restoring HP body panels ? - Page 1
Forum section: electronics / testgear

author: coppercone2
author_rank: Super Contributor
timestamp: March 19, 2021, 08:19:32 pm
content: So some of my HP gear has this body panels that remind me a bit of a grippy leather texture. This is usually likw a brownish color, but on some stuff it almost feels like there is a hint of green there.This stuff is usually intact and pretty good, but I was wondering what can be done to restore it. I know you can do brown plastic with UV + hydrogen peroxide to make it a little better. Is there anything you can do with this save for scrubbing?Some of my HP gear that has the same idea for the chassis looks a bit different then the other gear. I wanted to know why.

author: Algoma
author_rank: Frequent Contributor
timestamp: March 20, 2021, 12:28:33 am
content: Its often Oxygen, ozone and UV that attacked the the plastic blend and yellowed it in the first place.. Only real way is to chemically or abrasively remove the yellowed surface, or cover it with a new surface. Depends on your goals to preserve the original factory look.I recall something along the lines ofhttps://www.howtogeek.com/196687/ask-htg-why-do-old-computers-and-game-consoles-turn-yellow/Note the Hydrodgen Peroxide needs to be the 10% – 12% .. far higher than the 3% you find in most stores, You likely need to search more for the right strength.Photos of the issue are always greatly valued.

author: coppercone2
author_rank: Super Contributor
timestamp: March 20, 2021, 01:41:52 am
content: I don't think I can photo it because it seems almost the same but maybe a little green, the camera sucks too much at thisI know plastics brown, but their panels start brown, so it like turns green? I can't describe it any other way then it looks somewhat dodgy.Maybe automotive compound will work good here?

author: Algoma
author_rank: Frequent Contributor
timestamp: March 20, 2021, 03:22:11 am
content: Is there a model number, so we can lookup a few models on Ebay. Perhaps see if any other units show the same effect?

author: coppercone2
author_rank: Super Contributor
timestamp: March 20, 2021, 03:38:39 am
content: I don't know where the hell you will find good pictures of HP, probobly not on ebay, the trick is before you list an ebay auction you smear bacon on the lens and put your thumb on the flashLike HP Harrison brand supplies, HP function generator like 3310B, Keithley 616 amplifier.. they all kind of look the same but it seems like they have different tints under the right kind of light.The good one make me think of like Dune or some kind of SCIFI military desert stuff, the bad ones look like they are moldy like the x-wing from episode 2 of star wars. It's like they get this swamp rotten green string bean like tint that is noticeable.I am actually going to take a panel and try some automotive compound on it, I will try xtra cut. Maybe it is just surface oxidation making it turn bad like a black head pimple

author: coppercone2
author_rank: Super Contributor
timestamp: March 20, 2021, 03:59:54 am
content: Ok, this is the best I can do for a picture. The left side is foam buffed/polished with xtra cut, medium cut and polish from mequiresthe right side is left aloneI don't know if I can describe it but do you feel like the left side is almost like stones in a river filled with dirty silt between them? It is hard to picture because the flash makes it look reflective on the left side but without the flash it just looks like the texture is more defined, even in low light. I would say the change is visible in low light but its not going to be possible for me to photograph.To me the left side looks actually textured, the right side looks mossy/nasty/moldy/etcI think this solves my problem actually, maybe mequires plastic-x polish would be better, but I don't have any of itmaybe I can say it looks like a dirty fish vs a healthy fish.. before I was just trying to clean this up with solvents, but I am thinking the texture is just some how ratty/rusty (as far as a plastic can rust)or maybe I am trying to say that I thought polishing would not be a good option for this unit because I thought it would accentuate the bad parts, but to me it appears to overall make it look better. I never tried to polish a textured surface beforeTo my fingers the non treated side feels like really fine sand paper in comparison, since it has feet I don't think high grip was what HP had in mind 50 years ago, and that the surface after a polishing job looks more uniform and less spotty with what looked to be darker spots.

author: Algoma
author_rank: Frequent Contributor
timestamp: March 20, 2021, 05:02:09 am
content: That surface is a spray on coating, overall more like a plastic. Is ng anything abrasive is going to leave other effects that wont look good at all. a mild cleanser / solvent would be a start. Various Standard household cleansers. Try each and wash, rinse and dry to see if any had an effect. Clean and rinse between each and do not mix them. Simple Things like soap and water, isopropyl, vinegar, Windex. Generally if the coating is cracking, then it's a physical breakdown and repainting the surface may be the only real fix.

author: coppercone2
author_rank: Super Contributor
timestamp: March 20, 2021, 05:32:13 am
content: I think it looks fine after the polishing but each to his own

author: tautech
author_rank: Super Contributor
timestamp: March 20, 2021, 06:09:19 am
content: This sticky in the Repair board has all the info needed for restoring instrument panel work:https://www.eevblog.com/forum/repair/vintageclassic-renovation-techniques/