The Horror the horror [basing nightmare]

[H.M.Stanley]

Chaps,

I've been basing figures for my skirmishing games on 2p pieces (UK) and using pumice gel as the base material.

In the past, some of my figures had an attack of what I can only describe as the coins oxidizing which in some cases ruined the bases and the paintwork on the figures. However, I put this down to the figures being stored in an old metal tool-box and I thought that rain may have leaked in once.

Unfortunately, I’ve noticed that other figures are becoming affected. These are stored in box-files in a spare bedroom. I have to admit that the apartment as a whole is quite cold and that particular bedroom especially.

I suspect that it’s a case of using old 2ps that’s the issue, possibly combined with a chemical in the pumice gel.

So, choices. Do i:

A.      Bite the bullet and rebase everything affected with new coins: or

B.      Rub down the affected bases (with what? Wire wool and wash with lemon juice.vinegar?) and repaint including underside; or

C.      Stop using coins altogether?

Thanks

James

 

[Ninja]

I would choose C it is simply not worth the extra effort to fight it when there are Sooo many basing options out there.

[Red Orc]

Hmmm. Worrying. I have recently gone over to using 2ps, as of course similar-sized plastic bases often cost more than the 2p. And they give a nice 'heft' to minis. What will I do with the £2.40 I have in my little pot for basing minis with?

What are the 'symptoms' of the oxidation? Does it make 'bubbles' (like rust does) or is it discolouration?

I don't know what pumice gel is, and I wish I could tell you it's that that's doing it (because I don't use it so it won't affect my minis) but unless something very strange happens to the pumice to jellify it, I can't think of any reason why it would.

Or cold either.

So it's probably something else.

[Svennn]

I use and have used 2p coins for years and have never had any problems which leads me to believe it is the pumice gel.

[Bugsda]

I use and have used 2p coins for years and have never had any problems which leads me to believe it is the pumice gel.

Yep! Me too.

[H.M.Stanley]

Its a dry white powdery substance that comes through the bottom of the coin and eventually forces its way through the base (or perhaps creeps round/over the lip of the base)

I've used the gel (Piedra Pomez 599 - Course) on plastic bases for Blood Bowl etc and on MDF without any problems so it has to be a combination of the two. I think that its the older coins that are the problem. The Mint changed to steel coins in the last few years. The brighter coins, which i assume are newer/steel seem ok

Agreed! No more pumice gel, or at least not with coins (1ps are also affected)

I'm going to try to salvage what i've done already by sealing the bottom og the coins but i fear its only a matter of time before i have to rebase

[H.M.Stanley]

Its copper sulphate and the (older?) coins are reacting to a chemical in the pumice gel.

There no stopping it; everything will need to be rebased. Joy!

[Red Orc]

That's a real shame. Sulphur was the only thing I could think of that might be a cause but I have to admit I wasn't all that good at chemistry, I don't know why it should try to form copper sulphate particularly (obviously, it's copper and sulphur, but why that is a particularly volatile combination I don't know).

As you have to rebase stuff anyway, seems to me you have a bunch of options:

1-abandon the pumice gel, but keep using coins;
2-abandon coins as a base, but keep using the pumice gel;
3-abandon both coins and pumice gel;
4-be careful about only using newer coins and continue the way you have been.

What is it about the pumice gel that makes it attractive? Is it possible to get the same result using other things?

[Klingsor]

PVA glue generates acids that attack metal. This has caused some concern in the model railway world where it had been used with sand to give weight to some locomotives and now they are splitting at the seams as the PVA attacks the brass.

I wonder if PVA is used in the pumice gel? It does seems the obvious stuff to use. It worked for Zimmerit after all.

[H.M.Stanley]

Come to think of it, i first had issues with copper sulphate when using coins and particularly cheap PVA glue/sand

I'm talking myself into using mdf circular bases in future

[Verderer]

PVA glue generates acids that attack metal.

Really? Dear me, who would have thought, it seems so inert and harmless? Does it attack white metal too, or just the metals used in coins?

[cram]

Sorry to hear about you're basing woes H M Stanley. How long have you're figures been based for before the 'attack' starts?

Been using coins myself for the past couple of years. My method is to super glue the figure to the coin, then I built up a thin layer of Milliput around the base the figure was cast with. After the milliput has dried I decorate the base, using PVA to glue down the materials I use. I'm hoping that having just read about the damage PVA can do to metal, that this layer of Milliput will prevent any damage to the coins, after all its the milliput I'm applying the PVA to and not the coin beneath it.

[Mike D. Mc Brice]

I've used PVA glue on a lot of coins for basing for years and never had a problem. A lot of other painters are using the same method and this is the first time I read about these problems. Makes me doubt it's the PVA that causes the problems. Low temperatures and damp places are never a good idea for miniature storage.
I think pumice gel uses acrylic medium as a basis.

I've changed to lasercut wood for basing, mdf and plywood, as the paints often chips on the rim of the coins. There's also unlimited choice in base sizes with the lasercut stuff so I can get 30mm round or 60mm round.

Any pictures of the desaster?

[cram]

Agreed. I have never come across this issue before, and nearly everyone seems to use PVA it seems. Must be the gel.

Storing in a cold and/or damp place raises an interesting subject. What happens if you had little choice but to store in such a location, maybe because you're figures collection has grown so large (never going to be a problem for me, the pace that I paint) that you have to resort to storing some of it in the attic for example. Is there a means of boxing them up which will protect them from the elements??  lining the box with something for example?

[Mike D. Mc Brice]

Below 14°C tin startes to change its chemical conformation, basically it changes from solid into dust. It's a very slow process and the speed varries according to the alloy used and the temperature (the lower the worst). I don't know if this could lead to trouble in real life but I wouldn't risk storing my excess metal figures in the (unheated) garage for the next 20 years. It's especially bad if you add aluminium or zinc to the alloy, that's what recasters often do because it's cheap.

There's a myth that the tin buttons of the french soldiers in russia in 1812 fall apart because of this chemical process. I don't know if this is true though.