Home-Made Acrylic Retarders

by Assistant Doctor Elliot Saunders of

Note:A retarder is an agent, usually added to water, used to slow the drying time of acrylic paints, giving you more time for blending or layering highlights. 

- Doctor Faust

In my years of painting I've always wondered what the hell we buy when we pay for a pot of acrylic retarder and so I sat down one afternoon and decided to do a bit of research.

It seems that in general, that the substance we buy is either a synthetic or organically derived emollient and humectants.  That is, a product that retains moisture, and then keeps it 'locked' in respectively.

So, I spent some time finding out what natural and synthetic products that are reasonably easy to obtain could be substituted for the expensive retarding mediums used for acrylic paint.  Here's a little info on some of the substances that can be used:

Natural emollient oils and esters are derived from avocado, almond, jojoba, corn, olive, safflower, cottonseed, soybean, and cocoa oils as well shea butter and other various  oils or naturally occurring emollient substances like Squalane, Lanolin , Sorbitol Cetearyl Alcohol (produced from coconut oil) or Glycerin.

Emollients can also be produced from various petrochemical substances, like oil or natural gas.  Mineral Oil, Butylene and  Propylene Glycol are all well known, and widely used petrochemical emollients.

Similarly, once you've got the moisture in, you don't want to let it back out quickly, and that's where humectants come in - they help retain the moisture. Examples include Glycerin, Propylene glycol, Lactic acid, Glycolic acid, urea, Hydrolyzed proteins, Citric acid, Hyaluronic acid and Salicylic acid.

So, rather than try distilling my own, I spent time trying various substances that are available to alternative health practitioners and
'natural' product producers - almost anything can be bought in its natural state on the net so if you want to get cheap 'ingredients' then buying those meant for alternative health stores, combining several and then packaging it might be a great way of getting your own, custom (and cheaper) acrylic retarder.

In the end I settled for glycerin, partly because we had some in the kitchen cupboard, and secondly because its a naturally occurring substance that is used in food (although, saying that so is propylene glycol...) and so it would be a safe and easily obtainable retarder.

NOTE: Any of these substances mentioned could be used, but always test a small amount of the substance for compatibility with your paint first. Always be cautious of mixing any chemicals whether they are inert or 'safe' or not.  This tip is a suggestion and should be taken as such -  I will not be held responsible for any injuries or deaths that could result from your purchase of several gallons of some chemical off the Internet! 

UPDATE!

I've confirmed that glycerin can be used successfully as a retarder in the following acrylic paints:

Citadel
Inscribe's range
Anita's Acrylics range
Delta's Ceramcoat range
Plaid's Apple Barrel range

I watered glycerol (the refined pure glycerin alcohol used for medical or food-grade uses) down about 5:1 (water: glycerol) and applied about 3 drops to my paint (there was about a centimeter of paint on my palette).