Retrobrite streaking

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VincentVega
Posts: 212
Joined: Thu Sep 11, 2008 9:19 pm

Retrobrite streaking

Postby VincentVega » Mon Jul 17, 2017 5:11 pm

(Apologies in advance if this is in the wrong forum.)

I have been taking advantage of some unexpected free time (read: unemployment) to try out Retrobriting a few of my old computers, some of which are rather yellowed. I decided to use Bblonde as it seemed simpler and stocked up from eBay. So far, I've done a Viglen disc drive unit (sacrificial lamb), two Electrons and a Master 128.

The Viglen was my test piece (the drives don't work anyway). It came up pretty well, but I could probably have done with leaving it out a bit longer in the sun. I then turned to the top of Electron #1, which again came up well. Problems started when I treated the top of Electron #2, and continued today when I turned my attention to the Master. The particular issue I'm having is that the colour just isn't consistent. With the Master, for example, most of the top is now a pleasing shade of beige, but there are areas that are noticeably darker. This continues on to the sides of the unit, which quite frankly look a mess. Strangely, the bottom part of the case isn't that bad at all - only a few minor blotches.

With Electron #2, again, most of it is more than acceptable, but there's an area on the left side of the top that's lighter than the rest. I tried putting it out again today, and masked off the areas where I didn't want any lightening with some tape. It's better than it was, but still not great.

I think the problem is arising when I'm wrapping the pieces up after applying the Retrobrite. I've been using large freezer bags with the Electrons, as they fit in nicely. With the Master, I resorted to wrapping it in clingfilm. None of the instructions I've read have mentioned whether it's acceptable or not for the clingfilm or freezer bag to be touching the case (and the Bblonde/Retrobrite); I certainly can't see how I can avoid it with the Master, unless I splash out on a UV lamp and whatever else I need, or stick it in a large see-through plastic box and cover the top of the box with clingfilm instead. I've been leaving the parts out for four or five hours each time, and have been rotating them once or twice. I'm applying a thin layer of Bblonde with a paintbrush - so far I've used about two bottles.

Can anyone suggest anything that I could do to fix the streaking? I could probably live with the Electron as it is, but the Master looks terrible. I'm happy with the shade where it's been lightened, but the inconsistency is a different matter entirely. Should I mask off the "good" bits and re-apply?

DigitalDunc
Posts: 43
Joined: Fri Sep 02, 2016 6:27 pm
Location: Oadby, Leicster, UK.

Re: Retrobrite streaking

Postby DigitalDunc » Mon Jul 17, 2017 7:44 pm

Do it all again for a bit longer. Also, don't make the cling film too tight or you'll displace the stuff doing the magic. I used very powerful UV lamps to do my last computer which took longer but we're more consistent.

Another important point is that the plastics have to be squeaking clean of the dirt will form a mask.

Finally, wear gloves! I ended up with white patches on my fingertips.

lcww1
Posts: 3
Joined: Wed Mar 15, 2017 11:16 pm

Re: Retrobrite streaking

Postby lcww1 » Mon Jul 17, 2017 8:06 pm

There's a recent episode from the 8-bit guy on YouTube that addresses this very issue:

https://youtu.be/lXkkJfWWPDk

he talks about retrobrite streaking towards the end of the video.

VincentVega
Posts: 212
Joined: Thu Sep 11, 2008 9:19 pm

Re: Retrobrite streaking

Postby VincentVega » Tue Jul 18, 2017 10:55 am

Thank you both. The video was particularly interesting. I think I'd agree with his choice of words - my Master looks worse now it's been Retrobrited.

I ordered five litres of hydrogen peroxide from eBay last night, so I can try immersing instead. I find the wrapping a bit difficult - clingfilm isn't the easiest stuff to use when you're wrapping something that large. I have a suitable transparent plastic box in the shed I can use, once it's been cleaned up.

chinnyhill10
Posts: 43
Joined: Mon Apr 27, 2015 7:37 pm

Re: Retrobrite streaking

Postby chinnyhill10 » Tue Jul 18, 2017 11:46 am

VincentVega wrote:Thank you both. The video was particularly interesting. I think I'd agree with his choice of words - my Master looks worse now it's been Retrobrited.

I ordered five litres of hydrogen peroxide from eBay last night, so I can try immersing instead. I find the wrapping a bit difficult - clingfilm isn't the easiest stuff to use when you're wrapping something that large. I have a suitable transparent plastic box in the shed I can use, once it's been cleaned up.


Future Was 8 Bit did this with the VIC he supplied me. A tank filled with Hydrogen Peroxide, UV lamps and a fish tank heater. A very gentle heating helps the process.

The problem with a Master is that the process can damage black parts it seems to be careful.

steve3000
Posts: 1690
Joined: Sun Nov 25, 2012 12:43 am

Re: Retrobrite streaking

Postby steve3000 » Tue Jul 18, 2017 8:38 pm

VincentVega wrote:I find the wrapping a bit difficult - clingfilm isn't the easiest stuff to use when you're wrapping something that large. I have a suitable transparent plastic box in the shed I can use, once it's been cleaned up.

I've never used cling film or bags when I've retrobrighted cases in the past - so far I've done a Beeb, a Master, a disc drive, an A5000 front panel and a RiscPC keyboard, although I've not put them out in weather quite as hot as we've had recently.

I just deep cleaned the parts, then painted on the BBlonde, not thick, just thin and evenly - and left them out for 2-3 hours on a partly sunny day. Topped up on the BBlonde every hour or so, when it dried out. After hosing down, the BBlonde had worked wonders. The beeb and Master worked first time. The disc drive and RiscPC keyboard needed a couple of afternoons in the sun, as they had been close to orange...but eventually they came back to a reasonable shade of grey/beige.

The only item which went slightly streaky was the A5000 front panel. This had a serious 'tan line' before starting, where the upper half was burnt-orange, and the lower half was near original Acorn-grey. Trying to get the upper half retrobright-ed back to match the lower half was a nightmare, needed many attempts and although it now has a fairly original colour, the upper half gained some faint streaks after about the 4th attempt. I think this was because I got lazy and applied too much BBlonde - and it wasn't spread evenly...

DigitalDunc
Posts: 43
Joined: Fri Sep 02, 2016 6:27 pm
Location: Oadby, Leicster, UK.

Re: Retrobrite streaking

Postby DigitalDunc » Fri Jul 21, 2017 5:58 am

Could it be that the brownness goes too deep for the h202 to get at in some cases, pun not intended?

I've often found that a second application is required because the peroxide gradually breaks down. In fact I needed three goes on my Sam Coupé.


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