Paint Thinners?

I don't use Model Master—don't they make both acrylic and organic solvent lines?

For organics, try "odorless" mineral spirits (often sold as paint thinner), or lacquer thinner. I'd avoid turpentine. For these, you need a good, externally vented spray booth.

For anything acrylic, the test solvents are: water, 90% isopropyl alcohol, Windex, and ethyl alcohol. Formula 409 used to be a good one to try, but they have apparently changed the formula, and it is now incompatible with PolyS and Tamiya—perhaps the others, too. One of these should work, but test in small quantities before you put it in an air brush.

Be aware that paint, and  the alternate solvents, change formulation over time, and what worked on your last bottle of paint may not work on the new one!

I'm new to AB'ing but have read a lot about it. I'm however not new at all to painting - brushing or spraying auto's.

You can use those cheap gallon jugs of mineral spirts, paint thinner, oderless (my favorite), even linseed oil (slows down drying time). Test different brands, some seem better than others, at least I prefer some over others.

Becareful using lacquer thinner. You don't need, or shouldn't mix it with enamel and it might have an adverse effect on your plastic. Save the lacquer thinner for thinning lacquer paint and spraying in a well ventilated spray booth wearing a respirator.

More good advice, jhandle! I'd be interested to know how using linseed oil to slow drying time works on plastic models—it might slow drying time a little too much, I'm thinking. It's been so long since I actively formulated paint, or made much use of organic solvent "oil based" paint, I'd forgoten that trick. If I was still using organic solvent systems, it would be interesting to experiment with varoius oils and model paints. For example, trying to get a scale frosted or crackle finish using tung oil—this would be fantastic for instrument panels, among other things.

If you or any other "oil heads" (as oppossed to those of us (me) who have water on the brain and only use acrylics ) try this, I'd love to hear about the results.

I once worked in the coatings industry, where I was overexposed to solvents (pre-OSHA) so I try to minimize my exposure.

I had been having some painting issues recently using MM enamels.  I had switched to a Home Depot odorless mineral spirits for the “economy” reason.  I have gone back to the $7.49 a can MM thinner for mixing the paints only and use the cheap stuff to spray though the AB in quantity to clean.  It may be all in my head but, it all comes down to perception, but I like matching the manufacturer’s products.  And when used only for mixing the paint that can does go a fairly long way.

 

I also don't see the sense in spending $20-$30 for a kit, maybe more than that on AM PE/resin details and decals then all of a sudden decide to go into "keep the cost down" mode for the paint thinner. 

Marc, I have to disagree. I am sick to death of the manufacturers trying to turn this into a rich person's hobby, as they did with model railroading.

Anything a person can do to keep their hobby costs down is a good thing. The $4 saved by using an off the shelf thinner (as opposed to an overpriced proprietary thinner) is the special set of decals, or a detail part that will add much to the builder's enjoyment of the hobby.

Frankly, I'd rather spend that money on the paint—which, at least for the better lines, is worth what it costs. Tamiya= ~$960/gallon; Humbrol: ~$460/gallon based on prices for the 1/3 and 1/2 ounce sizes, respectively. These prices may seem outrageous, but they are not. (Inflated, yes; exorbitant, probably not. There are good technical and economic reasons why hobby paint is so expensive.) Economizing on paint just doesn't work. You can buy an old, cheap kit and make it a prizewinner with enough effort and ingeniuty. There is no way to make an inferior paint perform well.

The proprietary thinner may be no more than repackaged mineral spirits—or it may have been specially formulated for that particular brand of paint, or both paint and thinner may have been formulated to give less than desireable results unless both are used together. Considering modern business practices, either the first or the second are most likely, and you are paying approximately $30 per gallon for solvent—that's the price per gallon of a premium interior latex!

That being said, using the proprietary thinner for thinning before spraying has the justification you mentioned. But for cleaning, when you blow the stuff out the window in profligate amounts, the cheaper you can get it, the better.

Bear in mind that the cheapest mineral spirits you buy at Home Depot, etc. , may also not be the best quality in the world—not all solvents are created equally, and the stuff sold for cleaning brushes or thinning paint by the pint, quart, and gallon may have permissible contaminants that may not affect its performance when used in large volumes of paint, but will play havoc with hobby paints, where the reduction percentage may range up to 50 percent. Discount houses, in particular, will stock the cheapest stuff they can get, as well as better quality materials. When buying non-proprietary solvents for cleaning or thinning, it is best to go with a premium brand, or at least one with a reputation you trust.

<climbs creakily down from his soapbox>

jhande wrote:

Test different brands, some seem better than others, at least I prefer some over others.

When I was painting cars for a living, we usually always matched the brands of paint and thinner. Heck, that's usually all the part store carried anyway.

For my modeling, yes I try to use a better quality oderless thinner (mineral spirits, same thing) whenever I need to add a few drops to my little 1/4oz bottle of Testors paint. Maybe because I'm not adding more than a "few" drops (probably max 3 drops per an almost full bottle) of thinner to the paint that I'm not getting any adverse effects. I don't know what would happen if one was to try using it for spraying? I was told long ago that most quality thinners are all alike. Maybe I shouldn't have added my 2 cents... sorry...

I usually try to keep on hand a smaller container of the better quality (quart size, easier to handle) for mixing with paint. I will use the gallon size of cheaper oderless for cleaning my brushes and any mess that I might have made. Just as a note - I have added some of that cheaper thinner to my paint without any adverse effects.

I had a problem with a bottle of brown Testors gloss enamel that would always dry leaving the brush strokes visible, I think I had a couple of other colors too but hey... I used to spray cars without a respirator, plus I had a head injury, oh yeah and I still use the old Testors glue with the fumes warning message so bear with me folks...   I added a few drops of linseed oil to the bottle of paint, it thinned it and slowed down the drying time long enough that it would now dry without the brush strokes. I just had to put the parts in a sealed container (Tupperware) to prevent dust from settling in the finish.

Actually I learned that linseed oil trick from my grandfather years ago.   

Sorry for what? Passing along info does not need an apology—and what you were told applies to "quality" thinners. There are more poor quality products available today than there were 10 to 15 years ago, not to mention that there are simply a lot more of them.

I hope your young mistakes don't come back to haunt you!

To be prepared for any situation and any type of modeling paints (enamel, acrylic or laquer) you should have the following thinners in stock:

-Isopropyl alcohol (for acrylics)
-Distilled water (for acrylics)
-Mineral spirits (for enamels)
-Lacquer thinner (for lacquers)
-Acetone (for airbrush cleaning)

All are available from hardware stores and come in very big containers that will last for a very long time and at 1/10 of the price of something with a Testors logo on it. Acetone is the most powerful thinner and does a wonderful job cleaning airbrushes and paint brushes; we used it in organic chemistry labs in college. Acetone will attack and dissolve everything, including acrylics, but you shouldn't use it as a thinner because it might destroy the plastic. A mixture of isopropyl alcohol and distilled water will work as a great acrylic thinner although I admit I use Tamiya thinner with my Tamiya acrylics becasue in my early modeling days those paints were giving me a hard time when airbrushing. Distilled water has other uses as well; for instance when you're decaling clear parts such as canopies. Because it contains dissolved ions, tap water may leave water marks on a transparent surface but distilled water won't.

To dispense thinner you should supply yourself with a few solvent-resistant polyethylene bottles as seen in the picture below. Online stores that sell supplies to chemists offer those small bottles. The bottles must have some kind of a sealing cap. Without them dispensing thinners from their big metal cans will be a challenge. I used to use pipettes to draw thinner from the big cans but more then once ended up dropping the pipette into the can and good luck trying to get it out!

A little caution about Acetone as an air brush cleaner: it will attack many rubber and synthetic gasket materials. If you use acetone as a cleaner, check your gaskets and seals frequently. You can protect them by lubricating them with silicone stop-cock grease, also available from almost any chemical supply house, some automotive supply places, and places that sell brewing supplies.

MZ, you left one out: ethyl alcohol, often sold as Everclear. You have to be over 21 to buy it, most places (yes, this is the stuff you can drink). It is one of the safest organic solvents around, mainly because it has been around about as long as rotten grain… It will not attack most plastics and rubbers, and is as effective as acetone for cleaning acrylics out of air brushes (not quite as effective as Windex). It is highly flammable! For that matter, so are the others except for water.

BTW: distilled water works just as well as deionized. For our purposes, there is no difference.

All of these except deionized water require the use of forced ventilation in the work area—an externally vented spraybooth or better. Avoid skin contact with all of them except water.

Do not use denatured alcohol (methyl alcohol), "wood alcohol" or "denatured ethyl alcohol"! The stuff is poisonous, possibly carcinogenic, and has no solvent benefit over ethyl alcohol.

I use Model Master enamels for for probably 95% of my airbrushing and have always used Kleen Strip Paint Thinner from Home Depot at a cost of about two or three bucks a quart, for both thinning and cleaning.  I have never experienced any airbrushing problem due to paint/thinner incompatibility.  For my acrylic painting, I was a little less confident in using plain water or alcohol, so I picked up an 8oz (250ml) bottle of Tamiya thinner for seven bucks.  To save money though, I use the expensive thinner only for thinning paint and use bulk alcohol or ammonia for cleaning.

It's a valid point about the aggressive action of acetone and potential damage to seals so I guess it's best to use it only once in a few months for general overhauls of the airbrush if the buildup becomes severe. In between a milder nitro thinner will do the job.

For ModelMaster, Testor or Humbrol Enamel paint , I use Enamel thinner that I get at hardware store. 3$ for 3 gallons

For Tamiya Acrylic, I use Isopropyl Alcohol, 0.97$ for 1 gallon

For Other Acrylic, I use Windex Cleaner, then Isopropyl Alcohol, less than 1$ the bottle

For Lacquer paint, I use Lacquer thinner at hardware store. About 3$ for 1 gallon. This can clean any type of paint also, but being very hard stuff, I prefer using other type of thinner for other paints.

Triarius wrote:

BTW: distilled water works just as well as deionized. For our purposes, there is no difference.

Yes, I actually meant distilled water (available in 1 gallon bottles at Walgreens pharmacy). I went back to my post and updated it.

Just curious...

Has anyone tried using windshield washer fluid for cleaning out their AB after spraying acrylic?

I know my wife uses it for cleaning all our windows now instead of Windex. She say's it's much cheaper when she buy's the gallon jugs on sale. Sometimes she'll add a little Isopropyl Alcohol (rubbing alcohol) to it, makes it evaporate quicker or leave less streaks or something...

I don't know why it wouldn't work, however...

I bought a gallon jug of ammonia based window washing concentrate that I mix 30:1 to get regular strength. It was $9 CDN, that's only $0.30 per gallon, which is much cheaper than windshield cleaner. I found it at Home Depot.

That's a nice price...

Come to think of it... a buddy of mine that owned a window cleaning business used TSP (tri-sodium phosphate... spelling?), about a tablespoon mixed in a five gallon bucket.

TSP from what I understand is what painters use to wash the shine off of gloss paint before painting over it.

I'll have to look around Home Depot next time I go there.

They just built one up here and I haven't been to it yet. Dang... I'm slipping... Haven't been to a Home Depot in going on 6 years...

jhande wrote:

Just curious... Has anyone tried using windshield washer fluid for cleaning out their AB after spraying acrylic? I know my wife uses it for cleaning all our windows now instead of Windex. She say's it's much cheaper when she buy's the gallon jugs on sale. Sometimes she'll add a little Isopropyl Alcohol (rubbing alcohol) to it, makes it evaporate quicker or leave less streaks or something...

I've heard of that, never tried it though. Some are probably better than others.

She does prefer certain ones more than others. But she can't remember the name off hand. She would notice the label though. We'll be shopping for more soon... I dumped the last in her car and my truck a few days ago. The jugs already gone to the dump...

But she only buys the $1.00 stuff from Wal*Mart, not that Prestone or other expensive stuff.

I wanted to say thanks for all the comments here especially the ones regarding acrylics which I have only just started using.   And having twice, yes twice, mixed them with enamel thinners by mistake I need to be storing them apart from the other paints.

Again I appreciate all the information you offered.

Cheers!