The Little World – Thick And Sticky

I have revisited my childhood and I’m thinking that things has changed down the ol’ hobby shop.

As a kid in Canada I had access to basically four brands of model paint – Revell at first, then Humbrol, Testors, and Pactra. Enamels all, with different characteristics and markedly different vehicles.

The smell of the paints was a clue to which they were – you could tell a puddle of Pactra from a similar amount of Humbrol with your nose. Revell was lousy paint but it had a particular odour – probably sourced from Love Canal. Just as well I graduated to Humbrol early.

But earlier in the year I tried Humbrol 22 – gloss white enamel from the familiar little tin. I was flabbergasted at the thickness of it. Admittedly it was a cold day here in Perth, but it was a cold in Calgary too and the paint was never like this. Fortunately I was not going to brush it on – it was destined for airbrush use and I had purchased a bottle of the recommended Humbrol thinner for it.

Thinning is a sometimes art – more akin to alchemy than science. I use a souvenir teaspoon as the basic measure of quantity and dilution, and am getting pretty good at estimating the amount of paint needed for any particular job. This is a doddle with the acrylics as they flow so readily. But this Humbrol needed two scoops and three dollops before it even approached the consistency of milk. It did go through the gun successfully and it did coat the job, but I made sure that I flooded out the mechanism with about 5000 gallons of mineral turps afterwards to clean the nozzle.

I was undecided about whether I wanted to move back to enamels or not. Next coat on the job was a matt brown – I still used Humbrol and see if it was any better. I was not prepared to reject a useful tool that others seem to employ based on just one experience. If it allowed for multi-layer effects that were less prone to dissolution than acrylic, I decided to continue to pursue it. I still had that much affection for dear old Humbrol and I had always thought their tins the cutest thing in the world.

Addendum: Next day analysis showed that the sprayed 22 Humbrol had done as well as could be expected – given that it was covering a dark plastic with no undercoat. The test wasn’t as fair as it might have been, and should not be taken as gospel. I thinned the tin mix slightly and used a brush to re-coat the job, and it came out splendidly. I was wary of touching it for a week, however, as this was not good drying weather.

I’ll suspend judgement now that warm weather has returned – time will come to try another colour or consistency.

Advertisements

The Spray Booth

sprayMy Christmas present this year is a spray booth.

I build model cars and structures. Once confined to brush painting, I have blossomed into a spray paint enthusiast over the last two years and the appearance of the models I make has improved immensely. It is as great a leap forward for me as it was in 1962 when I was introduced to matte paints instead of gloss ones. It has changed my choice of paints, too – I now go to the acrylic rack rather than the oil enamels for most of the colours.

It was a bit of a shock to change over to these whilst still in the brush days. I found the consistency and flow different enough that my brush control went out of kilter. Of course, I am getting older, and hand/eye coordination is not what it might have been, but I know so many ergonomic tricks from my first profession that small brushes and parts are not a worry. Still…the acrylics were different.

Roll forward to the first airbrush experiments and the arcane science of dilutions and vehicles. I did cotton on to the need for a compatible thinner and have always stuck to the proprietary product matched to the paints. I adopted the practical solution of measuring out paint and thinner with a small souvenir teaspoon into a shot glass and it has finally settled to about 2 parts paint to 3 parts thinner for my guns. Any thicker and the nozzle starts to close up prematurely – any thinner and I risk runs on the finish.

I have had my lesson about getting too greedy with the thickness of a coat, thank you.

Up until now I have been using a home-made paint booth constructed with foam-core board and a big electric fan…plus an open window. It has worked, but at the price of a lot of overspray and mess. Christmas solved that, as I have a dedicated mini-spray booth now with an extractor fanĀ andĀ vent to the outside. I tried it on Christmas Night ( Of course I tried it. It was a new toy. What did you expect? ) and it worked a treat. Absolutely no backwash of paint odour and what I suspect may be a finer distribution of paint on the small parts.

Note: I cannot use it for my next experiments. I am going to try to thin the acrylics with a proportion of methylated spirit as well as the proprietary thinner. I want to see if the nozzles stay patent longer. But the fans instructions say not to risk flammable or explosive vapours. So I’ll try it outside in the breeze.