'Oxidised' metal model

[Beaky Brigade]

I recently agreed to help out a modelling shy friend by de supergluing a OOP metal model he bought on ebay. I used super glue remover and it came apart a treat. I then chucked the whole thing in my ultrasonic cleaner with the normal dilute cleaning solution I've used with other metal models. They usually come out shinier, if not a mirror sheen.

 

Now I then left it for about a week and forgot about it (turned off obviously) and when I came back I found to my horror the model was covered in a thin layer of 'black/grey' oxide. The only explanation I have is that superglue remover residue reacted with the cleaning solution to produce this oxide.

 

Now the ultra sonic cleaner won't shift the grime. Course tooth paste and hard scrubbing won't do much, I've tried silver cleaner (which is most likely designed to react with silver oxide but ho hum) Vinegar, dishwasher tablet solution... and it's currently soaking in coca cola.

 

Now all this hard scrubbing and chemical offensive has shifted some of it on the most sharp, raised areas, but I have no hope of restoring it to a normal appearance. Is there a 'wonder chemical' I can try, that's reasonably available? I don't want to spend my next few weeks of hobby time polishing this thing like a gem smith.

 

Any ideas welcome.

 

[Subtle Discord]

I hate to say it, but if it's actual oxidation and/or a chemical corrosion that has cause this, the surface of the model itself has been transformed by the process. You've listed a good number of things that are very good tires at solving the problem, and hit most of what I might suggest; abrasives, acids, bases, and detergents all make sense to give a go at it, and if they didn't work you're down to physical polishing and refinement. I wish I could offer some other idea other then confirming the conclusion you're coming to. Given the potential time and labour involved, it might even be more cost effective to find a replacement, even if it is out of production.

[SW1]

Spray it with a decent primer and then decide if the detail has been negatively impacted. If it's just discoloured which it might be then don't worry about it. Some of my old lead models have dark discoloration with no visible impact to the model.

[Ovidius Incertus]

Maybe some Flitz polish?

 

http://www.flitz.com/flitz-polish-paste/

 

Readily available in the US, and their website seems to indicate international distribution.

 

Perhaps a Dremel buffing wheel?

[Beaky Brigade]

Thanks for the suggestions guys. The layer is actually thin enough to probably be ok to paint over, and it's so tough it's not going to flake away or anything. That said, it is someone else's model, and I feel it's not right to return it in a 'worse' condition even if it is technically ok, so I've decided to fork out for a second one on ebay. The cost is annoying, but equivalent to buying a couple of cleaning chemicals which I'm not sure will work.  I'll just keep this one in case I ever get more time to 'fix' it, and as a reminder to be more careful with what I leave models soaking in.

[Major_Gilbear]

I have models turn dark all the time (and I have piles of stripped metal models), and there's nothing wrong with any of them.

 

Out of interest, what was the cleaning solution you used?

 

 

 

 

Edit: Spelling

[Khornate individual]

Kind of off  the topic, but where do you get super glue remover and is it safe for plastic?  All the years I've messed with stuff like this, I always thought that there's got to be something out there like that, but never seen or heard of any.

[Beaky Brigade]

@Khornate I imagine it's usually sold next to super glue in most hardware type shops (who are not evil!), often made by the same manufacturer as the super glue though it's universal for all cyno type glues. I have used it on resin plastic models and it works well, though I would not leave it on there too long. How long it takes will depend on how set your glue is, recently stuck fingers a few seconds, years old models may take a few hours or overnight, clean off with soap and water. I found it can leave a sticky invisible residue on the plastic where applied, even with a through clean, but that dried within a few days. That may have been the remnants of the glue.

Your mileage may vary, always test on a bit of sprue or non visible area, and read the instructions

I have models turn dark all the time (and I have piles of stripped metal models), and there's nothing wrong with any of them.

Out of interest, what was the cleaning solution you used?

Edit: Spelling

It was fairy power spray, diluted about 33% power spray to 66% water. I'd been using the same stuff in my cleaner for about a month to wash greasy forge world models so who knows what extra stuff was in there as well, though I'd also cleaned metal models without issue.

Left hand model is the 'oxidised' model. It's actually not too terrible after all I've done, though there is a texture you can feel on the sword. It will probably be fine painted, I just can't return it like it is to my friend. 'I was only supposed to blow the +censored+ arms off! Middle model is one successfully paint stripped, and right hand model is a new model bought from GW relatively recently. The chaos lord started off more like the middle model.

[Major_Gilbear]

That's honestly fine as it is - nothing wrong with that at all.

 

What many people don't realise is that the surface of a metal model is very rarely perfect or smooth.

 

The moulds are dusted with talc, and then the metal is poured. If you get it right, and the metal is not too hot, you get a nice shiny cast of a metal model. If you overdo the talc, or if the metal gets a bit too hot when you come to pour it, the model ends up with what look like golden/brown tea stains over it. In either case, some tiny amount of the talc does nonetheless end up embedded in the very surface of the models themselves, however it casts.

 

That's why when you quick-strip a model, the paint sloughs off; but if you let it soak, the colour gradually stains the surface of the model (often unevenly too). Some models still end up with some dark patches after a quick strip anyway - in these cases you can often see the "speckling" of the stained talc release agent in the metal's surface, perhaps where it was dusted a bit more thickly in the mould, or where it was pushed by the molten metal as it flowed into the mould.

 

If you want to polish the model a little bit (particularly any areas you feel may show up when primed), you can do so with a small brass brush. Just lightly and carefully brush the model all over in different directions to polish the main surfaces to a bright finish. Sparkplug brushes are ideal for this, and cheap to buy (example).

 

If any very fine roughness remains even after brass brushing, it will also help the primer bond better to the model too. In fact, a light brass brushing over areas that are likely to chip on even a brand new metal model adds that tiny little bit more "tooth" to it's surface for the primer to really bond to the model, and will help to reduce chipping after it's painted. ;)

[Major_Gilbear]

Kind of off  the topic, but where do you get super glue remover and is it safe for plastic?  All the years I've messed with stuff like this, I always thought that there's got to be something out there like that, but never seen or heard of any.

 

Most superglue debonder contains acetone, which will melt/dissolve plastic models and many epoxy putties (given time). If you apply it locally in a small amount, then release the parts, and then quickly wipe and rinse the affected area, you can probably get away with it. I would not use it on any areas of plastic models which are detailed, or which cannot be hidden/puttied up afterwards just in case though. And any thick glue you can forget about - the debonder will most likely damage the plastic irreparably at the point it also released the bond.

 

If you want to strip superglue from a metal model quickly though, a jar of acetone will do that a whole lot faster, and without affecting the metal itself. Well, it may darken the metal as noted in my post above, but that's it. :)