Sanding Down Platens
I've never been a huge fan of the sanding method and after watching some videos, I figured I had a good candidate for trying it out again. This post talks through the ups and downs of that project as well as overall takeaways.
In the past I had turned my nose up at the idea of doing an at-home platen resurfacing. In particular, I found that most of the ways to address thickness changes weren't to my satisfaction, as they usually either changed the function of the machine or required expensive tools. So, I stuck with what had worked and yielded great results; I sent anything which deserved a new platen off to JJ Short and wound up with quite a few lovely machines that were a joy to type on. If you're just here for the brass tacks of how to actually this; skip down, but for those of you who don't mind a little context, I'll say that the final result here isn't as great as what you can get from the professionals.
Last year however I acquired a Remington Model 5 which had been partially sanded down to try and grip the paper a little better. The end result was underwhelming and so I found myself considering cheaper ways to recover the platen. This was a unique machine that I would have liked to do some typing on (it has the lovely Magnatype slugs on it after all) however it was tough to justify sending off the platen for a machine that really wasn't likely to be used very much.
When looking around at some of the techniques, it seems that some suggest to simply add on a layer or two of shrink wrap to the platen. If this wrap has much thickness however, what you'l | find is that it has changed the relative position of the ring-and-cylinder adjustment. While it is possible to adjust this, you'll also have to adjust the shift height and the feed rollers are likely to be a fair bit tighter.
For me, this meant that any serious effort to resolve a damaged or overly hard platen was out of the gate going to require some method of removing thickness off the platen so that it could be replaced with a proper thickness of the new rubber. In this case, some fairly soft "marine" style sealing wrap with a final thickness around 0.050" around most of the platens. While discussing with some folks it sounded like you might elect to remove everything and build your way up "turboplaten' style, however for this case I opted to keep it as "simple" as possible.
Just Start Sanding
Following one of the guides (perhaps from Typewriter Muse?) for doing it with sandpaper, I set out to try this in the lowest tech way possible. Using an electric drill and some coarse sandpaper, I planned to remove as close to the right amount as possible. Knowing that it would be a challenge to hold everything in place, I screwed a few pieces of 2x4" together into a jig, then embedded a small ball bearing into the vertical part. One end of the platen could be mounted here, then the other could be chucked into the drill, giving a low-friction setup.
This whole jig assembly was arguably overkill however it did make it quite a bit easier to check progress and make sure that each pass was removing roughly the same amount of material. Using some clamps it was also possible to free up some hands to focus on the sanding and not the work holding. The original method of just holding the platen in your hand seemed to work, but seemed like it would be difficult to prevent tapered or inconsistent results.
Even with the coarsest of sandpaper and the jig, it still felt as if it took forever and makes a huge mess. In the image above you can see some of the dust coming off when wiping it down between passes. I attempted to use a cheap carpenter's slide-style caliper set which was not very precise and which made it very difficult to determine if I had removed enough of the material; if possible, a cheap set of digital calipers can go a long way for those who aren't familiar with using the dial models.
In addition to the slow going, the dust that came off the platen was rather noxious. I quickly realized that lots of PPE was going to be useful here, so I wound up donning gloves, eye protection, and perhaps most importantly a respirator. Cleanup was still a mess, but I'm glad this stuff wasn't ending up in my lungs.
Despite all that, the final result did work and produced a platen properly reduced diameter, making sure to use consistent, directional passes, I managed to avoid over-sanding in the middle. If you just go back and forth, the center will tend to get more of the material removed. I also found that cleaning off the dust with a solvent in between measurements helped as did switching to different parts of the sandpaper once a section got clogged up and full of dust.
By holding the two ends of a strip of sandpaper, you could hold the trigger of the drill with one side and then remove material with your other hand, however at times it felt like a three-person job to be sure. Having a more secure drill setup that would allow you to keep the work running seems like it would be very useful (a lathe perhaps?)
Ultimately, this particular process using sandpaper probably isn't a type of approach I'Il use again in the future. It resulted in a final product that wasn't as even as I would have liked and was both slow and messy. That said, if you have a machine with a damaged platen and simply can't send it off, this approach might be viable. This is most specifically for the folks who already have a few of the following tools, such as:
- Chucked drill (corded or cordless)
- Dial or digital calipers
- Solvents & shop towels
- Shrink tubing
- Heat gun
If you had none of the supplies above, you could probably get away with finding all of them for fairly cheap (plastic jaw calipers are fine and often run $5-10, heat guns usually under $20), however between the supplies and tools, plus the time - just adding a backing sheet may be a better choice if you can manage it!
Putting it All Together
So far I described the process of removal, but I've glossed over a few of the re-assembly steps. Once you've gotten it down by the dia. you need (make sure to measure the thickness of your shrink tubing), cut off a length that's about 1" longer than the platen, then slide it over and you can begin using the heat gun from the center and work your way out. Make certain not to "enclose" any areas from the ends as this could seal in some air bubbles, which will force you to remove the wrap and start over. I find that this can take quite awhile, but it's worth taking a little longer with the heat. Keeping the whole platen on the chuck and rotating it slowly can be a good way to avoid overheating or burning the rubber.
When it comes to getting the right thickness of the material, consider cutting off a small amount and heating it onto the original platen. Then you can cut it off and measure the "shrunk" thickness, ensuring that your target diameter accounts for how much it will gain when it shrinks to the platen size. he extra effort, the whole project did come together fairly it was a marked improvement over the original state.
Despite the extra effort, the whole project did come together fairly well and it was a marked improvement over the original state, which was too hard and undersize to even grip the paper, resulting in failures to feed paper in most cases. I think wound up a little oversize, so I may it down a little more.
One note about the softness of the material, the particular variety that I've been using seems to be a fair bit softer than the usual hardness of original platens. This softer material does sometimes result in squishier and fuzzier looking print impressions, however this tradeoff results in much quieter machines. Some machines might benefit more from this trade than others, for example thte Olympias with their percussive platens could really stand to use their inside voices, however a machine in Elite might wind up being harder to read with a fuzzier type impression. These aren't hard and fast rules, just things to consider when you're planning a job like this.
Since trialing this sand-at-home method I've dabbled in other more methods of removing material from the platens, so I think I'll pull that together in a later post. In the meantime, good luck to and do remember to wear your respirator!