I have one machine with platen re-coated by JJ Short. It is a benchmark quality and it is the most appropriate for such ancient machine.
The issue I have with doing it for all my machines is that, well: I have too many candidates and I simply cannot afford sending all these platens for professional service.
… and I am a bit afraid of the package getting lost.

Besides - where is the challenge in this?

I was looking for an alternative, some other process which I could do in home workshop without breaking the bank.

Cork

Inspired by Oliver with cork platen I had a brief adventure with making these. Started with Blick by using synthetic cork. It prove to be too soft.

I then imported natural cork stripes, bonded together with some modern glue. Unfortunately that too prove to be too soft.
It was certainly not cork itself but the glue holding cork bits together.

My conclusion was that it is a dead end. Modern PU-glues used for making cork sheets are simply too soft.
Trying to make them harder by soaking-in superglue or impregnating with varnish was a desperate and failed try.

Heat shrink tubing

This DIY method is widely used.
It kind of worked for me for long time although I was not very happy with surface finish. Maybe it was the material I used?

It is essential thou that one uses a lathe in the process, even if it feels unnecessary. Heat shrink tubing very rarely shrinks uniformly, throwing concentricity of the platen through the window.

Grinding this on a lathe gives such ineven surface finish. It can be, as stated, material with such defects. It can be that grinding I did was too fast and caused heating up the material and “bubbling”.

I saw no future in this to spend more time in fine tuning the process anyway.
There was another idea, much more promising, lurking on the horizon!

Vinyl

While searching for rubber hoses of adequate diameter and hardness I stumbled upon vinyl hoses. Transparent ones.
That reminded me that there is already someone who refurbishes platens using PVC, he called his product “turboplaten”. I found this seller on eBay: Writertypes
There are generally good reviews of his service, with some concerns regarding affecting escapement timing. Interesting!

Keeping that in mind I started experimenting with developing my process.

The first “patient” to treat was Corona foldable with broken platen.

Primum non nocere, I thought, it can only be better, even with experimental platen.

Using standard lathe tools I managed to turn this down to required diameter. Fine-grinding to obtain the final diameter.

Resulting platen became milky-whitish.
Not bad but could be better. And grinding process was a pain in the neck.

Adam was brave enough to send me his platen, for Erika 5, to recoat in this process.
I managed to minimize scratches on the vinyl and decrease “milkyness” of the result but still there was a potential for improvements.

As a comparison to heat-shrink-tube platen the surface is much nicer, even if still milky.

Only after I made my own tool for turning soft vinyl I could finally achieve the result I was after: transparent platen which can be customized with color/texture/text!

First “patient” for this platen was black&red Royal. It had broken platen when I got it, repaired with heat-shrink version but I was still not happy with the imprint.

Platen core is wooden on many old machines.

I used a newspaper from the day when the World markets went down, showing red charts everywhere. Matching nicely red body panels - at least one positive thing in this whole situation.

It prove to be quite sensitive material to turn with my tool. Some lessons were learned at this stage.

Another trial and finally the new platen is ready!

Test typing.

The imprint is better but most importantly the machine is more quiet. And I like the look much better than with heat-shrink.
Paper handling is superb, too - vinyl is grabbing the sheet like a bulldog.

After a few days of using this new platen I got confident that this is the way to go. Especially for mass-produced, non-unique machines like most in my collection.

Next specimen on the bench was early Halda which I bought while traveling to Norway. She got comic-book platen, with Swedish version of “The Phantom” from SvD.

A typewriter friend sent me his platen for early Facit P1.
Here we went wild and chose bright green color, to nicely match green keys on his Facit.

Measured hardness of this material is around 85 Shore A. Which is on the lower part of appropriate hardness spectrum.
I found another supplier of vinyl, this time a bit harder. We have not yet measured its hardness but I estimate it to be 90, circa. Which is optimal for me.
I already started making platens for my other machines using this new material. It is bluish and not as transparent as the first one so I use it mostly for single-color (or black) platens.

Here are some recent examples.
Facit P1:

Olympia SM4:

Print quality on this Olympia was good even with old, hard platen. With a new one it still is very good but also the machine types more quiet.
Not a ton but a tone lower ;-)

Results & discussion

So far, with my limited experience, I have not encountered any problems whatsoever with these platens.
They are not more “bouncy” than standard rubber, I would say they behave same as my proper rubber platens from J J Short.

Someone mentioned a risk that “bouncy” platen can affect escapement timing.
I am yet to experience that.
All the machines I did live perfectly happy life afterwards. But maybe my material is not more bouncy?

What I like about these vinyl-platens is that I can make them myself at rather low cost. Sure, one needs a lathe to make it but, honestly: how can one be happy without a metal lathe??? ;-)

To be able to customize color or background is a plus for me, too.
With two types of vinyl I use now I reserve clear one for older machines which would match warm look better. Blue vinyl is more suited to more modern machines and to solid colors. Like standard black or blue. At least how I feel right now.

Example of different “feel” with both materials shows sample below.
It will be a “musical” platen for old Erika 5.
I chose Bach notes, inverted to negative and with sepia tone for more warmth.

We are about to test Facit platen with bright green core, soon, so no hard rules here either.

Last but not least - this is perfectly reversible process.
The platen material is a consumable, once it gets damaged/hardens/owner-does-not-like-it it is easy to replace without harming the machine.

What do you think of this idea?