Retrobiting did not work

[Shift838]

So I have a MEGA ST4 and a monitor was sitting on it for years before I got it and as you can see in the photo where the monitor base was not there is major discoloration.  I tried to Retrobrite it with a couple of different methods that typically work, but it did not work much on this unit.  

 

My question is has anyone had any luck with any other method to get something as dark as this off, or would I just need to work on priming and painting it?

 

[tjlazer]

I've had a lot of luck with watered down creme conditioner.  I do NOT use plastic wrap as that tends to cause damage called blooming.  I water down the creme conditioner with some water until it is watery, and brush it on (making sure to get as much off the brush to avoid excess drips) and place it out in the hot sun (or a UV lamp in a box.)  I then reapply every 30 min or so, depending on how hot it is.  Then every 10-15.  Do this for a few hours.  Shoild work well.  Yes this is a pain, but it's better than damaging it with blooming.  I also don't take the machine apart unless it's very easy to do.  If you are careful you can avoid and spillage or damage.  And because this is only temporary, I like to do this every other year or so on my systems for wasy of use.  I never remove badges either.  You can brush around it and wipe them down with a damp sponge if you get any on.

 

On your Mega ST top case I would concentrate on those yellow areas and do it when it's really sunny our.  But a UV box works really well too.

 

This is what blooming looks like on the ST when using plastic wraps.  Seems to happen a lot more often than other beige or white computers.  

Edited April 15, 2023 by tjlazer

[oracle_jedi]

I got a PC1 from Germany a few years back.  Badly discolored.  

 

The top case looked like this:

 

 

The back was even worse:

 

 

I ended up using a 30% hydrogen peroxide bath to submerge each of the plastic pieces.  In the weak Seattle summer sun it took I think two days for the discoloration to go.  Not cheap, and not especially fast, but I got the PC1 for a song so I wasn't complaining.  

 

Here is the machine today:

 

 

One word of warning however.  The 30% solution has water in it, and the water will evaporate over time in the sun, so your 30% becomes 40% and then more.  If you're using your bath again for more retrobriting projects later on, either add some water or keep a super close eye on it.  I managed to damage a keyboard for a Camputers Lynx after it bleached the keys in a matter of minutes.

 

Good luck

 

 

 

 

 

 

[MasterMotorola]

I would soak the yellowed areas in baby oil a few times, wipe clean, then try retrobriting again.  This moisturises the plastic, helps release discolouring, and improves uneven results.

 

If it does not work or you still get inconsistent colour, there is a paint that is an exact match to the XE/ST grey... Rust-Oleum Painter's Touch Stone Grey in satin finish.

[SlagOMatic]

Most of the "retrobright didn't work for me" posts that I've read seem to have low/insufficient light levels as the main culprit. To that end I'm currently building this retrobright box with the intention of cleaning up a bunch of old consoles and computers.

[Shift838]

wanted to post my final painting of the unit, as you can see i did not go with anything close to the original color.  I went with metallic gun metal gray.  I may paint the keyboard to match but not sure since the retro-briting did well on that one.  I did not even try to do the mouse as you can see.  This mouse is an original Atari ST mouse that has been modded to be completely optical.

 

[Cyprian]

that painted Mega looks really cool now

[Atari74user]

I have never had any issues with Retrobrighting, which I have been doing for years now, very much the same as tjlazer. I only use a maximum of 12% Food Grade Hydrogen Peroxide as a liquid solution.  I have never used baths or creams, and like tjlazer, brush it on after mixing up a concoction which only serves for easier application, and keep re-applying so it does not dry out.  Similarly I repeat this on stuff that I like to keep 'clean' every few years.  I have documented it on my site here:

 

This post firstly shows shows using Painters Touch Stone Grey which is not a good finish or match as you can see.  I did this on my spare STFM, Retrobrighting the keys as an experiment:  https://sites.google.com/view/ataritosser/my-atari/my-atari-projects?pli=1#h.p_isKEwKuzeFFa

 

On this post I Retrobrighted my main STFM: https://sites.google.com/view/ataritosser/my-atari/my-atari-projects?pli=1#h.p_r-zUbjTl8Ju0

 

I then experimented with various RAL spray paint colours which are said to be a match, and concluded all the colours which are often mentioned do not exactly match (some are close and not bad).  I subsequently decided the only solution is to colour match my ST, documented on this post amongst upgrading: https://sites.google.com/view/ataritosser/my-atari/my-atari-projects?pli=1#h.fncajzi7b525

 

I already commented on your post on FB, but your gunmetal option looks good!

 

 

Edited April 29, 2023 by Atari74user

[Atari8guy]

I usually prefer sticking to the original colours, but that gun metal mega looks pretty sexy!  Nice job.