Edge jointing and gluing

Thanks Pete and yes...the new shop looks great. I'd love to see a video shop tour ala Kathy Matsushita's of a couple of years ago.

One quick question regarding the process. Why did you make the stop on the shooting board removable?

Again...thanks for sharing your expertise.
 
It allows for wear and shrinkage - and it's how I was taught to build woodworking tools using as few screws and as little glue as possible.
 
Thanks so much Pete, excellent video. Nice shop.
 
Pete, thank you for this. I have one question. For the alternate shooting method (where you move the work to the plane), what is the advantage of using a plane over having a piece of sandpaper adhered to a flat piece of glass? I have seen others suggest using sandpaper. I guess my real question is why is a plane better than sandpaper in this situation? Thanks in advance!
 
i love these clips and watched them on repeat whilst making my tenor, and thanks for posting the slotted headstock one for me pete.. i still havent made the jig yet though.. the clips are great.. but i think its now time for a movie maybe? a real time series of two hr episodes to build to... ;)
 
Nice video and a great looking shop Pete. If you step aside a bit it looks like you've got a pretty good view.

In theory at least, a planed edge is supposed to give you a better surface for gluing than a sanded one. In practice, I have never been successful planing very curly koa. With curly koa I true my edges up on a joiner, just taking dust off with each pass. Then I follow up with a plane, identical to the one you show but with fine sand paper glue to the surface. I check the fit by holding the mating surfaces against a window, looking for any light.
The attached pics show a jig I made to glue up my tops and backs. It's self explanatory but I think the pictures are out of order.
 

Attachments

  • DSC_0027.jpg
    DSC_0027.jpg
    40.9 KB · Views: 87
  • DSC_0026.jpg
    DSC_0026.jpg
    46.1 KB · Views: 83
  • DSC_0028.jpg
    DSC_0028.jpg
    40.5 KB · Views: 85
  • DSC_0030.jpg
    DSC_0030.jpg
    43.1 KB · Views: 83
Ken W said:
That is what I was taught. Sanding forces fine dust into the grain/pores of the wood which hinders glue absorbtion.
Click to expand...

That could be, I don't know. It sounds right. If that were a concern you could probably shoot the dust out with compressed air. I know a builder who uses a router to radius his braces so that he has a clean surface instead of a sanded one. But then again, the plate he is gluing the brace on to has been sanded so.......
Our guild did a barely scientific experiment on this a few years ago where we tested sanded joints versus machine ones and found no difference in holding strength. I admit it wasn't a very controlled test but in the practical world I'm not sure how important it is in our every day applications. Wiser ones will correct me if I'm wrong.
Depending upon the type of wood I'm working with I will plane some joints and sand others. I've noticed no difference with either approach.
 
Last edited:
Great jig and good points Chuck. As a trained cabinetmaker the thought of using sandpaper to join is anathema to me though of course that rule goes out of the window when it comes to braces which have a larger surface area. And of course, very old cabinet makers used to 'key' gluing surfaces with a toothing plane (look at pre-ware Martin bridge areas on repairs). It is the usual thing - what works for you is OK for me buddy and luthiery is largely a self taught and idosynchratic craft.

I have a few of Snowdonia out of that window and another window on the adjacent wall - the room is filled with light - see next set of videos today :)

Thanks for all your kind comments BTW - I do appreciate them
 
Hey Pete, what type of clamps are those? Do they have a specific name? Thanks for the awesome videos.

Nevermind, I watched the video again and searched for Record cramp heads. Came up with these:

cramp heads
 
Last edited:
I'm not so concerned about joint failure as much as appearance of the joint. Planed and sanded joints seem to be much sharper looking than a mechanically created joint. I had a chemist tell me that the strongest joint is one that has a single glue molecule between the two gluing surfaces and that the joint weakens the more glue that is in the joint.
 
thistle3585 said:
I had a chemist tell me that the strongest joint is one that has a single glue molecule between the two gluing surfaces and that the joint weakens the more glue that is in the joint.
Click to expand...

We've been gradually cutting down on the amount of glue we apply, so that we only get very minimal squeeze out now. One thing I have noticed is that if the layer of glue is too thin the joint can "dry out" before you put the pieces together. So too thin maybe isn't a good thing....

Which brings me to my question: I've read about "starved joints" - not with precuring prior to contact but with too much pressure. The idea, as I understand it, is that too much pressure between the two wood surfaces would force all the glue out and weaken the joint as a result. I never really believed this, and never really decreased the clamping pressure - after all, what you want is an invisible joint, right? So, the thinner the better....

So, if Andrew's chemist (or chemical engineer) is right about the single-molecule joint, can we just ignore the starved joint warning or are there cases where it may still hold? Hmmmmmm.
 
I just read an article from Fine Woodworking a couple of weeks ago where they tested all the common glues and tight and loose joints. As well as clamping pressure. There conclusions about starving joints from too much pressure was it's a myth.
 
I think its a myth from the aspect of clamping but I don't think that's the case from not applying enough glue. Dryer woods are going to "absorb" more glue, so there is the risk of having a starved joint in that manner. I know a few builders that apply a coat of hot hide glue to each edge then "re-activate" it by a thin third coat just prior to clamping. There was also an article in a recent past issue of the GAL magazine where a builder applies glue to both parts, clamps them together and then activates the glue with heat and steam.
 
Hey Guys,

As far as glue vs planed surfaces, I know that the FAA won't approve a glued joint that was sanded. As one airframe inspector explained it to me, "It's the difference between trying to get traction on a gravel road vs asphalt.

Tom
 
Lot's of good info. I've got the Bailey #6 scary sharp. :)
Thinking out loud, they say folks who don't really understand something can't convey it well to others. Pete, I get everything you put forth right off the bat, even when you use those big words like impede n' stuff.
 
Last edited:
You must log in or register to reply here.

Similar threads

R
Edge Jointing and Clamping jigs
Replies
10
Views
897
rudy
R
Farkvam
My Strumming Hits the Edge of the Fretboard...Tips?
2
Replies
23
Views
1K
clear
C
Veritas99
Fixing a rough edge in string thru bridge
Replies
11
Views
521
Kenn2018
Kenn2018
R
How good is a ukulele without kerfing (the inner edge bracing)?
2
Replies
27
Views
2K
Tin Ear
Tin Ear
kkimura
Cutting Edge Ukuleles
Replies
10
Views
707
VegasGeorge
VegasGeorge
Top Bottom