Replies to This Discussion

Permalink Reply by Ron "Oily" Sprague on July 23, 2012 at 4:47am

ron,

1) Grain on each piece not running / glued opposite one another, but running / glued in the same direction?
2) 5/8" is just a shade over 1/2", so possibly too thin?
3) Saw not properly set up for this thickness?
4) Not pushing / holding the piece down close enough toward the saw blade, but trying to push it through from too far back?

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Permalink Reply by ron carlson on July 23, 2012 at 5:16am

Well, the Canary Wood was Rift cut and the ash was Flat Sliced.  The table saw was adjusted for the material and we didn't use a hold down feather board, everything was set-up just fine.  It really wasn't a complicated rip. I've never seen that happen before but I suppose there is a first time for everything.  

The only thing that I can think of was that I hit the Canary Wood with some Acetone just to knock down the oils. I let it dry/evaporate for what I thought was enough time but maybe it hadn't and it reacted with the glue (Tightbond II) I used. 

I agree, 5/8' is a relatively thin glue-up but this was crazy.  You could almost watch it bow and crown as it went past the saw blade :)

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Permalink Reply by Jim Woods on July 23, 2012 at 6:08am

Interesting, My guess is the Rift cut expands / contracts much less in width than the flat cut Ash.  Not sure why it did not bow prior to sawing unless some heat from the blade (possible not enough set in the balde?), but then the bowing would be only near the kerf?

You could always make radiused necks with them ? :-)

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Permalink Reply by ron carlson on July 23, 2012 at 8:01am

Maybe it would work well in a CBG that is designed for playing psychedelic music only.  You'd think you were trippin just by lookin at the neck.

 

That or just string it up letting the strings fall where they may and call it the Dr Seuss.

 

RC

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Permalink Reply by ron carlson on July 23, 2012 at 5:14am

 

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Permalink Reply by Bad Finger (Eric) on July 23, 2012 at 5:39am

Just looking at diagrams, the rift sawn probably has very little resistance to crowing and the flat sawn, depending on where the slice is taken would have a higher tendency to crown.  My amateur eye would also suggest this isn't the most stable laminate configuration.  But I humbly reserve the right to be wrong.  :)

My guess would also be that unless the wood was soaking with acetone, it probably didn't affect the glue joint.  Titebond recommends wiping oily woods with acetone prior to glue-up.  

"When working with woods that are oily or high in tannic acid, wipe the joints
with acetone before gluing. Acetone clears the contaminants from the wood pores
on the bonding surface and dries quickly without leaving any residue. Sanding
or planing the wood before gluing will also help create a good bonding surface."

From the description you have given, I think the bond strength is just fine as it is deforming both pieces of wood.

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Permalink Reply by ron carlson on July 23, 2012 at 6:00am

Exactly, Rift or Quartered is the most resistant to movement. The flat sliced isn't but I didn't think that a 1/8" of flat sliced, particularly when it's used in a glue-up with a 1/2" rift cut board would create a problem like that. Apparently I was wrong.  

On the bright side, I think I have a good start material wise if I ever want to make a barrel ;)

RC

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Permalink Reply by Bad Finger (Eric) on July 23, 2012 at 8:57am

Drum stave.  :)

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Permalink Reply by wormil on July 23, 2012 at 6:11pm

Generally lamination layers are done in 3's (or odd numbers). What you do to the front you always do to the back. What you created was a lamination with very different properties on each side. I wouldn't think an 1/8" of ash would make that much difference either. One other suggestion is that sometimes there can be stress inside the wood that is relieved when cut, maybe the combination of factors all weighed in.

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Permalink Reply by ron carlson on July 24, 2012 at 4:21am

Not sure, Jay.  This was all Kiln dried and sized lumber.  The glue I used was Titebond II and have used this bottle for several projects and never had any problems with it and it's not much over a year or so old. I have a couple of bottles about the place but now that I think about it, this one may have spent the winter in the garage.  Maybe the sub-zero temps of a Minnesota winter just weren't kind to it ;)

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Permalink Reply by ChickenboneJohn on July 24, 2012 at 2:25am

Not sure what you've glued-up, but is doesn't sound like any laminated neck I've ever come across. Typical is a centre strip say 1/4" wide and two pieces of contrasting wood glued both sides of the centre piece. You can just take take one board, rip it down the centre, plane it , reverse the pieces and glue together without a centrestripe for a non-contrast neck. It sounds like what you've done is just glued one piece of thin wood on top of another (like you'd glue a fretboard onto a neck) - that's not how you laminate a neck.

It's likely that the timber wasn't properly seasoned - it's quite common for a piece of timber to warp as it's ripped, as the stresses are unlocked by the sawing. In which case, you need to stack it, leave it to season, plane it all true and square and try laminating it..you might get away with it..but otherwise, it's firewood

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Permalink Reply by ron carlson on July 24, 2012 at 5:06am

"...that's not how you laminate a neck."

Normally I would agree with you, John.  I'm a far cry from being a Luthier but know a little about lumber. Considering the stresses involved, laminating as you say is the proper approach.   The variable here (at least in my original thinking)  was that I was going to be using a Aluminum fret board I'm finishing that's from 1/4" bar stock. That being the case, I figured that once everything was glued up along with the fret board, it would be hard pressed to do much of anything but to lie true. 

I was hoping to be able to get two partial neck blanks out of this by gluing up this way. Both were going have a 1/4" fret board applied afterward so all I figured needed was 1/2" to 5/8" and had 1/2" with the Canary Wood. The addition of the 1/8" Ash was an effort to add stability (ironically enough) and get it to time out to the top of my box.  The fret board was going to be installed and it would run onto the top some. 

I was anticipating some bowing but thought I could use that to my advantage. The crowning, not so much ;) Live and learn I guess.

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