Thread: Glue blackening

Obviously it is not black iron pipe and glue causing the problem. I think that it is something on or in the timber that rose to the surface causing the problem. I would just sand it all smooth and as a counter top / cutting board apply a goodly amount of walnut oil.

It could be pulling the tannins out of the timber?

Originally Posted by Cal

It could be pulling the tannins out of the timber?

sounds highly probable on that one. Lucky it's for me and just to butter toast on so no biggie. Hopefully it will sand off of not it might look nice as a feature!!???

I've never seen US Oak do that to PVA before

Maybe the glue is bad. I've never had any of the titebond pva's go bad on me, but I suppose it can happen since it's just water and other stuff in a bottle. I'd do a test and squirt some of the glue onto some plastic and see what happens as it dries/cures. If it turns black, then there is something seriously funky with the glue, if it dries translucent yellow, then all is well with the glue and something weird is going on with the timbers.

Titebond tends to go lumpy when it’s getting old, then starts to separate, a little like curdled milk [emoji13]
I have had blackening with some timbers when I wipe with a rag that is too wet with titebond 2, can’t for the life of me remember what timber it was though.

At the local mens woodworking club, this is quite common with oregon.

Not sure what PVA is used, but assume that it is 'cheap'.

We'll all is not lost, after running over the jointer the drum sander, table saw and router, then the table saw again, she's apples and ney a black line to be seen.

IMG_5006.jpg

I would send the entire thread to Titebond and see what they might have to say.

What is the timber used in the laminated benchtop material? Some of the stuff the big green shed sells is some form of acacia imported from probably South Africa.

Its not a fault with the Titebond as I have experienced PVA glues (Selly's Aquadhere, Titebond I & II and AVSyntec AVXL Plus) showing as black on some euc's and acacias when there has been some form of steel / iron present. A wipe over with OOO or OOOO steelwool is enough to cause the problem at times or even a bit of wind blown iron dust from grinding contaminating the surface.

Being an end grain laminate makes it easier for the chemical reaction to occur.

The MSDS for Titebond II states that it has a ph of 3.0; so it is acidic, AVSyntec AVXL Plus a ph in the range 4.0-5.0; Aquahere - not stated. A ph of 7.0 is neutral, under 7 is acidic. Think about the "ebonising solution" that we use to "blacken" wood - a mild acid, with iron / steel in solution is more effective on woods with a high tannin content. Titebond appears to be the most acidic so potentially will highlight the iron / tannin issue more so than the others.

Generally it machines / sands away as you have experienced, but not always as the ebonizing can penetrate into the timber.

Test a bit of any PVA glue with the timber and some steel wool.