Tuesday, October 10, 2017

Tips for beginners: let paint sit!

Of course, being an impatient idiot, I couldn't let the paint sit on the D-Type. Instead, I decided it needed another coat which promptly ran and created long rivulets of wet paint dripping onto the floor of my 'paint booth'. In a panic to hold it up and force the rivulets to flow in other directions across the rest of the body, I dropped the body onto some paper towels, which promptly stuck all over the wet paint. Of course I knew this would happen, having done it before; it just goes to prove the old saying that if you don't learn from history, you are doomed to repeat it.

After pondering the options, I decided not to try and make small localised fixes but to strip it all off and start over. This was at least partly due to the fact that the blue, while nice, is not entirely right for the Ecurie Ecosse cars. So it all went into my bath (described below) with lots of 99% isopropanol to take off the Tamiya paint. (Tamiya thinner is mainly isopropanol with some n-butanol and isobutanol thrown in for good measure; it is also a lot more expensive than straight isopropanol from the pharmacy which seems to work well.) After soaking overnight I went at it with a toothbrush. Surprisingly, once the Tamiya paint was gone, the primer too began to lift, so it is back to the resin. At least there will be no mold release agents after all this!

I'll post more as I recover from this setback, but the items you should have on hand for this sort of thing include:
  • A fine mesh strainer to put your bits into so they don't disappear down the sink;
  • A shallow pan (non-aluminum metal baking tin) which should be just a bit bigger than the strainer to hold the solvent;
  • A box of disposable latex gloves from the pharmacy to protect your manicure;
  • Toothbrushes which you should keep away from the bathroom so there is no confusion! and
  • About a litre of the appropriate solvent (isopropanol for Tamiya, lacquer thinner for enamels);
  • A funnel with a coarse strainer for putting used solvent back in the bottle or can for future use or for disposal. 




You should pay attention to safety here as well. Solvents and their fumes can be bad for your health as well as flammable. Do your best to trap and recover used solvent, but any solvent that accidentally winds up going down your sink drain should be accompanied by dish soap and lots of warm water to dilute it and get it to the sewer system without pooling in drain traps. And note that some solvents (I am thinking of Easy-Off oven cleaner or other very caustic stuff that is used to strip chrome) may corrode through aluminum pretty quickly, and can make a significant mess if left where a spill won't be contained. A stainless steel utility sink is a good place to put your pan if you are going to let it sit overnight, and will capture spills while pouring the used stuff back in the bottle. If it is going to sit for any length of time, I also enclose the solvent bath in a large Zip-Loc bag to minimise fumes and smells, and to keep the solvent from evaporating and disappearing.

One step forward, two steps back ... stay tuned!

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