Diecast Doctor: Part 2 - our expert answers your modelling questions

In Part 1 of our regular monthly series, our expert answers your modelling questions... everything you need to know about restoring your diecast models and more! Send your queries to our expert at [email protected]

Much of my model making is done in the winter, but aerosol spray paints work best in warmer weather. Any suggestions on how aerosols could be used in cold weather? Is spray painting indoors an option?
Bill Thompson, Liverpool

Using aerosols indoors causes many problems – the smell lasts for hours and dust the colour of the paint settles just about everywhere, so you won’t be popular! This also still happens if you try making a little ‘spray booth’ out of a cardboard box. But don’t despair, there are ways of spray painting outdoors, even in quite cold weather.
Paint makers often say not to use their products below 15º or so. Below this temperature, problems can arise with low gas pressure, slow paint drying, excessive ‘runs’ in the paint and with gloss paint drying matt finish. Here’s what to do:

Step 1 If you keep your aerosols in the shed or garage, bring them in the house a day or two before you plan to use them. This brings them up to room temperature.
Step 2 Choose a sheltered place outside to do the spraying, as near to the house door as you can. A patio near a back door would be ideal. Set up a firm but moveable base for spraying – a kitchen stool, well covered in newspaper, is fine. You will need to carry this base in and out the house with the painted model sitting in it.
Step 3 Fill a washing-up bowl with hot water, just hand-hot not boiling, and place your aerosol can or cans in it. They will probably need weighting down to stop them floating on the surface. Leave for five minutes to thoroughly warm.
Step 4 Have the model ready for painting at room temperature on the stool or other base, and place by the back door. Take the aerosol can out of the water, dry it then shake the can for two minutes as per usual instructions.
Step 5 Move the model on its spray base outdoors and spray the first coat. Watch for runs in the paint and remember to close the door to the house or the paint smell will drift in! Immediately this paint coat is on, carefully lift the model on its base back indoors. Try not to disturb the air around it too much to avoid dust settling on the paint. Leave to dry for 10 or 15 minutes.
Step 6 Lift the model back outdoors and repeat further coats as required, bringing it back indoors each time. If you have someone to help with opening and shutting doors the work is much easier. I have spray painted models this way successfully down to about 5º or 6º on fine winter days but this method does have its limits. Don’t try it in freezing weather nor when it’s damp or raining. This paint will probably not have a full gloss when sprayed in cold weather but this can be fixed by careful polishing of the top coat after a few days to let the paint harden. One last point – don’t be tempted to warm the model itself with a hairdryer – if the surface is too warm, the paint will dry instantly and not stick to the model.

This is an excerpt of Part 2 of Diecast Doctor, first published in the December issue of Diecast Collector - see the magazine for other restoration queries. To see which issues of Diecast Collector are available to buy online, click here.