Sunday, 13 December 2015

Building modular fortifications: Another short progress report

I had hoped to have completed painting the wall, tower, and gateway modules by now ... but real life and a minor disaster has rather slowed my progress.

The disaster that has set me back somewhat concerns a pot of Humbrol Matt Sea Grey enamel paint (No. 27), which I was using as the undercoat for my modules. I had already primed the modules using two thin coats of Humbrol Matt Black enamel paint (No. 33), and when I opened the new tin of Matt Sea Grey paint I made sure that it was thoroughly stirred for nearly five minutes before I started to use it. Despite this, the first coat dried with a silky sheen and took far longer than normal to dry. I therefore set the whole project aside for twenty four hours to make sure that the paint was thoroughly dry before I began to apply another coat on top of the first coat. This second coat seems to be drying matt and at the normal speed.

I have come across the phenomena before with newly bought, unopened Humbrol enamel paints. I have no theory as to why this happens but I suspect that it might well be due to the length of time that the paint has been in storage before I bought it. As far as I know the paint does not come with a 'best before' date on the tin, but there seems to be a correlation between the length of time the paint has been stored and it drying with a silk sheen. This particular tin of paint was bought from a branch of Hobbycraft, and had a thin layer of dust on the tin's lid. I must assume, therefore, that it has either been on the sales rack or in the shop's storage area for some time, and that the matting agent in the paint may have separated slightly and settled at the very bottom of the tin. Even my vigorous initial stirring was insufficient to mix the paint as thoroughly as it needed, and once some of the paint had been used and the paint was stirred for a second time, the problem was solved.

The morale of the story is ... don't buy paint that looks as if it has been stored for a long time and stir your paint even more thoroughly that is states on the instructions on the tin. That way I might avoid this problem occurring again in the future.

8 comments:

  1. The moral of the story Bob is to undercoat in Dulux. Get the colour scanned in your local DIY store and they'll produce you a 250ml can of matt acrylic paint suitable as an undercoat for about £2.

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  2. Do they sell Kilz in the UK? Its a primer for walls and wood trim. I think it would work well on your project.

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  3. Trebian,

    Thanks for the suggestion.

    Because I always seal the wood with PVA - which is water-soluble - I always prime with a non-water-based paint. In this case I then used a spirit-based paint as an undercoat ... and could have used a water-based paint like Dulux instead. I had not realised that Dulux could match the colour that I wanted to use for the undercoat, but now that I know, I may well use that facility in the future.

    All the best,

    Bob

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  4. Chris,

    I have never heard of Kilz ... but I suspect that there is an equivalent product on sale in the UK. All I have to do is to find it.

    All the best,

    Bob

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  5. Hi Bob
    I did a colour match at my local Homebase. I needed some hills to be painted in the same colour as a grass mat. I cut a small section of the mat off and took down to the DIY shop. They scanned it and it was a pretty good match.

    Bob

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  6. Bob K,

    It sounds like a very useful service. I will certainly look further into this as an option for matching paint colours in the future.

    All the best,

    Bob

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  7. Hi BOB- as a suggestion- for large surface area painting for models I use either Atists Acrylics (Tube Paint) or 'British Paints' assorted Acrylic - Sample Pots...unfortunately for me the Hardware shop I frequent no longer sells the British Paints - Sample Pots...and I would have to go to another town to buy them....I recommend British Paints Sample Pots...and tend to leave my precious HUMBROLS only for Figure Painting. Regards. KEV.

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  8. Kev,

    The problem I have had using acrylic paints directly on top of PVA is that they are both water-soluble, and the PVA can 'lift' when the acrylic paint is applied. The two can also react and the paint can dry with a silk sheen. To avoid this I wait for the PVA to dry thoroughly, then apply a solvent-based primer. In this case I then wanted to undercoat using a shade of grey ... and the only one that was available was a Humbrol Matt Enamel paint. I intend to use acrylic paint for the topcoat, and will probably use a tube of cheap acrylic artists paint, as you suggest. I know that I can buy a big tube of it for about £3.00 ... and that will be more than enough to complete this project and probably several others.

    All the best,

    Bob

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