What paint should I use?
The basic options are enamel (Humbrol and Testors) and acrylic (Tamiya, Vellejo, Gunze). There are of course other brands and most companies make both types. There are also special paints for reproducing metallic surfaces.
The short answer is different people like different paints so try them and see. Acrylics are safer and less toxic. Thin them with rubbing alcohol, water or methylated spirits. Enamels should be thinned with brand-name thinner or quality artist’s turpentine, and brushes cleaned with white spirit or cheap turps, then cleaned again at the end of your session. Look after your brushes.
Personally, I find enamels better for brush painting and acrylics better for airbrushing.
For large, single-colour areas such as tanks and car bodies, spray cans can be very helpful. You can buy authentic colours fro the hobby shop, but I have got excellent results on car bodies with cheap hardware store spray paint, used over a primer coat.
When should I paint? On the sprues or at the end?
There is no one answer to this. The basic approach is to paint things as late as you can, so paint anything before you lose access to it. Starting out it can be easier to paint earlier, but bear in mind model cement will not glue painted surfaces.
Armour models represent a particular challenge: the suspension and tracks can be a painting nightmare once assembled. There are various approaches, one of the best is to leave off any outer suspension wheels, paint the inner wheels and tracks in place, then fit up the separately-painted outer wheels. Another approach is to assemble and paint the tracks in sections, usually upper, lower, and four other smaller sections to go around the sprocket and idler wheels. Yet another approach is to paint everything black or very dark brown, then pick out the separate parts- wheels, tracks, suspension frames- with highlights and drybrushing.
One thing to note is to leave off any delicate parts until after general painting. On aircraft this includes landing gear, antennas and guns.
Painting #
- Paints. Depending on what you want to use, you can either choose enamel based paints, acrylic paints, oil based paints or lacquer paints. Each type of paint gives a different finish and have different working properties. Enamel tends to give a glossier finish than others, but takes longer to dry. Acrylic is water based, and must not be mixed with enamel or oil based paints. Acrylic can be washed off the brush easily in water, but enamel and oil based paints need to be washed off using thinner. Lacquers dry and cure the fastest and are the most durable paint but their solvents have a very strong smell and should never be used without a respirator and a very well ventilated area due to their toxicity. Magic markers should not be used unless as the final layer, do not cover them with anything.
Paint Safety and Safety Equipment Discussion (AS-IS information only – please be sure to conduct your own research for your needs)
Generally, you should use respirator to spray or airbush any kind of paint. I recommend it even for painting outside to avoid repeated exposure to the organic compounds in paint and thinners. Respirators are cheap. Dealing with cancer or asthma is not. Most commonly recommended respirator is 3M. Look for organic vapour protection when choosing one, and get it today if you plan to paint tomorrow.
** What is paint?** Paint is a mixture of solid pigment particles, bonding agent (e.g. acrylic resin, latex) and thinner. Most paints are too thick in consistency to be sprayed, and required to de diluted with a thinner. Paint dries (solidifies) as its thinning agent evaporates into the air.
Paints can be broadly divided into two categories – non-toxic (water based) and toxic (alcohol or petroleum-derivative based. This post focuses only on toxic paints. As u/IckyOutlaw pointed out, water based paints will have a ‘non-toxic’ mark on packaging, and only a dust mask to stop paint dust is appropriate protection to spray them.
*** What is thinner?** Thinner is a volatile liquid used to dilute paint to desired consistency. Adding thinner to paint will increase its volume and make it less thick, thus more capable to flow out of airbrush nozzle evenly. Thinners will also increase paints drying time, making it spread on the painted surface more evenly. Basic job of a paint thinner is to evaporate completely into the air once sprayed onto the surface.
What are the most common thinners? Most commonly used brands for paints, paint cans and thinners are: Tamiya, Vallejo, AMMO MiG ,AK, MR Hobby. Note that thinners are not “universal.” Buying one brand or kind of thinner does not make it usable for ALL types of paint.
This post is built around what I found in the MSDS Sheets listed below.
What are the most common thinner ingredients? Why is it not water? Sure, some paints like Revell aqua can be thinner with tap water. Most thinners however, definitely those listed above, use alcohol or petroleum-derived Volatile Organic Compounds (VOCs) as paint thinning agents.
Idea behind using VOCs instead of water is that they evaporate into the air more readily than water, and interact better with paint bonding agents.
4. Most common ingredients that I found on easily available MSDS sheets are (as part of the total composition, not in pure form):
- Isopropyl alcohol – known as rubbing (isopropyl) alcohol. Used as solvent, cleaning agent. Irritates skin and lungs.
- Butanone – solvent, plastic bonding agent. Irritates skin, eyes and nose.
- Acetone – solvent, plastic bonding agent, cleaner. Irritates, eyes, skin. In large amounts impacts central nervous system. (PLEASE NOTE THAT YOU SHOULD NOT BE USING STRAIGT ACETONE AS THINNER. ACETONE WILL DAMAGE PLASTIC)
- Dimethyl ether – solvent, refrigerant
- 4-Methyl-2-pentanol – solvent, toxic with long exposure
- 2-Butoxyethanol – solvent, antibacterial. Cancerogenic to rodents.
And obviously – Paint pigments – ranging from organic like indigo, rose red to artificial, heavy metals like chromium, lead, titanium. Some formulations as noted above are designed to be non-toxic and should not contain heavy metals, but not all model paints are of this variety, and in those cases, often you will not find data on what’s used in the pigments~~~~.
What gets into the air when spraying paint? Simplest answer – everything. All that is in your spray can, or airbrush cup, will also get dispersed into the air as mist and dust. This includes VOCs, as well as paint bonding agents and pigment particles.
Why do I need to protect myself from all this stuff? Valid question. You will probably be fine spraying outside without a mask every so often. Keep in mind that noone really tested long term or repeated exposure of this stuff on humans. Testing was mainly done on animals, and negative effect on humans were discovered by accident, not by exposing people purposefully, in a controlled way and with a control group.
After a quick afternoon spray session you might get dizzy or get a headache and be fine after some minutes. After 10, 100 or 1000 such sessions, more complex and long lasting health problems can develop, ranging from asthma, nervous system dysfunctions and cancer. AU safety regulations for spray painting document health risks and carcinogens.
The general advice and reason behind this discussion – better safe than sorry. We’ve got the money to maintain a hobby. We must have the money to protect our health and wellbeing. We are working with chemical that have adverse effect on health, and it does not take much effort or money to have protection from them.
What kind of protection do I need?
Primary safety goal is to stop VOCs from reaching your airways and penetrating into lungs and bloodstream. Respirator suited to work with those chemicals will absorb the VOCs, not letting them through.
Secondary goal is stopping solid particles (paint pigment, bonding resins). It’s therefore best to use VOC absorber as primary filtration for the face mask, and add dust filtration to it. This should extend the longevity of VOC absorber, as it will on need to be dealing with VOCs, not VOCs and paint dust.
Which face mask should I choose? When shopping for a mask, make sure it can absorb VOCs with boling temperature above 60°C / 140°F. Most of the compounds listed above boild at 60+ degrees. There is always more than one VOC in given thinner, and by interaction their boling temperature changes. Also, best if dust filtration is there or can be added.
Keep in mind that absorbers need to be replaced as they reach their longevity after some time.
Which faces mask and absorbers is the author using?*
One commonly used choice is based around 3M’s system, and an example setup of this is:
- 3M 6200 halfmask – covers nose and mouth
- 3M 6055i A2 absorber – VOCs absorber. A2 is their class indication. A1 filters up to 1ppm (part per milion), A2 up to 5 ppm. As we are generally up close to our work, it doesnt hurt to have better filtration. This absorber also has a neat trick – usage indicator. It changes colour when its time to replace, leaving guess work out of it.
- 3M 5911 and 3M-501 – dust filer and adapter – targeting secondary objective I talked about.
My advice (specific to one author; please conduct research on your own requirements and in your local country) on choosing the right respirator, if you don’t want to get the 3M, is to find a local or online Health and Safety shop and browse their offer. Look for replaceable absorber, organic gas filtration and dust protection. ** Additional tips around safety**
- Should be obvious – but keep your pets away from the room you are painting in.
- If you can, invest in a painting booth. It forces airflow away from you. If there is filtration built in, it should help to catch some of the paint dust.
- Vent your booth outside, if possible, buildup of VOCs will be much less in your room or workshop. If not possible, make sure to open a window.
- Have a spill plan. Everyone will knock over an open bottle of something, eventually. If it’s X-20 – probably no big deal, some paper towels will do. Have them handy.
- If it’s a bottle of acetone or levelling thinner, it could damage your carpet, flooring or desk. Keep it in mind when working with especially the more aggressive chemicals.
- Once finished painting, store your absorbers away from the chemicals you used. Best stored in an airtight bag.
- Give the inside of your mask a wipe with alcohol tissue every so often. It gets damp in there really fast, and the mask stays on your face for some time. Keep it clean.
- Once in a while, check the integrity of the vales in your mask, replace them when worn out. Also stay on top of replacing absorbers.
Further MSDS s (These are for Materials Data Safety Sheets, which includes information regarding composition, hazards, boiling points, and other potentially useful safety and handling information.
https://www.hajekhobby.cz/user/related_files/mc129_mr_cement_s.pdf
https://manualzz.com/doc/8122791/gunze-mr-colour-thinner–t101–102–103–104-
Please note that the safety information, lists, and discussion above is not exhaustive, and that each builder is strongly recommended to conduct their own follow-up research. The information provided here is on an as-is basis only, and obviously, we are not responsible for any consequences relating to its use. It is provided for informational purposes ONLY, and you are expected to use your judgment and conduct your own research on something as important as safety equipment. We accept no responsibility for any issues you may encounter relating to safety related issues.