*bumping* this to see if there is more interest in this topic.

I was doing some research on molded plastic repairs and came across this video about using baking soda and super glue to recreate either missing broken bits or reinforce broken plastic seams: https://www.youtube.com/watch?v=n1meoZaHYZo

I'm wondering if such a technique could be further combined with dyes to create cosmetic repairs where the repair parts are visible. Also wondering if other glues or resins could be used in these instance, instead of super glue.

There is also discussion in the comments of that video about using heated thin metal rods to further strengthen the repaired joints. I've done similar by drilling tiny holes and using metal pins from staples, but haven't tried heating the metal and melting it into the plastic.

I'm merely commenting here as a more noble way of watching this thread to lurk about, but so far, have little to contribute.

AFAIK, paint jobs that don't look like utter shite take quite some skill and experience.
There is at least one AT case close to my heart as that was my first PC ever - a typical early 90s case, fuckugly and yellowed. But mainly, it's missing a piece of the front panel, so some day i might learn more about that.

So far, I know that people who fix antique furniture are bloody wizards. They work with wood, obviously, but it's the same skill set.

I've never bothered with retrobright as I've heard its not a permanent solution (the yellowing will eventually return even when stored in a dark cupboard) and that each treatment can make the plastic more brittle (something a lot of old plastic doesn't need more of). Though I guess I might consider it if something had yellowed so badly it was now an ugly brown and nothing (including damaging it) could really make it look much worse.

Re-painting metal parts is something I've wondered about though. I've got lots of machines that weren't treated as carefully as they should have been back when they were worthless junk and so the metal panels have the odd scratch/gouge. Would be nice if there was some way to restore those panels to the factory finish but I'm betting its more effort than its worth - re-powder coating doesn't sound like it would be an easy thing to do.

Shponglefan wrote on 2022-04-14, 20:38:

*bumping* this to see if there is more interest in this topic. […]
Show full quote

*bumping* this to see if there is more interest in this topic.

I was doing some research on molded plastic repairs and came across this video about using baking soda and super glue to recreate either missing broken bits or reinforce broken plastic seams: https://www.youtube.com/watch?v=n1meoZaHYZo

I'm wondering if such a technique could be further combined with dyes to create cosmetic repairs where the repair parts are visible. Also wondering if other glues or resins could be used in these instance, instead of super glue.

There is also discussion in the comments of that video about using heated thin metal rods to further strengthen the repaired joints. I've done similar by drilling tiny holes and using metal pins from staples, but haven't tried heating the metal and melting it into the plastic.

This is interesting. Never knew this was a thing 😋
Concerning dyes, I'd guess you could use a colored powder (or perhaps color the baking soda). The superglue is probably used because of its durability, which is especially essential with moving or interlocking parts.

Well, I can share some experience of a recent restauration that went wrong (real drama). I recently got me a compaq 486 which is an awesome machine (design and spec wise). The problem was that the front bezel was broken badly (I attach some images) and the machine was incredibly dirty (really bad).

For the most serious cleaning (beyond IPA etc) there is this method:
https://www.youtube.com/watch?v=kRkgwVMW3_0

What worked also well was the rewelding of the plastic with a soldering iron. I got that idea from here:
https://hackaday.com/2017/03/17/broken-plastic-no-problem/
I usually reinforce the soldered seams later with a slow curing 2 component epoxy (from the backside)

After that - acrylic putty can be used to get a "like new" seamles appearance. The quality of such a task depends probably a lot on your general crafting skills.
https://www.youtube.com/watch?v=YdJ4aVXMK-Q

But some people really do amazing things:
https://www.youtube.com/watch?v=7QY1LzkJGeM

Back to my compaq - the final job was to spraypaint in the proper color and reasamble. It looked as good as new. And here disaster struck. By reassambling the front bezel to the iron chassis a slight tension to the bezel completely ripped it apart. The reason for this was the condition of the plastic which had lost most of its integrity. This is the second time that I lost against weakening plastic. The first time was a Toshiba PV3000 an equally great machine (I love that design - picture attached) where the plastic just crubled under my hands.

So Im also always on the outlook for novel repair and preservation methods - hope to see more posts here

good luck with your efforts

davidrg wrote on 2022-04-14, 23:05:

Re-painting metal parts is something I've wondered about though. I've got lots of machines that weren't treated as carefully as they should have been back when they were worthless junk and so the metal panels have the odd scratch/gouge. Would be nice if there was some way to restore those panels to the factory finish but I'm betting its more effort than its worth - re-powder coating doesn't sound like it would be an easy thing to do.

I think the biggest challenge with powder coating would be having an oven big enough for the respective parts. For large computer cases that might be prohibitive for a lot of people.

OTOH, for smaller metal components even something like a toaster oven sounds like it could work. I've got a bunch of old sound modules I'd love to refinish with a new powder coat, so this might be something I attempt in the near future.

Tetrium wrote on 2022-04-15, 01:59:

Concerning dyes, I'd guess you could use a colored powder (or perhaps color the baking soda). The superglue is probably used because of its durability, which is especially essential with moving or interlocking parts.

There are companies that sell fillers and dyes for plastics. For example: https://www.tapplastics.com/fiberglass/resin_fillers_dyes

Seems to be more of a thing in the automotive world. Though I'm bit surprised I've yet to run across an example of such a restoration with retro computers or other electronics.

Being able to repair things like scratches and gouges with dyed fillers is very appealing.

Cuttoon wrote on 2022-04-14, 22:29:

AFAIK, paint jobs that don't look like utter shite take quite some skill and experience.

In my experience the biggest thing is sheer patience and discipline in applying thin layers.

I've been amazed at the types of finishes people can get even using things like ordinary spray paints. Thin layers and frequent sanding can go a long way in producing a good finish.

Aui wrote on 2022-04-15, 07:57:

Back to my compaq - the final job was to spraypaint in the proper color and reasamble. It looked as good as new. And here disaster struck. By reassambling the front bezel to the iron chassis a slight tension to the bezel completely ripped it apart. The reason for this was the condition of the plastic which had lost most of its integrity. This is the second time that I lost against weakening plastic. The first time was a Toshiba PV3000 an equally great machine (I love that design - picture attached) where the plastic just crubled under my hands.

So Im also always on the outlook for novel repair and preservation methods - hope to see more posts here

good luck with your efforts

That's really rough what happened to your Compaq machine. It's unfortunate that plastic can degrade like that over time. I wonder if there are options to add internal fillers or bracing to try to mitigate that from occurring.

Thanks for the various links, btw.

Just watched that Commodore 64 restoration. That was wild they were able to get it looking as clean as it was. It looked like a goner for sure.

Guess it just shows what is possible with the right restoration techniques and experience.

I don't have a *lot* of experience doing cosmetic repair, but these things worked well for me in the past:

- Bike/Steel wire and superglue for fixing notebook frames that have broken in half. I used it to repair a ThinkPad T23:

- Talcum powder for rubber that turns into goo. I used this to make a Dell Axim X51v Pocket PC "grippy" again and it doesn't look too bad.
The powder method made my ThinkPad 770 look very horrible, though - so it probably doesn't work on big surfaces or machines that have completely turned into goo.
- Baking soda and superglue is a very neat trick. I used this to repair the tape deck doors on my 80's boombox - the bond is unbelievably strong.

Found a video on hammering out dents. This particular example was on a server rack, so seemed very applicable to things like computer cases: https://www.youtube.com/watch?v=Aoaq8OAqzyc

I've got some computer cases and sound modules that need dents repaired, so this is another area I want to practice.

This is something I've been messing with a lot with the NEC Versa laptops I have that are notorious for cracking plastic. I've been experimenting a lot in this area.

• Internal Tape Repairs with Aluminum+Packing Tape - The insides of a lot of laptop cases, including the Versas, are conductive, so some of those surfaces that are very flat, and have very little space between it and working components on the motherboard I'll just lay a thin layer of aluminum "muffler tape" over it and then cover that tape with packing tape as an insulator. I also do this without the packing tape in some spots, such as the bottoms of the Versa Bays in my 40EC and P/75 tat tend to frequently get cracked. I also use packing tape as a "quick fix" for external plastics that break off before I do a full-time fix to them.
• J.B. Weld Alone - I use this sometimes for filling in gaps in a plastic structure prone to cracking, and then grinding/drilling back into shape. I did that with at least one of my NEC Versa (M/75) with regards to the hinge cover. I've been looking into molding replacement parts with the stuff but it seems prone to breaking too if stressed too much.
• Superglue + Baking Soda - Thi s is what I've used the most. About 90% of the bottom of my Versa P/75 is stuck together with this kind of fix (and I have a 3 hour YouTube video of the repair over the course of a Saturday). Other things I've done with it were the hinge cracks on my V/50. How it works is it's a hyperthermic reaction between the Superglue and the Baking Soda, so two things happen - a delrin-like plastic (guitar picks) forms that's a bit flexible, and it melts itself into the existing plastic of the computer to make the structure stronger. The only downside I see is it sometimes shrinks/cracks in some cases. I also have used this with foil tape to rebuild screw anchor posts by sticking the screw anchor in with a screw in it, and then building up layers and layers of baking soda and superglue around the anchor while using foil-tape as a mold. I do a lot of work with q-tips, hibatchi skewers, and toothpicks to achieve this stuff.
• Superglue/J.B. Weld Hybrid - This is what I did to my 40EC. Basically, the initial repairs are done using the Baking Soda/Superglue and the J.B. weld is used as a "mass thickener" or "filler" to fill in various parts of the plastic that are weakened by both boad plastic and a weak structure in that region.

Something else I'm looking into is just molding brand new parts using the fixed up old ones to generate silicone molds and then use Alumalite - which is sort of a resin-cast-plastic thing that's very durable and can be tinted to any color wanted or needed - and then start making my own replacement parts that way. Basically, reproducing the original part, and maybe even using the mold to make alterations that would make the part even stronger and more sturdy than the original part was.