Page 19 - March April 2002

crannies; the worst place of all is under domes, sandboxes or boiler bands. The tiny bit of old paint wriggles and squirms out when the new wet stuff hits it, ruining the finish. When touched with a needle point it soon comes away. Look inside cab and boiler for pieces of old paint or crud which can be flushed out by the pressure of a spray (or by gravity when you turn the body over to paint the other side) “Brillo” pads or wire wool are used to polish up surfaces but bits of wire get caught on handrail knobs etc - use the magnifying glass and don’t miss anywhere! If bare brass or nickel silver parts are added or revealed, then the model is first warmed and then lightly brushed over with FERRIC CHLORIDE solution. This is a DANGEROUS CHEMICAL and fatal if swallowed, so take not the slightest risk but mop up all splashes at once and keep off hands. It will etch warm brass in from two to ten seconds and paint will stick like glue if given 48 hours to dry thoroughly. Brass goes pink, solder goes dark grey and you know things are happening. But any greyish brown areas tell you an oxide skin has formed and you must remove it with wire wool after rinsing thoroughly with water. Ferric chloride crystals are sold by good radio parts shops for etching printed circuit boards. Just dissolve in water and store in firmly closed glass bottle. Best to make it strong so you only have one bottle to store and less risk of a bottle getting lost or overlooked. Apply small amount with small paintbrush and wash brush thoroughly. Any splashes or drops will stain kitchen sink in seconds and may etch it ready for painting. . . . .
“SUGAR SOAP” or FLASH degreasants
sold by paint stores and hardware stores respectively; small amounts are mixed in warm water and brushed all over the model which is then rinsed in tap water. KEEP HANDS OFF! When dried - and NOT touched by human hands from now on, the model is ready for painting. All you have to do is to choose the right paint. The procedure above is suitable for any kind of paint and in my experience gives better results than small pots or jars or aerosols of model paint. But not everyone is prepared to go through all the operations or to use potentially harmful chemicals (not knowingly, that is) and I fully accept that others may beg to differ. Different ships, different longsplices, as they say in the Grey Funnel Line.
ETCHING PRIMERS may of course be used, but my next task is to shake an aerosol can of CAR PLAN RED OXIDE for ten minutes and then make a cup of tea. Shaking mixes the pigments with the binder and the carrier in the right proportions, but the spray will be thick and wide. For a thin and narrow spray a compressor and air gun are needed, with a lot of adjusting to match pressure and amount of thinners etc. Again it means a lot of extra trouble which not everybody accepts. Tea break over? “Out pipes, hands carry on with your work!” After ten minutes the larger particles will start to settle, so the paint is a bit thinner. For a thin, smooth finish you leave it to settle overnight. For intermediate situations,
experiment on old bits of metal or cornflake boxes. Years ago, car paint aerosols gave a dreadful finish, full of lumps and blobs; but today they are greatly improved and with a bit of care quite good results can be obtained. I have just used a can which behaved itself perfectly right down to the last gasp. The expected thickening and lump throwing near the bottom of the can did not happen - fingers crossed for the next can!
DEFECTS always show up and look far worse than they really are. A tiny piece of grit looks like a mountain and a tiny curly hair looks like the Himalayas. Panic not, O Ye of little faith! Let it dry and then decide what to do. When using car paints you have a reliable supply of easily matched colours so you can afford to wipe off and start again. I keep half-litre tins of specially mixed paints with the catalogue and/or batch numbers on them. However, nearly always I leave small defects to be dealt with after the top coat has dried. Firstly because they are then easier to deal with and secondly because the top coat may go wrong (a moth crash-landing, for instance) and wiping off and repainting may be on the cards. AEROSOL CANS have removable plastic spray heads which can get clogged up - but a drop of thinners and wiping with a clean cloth nearly always does the trick. SPRAY GUNS have many parts which can easily clog up and anyone buying one should sign on for a practical demonstration by an experienced user. Those unaccustomed to strong language should be warned, however! ACRYLICS are taking over from CELLULOSE paints but some cans are marked “suitable for use with” either. Now normally it is unwise to spray cellulose over ANY other kind of paint, while acrylics can be sprayed over cellulose but NOT over household or Humbrol oil-based paints. DRYING TIMES vary but normally cellulose dries in five to ten minutes, acrylics in ten minutes upwards and Humbrol type paints in two to forty hours. For a really reliable finish dry for 48 hours, regardless of paint variety. Fine rivet detail starts to appear after a few minutes but it goes on getting sharper for at least another four hours and what may at first look like a disappointing paint job may look quite different at breakfast time next day.
TOUCHING UP defects can spoil a nice finish if too much wet paint is applied all at once. Red oxide and other undercoats or primers are liable to swell up and crack unless put on in very thin layers; if in doubt do all the filling of dents with layers of the same paint as the top coat, or maybe some similar shade of the same type of paint. Reds tend to be transparent so they should be applied over black or dark red and a can of darker red for use as ‘’middle coat” may be of use. Maroon applied over a middle coat of streaky light reds, yellows and browns can look convincingly like badly weathered surfaces - put streaks next to safety valves or tender water filler etc. for best effects. But most people don’t start to think about weathering until after the paint job has been finished.
HOLDING AND MASKING are arts acquired by experience. But to be safe never rely on a single layer of masking tape but place a piece of cardboard to cover up as much as possible of the masked area. Then no insecure tape can curl up and let you down when under fire. Watch out for backspray and fine particles floating in the air, and wrap a newspaper right around the model except in areas being sprayed. When removing tapes, pull at an angle away from the surface and do not allow a tape with wet paint still on it to bend or curl and wipe across the newly painted surface (bad language is likely to be heard when that happens!)Tapes that pull paint off with them can be tamed by rubbing the gummed surface over thumb or forefinger a few times before use. Tapes must never be placed in warm air or over a fire to speed drying - unless you want to spend the rest of the day trying to remove sticky stuff off the paint surface. There are lots of efficient glue removers but they all remove paint as well. Washing-up liquid plus foam plastic dish-washer pads may help, but not until after at least 48 hours drying time. Hands should not be sprayed but it may be possible to wear rubber gloves or to spray just the far end of a model. Then, if paint starts to run a quick spray in front of the tidal wave may catch it and turn it into a useful coat of paint. Or the model may be turned over so the paint runs back or off in another direction. It doesn’t always work. Like bullfighting, there’s an art in it.
STAINLESS STEEL is difficult to represent but HUMBROL JUST METALLICS S1006 SILVER MET may be sprayed on about ten minutes after a good shake, left to dry overnight and given a final coat without further shaking. This may not be exactly right but it has a nice shiny surface - not too shiny - and you can’t, as a rule, see particles of metal under a magnifying glass. I got an aerosol can from a Homecare hardware shop after trying just about every other type of paint on the market. Humbrol tinlets labelled as metal finishes require polishing after the paint is dry - and all those handrail knobs get in the way.
PLAIN DECAL PAPER is useful for applying strips or panels of maroon etc over a basically black engine body. The maroon or whatever is sprayed on the active surface, then the paper is turned over and patterns are drawn, cut out with knife or scissors and floated in tepid water. Some makers advise removing all the gum and relying on a setting fluid to snuggle the decal to the paint but others tell one to keep the gum and prick bubbles with a pin if they show up when all is dry, then treat with setting fluid again and wash off excess fluid or gum with water when it is safe to do so. DECALS do not always keep for over a year or so and older varieties go off the market.
Right now I cannot get all the Dulux yellow CPR ones I need from CDS or Champ, but I am expecting samples of new ones from Black Cat in Winnipeg in 2002. Watch this space!
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