Dark line along the glue line

Steve-atl · May 24, 2019

So I am final sanding my body and neck. I’ve noticed everywhere there’s a glue line, (scarf joint, and neck block, etc.) there’s a black line. See photos.
I’m using Titebond II. I thought this dried clear. I don’t remember having that problem before. I bought a gallon of the glue a while back. Could the glue just be getting old?

Thanks as always

Beau Hannam Ukuleles · May 24, 2019

Don't use T2, use red cap.
T2 dries very yellow.

Either the joint wasn't tight or each edge of your joint is right on a dark grain line
This mostly happens with tops and you just have to bandsaw it in half and do it again paying attention to the dark winter grain line.

Also, epoxy leaves a dark line regardless of how good your join is.

Steve-atl · May 24, 2019

Beau Hannam Ukuleles said:
Don't use T2, use red cap.
T2 dries very yellow.

Either the joint wasn't tight or each edge of your joint is right on a dark grain line
This mostly happens with tops and you just have to bandsaw it in half and do it again paying attention to the dark winter grain line.

Also, epoxy leaves a dark line regardless of how good your join is.

Thanks, Beau

I am relatively sure the joint was tight, and the black line runs perpendicular to the grain in some cases.

When you say "tight joint" are you referring to the clamping pressure?

sequoia · May 24, 2019

Not sure what we are looking at in the picture. Almost looks like a pencil line. Please send more pix... I use T1 also but have used T2 in the past. Did not get black lines.

Beau Hannam Ukuleles · May 24, 2019

Tight as in well fitting, no gaps

Titchtheclown · May 24, 2019

A pretty common occurrence with some wood types I just had something similar on a headstock where despite identical treatment and cutting my pieces from the same piece of wood (tassie oak I think), the right side is almost undetectable and the left looks like someone went over it with a black pen.

Steve-atl · May 25, 2019

Titchtheclown said:
A pretty common occurrence with some wood types I just had something similar on a headstock where despite identical treatment and cutting my pieces from the same piece of wood (tassie oak I think), the right side is almost undetectable and the left looks like someone went over it with a black pen.

Great. What glue are you using?

Titchtheclown · May 27, 2019

Steve-atl said:
Great. What glue are you using?

I am using an Australian brand PVA called Aquadhere

Here are the photos in the spirit of or it didn't happen.

I decided not to remove and retry because then I would have to fix all the other cosmetic issues as well.

Dark line along the glue line

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