Replies

1. 
   SgianDubh | Jan 29, 2010 06:24pm | #1

   If you go to this page at my website and scroll to the bottom of that page to the text in the yellow box you'll find an explanation for what you have experienced. It's my guess you used a PVA type glue, and there are a couple of suggestions at that page that may help you in the future. Slainte.

1. 
   JohnPT | Jan 29, 2010 06:45pm | #3

   Hi,
   Thank you for the
   Hi,

   Thank you for the information (good web site), it is very helpful, and yes in all the cases where I had this problem, I used a PVA type glue, Lepages Yellow or White wood glue.

   Before my next glue-up, I think I need to do a little research on available wood glues.

2. 
   mrbird90 | Jan 29, 2010 06:27pm | #2

   I have experienced this but mostly with liquid hide glue. I have not seen this problem with Titebond I or III If you sand too soon after glue up the wood sometims shrinks and you get the opposite of what you describe.

3. 
   DonStephan | Jan 29, 2010 08:03pm | #4

   It doesn't seem likely, but
   It doesn't seem likely, but there could be a significant difference in relative humidity between the workshop where the wood is stored, and the final destination. Having said that, a varnish coating should slow down the rate of change of moisture content in wood, as long as all surfaces are similarly coated.

   What was the time interval between gluing the panels and applying the varnish? Was the piece moved within a weed to final destination after varnishing? Finally, how long before the raised line(s) appeared?

   If relatively short time periods were involved, it might be interesting to glue a couple pieces of the same wood, in the same way, with epoxy; finish similarly and see if the line appears.

1. 
   oldusty | Jan 29, 2010 08:48pm | #5

   Don , I know what you mean but I have noticed it in just a few days while still in the shop with no change in location.

   The Titebond has water in it , perhaps the core of the problem ?

   regards , dusty

4. 
   joinerswork | Jan 30, 2010 11:58am | #6

   John,

   In addition to the glue itself exuding from a glueline with a decrease in moisture content, I have seen (felt) a distinct line when adjacent boards have different grain orientation, ie. one board is flatsawn (facegrain), and its mate is rift or quartersawn (edgegrain). Changes in moisture content in this case results in a differential in expansion (of the boards' thickness) along the glueline, and is seen/felt as a very slight step, where the two boards' differing thicknesses become apparent.

   Ray

1. 
   DonStephan | Jan 30, 2010 07:15pm | #7

   That's a great point, Ray.
   That's a great point, Ray. You reminded me that Hoadley, in "Understanding Wood" recommended putting "inside" edges together and "outside" edges together for that reason. The "inside" edge is the one that was closest to the center of the log, and the "outside" edge was the one closest to the bark. No doubt this would be less effective if a qs board was edged to a flatsawn one.