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| Here you see me having a relaxing evening session, preparing my 15mm fortifications for painting |
Hmmm. Interesting.
I took advantage of an odd free evening to make a start on my medieval wall castings, safely received from the maker last week. I've done a fair amount of this sort of thing before, and I find it an enjoyable job - especially on something like stone walls, which have relatively few colours and produce a pleasing result very quickly. The new castings, as ever, are resin, and - as ever - I've taken care to scrub them down thoroughly with very hot water and washing-up detergent, then rinsed them very carefully in clean water and left them to dry off completely. I know that some of the release agents used with resin castings are petroleum based - once, long ago, I made a resin chess set using silicone rubber moulds, and made up my own release agent by dissolving Vaseline in white spirit. So the keywords are greasy, waxy, and the response is hot water and detergent and a good scrub.
Never had problems, really. Sometimes the first coat of paint doesn't cover too well, but a second undercoat covers the gaps nicely, and then everything goes to plan. This shipment seem to have traces of something a bit more stubborn. The first coat of the old Dulux Rum Caramel #2 (household wall emulsion) has rolled back a bit to leave some white spots and streaks showing. In other words, the paint has covered about 98%, maybe more, but there are gaps.
I'm not unduly worried - I usually use two coats of the base colour, and I think the second layer of undercoat should fix it, but this is the worst experience of non-sticking paint I've had, so I stopped about 20% of the way through the shipment just to be on the safe side. If I'm not happy with progress on the second coat on the ones I've started, I'll consider some more serious cleaning and preparation of the remaining castings, but I'm a bit surprised, really, and I'd rather not have to. I don't think I've skimped on the scrubbing-up. I've read before about guys who prepare their castings in the dishwasher, but I fear that dishwasher products might deposit something undesirable on the castings anyway, and some of the battlements and fiddly bits look a bit fragile for a dishwasher - I've already had to glue a couple of parts which I de-flashed with too much enthusiasm.
Anyone got any suggestions? I have various additive things in the drawer like acrylic flow enhancer (which I think is a sort of detergent) - I emphasise that I am not unduly concerned, but this is the worst coverage problem I've had with this kind of paint in this context.
[I wonder what happened to that chess set, by the way.]
I have to say I never clean anything - if it's stubborn and won't take acrylics I just blast it with a can of spray paint and then go the acrylic route.... if that's not to taste I have to say I would probably have gone the dishwasher route, but only if the current Mrs Steve the Wargamer is out....
ReplyDeleteI don't deal with resin often, ok close to never, b6t I've hwd similar problems with other surfaces. A good purpose made primer seems to do the trick. Best applied before the first coat of course, but.....
ReplyDeleteI tend not to clean resin or plastic kits, I just stick them together and use a good quality black polyurethane primer (vallejo in my case), key is not to be tempted to thin it at all, I find if used straight from the pot it covers well, but get the brush anywhere near water and it does indeed streak and roll back. It's frustrating when it does that I know.
ReplyDeleteI had a similar problem and cured it with an application of spirit based matt varnish.
ReplyDeleteThanks very much gentlemen - appreciated. In fact this post turned out to be something ado about nothing, because my tentative second coat of base colour fixed the problem completely - I wonder how this works? Does the first coat give some kind of invisible coating which stops the second rolling off? Do the "holes" in the first coat result in little puddles of second coat, which have nowhere to roll to?
ReplyDeleteAnyway, it's a small relief that the problem fixed itself, but the paint rejection on the first coat was the worst I've had.
All you need is love.
Have you tried spraying a flat black primer or enamel from a can as the undercoat? I have never experienced spray paint not sticking to the raw material and it lays down an even coat of paint.
ReplyDelete