Need advice on how to best clean/de-rust an IBM 5051 w/o damaging it any further

[ropersonline]

Hi,

I have an IBM 5150 that's been out of commission for a long time and that I want to restore. I've already dusted things off, but most parts need further cleaning to de-gunk and rust-strip them.

I am particularly worried about damaging the electronics or the exterior surfaces with my cleaning.
Once the spots of rust have been removed, I reckon I may want to try to treat (and spot-paint) the case and PSU case surfaces to stop and avoid any future rust, and also to restore or at least not ruin the appearance.

How have others proceeded with such restorations?

To start off, this is a picture of the main (CPU) case tray. Sorry about my potato quality camera:

Here are two detail views that show the damage more close-up:

What cleaners should I use and avoid?

I thought about non-abrasive cleaning with general household kitchen/bathroom cleaner and water, and I have WD-40. I also have some model-making matt enamel paint. Clean, WD-40, then paint: Does that sound like a plan? Does anyone here have experience doing this? Are there any tricks to getting an even finish, even once I've touched up the rusty spots? Should I rather use spray paint?

There's rust on the power supply case and fan also (it's actually a metal fan in the PSU). Any hints on dealing with that? Just WD-40 and elbow grease?

What about the gunk on the electronics? Should I rather leave it alone, to avoid doing damage? Here's how the mainboard looks now:

I'm particularly concerned about the rust on the chip (1), about whether the electronics are damaged at (2), and whether the card slots are corroded, which could prevent cards from working (3).

Is there anything I can use to clean especially the contacts of the ISA bus cards, etc., w/o damaging them, to ensure good, corrosion-free contact? Is it a good idea or even safe to spray WD-40 on the board? What about other fluids?

I have distilled water, lighter fluid, white spirit – are any of these a bad idea on the case or electronics (even if I get everything to dry thoroughly before reassembly/switching anything back on)?

Speaking of electronics, right now, this machine hasn't been on in a long time, but once I try it again, I'm worried about capacitors holding charges and about zapping myself. Does anyone have experience on what to discharge and how to safely discharge caps or similar without damaging either the electronics or myself?

Any hints and tips --dos and don'ts-- would be very much appreciated. Thank you in advance.

 

[modem7]

The topic of metal chassis treatment appears from time to time. A recent thread is [here].

Be aware that WD-40 leaves behind a film of oil. That is bad for painting on. Perhaps you should consider a rust converter product.

 

[modem7]

Speaking of electronics, right now, this machine hasn't been on in a long time, but once I try it again, I'm worried about capacitors holding charges and about zapping myself. Does anyone have experience on what to discharge and how to safely discharge caps or similar without damaging either the electronics or myself?

You do not need to worry about the capacitors on the motherboard.

The large capacitors in the power supply can hold large charge over a long time. In rare cases (e.g. [here]), the PSU maker will warn about those capacitors. Play safe; wait an hour or so after mains power (house power) removal before opening up the power supply.

 

[GiGaBiTe]

I think the best solution on a budget would be to use paint stripper to remove as much paint as possible, then go back with KrudKutter de-rusting solution to treat the rust spots. After that, prime and paint it back to black or any other color you want.

Most rust converters/removers destroy paint so just treating the rust spots would pretty much guarantee to ruin the paint near the rust spots. If you want to spend a bit of money, you could take it somewhere to have it bead blasted and powder coated to get a really nice looking factory finish back.

As for cleaning the motherboard, just wash it. Remove all of the socketed ICs and battery then hose it down under a faucet with an optional mild detergent. A soft bristled tooth brush works to get in between IC legs to remove stubborn detritus. When you got as much detritus and grime off as possible, get an air compressor and blast out the water from under the ICs (40 PSI is more than enough.) Work your way from one end of the board to the other at an angle so you're sure all of the water is removed. Don't forget to also blast air into connectors and slots to remove water trapped inside them. Make sure you also get the back of the board too, and then just put it under a semi-powerful fan or out in the sun for the afternoon to remove any residual moisture.

If the battery looks like it's corroding the motherboard, you can try pouring some coke on the area in question to neutralize as much acid as possible, or making a paste solution of baking soda and slathering it over the area for a few minutes and wash it off.

 

[Stone]

If the battery looks like it's corroding the motherboard, you can try pouring some coke on the area in question to neutralize as much acid as possible, or making a paste solution of baking soda and slathering it over the area for a few minutes and wash it off.

I don't think a 5150 has a motherboard battery. As for those boards that do have batteries... they do not leak acid -- they leak base and therefore you need an acid to neutralize their discharge. Car batteries contain an acidic electrolyte but (computer) NiCads do not and work on different chemistry that is basic.

 

[Agent Orange]

I would try Naval Jelly. Assuming you are somewhere in NA, you can buy an 8 oz. bottle for about $5.95 at any ACE hardware or similar store. Apply the Naval Jelly with a small brush and let set for about 20 minutes, then wash off with fresh water. Another product that is very useful for removing light rust is Never Dull - a cotton wadding that come in a small tin container.

 

[GiGaBiTe]

I don't think a 5150 has a motherboard battery. As for those boards that do have batteries... they do not leak acid -- they leak base and therefore you need an acid to neutralize their discharge. Car batteries contain an acidic electrolyte but (computer) NiCads do not and work on different chemistry that is basic.

Coke would work fine then since it's acidic.

 

[Chuck(G)]

Well, if it were my case--I'd blast it with walnut shells and repaint it.

 

[ropersonline]

Be aware that WD-40 leaves behind a film of oil. That is bad for painting on. Perhaps you should consider a rust converter product.

Thank you very much, everybody, for all your help.

Is there any harm in trying WD-40 first, and then, if results don't satisfy, try something else? In other words, is there any way to get that film of oil off after previous WD-40 application?

 

[ropersonline]

The large capacitors in the power supply can hold large charge over a long time. In rare cases (e.g. [here]), the PSU maker will warn about those capacitors. Play safe; wait an hour or so after mains power (house power) removal before opening up the power supply.

Is there any other procedure I could follow in addition to waiting an hour? Is there any way to safely deliberately discharge the capacitors in the PSU?

This is what the PSU looks like:

I could probably unscrew the PCB to get access to solder points on the other side (for discharging). Note that that fan is actually metal, not plastic, and it's 220V too (=non-US mains power). It will be hard to get a replacement if that were to be needed.

Is there any harm in actually spraying WD-40 onto/into the PSU and onto the mainboard? Would that help in stopping any rust progression? Could it harm anything?

My thinking went, since GiGaBiTe suggested water-washing the mainboard (does anybody else advise against that?), and since the WD in WD-40 reportedly stands for Water Displacement, after any washing and drying, spraying the electronics with WD-40 ought to make doubly sure that any residual water is out and stays out. Is this a terrible idea?

 

[ropersonline]

Well, if it were my case--I'd blast it with walnut shells and repaint it.

See, there I'm worried about losing not just the original colour but also the original "grainy" spotted texture of the finish – especially of the exterior case, which, granted, has severe rust on it:

But I'm actually far less eager to get a "perfect" finish than I am to stay true to the original, even if it shows its age. So given a choice between a polished bright off-colour yellow on the one hand, and a very spotty exterior with much of the original paint and texture still on (but the rust removed and further corrosion prevented) on the other, I would opt for the latter.

OTOH, if it were possible to not just accurately match the colour but to also reproduce the original texture, then I might go for that. Does anyone know?

 

[Moondog]

Well, if it were my case--I'd blast it with walnut shells and repaint it.

I was going to recommend soda blasting. I heard the wet baking soda neutralizes rust. Either process shouldn't hurt the metal. Of course, this would very likely damage any stickers or labels.

 

[Chuck(G)]

I was going to recommend soda blasting. I heard the wet baking soda neutralizes rust. Either process shouldn't hurt the metal. Of course, this would very likely damage any stickers or labels.

One can always tape over the stickers--I've used real (aluminum) duct tape for that sort of thing--before blasting. The problem with rust popping through paint is that it tends to be the tip of the rust iceberg.

 

[griffk]

Is there any harm in actually spraying WD-40 onto/into the PSU and onto the mainboard? Would that help in stopping any rust progression? Could it harm anything?

I would definitely NOT recommend WD-40 for the electronics--you don't want ANY oil left behind on the ICs.

What you can use is something like Trichloroethane (that's not very available any more), but basically ANY residue-free "electronics cleaner" will work.

Also, to clean the pins and sockets, DO NOT USE SANDPAPER!!!

There is a specific contact cleaner made from fiberglass strands, in a pen form. I think its made by GC Electronics--maybe others. Works GREAT!

gwk

 

[ropersonline]

I would definitely NOT recommend WD-40 for the electronics--you don't want ANY oil left behind on the ICs.

But the water-based cleaning that was recommended earlier is fine in principle, so long as it's thoroughly dried and left to dry out afterwards?

What you can use is something like Trichloroethane (that's not very available any more), but basically ANY residue-free "electronics cleaner" will work.

So most of these should be fine?
(I see there that they're also offering WD-40 brand contact cleaner, but I guess that's not the same product as the original WD-40 and only carries that name for stupid marketing reasons. So that kind of WD-40, i.e. WD-40 brand contact cleaner should be fine, I guess?)

Also, to clean the pins and sockets, DO NOT USE SANDPAPER!!!

There is a specific contact cleaner made from fiberglass strands, in a pen form. I think its made by GC Electronics--maybe others. Works GREAT!

This sort of thing?

I'm also very worried about getting the rust off and out of the PSU, because I can't fully disassemble it. I could disassemble most of it, with difficulty, but that metal fan is actually rivet-fastened to the PSU casing, and its cables are soldered, and they're 220V, so I don't want to mess with them if I don't have to. Translation: That's half of the PSU case/cover that I can't separate from the electronics, which will make it difficult to clean. That's also the half with the most rust on it.

OTOH, I have actually powered up the PSU (with one molex connector plugged into one of the floppies, because I've hear somewhere that this PSU didn't like running w/o a load), and I've taken a multimeter to the other molex plug, and the 5 and 12 volts seem to be there. The exotic 220V fan also still runs, and it's relatively quiet, which is a good sign. So despite the cleaning qualms and trouble, it does seem as if the PSU still works. I also know that the CGA card works, because I've run it in another PC (where I slightly physically modified the mainboard to accommodate – the original CGA adapter is very demanding in terms of space). If I get really adventurous, I might work my way up all the way to booting. That wouldn't solve the cleaning challenge though. I still gotta stop the rot and remove the rust already present.

 

[ropersonline]

I was going to recommend soda blasting. I heard the wet baking soda neutralizes rust. Either process shouldn't hurt the metal. Of course, this would very likely damage any stickers or labels.

So just take ordinary household baking soda, wet it to make a paste (or liquid?) and then use that to treat the rust spots?

 

[Chuck(G)]

See, there I'm worried about losing not just the original colour but also the original "grainy" spotted texture of the finish – especially of the exterior case, which, granted, has severe rust on it:

But I'm actually far less eager to get a "perfect" finish than I am to stay true to the original, even if it shows its age. So given a choice between a polished bright off-colour yellow on the one hand, and a very spotty exterior with much of the original paint and texture still on (but the rust removed and further corrosion prevented) on the other, I would opt for the latter.

OTOH, if it were possible to not just accurately match the colour but to also reproduce the original texture, then I might go for that. Does anyone know?

I wonder if the original isn't a powder coat--it probably is.

Beyond refinishing, there's the matter of archiving. A museum archivist may well use a water-based acrylic paint to restore the original color for exhibit and leave the rust and all intact--the acrylic can always be washed off after exhibiting. But since there's no shortage of 5150s, I'd strip and repaint--or, if you're flush, have a commercial company re-do the powder coat (they can pretty much match any color and texture). There are also DIY powder coats, but they're very expensive.

To reduce the staining in the paint from the rust, you might try a strong solution of oxalic acid--it's sold in most home improvement paint departments. It's used to remove rust stains from masonry and wood--it works very well. "Naval Jelly" is a combination of oxalic and phosphoric acids with a thickener.

 

[DDS]

I'm one of those people who has too many hobbies and can't seem to stay focused on any of them for long. Oh well!

One of my other time and money wasters is/was tinkering around with cars that are old & fast. I have seen my share of rust. I have won a few and the rust has won a few. So far I have not seen any product or technique that will truly kill rust yet leave the paint undamaged. Nor have I had any luck with the "rust converter" or "rust encapsulation" products. But that might be because I live in South Florida. Our humidity isn't quite at rain forest levels but we come close. What works for folks in Arizona will not work here. The process that generally does is:

1. Media blasting with low pressure air and low mass particles (soda is best).

2. Make sure all the soda is removed/neutralized.

3a. Powder coat.
or
3b. Use a name brand etching primer and a compatible top coat.

I believe that in previous threads we covered that the case itself is a low gloss but not flat black, and the case cover is a shade called Pantone 413. The tricky part is recreating or coming close enough with the pebbled finish on the case cover. I believe it can be done by controlling air flow and media viscosity through a quality paint gun but haven't actually done it. I don't think I saw the answer to that if one was posted. IIRC people used to sell rattle cans that claimed to create a pebbled finish but I seem to remember they were actually more like "wrinkly". Good luck and let us know how you did. You're not the only one out there with a grungy looking case.

;-)

 

[ropersonline]

The problem with rust popping through paint is that it tends to be the tip of the rust iceberg.

Actually, I seem to be lucky on that front. Despite significant surface rust especially on the main case cover, these metal parts look, feel and sound still pretty solid.

Maybe it's more than luck. Everything about the 5150 speaks to its sturdiness – from the fact that many are still running over three decades on no problem, to the six pound steel keyboard, to the extremely thick front frame/plate:

I initially thought that was metal too. Nope, it's plastic, but very, very thick and sturdy plastic. (Anyone know what type of plastic?)
Admittedly, there was a small detent nub that had broken off in one corner (so the material is at least somewhat brittle), but I was able to superglue that back on.

Anyway, so WD-40 on the case (not the electronics) to get the rust off: Go or no go?

And if it's okay to try it, what should I do to get the WD-40 oil film off afterwards, so I can paint with confidence?
Of course if WD-40 is a bad idea from start to finish, then I probably should try the soda method or the rust converter method, right?
(I understand that with the latter at least, some paint damage may be unavoidable.)

Or, to repeat another option that was mentioned earlier in this thread, if I really went to an auto shop with the case cover, would it be possible to faithfully reproduce the colour, finish and original grainy texture? Preferably w/o spending an arm and a leg?

"Further bulletins as events warrant."

 

[paul]

I could probably unscrew the PCB to get access to solder points on the other side (for discharging). Note that that fan is actually metal, not plastic, and it's 220V too (=non-US mains power). It will be hard to get a replacement if that were to be needed.
Is there any harm in actually spraying WD-40 onto/into the PSU and onto the mainboard? Would that help in stopping any rust progression? Could it harm anything?
My thinking went, since GiGaBiTe suggested water-washing the mainboard (does anybody else advise against that?), and since the WD in WD-40 reportedly stands for Water Displacement, after any washing and drying, spraying the electronics with WD-40 ought to make doubly sure that any residual water is out and stays out. Is this a terrible idea?

I think you're worrying excessively about the capacitors. An hour is enough and it's only the big silver one on the right to be concerned about. The fan is not hard to replace and the Papst brand is top notch.
Forget the WD-40. Wash the PCB in warm soapy water and brush lightly, rinse and dry in a warm air. Use compressed air sparingly if needed.
As others have said, if you want it to look great have it refinished professionally.