celetic knot not working

[Bill Clark De]

AFTER Several attempts at turning larger than Normal celtic knots the glue joints on them let go ..Some times in the stress of turning these joints get lots -maybe too much pressure... anyway my yellow glue isn't holding nor did the CA .I'm open for suggestions if you will ..
I am using birch with walnut insets and maple with walnut strips and =walnut with yellow heart
Thank you

[Mike Golka]

I use Titebond III on everything and have never had a problem. I have done knots as big as a 3" square blank. Even had a segmented bowl fly off the lathe and bounce across the shop without coming apart (waste glue block failed). The key I believe with most glues is good tight joints.

[Richard Madison]

Bill,
How large?

[Bill Clark De]

ABOUT TWO INCH SQUARE ..THE Problem USUALLY SURFACES WHEN AFTER rounding it out i attempt to form the neck -which is at the far end of the piece about 6 inches long ,,,once i got minor catch and the entire bottom of the glued up part let go ...another time i was taking out my drill bit and weight of the DRILL bit and the Jacob's Chuck broke off the end ..My joints cannot be tighter / perhaps even too tight.... perhaps the joint is starved for glue ....i /m reasonably sure the glue is OK.

[Curt Fuller]

It's difficult to now for sure but a couple things that might help, make sure the surfaces are flat and have a good fit and rig a clamping system to hold the joints tight over the entire surface for a while until the glue sets. Also, how is the wood oriented? If the slices for the ring are long grain and the main body is endgrain or visa versa, it might be that the endgrain is absorbing the glue. I've had them come apart before turning because of that and then reglued the joint rubbing a lot of glue into the endgrain. Hope that helps.

[Bill Clark De]

i suppose i should of mentioned as this procedure involved 4 cutting and gluing procedure -----i heated the joints enough to enable me to install the other three. also i let the glue up sit overnight

[Bill Clark De]

i haved just reglued he last piece and will try to clamp it...thanks

[Richard Madison]

Heated the joints?? What is that about?

[Bill Clark De]

when i make my knot i do it on a tablesaw and inorder to arrest thegluing procedure quickly - i used a heat gun // pain remover -electric= this speeds up the gluing enough so i can put my next piece in without anydelay

[Richard Madison]

Bill, That could certainly be the source of your problem. Would be willing to bet that if you use Titebond II and allow each joint to set up two to four hours before removing clamps and applying any stress to the workpiece, the problem will disappear. If your joints are failing, your procedure has not saved any time.

[Bernie Weishapl]

Bill I don't think I would heat Titebond. I have always glued and clamped for a couple of hours. Then did the next one without any problems. I think if I were in a hurry I would use thick CA glue.

[Bill Clark De]

Bernie - I've tried ca and had mixed results .The problem i think may be the glazed /smooth cut of my blade leaving too fine a surface thus not allow the glue to penetrate ..but it would seem as though the ca would penetrate better than the regular tite bond...
Do you think i could use a combination of tite bond and ca ON THE JOINT WOULD GIVE ME THIS BEST OF BOTH WORLDS OR WOULD THEY BE OPPOSED TO EACH OTHER .. thanks

[Jeff Nicol]

Bernie - I've tried ca and had mixed results .The problem i think may be the glazed /smooth cut of my blade leaving too fine a surface thus not allow the glue to penetrate ..but it would seem as though the ca would penetrate better than the regular tite bond...
Do you think i could use a combination of tite bond and ca ON THE JOINT WOULD GIVE ME THIS BEST OF BOTH WORLDS OR WOULD THEY BE OPPOSED TO EACH OTHER .. thanks
Bill, A little rough up with 320grit on a flat piece of glass will take away some oth the burning/glazing left from the saw, this will give you better penetration with all glues. I think the seggy guys sand every piece to make sure the glue gets in the pores and hold on! Good luck and stay with it!

Jeff

[Jim Underwood]

Lately, several people I've spoken to about glue-ups for various things, have told me that a good glue-line rip saw is one of the best ways to get a good production glue up. They say that the jointer leaves too much of a polish on pieces. Even better, I suppose, would be to have a precision sander put a straight square edge on things. I dunno where one would get such a creature though. Sounds like the glass/sandpaper is the way to go. In the segmented symposium held recently by the AAW, attention was given to that subject if I remember correctly.

[Brian George]

I glue up celtic knots on 3x3 inch peppermill blanks using Titebond II and have yet to have any problems. I haven't used any veners, just walnut on fir, cherry, ashe and maple.

[Brian George]

I've also been gluing up 1/2" veneers on 2" blanks with T II and having no problems at all.

[Joe Aliperti]

Lately, several people I've spoken to about glue-ups for various things, have told me that a good glue-line rip saw is one of the best ways to get a good production glue up. They say that the jointer leaves too much of a polish on pieces. Even better, I suppose, would be to have a precision sander put a straight square edge on things. I dunno where one would get such a creature though. Sounds like the glass/sandpaper is the way to go. In the segmented symposium held recently by the AAW, attention was given to that subject if I remember correctly.

Wouldn't a combination blade get a better glue joint during a crosscut than a glueline rip blade?

[Richard Madison]

There is some actual test data (forgot where I saw it) showing that a sanded and glued joint is indeed somewhat stronger than a similar sawcut only and glued joint. That said, I have made literally thousands of glue joints with sawcut surfaces (80-tooth Freud) without a single joint failure. Admittedly, few of these joints have ever been highly stressed.

For end grain joints there is also test data showing that if the joint surfaces are treated with glue, allowed to set up, sanded to clean surfaces and then glued together, the joint is stronger. Presumably there are applications where this extra effort is justified.

[Thom Sturgill]

I posted pics yesterday of a peppermill/salt shaker set that has a celtic knot. I glued up four layers of veneer between the pieces with titebond II, and other than slippage (which I cured by adding clamps on the sides) I had no problems with the glue up or with the bond holding. I allowed about 2 hrs between 1st and 2nd cut, then overnight and about 2-3 hrs between 3rd and 4th cuts and then overnight before turning. If I were to use veneers again, I think I would laminate them first.