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01-7-2017 18:11:56  #11


Re: On the subject of platen rubber

SoucekFan wrote:

From an earlier post on the subject...

Replacing a Platen

I use a durometer to test my platens. Having tested hundreds this way I've concluded that you should simply assume the platen you have is too hard. The vast majority of platens I come across are far harder than they should be, and only the odd one will still be within the acceptable range, presumably because they were refurbished in the not too distant past. I have never encountered a platen that was too soft, and one in that category is probably the result of a shade tree repair (I wouldn't buy a typewriter that had a bicycle tube or layers of shrink tubing as a platen).

​What to do about it? If the machine is of great value to you, have the platen professionally restored. If it's just a casual typer, give the platen a good cleaning with rubber rejuvenator and always use one (or more) backing sheets.

 


"To save time is to lengthen life."
 

02-7-2017 13:37:56  #12


Re: On the subject of platen rubber

Uwe wrote:

SoucekFan wrote:

From an earlier post on the subject...

Replacing a Platen

I use a durometer to test my platens. Having tested hundreds this way I've concluded that you should simply assume the platen you have is too hard. The vast majority of platens I come across are far harder than they should be, and only the odd one will still be within the acceptable range, presumably because they were refurbished in the not too distant past. I have never encountered a platen that was too soft, and one in that category is probably the result of a shade tree repair (I wouldn't buy a typewriter that had a bicycle tube or layers of shrink tubing as a platen).

​What to do about it? If the machine is of great value to you, have the platen professionally restored. If it's just a casual typer, give the platen a good cleaning with rubber rejuvenator and always use one (or more) backing sheets.

 

 
Informative, as ussual, Uwe. I will keep that in mind. I am slowly resigning myself to the fact that I will probably have to invest in professional platen for whichever machine I get. I plan to use them too heavily to rely on backing sheets, so it should be worth the money.


There is nothing to writing. All you do is sit down at a typewriter and bleed. -- Ernest Hemingway
     Thread Starter
 

02-7-2017 13:40:24  #13


Re: On the subject of platen rubber

I still plan on using a spare platen core I have to perform a makeshift recover just to compare the results with a professional job. I know which one will win, obviously, but I'm interested to see the difference.


There is nothing to writing. All you do is sit down at a typewriter and bleed. -- Ernest Hemingway
     Thread Starter
 

02-7-2017 22:25:08  #14


Re: On the subject of platen rubber

On the subject of platens:

If you were to have a platen recoated by, say, jj short, is there any sort of preventative maintenance you could do to ensure it stayed soft over the years?

 

03-7-2017 08:36:46  #15


Re: On the subject of platen rubber

SoucekFan wrote:

DRH wrote:

If you are looking for something to compare a platen to, I would look for something in the 60A to 70A range. Hope that helps

From an earlier post on the subject: "A general purpose platen would originally be rated in the 90-92 range."

 
Yeah, 90 makes good sense to me. I suggested those for a quick comparison to something around the house to get an idea for the "grippy" feel and fingernail test. I have only used rejuvenator, and have never tried to replace a platen at home. I'm not that confident.

 

03-7-2017 08:42:59  #16


Re: On the subject of platen rubber

schyllerwade wrote:

On the subject of platens:

If you were to have a platen recoated by, say, jj short, is there any sort of preventative maintenance you could do to ensure it stayed soft over the years?

 
There are a number of rubber care products out there, but also, keeping the machine in a good climate can add many years to the life of the platen, and feet!

 

03-7-2017 09:32:35  #17


Re: On the subject of platen rubber

DRH wrote:

schyllerwade wrote:

On the subject of platens:

If you were to have a platen recoated by, say, jj short, is there any sort of preventative maintenance you could do to ensure it stayed soft over the years?

 
There are a number of rubber care products out there, but also, keeping the machine in a good climate can add many years to the life of the platen, and feet!

These are questions better asked of J.J. Short or someone else actually in the rubber industry, rather than of us amateurs. Our hodge-podge of personal experience anecdotes based on chance encounters with chemicals and techniques in dealing with an unknown variety of rubber compounds of 50+ years ago and lacking rigorous testing is unlikely to meet your needs. Probably (I don't know) today's rubber compositions and their maintenance needs are very different from what was useful in the past, so it would be best to go to the easily-accessible source, <​http://www.jjshort.com/Contact-Us.php>

 

03-7-2017 13:10:03  #18


Re: On the subject of platen rubber

Thanks for the responses, everyone. I'm actually inspired to do research on rubber, see what I can find out in a more general sense that might be of use.


There is nothing to writing. All you do is sit down at a typewriter and bleed. -- Ernest Hemingway
     Thread Starter
 

03-7-2017 13:25:57  #19


Re: On the subject of platen rubber

Good point. Although I've been pretty astounded thus far with the knowledge on this forum
I'll look into it

 

03-7-2017 21:08:31  #20


Re: On the subject of platen rubber

Here's my 2 cents.  As SourceFan correctly pointed out, platen rubber hardness runs in the 90-92 Shore A. That is somewhere between a high mileage car tire and a shoe heel.  If it's too hard, it may not grip the paper properly even with the feed rollers engaged and having the correct pressure.  It also makes for a noisy clacking machine and can be hard on the typefaces.  If it is too soft, the type may not be distinct and there is always the problem of punch through where characters such as the period can tear or emboss the paper.  You turn the copy over and the back side looks like Braille.  To add to the technical, all typewriters have a specified platen diameter.  Unless you have the books and service literature with tooling,  it's best to leave recovering to the experts.

 

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