“RetroBrite”: Lightening up Old, Yellowed Plastics

If you follow me on Instagram (and you should!) you will have seen these photos already, but I thought I’d throw a post together with some more details.

My basement knitting/sewing room has been recently renovated, and I am finally getting all my things back out that have been packed away for almost a year, including my Singer SK155 bulky/chunky machine and ribber combo. I bought that machine for a song, and it knits perfectly, but it was extremely yellowed from being exposed to sunlight. (This is normal, and due to a chemical added to these old plastics to enhance fire retardant abilities.) It doesn’t affect anything knitting-wise, but cosmetically it wasn’t too pretty.

I had stumbled on the topic of “RetroBrite” online at some point, and since I was sad at the thought of putting such an aesthetically challenged machine down in my beautiful new space (with new, bright LED lighting you can REALLY see everything,) I thought I would give it a shot. I happened to have a tiny bottle of 40vol hair peroxide developer leftover from having bleached streaks in my hair a couple of years ago, and I had seen other people using just that successfully, without all the other additives talked about on the Retrobrite page.

I started with the KR7, since that was in a smaller box. It involved removing a few screws and pulling off the plastic knobs to remove the cover, painting all the pieces with the developer, and then leaving them in sunlight, reapplying every so often so it doesn’t dry out. I think the before and after results speak for themselves:

COWABUNGA! Look at that KR7 before and after, it looks like new.

Obviously after results like that, I had to keep going and do the whole machine. We’re talking end caps, punch card mechanism cover, row counter cover, carriage handle and thumb screws, accessory box and transfer tools, and then onto the ribber for the racking handle and end caps. And a Superba transfer carriage for good measure. It sounds like a lot, but if you can use a screwdriver it’s easy. My back yard did look kind of funny for a few days with all the weird baggies lying around though.

I should also add that the weather was now really sunny and HOT, and pieces were taking about 8 hours to get their brightest instead of 3 days. That was nice. Here are some more of the before and after pics:

Punch card mechanism cover before and after.

Whole machine, before and after, with the yellow box and tools left as a reference.

Box and tools before and after. Couldn’t leave them out!

Superba transfer carriage, before and after.

In case you’re wondering, I did try the process on the ribber covers, but they are made of a different plastic, and it didn’t work properly. They got all splotchy. So instead I decided to spray paint them with spray paint for plastics, one coat plus clear coat, and it worked extremely well:

Spray painted ribber covers looking like the bees knees.

Here is the machine, all fixed up and ready to knit. I’m so thrilled with these results that I’ve been telling everyone to give it a shot:

My lovely SK155/SR155 combo looking like new.

So! If you have a knitting machine that looks old and yellow and you’re wondering if this RetroBrite stuff really works, YES it does! Of course always test it on a small patch of your plastic first, and maybe don’t do this on something that would be irreplaceable if you’re worried about the results, but for me it was worth it – replacement parts for these machines are still available in the event things went sideways.

Happy knitting (on your freshened up machines!)