When I mentioned backing sheets in another post, it never occurred to me that everyone else didn't use one, let alone not know what it was, sorry about that. When I was first showed how to use a typewriter at the age of nine I was told always to use a backing sheet. In the commercial class at school woe betide anyone who forgot to use one, it was one of the cardinal sins of the typing classroom. Schools in England could be brutal places and any typing mistress worth her salt would spot it by the print if one had not been used. The platen on an office machine is hard as nails, it's supposed to be that way. If you are using one of these machines and the print isn't very good, don't blame the machine, it's your fault for not using a backing sheet.

A backing sheet is just a sheet of paper of the thickness you might use for writing or headed stationery as apposed to typewriter paper which is quite thin about the thickness of air post paper. Now for the exception that proves the rule. In an office when typing letters it would be normal practice to use one headed sheet of paper and two carbon copies, one carbon copy for your department and one for central files or just one carbon copy and often a thin sheet of typewriter paper as a backing sheet.

THE BACKING SHEET. Just a normal sheet of copier paper (80gsm) is fine. If you are using a backing sheet for the first time, look at impressions on it afterwards. Now you know why you should always use a backing sheet. Now throw the backing sheet away, we don't use it again, sorry that should now be put it in the recycling bin.

Okay, lecture over and sorry if I have gone on a bit about this. Typewriters are a disappearing part of our heritage and they are not going to make any more. When a platen is damaged it is unlikely to be restored and we have lost another typewriter. I like to think of them as we would a castle or valuable antique, we don't own them, we are merely their custodians for a short time.

I note in the post above by retro that the backing sheet - a regular sheet of copy paper - should only be used once and recycled / discarded. I always reuse my backing sheets. Am I missing something?

I second Pete's recommendation of using the Avery laminate as a backing sheet. I've tried 20lb paper, 40lb paper, cotton paper, various harnesses of rubber sheets, and the Avery works the best on the greatest variety of machines. I've only got one machine, with a platen like steel, that prefers the 90A rubber sheets.