Replies

1. 
   SgianDubh | Jul 12, 2010 04:00am | #1

   If there is a gap as wide as you describe all along every joint it seems likely to me that you could cause the joint to fail with very little effort. How large exactly is a gap the size of a "small Northern State"?

   If all your joinery preparation was executed properly and the edges mated up dry as you describe, but with the proviso that your sprung joint is correct, ie, a graduating gap from either end that goes from tight at the ends to about the thickness of a piece of tissue paper at the centre, then you shouldn't have this gap you describe.

   There are further provisos: these are that you put plenty of pressure on when you tightened up the top/bottom alternated clamps, and that your edge preparation was actually as good as your description seems to suggest.

   Off the top of my head nothing else immediately springs to mind that could be a contributory cause of your unsatisfactory end result.

   Incidentally, there are no special or different techniques that should be used for preparing the edges of 1/4 sawn oak (or any other radially sawn planks) in readiness for gluing up wide panels. Slainte. 

1. 
   Chrismitchell | Jul 12, 2010 09:38am | #2

   Northen State

   Thanks for the reply, Yeah I was trying to be funny in somewhat of a, not so funny moment. It's not so much as a gap like that so to speak it's just the glue line is obvious. I took my time choosing the boards to glue up, and I did it in a way that the flecks kinda of graduated up and to the back. It's beautiful wood. Being this is the first time that I've used quarter sawn wood so I wasn't sure positively if this was normal due to the radially cut boards. I'm really not happy the way they turned out but I'm not sure what I can do differently to change the outcome. On the dry fit I couldn't even see the joint. I use the cabniet master clamps so I had , I felt good and proper torque. I guess I was hoping that there was something obvious that I was doing wrong . I can always Re- Rip and try again but before I  do I wanted to see about getting some advice. Thanks again.

1. 
   SgianDubh | Jul 12, 2010 05:56pm | #3

   I'm not familiar with that brand but assume they are a form of sash clamp. If the glue line is obvious I'm guessing it's because it's 'fat' between each board in the glue-up.

   Everything else being equal, meaning that you are sure your prepared edges are good, I can only guess that you didn't put enough pressure on when you tightened the clamps. I always recommend that you tighten them as firmly as you can reasonably do so, ie, tighten up until you can exert no more pressure by hand tightening alone-- that'll be a bit before the effort leads to bulging veins in the neck and forehaead and before you bruise your palms and fingers on the toggle bar. 

   With most glues, including the common aliphatic or PVA types the manufacturers recommended a pressure of something like 200 lbs per square inch applied to the assembly for best performance. You could go to the Franklin website for example and read their spec sheets on their glues and you'll find these sorts of numbers mentioned. Of course none of those numbers mean much when you are gluing up mortice and tenons because you can't reasonably get any effective pressure between the tenon faces and their mating mortice cheeks-- all you can do is clamp up the assembly so that the shoulder lines are tight and the frame isn't put into winding. But you can apply plenty of pressure when you clamp up edge joints. Slainte.

2. 
   DonStephan | Jul 12, 2010 08:59pm | #4

   Just for grins, what type of glue did you use and how new?  How long between applying the glue and clamps snugged?

   if you dry clamped, were you happy with the tightness of the joint all along?

   How long did the joint remained clamped?

   Have you tried the same glue with other boards similarly prepared for comparison?

   You've got my attention and compassion.  I'm about to start a large desk project, with lots of glued panels, using rift sawn red oak.

   Don