Thursday, April 1, 2021

ZX Spectrum - logo restoration

I thought I'd share my attempt at restoring the white logo on the ZX Spectrum. The ZX speccy logo on the 16k and 48k plastic cases can get very worn and faded over the decades.. it has been over 30 years since the lauch of this little machine after all!

fig. 1 - faded :(
Phil Ruston has a good blog on his method to achieve this type of restoration, but I thought I'd share my own attempt, conceived way before I'd found Phil's blog. 

I had some good results, or at least not bad results, using dryish acrylic paint on tightly rolled up kitchen roll held together with tight rubber bands. This acts like a "stamping" tool, and the paint being slightly dry. 

As you can see, the fading can be uneven and the letters are very small, which are raised on the case. This means the "e" in particular can give lots of trouble with masking the main board from them.


Things you'll need;

  • Paper towel, kitchen roll will do
  • Elastic bands
  • Fine grit sandpaper or fine grit nail file
  • Acrylic paint, white
  • Masking tape
  • Isopropyl alcohol and a toothpick if things go sideways 
  • Steady hands!

Firstly, you need to mask off the logo from the rest of the case with tape. Just squaring off will do the trick, but as close as possible to the logo (fig 2).
fig. 2 - mask off area and sand carefully

Use some very fine grit sandpaper or the nail file and slightly abrade the surface of the logo. This will help the paint stick better. Don't overdo it, or you can damage the logo. Clean off the dust when you're done, and clean the logo with some isopropyl alcohol and allow to dry.

Take the one sheet of kitchen roll paper towel and fold it until half, and keep folding until you can't fold it any more. It should be about 10cm long and about 1x1cm thick, and one end should be rounded (basically, the last fold you make is the "end" of the "stamp"). Bind this in place with an elastic band or some cellotape, so that it doesn't unroll:

Fig. 3 - the "stamp"

I expect that a piece of clean sponge might also do, but I haven't tried it yet.

Next, dab a small amount of acrylic white paint onto a temporary surface. I sometimes use an old plate, but anywhere will do. Take the rolled up paper towel and dab it into the paint. Then, take off all the excess with another paper towel, or onto the surface next to where you spread the paint. The less paint you have on the end of the "stamp" the better. Give it a few seconds to dry (this can take a bit of practice to get the right timing and amount!) 

Fig. 3"Dabbing"
Dab the "stamp" very carefully on the logo. The paint does need to be fairly dry or it runs down the edges of the letters 😖 so if it runs, clean it off and try waiting some more and take more paint off the "stamp". Once you have a good coverage on the letters, allow it to dry for a bit and do another coat in the same manner. The trick is to build up layers of paint until it is fully white.

Fig. 4 first pass
Once in a while the paper towel stamp may get clogged with paint. Discard it and make another (its not like they're expensive!), don't try to take layers off to reveal paper towel underneath as this will mean strands of the paper will reach the none-letter surface and make it white too and you're back to square one!

It's very tricky to get good coverage, and easy to get paint outside and inside the middle of the lettering, so it's likely that you might have to start again if it bleeds into the letters or around the edges. Clean the whole area with the alcohol, wipe clean and try again!

This method is still under review, and I might also try Phil's PVA masking method and the dabbing method - anything is a good way to stop the paint going on to the case!

Good luck 🍀

Update 15th April 2021:

I have had slightly better results using enamel paint rather than acrylic. The viscosity is slightly better, and although the coverage is difficult still due to it being quite runny it gives a better finish. It's a good idea to let the paint dry completely before second coating otherwise the finish is rough.

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