I want to clean my switches. Good answer! Thank you. But I only have medical hydrogen peroxide.It has only 3% concentration.Seems ineffective. Do you have a good idea to restore clear switches's key-stem?Cattus_D wrote: High concentrations of hydrogenperoxide do, indeed, work (hydrogenperoxide is also the most important ingredient in retrobrite), but people restoring old toys in this way have reported that the yellowing often returns within a few years. A few people have also stated that the yellowing ultimately got worse, although this does not seem to be a common effect of the treatment.
The ultimate cause appears to be a fire retardant used in plastics through most, if not all, of the 1980s. As it was mixed with the plastic, it cannot be removed, and thus will continue to react with the other components of which the material is composed.
UV radiation (such as that from the sun) will speed up the yellowing process, and there is evidence that certain components in other plastics (such as the transparent plastic used for ziplock bags) can have a similar effect.
With white plastic, it should work, albeit very slowly. Put it in a closed jar, and check on the plastic a few times every day. Interestingly, UV radiation seems to speed up the whitening process (!). There's a post on the process here.Good answer! Thank you. But I only have medical hydrogen peroxide.It has only 3% concentration.Seems ineffective. Do you have a good idea to restore clear switches's key-stem?
Be very careful with the peroxide / heat method. I tried this on keycaps and while I got great results it bent a 10u space bar and some of the printing on the alphas started to bleed so switches or even switch parts that move may not be usuable afterwards.rich1051414 wrote: Hydrogen peroxide is a bleach, so it will make the stems white whether they ever were white or not. Also, UV is not required, and possibly will make them turn yellow again faster if they are exposed to heavy UV during the whitening process. All that is required to activate peroxide is heat. 120f-180f is ideal. Hotter and you will start concentrating the peroxide, and damage the plastic(and your hands if you touch it). Wear gloves either way, unless you want the outer layer of skin on your hands bleached. It itches, too.
That's good to know! Thus far, nearly everyone I've talked to thought that UV would speed up the bleaching process.rich1051414 wrote: Hydrogen peroxide is a bleach, so it will make the stems white whether they ever were white or not. Also, UV is not required, and possibly will make them turn yellow again faster if they are exposed to heavy UV during the whitening process. All that is required to activate peroxide is heat. 120f-180f is ideal. Hotter and you will start concentrating the peroxide, and damage the plastic(and your hands if you touch it). Wear gloves either way, unless you want the outer layer of skin on your hands bleached. It itches, too.
Yeah I hear that all the time but that simply is not the case. I have a theory that this is the source of the theory that peroxide bleaching causes the plastic to re-yellow even faster. I think it isn't the peroxide at all, but the people actually activating the peroxide with UV.Cattus_D wrote:That's good to know! Thus far, nearly everyone I've talked to thought that UV would speed up the bleaching process.rich1051414 wrote: Hydrogen peroxide is a bleach, so it will make the stems white whether they ever were white or not. Also, UV is not required, and possibly will make them turn yellow again faster if they are exposed to heavy UV during the whitening process. All that is required to activate peroxide is heat. 120f-180f is ideal. Hotter and you will start concentrating the peroxide, and damage the plastic(and your hands if you touch it). Wear gloves either way, unless you want the outer layer of skin on your hands bleached. It itches, too.
Yes, it is better to be too cold and just leave it longer than to push your luck getting too close to the plastic's melting temp. When I retro-bright, I do it at 130F degrees because I am scared of temperature swing causing the plastic to sag. I have heard of people retro-brightening in a translucent container outside in the summer to take advantage of the greenhouse effect, but that scares me even more, the temps can get so hot in there you cannot touch the plastic. I would much rather have the temp regulated. Funnily enough, I retro-bright in an ovenseebart wrote:Be very careful with the peroxide / heat method. I tried this on keycaps and while I got great results it bent a 10u space bar and some of the printing on the alphas started to bleed so switches or even switch parts that move may not be usuable afterwards.rich1051414 wrote: Hydrogen peroxide is a bleach, so it will make the stems white whether they ever were white or not. Also, UV is not required, and possibly will make them turn yellow again faster if they are exposed to heavy UV during the whitening process. All that is required to activate peroxide is heat. 120f-180f is ideal. Hotter and you will start concentrating the peroxide, and damage the plastic(and your hands if you touch it). Wear gloves either way, unless you want the outer layer of skin on your hands bleached. It itches, too.
The only mishap I had was when my brother was visiting and thought he would preheat the oven to cook a pizza... while my keyboard was in there. That was a mess.The assumption is that both UV and Infrared serve as a catalyst for the retr0brite reaction. UV doesn't actually warm up the water all that much, give it a try. I did a retr0brite experiment with a small 6 watt CF bulb (probably was xenon-mercury but I digress) that emits a decent amount of short wave UV and not all that much heat and it did turn the yellow plastic white again. What exactly it is doing is not all that clear but it has to do something with Chlorinated additives.rich1051414 wrote:Yeah I hear that all the time but that simply is not the case. I have a theory that this is the source of the theory that peroxide bleaching causes the plastic to re-yellow even faster. I think it isn't the peroxide at all, but the people actually activating the peroxide with UV.Cattus_D wrote:That's good to know! Thus far, nearly everyone I've talked to thought that UV would speed up the bleaching process.rich1051414 wrote: Hydrogen peroxide is a bleach, so it will make the stems white whether they ever were white or not. Also, UV is not required, and possibly will make them turn yellow again faster if they are exposed to heavy UV during the whitening process. All that is required to activate peroxide is heat. 120f-180f is ideal. Hotter and you will start concentrating the peroxide, and damage the plastic(and your hands if you touch it). Wear gloves either way, unless you want the outer layer of skin on your hands bleached. It itches, too.
UV is not required, I don't even think it does anything but serve as a heat source, but I could be wrong. Either way, since it isn't necessary, there is no reason to subject the plastic to it since UV IS what causes the flame retardant in plastic to brown. Seems quite counter productive, or at the very least, cancels itself out
I think Chyros is a chemist, maybe he can chime in if he stumbles by.
rich1051414 wrote: Hydrogen peroxide is a bleach, so it will make the stems white whether they ever were white or not. Also, UV is not required, and possibly will make them turn yellow again faster if they are exposed to heavy UV during the whitening process. All that is required to activate peroxide is heat. 120f-180f is ideal. Hotter and you will start concentrating the peroxide, and damage the plastic(and your hands if you touch it). Wear gloves either way, unless you want the outer layer of skin on your hands bleached. It itches, too.
Catalysis doesn't apply in this process. Peroxide bonds photolyse in UVB and shorter though, so yes, UV light will definitely accelerate the process. Heat will also work, but I'm pretty sure not as efficiently, and it should be noted that heat will concentrate the mixture which can lead to extremely hazardous situations.codemonkeymike wrote:The assumption is that both UV and Infrared serve as a catalyst for the retr0brite reaction. UV doesn't actually warm up the water all that much, give it a try. I did a retr0brite experiment with a small 6 watt CF bulb (probably was xenon-mercury but I digress) that emits a decent amount of short wave UV and not all that much heat and it did turn the yellow plastic white again. What exactly it is doing is not all that clear but it has to do something with Chlorinated additives.rich1051414 wrote:Yeah I hear that all the time but that simply is not the case. I have a theory that this is the source of the theory that peroxide bleaching causes the plastic to re-yellow even faster. I think it isn't the peroxide at all, but the people actually activating the peroxide with UV.
UV is not required, I don't even think it does anything but serve as a heat source, but I could be wrong. Either way, since it isn't necessary, there is no reason to subject the plastic to it since UV IS what causes the flame retardant in plastic to brown. Seems quite counter productive, or at the very least, cancels itself out
I think Chyros is a chemist, maybe he can chime in if he stumbles by.
