I didn’t notice any change in the stripe width. I think the resin is fluid enough that it draws down from the top.
As for how much it shrinks I bet the manufacturer has data. This is a small pour, the shrink is correspondingly small but nonzero. You can see it here:
Notice how the partial sanding hits the outer edges of the pour first. As it shrinks it gets a concave top surface. I assume it’s a result of viscosity and surface tension/ adhesion to the surrounding dam.
0.001 means it shrinks by 0.001” per inch. It’s a straight ratio.
Perhaps I’m seeing the surface drop due to slight seepage/absorption by the wood? Whatever the cause I overfill and then sand away excess for projects like this.
Probably. I’ve done some large resin projects (like the 11ft breakfast bar for our new house). Wood will indeed suck up the resin. You can see how deep if you dye the resin, you’ll see it wick into the cut edges of the wood. If you don’t want it to wick in, just “paint” the edges with a resin mix before making the pour. That also helps the pour bond with the wood.
That’s a really clever base treatment. I like it a lot.
Generally when dying resin you’re using alcohol inks. I wonder if what you’re seeing is the alcohol ink wicking into the wood and leaving the resin behind. It wouldn’t surprise me if the alcohol ink is not soluble in the resin, and that you’re essentially holding it in a very fine emulsion. Given the opportunity to wick into a porous surface, I bet the alcohol will leave the resin behind… But because of the viscosity of the resin only a small amount of the ink will ever come in contact with the surface to wick into.
It’s a theory. I have no idea how to test something like this. Maybe do clear resin and see how far that seeps in by itself?
I bet somebody has already tested this. I’m probably only one Google away.
OK so I googled. Apparently resin can work its way into porous wood, and how much it does depends a lot on the species of wood. Things with open grain tend to absorb more, and this actually makes a lot of sense.
I still wonder about whether or not the ink can be pulled out of the resin in a very local way. It’s an interesting academic question but I’m not sure it really matters.
No, I use powdered dyes. It’s easier to maintain consistency across batches of resin and you can still get anything from translucent to solid colors. You can also get powders with different effects on the resin including sparkling refractants. It’s the resin that seeps.
After painting the edges, you let it partially cure so that it will be a barrier to the main pour seepage but will bond with it better than if it were fully cured.
I just tried to break it. I bent as hard as I dared, if it snapped at that point I was likely to hurt my hands. I tough about putting it in the vise and getting tools to see just what it could take but decided that wasn’t necessary.
Seems pretty darn stout. Definitely tougher than it needs to be.
Just to close this out… I couldn’t find the previous lichtenberg coaster (I may have given it away) so I made another on a scrap of 1/16" ply just because. Soaked in WBPUm didn’t spend much time on it…