Retarder and Enamels

They exist—but this is so esoteric I can't think of one. I think I can only remember using one once, in a formulation for an unusual specialty coating—and we didn't have any in the lab. Had to special order it.

Generally speaking, retarders don't slow solvent loss, but rather retard the onset of curing so that the decreasing amount of solvent remains effective in keeping the paint fluid. Because of the wide variety of enamel binders, there isn't a "universal" retarder for them.

Because most aqueous or alcohol system acrylics share a high degree of molecular similarity, there are more or less universal acrylic retarders.

Generally, driers are more commonly used with enamels. "Japan" drier is generally available—and highly useful when you don't have air conditioning.

 "PENETROL" mixes perfectly with "MM" enamels and allows you to shoot @ down to 7#s psi, at least I can with my "IWATA" HP-CS gravity feed AB. You can buy it at "LOWES" home supply.

                                                                              doc

Winsor & Newton Artists Painting Medium, you can get a 2.5oz/75ml bottle at most arts/craft stores. You can make your own, its linseed oil thinned with mineral spirits. I buy the bottle because a little goes a long way.

When I get a new bottle of Model Master paint, I put in just 3 drops, stir it up and put it on the shelf. I have not lost a single bottle since doing this, I may lose solvent, but the pigment stays pliable and does not gum up. When it's time to paint I thin the paint 50/50 with xylol, but you can use mineral spirits or lacquer thinner.

I like Artists Medium because it makes the paint flow and level better and gives the paint a longer shelf life. Just use a little (drops) or the paint will never cure.

Lacquer Head wrote:

Winsor & Newton Artists Painting Medium, you can get a 2.5oz/75ml bottle at most arts/craft stores. You can make your own, its linseed oil thinned with mineral spirits. I buy the bottle because a little goes a long way. When I get a new bottle of Model Master paint, I put in just 3 drops, stir it up and put it on the shelf. I have not lost a single bottle since doing this, I may lose solvent, but the pigment stays pliable and does not gum up. When it's time to paint I thin the paint 50/50 with xylol, but you can use mineral spirits or lacquer thinner. I like Artists Medium because it makes the paint flow and level better and gives the paint a longer shelf life. Just use a little (drops) or the paint will never cure.

Turn the MM paint bottles upside down for storage and clean the threads on the bottle neck and cap before closing and you won't need to waste extra money on unnecessary retarders. 

MikeV wrote:

Lacquer Head wrote: Winsor & Newton Artists Painting Medium, you can get a 2.5oz/75ml bottle at most arts/craft stores. You can make your own, its linseed oil thinned with mineral spirits. I buy the bottle because a little goes a long way. When I get a new bottle of Model Master paint, I put in just 3 drops, stir it up and put it on the shelf. I have not lost a single bottle since doing this, I may lose solvent, but the pigment stays pliable and does not gum up. When it's time to paint I thin the paint 50/50 with xylol, but you can use mineral spirits or lacquer thinner. I like Artists Medium because it makes the paint flow and level better and gives the paint a longer shelf life. Just use a little (drops) or the paint will never cure. Turn the MM paint bottles upside down for storage and clean the threads on the bottle neck and cap before closing and you won't need to waste extra money on unnecessary retarders.

Extended shelf life is just a side benefit, I use it because it helps oil based paints flow and level better.

Lacquer Head wrote:

MikeV wrote:  Lacquer Head wrote: Winsor & Newton Artists Painting Medium, you can get a 2.5oz/75ml bottle at most arts/craft stores. You can make your own, its linseed oil thinned with mineral spirits. I buy the bottle because a little goes a long way. When I get a new bottle of Model Master paint, I put in just 3 drops, stir it up and put it on the shelf. I have not lost a single bottle since doing this, I may lose solvent, but the pigment stays pliable and does not gum up. When it's time to paint I thin the paint 50/50 with xylol, but you can use mineral spirits or lacquer thinner. I like Artists Medium because it makes the paint flow and level better and gives the paint a longer shelf life. Just use a little (drops) or the paint will never cure. Turn the MM paint bottles upside down for storage and clean the threads on the bottle neck and cap before closing and you won't need to waste extra money on unnecessary retarders.  Extended shelf life is just a side benefit, I use it because it helps oil based paints flow and level better.

Well I have never needed anything to help enamels flow and level better. 

Linseed oil is not a true retarder. What it is, is a drying oil. It, or a similar oil, is the binder/carrier in artists oil paints. What it does when added to an enamel is not so much delay the cure of the binder, but cure very slowly itself, and slow solvent loss.

Nevertheless, if you really want to extend cure time, this is a simple way to go, but heed the caution to use small amounts!

If you decide to make your own, be sure to use "boiled linseed oil" rather than "raw linseed oil."  Raw linseed oil hardens very slowly, whereas the boiled (and catalyzed) version will generally harden overnight.

Also, do not use a different drying oil, such as tung oil. Some drying oils (tung in particular) shrink enormously when they harden. The "crinkle" or "crackle" finish you see on some instrument panels at full scale is due to the addition of tung oil to the paint. 

ipmsfl wrote:

Can anyone recommend a retarder for use with enamels (not acrylics)?  I've got a huge stock of conventional enamel that I need to use up. Thanks in advance.

Exactly why are you looking for a retarder for enamel paints?

I have never worked with any that dry too fast.