Cleaning the Model Fs (including terminal keyboards)

[compgeke]

I'm stuck with a problem at the moment, and that is what is the best way to clean a Model F? I have a bunch of them ranging from relatively clean to the image below (yes I know it's a picture of a Model M...not all the Fs are here at the moment).


My question comes back to, what's the best thing to use to clean these? The things I want to avoid are taking off the key letters and yellowing after cleaning. I've found that just a wipe down works great on cleaner Model Ms, I've gotten this one that I'm using now clean, however I'm not too sure how well a damp rag will work on heavy dust, or if it'll just create mud.

Oh, and sorry if this question has been asked before, the search function on the site doesn't let me search for "Clean Model F" as "F" is only a single letter.

[sleepy916]

Dishwashing soap and warm water has worked well for me. Rubbing alcohol for the harder marks. You will probably have to repeat a couple of times if it is that thick.

[compgeke]

I decided to test out cleaning the Model M to see how well water worked, and warm water on a towel cleaned up most of it, the key caps were cleaned by hand. It didn't turn out too badly, although I could have done better.





I do have to say, whatever glue was used for the Lotus 123 stickers is great stuff, it survived hot water.

[fohat.digs]

Keycaps are easy. I mix up a strong solution of powdered laundry detergent and Oxi-Clean (I actually like Biz brand better) in hot water and soak them for an hour.  Rinse well, and that is all you have to do 99%+ of the time.

Sticker adhesive is another story. There are two substances that do a great job with it, but both can be very damaging to plastics and must be used carefully and washed thoroughly immediately after.

Organic solvents, commonly sold as "citrus oil" cleaners, and naptha, sold as "old-fashioned" cigarette lighter fluid (like you would use in a Zippo) will take off almost any sticker, usually quickly. If the adhesive has been dried out for decades, it may take more time and soaking, which greatly increases the chance of damaging the plastic.

Experiment first. I have done it dozens of times, with little or no damage to show for it (and this is almost all 1980s IBM PBT, not flimsy modern junk), but I was very careful.

[absyrd]

Organic solvents, commonly sold as "citrus oil" cleaners, and naptha, sold as "old-fashioned" cigarette lighter fluid (like you would use in a Zippo) will take off almost any sticker, usually quickly. If the adhesive has been dried out for decades, it may take more time and soaking, which greatly increases the chance of damaging the plastic.

You talking about stuff like "Gum-Out"?  Any other recommendation? I got a small stack of g81-1800s that I've been ignoring because all the cases were apparently heavily taped down to surfaces and have thick amounts of sticky residue on the bottom. I want to salvage the cases for swapping to g80s (and paint some).

[fohat.digs]

The only Gum-Out I know is a carburetor cleaner, and that is probably too strong, but would probably work.

Lighter fluid only costs a couple of bucks at the pharmacy or Wal-Mart, and works well on PBT if you are fast and careful. On ABS be even faster and more careful, and test first.

[absyrd]

I'll try the lighter fluid since they cost me $5 for the stack. Will not be upset if I lose one to "testing". Thanks.

Now back to OP... looks like a world of difference with just a bit of water. Perhaps you'll go back and brighten it up next time you are bored. At least it is functional now and won't get all clogged up with all that dirt.

[nsrexler]

I usually remove all the keycaps and soak them in hot soapy water, then wipe down the rest of it with a damp cloth. If you feel like it, you can also take the body moulding apart and clean those separately with soapy water, but I usually don't bother.
By the way, Unicomp is great if you're looking for replacement keycaps.

[Tym]

What are you going to do with the rest ? I could take one off your hands XD

[Parak]

My process is usually fairly extensive when it comes to Fs:

• Take off the keycaps, throw them into a tub with hot water and denture tabs for a while.
• Take apart the entire everything else.
• Scrub down the plastic parts with soap.
• Soak the barrels in soapy water, agitate for a bit, rinse, and dry.
• Check the springs and flip plates for rust, dirt, or detachment. Clean as needed.
• Go over the keycaps individually with a soapy sponge - at this point any dirt should easily come off. Rinse, dry.
• Check the condition of the mat. If ripped or crumpled, replace with new mat, using 1/32" silicone/epdm or thicker neoprene if bolt modding.
• Check the front and bottom plates for rust. Sand and paint if any is found, clean with 91% iso if not. If replacing the mat, mark the hole locations with the paint to be punched out with 1/2" arch punch.
• Apply converter internally or externally as preferred. With the PCB exposed and the controller connected to the backplate, check whether it works by thumbing the pads.
• Put the mat back in with the barrels, springs, and plates. Mod to ANSI as desired.
• Clamping may be needed to put the metal pcb sandwich sliding back together if mat was replaced without bolt modding.
• Verify that none of the flip plates/springs are stuck or misaligned.
• Reconnect converter. Observe that things totally don't work right because the keycaps are not on yet.
• Put the keycaps on, retest.
• Reassemble the rest of the case, and enjoy the finger porn.

[rknize]

ABS and PBT generally hold up pretty well to naptha ("lighter fluid").  Sometimes naptha isn't aggressive enough, but just give it more time and/or use a soft plastic brush to work it into the old glue.  Do not use products that contain xylene, like "Goof Off".  Xylene will attack ABS very quickly as does acetone, toluene, and MEK (found in lacquer thinner).

[fohat.digs]

ABS and PBT generally hold up pretty well to naptha ("lighter fluid").  Sometimes naptha isn't aggressive enough, but just give it more time and/or use a soft plastic brush to work it into the old glue.  Do not use products that contain xylene, like "Goof Off".  Xylene will attack ABS very quickly as does acetone, toluene, and MEK (found in lacquer thinner).

If the adhesive is even remotely fresh, naptha is usually enough. I do several fast applications with a soft cloth. But if not, after removing the majority of it that way, I move to the citrus oil product for the final bit.

On non-plastic surfaces, eg paper or cardboard, it is usually OK to let it soak a couple of minutes. On painted surfaces, it is all but sure to remove the paint, or at least wrinkle or blister it.

[compgeke]

I'll be honest, I have a lot more of these to get through than just 2 or 3...I guess it's time to get started.

[rknize]

That's a lot of salvaged Fs.  Well done.

[rootwyrm]

The only Gum-Out I know is a carburetor cleaner, and that is probably too strong, but would probably work.

Lighter fluid only costs a couple of bucks at the pharmacy or Wal-Mart, and works well on PBT if you are fast and careful. On ABS be even faster and more careful, and test first.

It works. Also, you are incorrect in saying that it is PBT. Absolutely none of the IBM Model F or M chassis are PBT - PBT is virtually impossible to work with at that size and in those shapes. Most manufacturers can't even get a 6.5 PBT spacebar without warping. All Model M and F cases are ABS and marked as such.

To remove very old stickers, the best way is by hand. You need a straight edge razor of some sort, fairly steady hands, and a lot of patience. I use an Xacto with a large number of shaped blades. IBM's beige ABS formula is very resistant to most casual damage - use Goo Gone Pro-Power and clean with 70%+ isporopyl afterward.

[fohat.digs]

When I referred to PBT I was talking about parts in general, not cases specifically.

The Model F plastic is so much more rigid and brittle than the Model M case, I assumed that it had to be a dramatically different composition. Also, it has that "skin" that is so easily damaged.

Although I love Model Fs, the case material is one area that was significantly improved with the M.

[Parak]

I'll be honest, I have a lot more of these to get through than just 2 or 3...I guess it's time to get started.

Awe jea. Reminds me of the mud covered stuff that Daniel Beaver dredged up from a farm pond* somewhere

*might have been a lake

[rootwyrm]

When I referred to PBT I was talking about parts in general, not cases specifically.

The Model F plastic is so much more rigid and brittle than the Model M case, I assumed that it had to be a dramatically different composition. Also, it has that "skin" that is so easily damaged.

Although I love Model Fs, the case material is one area that was significantly improved with the M.

Actually, most of the weakness is due to age. Years are not kind to ABS in general. Just how it is. I have a set of SP DCSes that shattered due to age induced brittleness. The actual formulation between F and M chassis isn't all that different, but the F was engineered based around a full metal base, meaning it's just a cover whereas on the M it has to hold and support all the metal inside of it, so there's more reinforcement to accommodate that.
The skin on the F's is NBD though; AFAICT it's just clear coat. And honestly when it comes to clear on any plastic, I recommend stripping and redoing anyways on general principles.

[AKIMbO]

I'll be honest, I have a lot more of these to get through than just 2 or 3...I guess it's time to get started.

Show Image

Holy crap....where did you get all of those Fs?

[rknize]

Indeed, ABS gets more brittle with age, especially when exposed to UV.  However, ABS is just a general term for a type of thermoplastic.  There are many ways to adjust its behavior when it is formed along with many additives and techniques used to augment various properties.  There is definitely something fundamentally different between the Model F and Model M cases.  I have had many Ms of different ages and even the oldest M is nowhere near as brittle as any F I have ever touched.  In fact, a brand new Unicomp case is much more brittle than an almost 30 year old M, even though both are ABS.  I wish Unicomp would spring for the nicer materials.  Their products would have a much higher quality feel to them. 

[rootwyrm]

Indeed, ABS gets more brittle with age, especially when exposed to UV.  However, ABS is just a general term for a type of thermoplastic.  There are many ways to adjust its behavior when it is formed along with many additives and techniques used to augment various properties.  There is definitely something fundamentally different between the Model F and Model M cases.  I have had many Ms of different ages and even the oldest M is nowhere near as brittle as any F I have ever touched.  In fact, a brand new Unicomp case is much more brittle than an almost 30 year old M, even though both are ABS.  I wish Unicomp would spring for the nicer materials.  Their products would have a much higher quality feel to them. 

Well, as I said, the primary difference between the M and F is the engineering and not the material. Remember that on the Model M, all of the plastic that makes up the chassis is structural whereas on the Model F the chassis plastic is largely cosmetic. The F is also guaranteed to be older than the M, meaning more brittle. In terms of economics, where production overlaps (1986), they wouldn't have used two different plastics. Just wouldn't make sense. As far as thorough chemical analysis, well, I'll defer to a chemist on that because I really can't say 100% if they did something silly like that. It doesn't strike me as IBM-like and I will say that I've had the same problem with 'cosmetic' IBM plastic cracking for many many years across many many different products.
I'd have to get out the calipers, but to the best of my recollection, the actual shell on the F is substantially thinner than the M at various points and also lacks various reinforcing elements that are present in the M. Basically the entire F shell is more like the hasty cutout area on the M13. (Unlike the well planned cutouts on M5-1 and M5-2 which avoided structural elements.)

As for current Unicomp ABS being brittle, yeah, there's major reformulations been required over the years due to EPA regulations and such. But seriously, ABS has been a done deal there for a very long time. And it's not like it's a high cost item either - the QFR is ABS. I can't explain it either. There just seems to be a continuing downward spiral there - a friend's brand new Unicomp, case never opened, lost enough melt-rivets to start failing in less than a year. I offered to fix it, but the chassis had serious cracks and warping.

[compgeke]

Holy crap....where did you get all of those Fs?

Someone had them stored in a barn on shelving, so some are somewhat clean, others are horrible, it depends on where they were on the shelves. It was a take everything or nothing at all, so I also have two IBM 5150s, a XT, two P70s and a couple other random systems.

I've gotten a couple cleaned and tested, three Model Ms, a Model F and I'm working on a Model F terminal now (won't be able to test tonight though). I've found the easiest way to clean key caps is to throw them in a bowl of hot water, put a lid on and let them sit while I clean the rest of the keyboard. Hot, soapless water seems to do a great job at lifting dirt off the keys. After I'm done cleaning the black plastic\metal take the keys out and lay them out on a towel to dry while cleaning the outer casing. By the time I'm done cleaning the outer casing and it's done drying, the key caps are usually dry so I can just reassemble the keyboard.

[rootwyrm]

Holy crap....where did you get all of those Fs?

Someone had them stored in a barn on shelving, so some are somewhat clean, others are horrible, it depends on where they were on the shelves. It was a take everything or nothing at all, so I also have two IBM 5150s, a XT, two P70s and a couple other random systems.

!!!

two P70s

GET OUTTA TOWN. D:

Next you're gonna tell me you found an IBM 7006-42W or gods forbid an 7007-N40, ThinkPad 850 or 851. I will gladly take ALL of those off your hands. Doubly so for 7008-M2A's and 7010-160's.

[sleepy916]

PM sent!