Tuesday 15 October 2013

Should I Fill A Platen With Silicon Rubber/Roof Sealant To Dampen The Sound?

Meanwhile, in other news, I used a piece of plastic, that's designed to be snapped off a Hewlett-Packard ink cartridge before it's loaded into a printer , to replace the missing carriage release lever on the right-hand side of the Galaxie II.
Here's the one on the left, which is still intact;

And here's the one I MacGyvered, courtesy of Hewlett-Packard;

I'll be the first to admit that it's a bit of an eye-sore, but it appears to work as it should. Still, I may remove it and just be extra careful with the lever on the other side. As Richard Polt stated, these levers were made from fairly brittle plastic and weren't designed to last. 

Which probably explains this picture of folk composer John Jacob Niles using a S-C Galaxie with a similar issue to my one. Picture courtesy of the outstanding;

 Influential American folk music composer John Jacob Niles with a Corona Typewriter.
The Antikey Chop

 Thanks for reading!


  1. oooh, very interested to hear your results - I really dislike that hollow Galaxie sound too. :P

  2. It wasn't because of density that the cotton didn't work. It would have worked had you compressed enough of it in. It needs to absorb the vibration of the platen core - which is probably not being absorbed by the platen rubber which has probably hardened.

    You can reduce the sound with this method though. Just remember that whatever you use needs to have a high surface tension against the inside of the metal core.

    And also remember you will probably need to get the platen shaft through it too.

    The reverberation is the biggest post strike issue. So you really need it to be spread hard against the sides. But not too dense that it would transmit the sound.

    Maybe this?


  3. That expanding foam Scott suggests sounds like a great idea.

    Perhaps another possible solution would be to wrap a bit of foamy padding on the outside of the platen... that might also help the pressure rollers do their job, should they be worn and hardened. This has the added benefit of being completely reversable - you could remove the foamy should you want to return the typewriter to its original condition.


  4. As for protecting the inside of the platen before filling with silicone, one idea is take a thick sheet of paper (or maybe even a paper towel tube that you've slit down the side), roll it up, insert it into the platen, let it spring out to the platen diameter. You can then tape the paper so you have a hollow paper roll that is the interior dimension of the platen. To be safe, maybe roll some aluminum foil on the outside of the paper? Reinsert the tube into the platen, and fill with silicone.

    Another idea for filler is instead of silicone, what about paraffin wax? Don't know how it would work--I just know my candles sound pretty dead when I hit them. You can get wax in bulk at the craft store or the beauty supply store. Or you might have old candle stubs you can melt.

    1. Interesting idea. Parafin has the advantage of not being a solid material - i.e. it is in a liquid but cooled state. As I vaguely described before, the biggest problem is reverberation inside the metal tube of the platen core. Just think of how a large pipe or drain-pipe sounds when you shout down it.

      High density material transmits sound more effectively than we realise, but if the material is able to move like medium density soft surfaces, the vibration of the sound gets absorbed because it the sound can't transmit through that kind of matter.

      So, if you are able to absorb both the sound moving around inside the core, and the reverberation (echo) you will reduce the sound dramatically.

      That still leaves the type bar sound, the carriage sound and the paper vibration sound, but it is theoretically possible to remove about (guesstimate) 40% of the sound from the key-strike.

  5. Dammit... now you have me thinking about ways of reducing typewriter noise. I was just thinking about the carriage sound problem (which is often translated to the base of the typewriter, and subsequently the surface of the table it is on).

  6. Awful, isn't it, Scott? I'm thinking about rolled-up rubber sheeting, wrapped around a length of coat hanger and then unrolled once it's fed inside the platen tube. Basically, what YaruGL suggested with rolled up paper. A couple of rubber sheets until I have a thin tunnel in the middle and then perhaps fill that with as many rubber bands as I can cram in. If that doesn't work, at least it will be a reversible process. Now I just have to remove all that cotton wool that I put in there.

  7. I had never thought about any of these possibilities. Keep us posted!

  8. What about that spray insulation foam, inside a cylindrical balloon (you all know what i'm thinking.). Feed it into the platen, fill it with the foam, perfect shape, quick drying, no leaks.

  9. I've thought about the same thing with the way my Classic-12 platens ring. I decided to wait and see (hear) how they sound when recovered if J.J. Short can recover them.

    1. Let us know how it goes, Bill. So far, I would prefer any measures I undertake to be easily reversible.