Polyurethane Glue and Pigment (update)

Anyone ever tried it? I did today on a stringerless glue-up (for a centerline). I used black pigment, worked like a champ! Next up, white pigment.

Update: Don’t try this at home folks, the expanding glue moves throught the pore space in the eps leaving about a half inch wide “stripe” of black spots near the glue line. Worked fine, just unsightly. Should have seen this one coming…

Updated

What if you spackle the EPS?

I tried pigmenting wood glue. My first test had the same unsightlyness that you had. On the second test I spackled the EPS, which kept the glue line to a relatively nice thin stripe, and the bond was still very good between stringer and foam.

However, I did a full blank glue up with pigmented wood glue and the working time is a little slow. I was struggling to even-up/adjust the foam/stringer rocker line while clamping. I’ve been wondering if there was a slower setting wood glue out there. …also, the colored glue line on the shaped board was ok, but not as good as those you see from the pros using PU foam.

Quote:

What if you spackle the EPS?

I tried pigmenting wood glue. My first test had the same unsightlyness that you had. On the second test I spackled the EPS, which kept the glue line to a relatively nice thin stripe, and the bond was still very good between stringer and foam.

You spackled the cut in the EPS where the glue went? That could work. I’ll look into it. My test batch was between two pieces of EPS that hadn’t been cut and there was no bleeding into the foam.

Why not use 1/2 oz cloth and wet this first and put in between?

Just doing some free thinking.

Soul