[KwartzLab] Paper Marbling Workshop: Sun Jan 29 1-4pm

[Kevin Martin]

I just found a page that states
"Borax is used as an agent that breaks the waters surface tension and lets the paint spread out over the surface" which would imply that it *reduces* the surface tension...
The article I found implies that oil-based paints are being used in their process (to "swirl" guitar bodies). The article James found was referring to marbling using powdercoat paints in the form of a water-based slurry and again, the borax seems to be there to encourage the paint to spread.

I think the effect is that the borax reduces the surface tension between the water and the paint/particles rather than having any effect on the open surface tension (between the water and air). This makes it energetically advantageous for the paint or particles to spread out on the water.

So perhaps the Magic Dip kit uses oil-based paints (which would also explain how they can claim to marble non-absorbant surfaces). Perhaps any alkali such as soda ash or TSP would work as well as borax does by (slightly) saponifying some of the oily materials in the paint.

Then again I've also found a reference to using borax to preserve the thickener used in the water (to prevent fermentation), and also to "soften" the water (i.e. reduce the effects of dissolved mineral content). Perhaps the borax also interacts with the resins in the paint (as one sees in the "flubber" recipes that combine white PVA glue and borax).

In the case of marbling with water-based paints (acrylics or watercolours) there is almost zero surface energy between the paint and the water, and the paint spreads because it contains surfactants so the paint/air surface has less energy per area (and thus less surface tension) than the water/air surface it is displacing. As a result nothing is needed in the water to adjust the spreading. There is however, stuff in the water to increase its viscosity to make it easier to control the patterns formed.

Having said all this, though, I might try adding borax to my tray water someday to see what effect it actually has on the paint.

-Kevin Martin
 the Papertrail Handmade Paper & Book Arts
 New Dundee, Ontario
 519-884-7123
 www.papertrail.ca

-----Original Message-----
From: discuss-bounces at kwartzlab.ca [mailto:discuss-bounces at kwartzlab.ca] On Behalf Of James Bastow

"The Borax will increase the surface tension of the water to the point that it becomes almost like a film, yet it will not contaminate your substrate."
MARBLING: The How To Guide <http://www.powdercoatingboard.com/forum/showthread.php?29-MARBLING-The-How-To-Guide&s=a636fcf15ef9540bc17f8dec5d2567e3> 

(http://www.google.ca/search?q=borax+marbling)