Finished two oak scarf joints last week and after clamping I always lay the neck on its side against parchment paper so it won't stick. After about an hour I remove and clean up any excess glue and reclamp.
Both necks had about 4-5 eraser head sized black circles that looked like mold, never happened with maple and only on the initial side laying down which had the most excess glue, using Titebond.
After drying tried to sand out but no luck, can I use a white vinegar or something else to remove that won't damage the wood? The final finish will be a clear gloss spray
I have used oak for several scarf joints and have not experienced this...
I wonder about bleach not vinegar. But either way, try to test on scrap.
I am fond of distressing the wood. In that view, they may be features, not blemishes.
Brent, I don't think you are dealing with mold. Oak has tannic acid within it and may be what you are dealing with. A good wood bleach from your local home improvement store will help remove it. Another possiblity is the glue you are using, TB 1 will not leave any dark spots on oak however TB 2 will leave a faint discoloration removable with sanding. TB 3 will leave a darker almost purple color on oak that has not been seasoned or kiln dried the correct amount of time.
Luck on your build
Hi Brent, I've had this and put it down to two things, tanins in the oak or my metal clamps touching the glue line and causing the stain.
Any way I always let the glue get very close to set before removing and ooze out, so the contaminated bits stayed in the glue and not rubbed into the wood. I have glued many necks [Titebond Original] but this only happened the once.
I tried to bleach out with not much success so my guess is it's tannins in the wood brought to the surface
Isnt too noticeable after clear coat