Blue streaks in glue squeeze-out

[Winston Chang]

I needed to extend a board, so I cut it at an angle and made a scarf joint. When I glued it together and clamped it together, I saw that some of the glue that had squeezed out had bright blue streaks in it! Has anyone seen this happen before, or know why it happened?

433289


On the other side, I don't see any of the blue coloration in the squeezed-out glue.

The board is cedar, and the glue is Titebond III. When I put the glue on, I used a credit card to spread it, and it looked normal. I didn't notice anything strange about it. For the cut, I used a track saw, then cleaned up the surface a bit with hand planes. Again, it seemed completely normal.

[Winston Chang]

I just had a head-smacking realization: when I marked the line for the cut, I used a pen so that I'd be able to see it easily on the rough-sawn lumber. A blue pen. I must have gone off the line by a little bit when I made the cut!

[Stan Calow]

Good catch! I sometimes use a pen to mark, so that's a good tip to remember.

[Matt Day]

That’s funny!

[Winston Chang]

That’s funny!

Glad to provide some amusement! :D

[Chris Fournier]

And that's why I use pencils! Good story and detective work.