For a quick and easy typewriter pad for portable typewriters, go down to your nearest Wal-Mart and pick up a low cost yoga mat (3mm works but 5mm is better). As Uwe says, this material is non slip and absorbs some of the sound due to the closed cell foam rubber. Cut it in half length wise, this will give you two 12" wide strips. Cut these strips into 13" or 14" lengths, round the corners off if you like and you have a stack of pads for portables. These are the pads I supply with the typewriters I sell on Etsy. All the best,
Sky
We humans go through many computers in our lives, but in their lives, typewriters go through many of us.
In that way, they’re like violins, like ancestral swords. So I use mine with honor and treat them with respect.
I try to leave them in better condition than I met them. I am not their first user, nor will I be their last.
Frederic S. Durbin. (Typewriter mania and the modern writer)