I decided to see if a glue joint would present an adequate barrier to dye. Thus enabling me to cut and glue a pattern in a light wood and dye only the section I want black.
I cut a scrap of Sycamore, 3mm thick, length ways, re-glued it, width ways and re-glued it thus having made absolutely sure the glue covered every square millimetre of the joint faces.
I then sanded both sides flat in the drum sander, along the grain, 150 grit. To get this
You can see the joint lines, just. These joints are PVA glued. The dye I’m using is spirit based, not water, so no glue dissolving problems.
First try. I’m using black dye on a cotton bud (Q-tip) and got about 1mm from the line as in yesterday’s cut box experiment. Not promising (look at the centre square). OK for the line along the grain, not across.For the corner square I went 2mm from the cross grain line.
It occurred to me that there may be some residual dust on the surface. I vacuumed the other side and repeated
The top left corner box is painted almost 3mm from the line. Still a slight bleed over the glue line. This isn’t working.
I may try sanding across the grain to see if this swaps where the problem occurs. I could also try a thin, non-permeable, membrane in the joint, such as clear plastic. A plastic that glues! All the same it looks like the glue line in this instance is not a sufficient barrier to the thin spirit based dye. The cut method works and this may be how I have to progress with the current project I want to use the technique with.
Be seeing you
-- Martyn -- Boxologist, Pattern Juggler and Candyman of the visually challenging. http://www.theartofboxes.com