banged-up calculators. For the last four months, I've been buying and restoring "For Parts" calculator listings on TAS. I've been able to acquire some 41's, a 42s, 27s, 28s and 20s this way at very low cost. But each though, besides not working, had defects that would certainly cause them to be rejected by a collector. This site has been a goldmine of information on how to bring one of these old calculators back to life, so I hope you might also know how to recolthe an old beauty.

I might add first of all that I am a calculator USER, not a calculator COLLECTOR. I really do enjoy restoring and mastering each of these that I acquire. Some have serious wear, while others have just a little cosmetic damage. Right now, I have a couple of Pioneers that have paint loss around the display bezel edges. A few hairline scratches also mar the surface.

I really can't do anything about someone who carves their name into a calculator face, but I would like to touch up some worn spots here and there to make an acquisition more pleasing to the eye. An attempt with brown and black Scripto markers was OK on a spot here and there, but no so good on larger loss areas.

Does anyone have experience with touching up visible paint loss that they'd like to share? I haven't seen any previous postings, but pointers to past discussions would be greatly appreciated.

Thanks in advance to everyone who responds!
~ Mark

[Nigel (UK)]

I bought one of the silver pens mentioned in this thread and it works well for the purpose described. (I've been using it on old Commodore calculators.)

Nigel (UK)

[wojtek]

i use an epoxy resin with some pigment added to preserve the color. Instead od the pigment a paint (for metal) of proper color can be used. The layer of epoxy resin makes the paint sturdy enough. You could try a sealing compound used for repair of cars (with a pigment added) but I not tested it

[striegel]

(07-01-2016 05:09 AM)mfleming Wrote:  ...
Right now, I have a couple of Pioneers that have paint loss around the display bezel edges. A few hairline scratches also mar the surface.

...larger loss areas.

Does anyone have experience with touching up visible paint loss that they'd like to share? I haven't seen any previous postings, but pointers to past discussions would be greatly appreciated.
...

If you can match the paint color closely, the best results would be obtained with an airbrush. Obviously when spraying paint, it requires that you mask carefully beforehand.

I wish I could point you to a perfect paint but none of my Pioneers have need of that much coverage.

Alan

[mfleming]

The wear I have looks as though it comes from years of wiping the display glass and rubbing off the paint along an edge in the process. Wish HP could have done a better job with the base coat!

I've tried using a brown Sharpie to cover the exposed metal bezel, but obviously that doesn't match the original color. I can get a somewhat better color match by alternating brown and black Sharpie layers and rubbing each layer afterwards, while the ink is still wet, to blend the colors.

I've seen a number of artist pens in various colors that can be blended to get the right color, but being water-based I'd guess the result would not last too long. Maybe applying a protective coat afterwards would do the trick?

I've hesitated to use acrylic paint because brushing it on would leave an obvious raised area. Spray painting might be a good approach though. Even if the color doesn't match exactly, I've seen some two-tone Pioneer faces, like the 21S & 32S. Maybe a contrasting upper plate would be attractive, and draw the eye away from someone's initials gouged into the bezel

Anyway, I do remember a thread somewhere about replacing the bezel or its upper part (perhaps by Geoff?). There seem to be shoeboxes full of HP10B's at flea markets, so a donor might not be too hard to find. Definitely worth reporting back if I have any success.

A last question - has anyone worked with inkjet printed model decals? A real lost cause calculator might be restored by painting the entire bezel after suitable cleaning and preparation, followed by applying water-slide decals that match the original lettering as close as possible. I swear some of the late model calculators look as though they've used decals instead of silk screening.

Thanks!
~ Mark