Nick Allen

Top center joint gluing suction gap...

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Lota complicated clampiness going on.

Here's my rubjoint fixture.  The two fingers on the back part extend just a little above the lower plate half, so it keeps the plates in line without having one side of the glue joint open up, like I found when forcing both plates down to a flat surface.  Quick and easy, and works perfectly.

5ad62be49a483_PlateGluingFixture1.JPG.fa3c66220cfcfe4042f2beb84b5531c4.JPG5ad62be61d4e4_PlateGluingFixture2.JPG.4f872a4a455dafbec08d6bf37bd1d06c.JPG

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Conor...Maybe I don't understand your question...if the joint is planed and fits perfectly when flat then how can it open on the inside? Never had an open seam yet but please let me know if there is a better way. I've done it both ways with success, that is leaving a tiny gap in the middle and no gap.

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30 minutes ago, lpr5184 said:

Conor...Maybe I don't understand your question...if the joint is planed and fits perfectly when flat then how can it open on the inside? Never had an open seam yet but please let me know if there is a better way. I've done it both ways with success, that is leaving a tiny gap in the middle and no gap.

So do you clamp it to the board to align the two pieces perfectly? I don't worry about that because I plane the face after I've joined the plate.

 

I just use a sash clamp. I cut back the edge on the face side so that the pressure is appliex evenly at the centre of the thickness of the plate. This stops it wanting to pop out.

Just for illustration....

 

20180417_192927.jpg

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10 hours ago, HoGo said:

I clamp the plane to my bench on one side and ride the wood on perfectly flat piece of laminate along the plane. This keeps the planed wood flat during planing. Few passes will yield perfect joint.

I do exact same thing. You need a very precise angle of clamping the plane and a really ideally flat surface to ride the wood. My band saw table works well for that purpose. And it's the easiest way to make a perfect joint with no strain and gap, which I think you have to avoid.

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OK, I see now what you mean...I surface the flat side of the wedge first and then join the outside edges that the clamps will touch at 90 degrees. I then plane the joint edges at 90 degrees off the flat surface. When the joint is good I'll clamp one half of the wedge down to the jig which is sitting on the pipe clamps so all that is needed is to apply glue and rub the joint. The excess will squeeze out into the drip channel. Lightly tighten the clamps and your done. To me it's simple and fast.

Making this work requires flat surfacing and perfectly flat and squared edges...Thanks for explaining your method. I do think leaving a very slight gap in the middle like you explained is a very good idea.

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46 minutes ago, Conor Russell said:

So do you clamp it to the board to align the two pieces perfectly? I don't worry about that because I plane the face after I've joined the plate.

 

I just use a sash clamp. I cut back the edge on the face side so that the pressure is appliex evenly at the centre of the thickness of the plate. This stops it wanting to pop out.

Just for illustration....

 

20180417_192927.jpg

That's similar to what I do too. On cellos, there's not always enough height at the edge to trim in such a way that it puts the clamping force at the center of the joint, so I glue on some junk pieces of wood, and shape to get the clamping force where I want it.

1038.JPG

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1 hour ago, David Burgess said:

That's similar to what I do too. On cellos, there's not always enough height at the edge to trim in such a way that it puts the clamping force at the center of the joint, so I glue on some junk pieces of wood, and shape to get the clamping force where I want it.

I do it similarly, sometimes I just plane the outside edge a bit off square so the upper edge receives the pressure or I glue tiny shims to my jig to press against upper side of the thinner edge when the wood is just barely wide enough and I don't want to loose any width (in the pic I posted you can still see some shims attached from previous use)

When I glued bass top I cut steps at the ends and bouts  close to the outline  so clamp pressure would not be on the quite thin edge pushing the joint apart.

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On 4/15/2018 at 3:53 PM, Conor Russell said:

I do spring the joints. I put one half in the vice, and place the other on top. If I move the top piece side to side I want it to rotate on the very end. When I rub the joint, the slightest turn of the clamp is enough to close the centre. It really is very little hollow, but enough to insure that the ends are closed tight. Sometimes a flat joint can open a whisper at the ends because of the wood swelling when the glue is brushed on.

This is pretty much how I do it. I know it wasn’t my bright idea so I may have learned it from you. I think everyone tweets methods to suit themselves best. 

I make both halves perfectly flat. I judge by feel rotating from either end.  If you can see light you’re a long way off IMO. When both halves are perfectly flat I hollow one half just enough to shift the rotation to either end when pivoting the top plate from the opposite end. Then rub and lightly clamp just as you explained. 

I haven’t sized the plates yet as David B. Explains in some previous thread, but I plan on giving it a try. 

-Jim

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1 hour ago, Jim Bress said:

This is pretty much how I do it. I know it wasn’t my bright idea so I may have learned it from you. I think everyone tweets methods to suit themselves best. 

I make both halves perfectly flat. I judge by feel rotating from either end.  If you can see light you’re a long way off IMO. When both halves are perfectly flat I hollow one half just enough to shift the rotation to either end when pivoting the top plate from the opposite end. Then rub and lightly clamp just as you explained. 

I haven’t sized the plates yet as David B. Explains in some previous thread, but I plan on giving it a try. 

-Jim

Nick...There are many roads, not all lead to Rome.

Jim...Please site that David B thread. That would be very useful.

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My contribution to the "this is how I do it" club.

Joint done as Conor describes, also edges rasped to put clamp pressure at the centre of the joint. I find "quick clamps" perfectly adequate, no need for anything more heavy duty.

IMG_0324.jpg.3e2da6c1aaec0afff2db7b864c8339cd.jpg

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I,ll share my method as well , like it cause it,s quick and accurate and does not require thinking much during the glue up, using the go bars to raise the deck into the center line of the clamps, outside clamps just finger tight followed by the bar in the middle, wouldn’t clamp the plates down ...ever just doubles the chance of introducing twist or other error if the angle of the dangle isn’t spot on ,within nothin perfect. I walk the ends like the others looking for no light to speak of, and give it what I call a pinch test on the flat plate ,If I can pinch one end together and have the other end stay closed ,Then it has passed.

image.jpg

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14 minutes ago, Don Noon said:

Is there some reason for not using a simple rub joint?  Everyone seems so clampy.

Clamps.gif.ccf00a9db627f00d4820f7b2c28f16e3.gif

Trust in god ...but tie your camel. For the small amount of time, ...maybe five minutes if I take a break halfway through... to prepare and executed he clamping it just seems like a good insurance policy.

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12 minutes ago, Michael_Molnar said:

I do a rub joint and find that when it's done wrong it's usually that the glue is too thick.

... or the wood is too cold.  With a rub joint, you can tell immediately if it's not working right by the feel.  With clamps, you lose that (unless you rub it, then clamp it... but that seems unnecessary to me).

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19 minutes ago, James M. Jones said:

Trust in god ...but tie your camel. For the small amount of time, ...maybe five minutes if I take a break halfway through... to prepare and executed he clamping it just seems like a good insurance policy.

Same here. I clamp pretty much everything except upper nuts, saddles, and purfling.

I suppose it would be possible to do a rub joint between a fingerboard and neck....

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On 4/17/2018 at 8:34 PM, lpr5184 said:

Nick...There are many roads, not all lead to Rome.

Jim...Please site that David B thread. That would be very useful.

Hi E,  About my notes.  They are subject based not thread based.  I also sometimes rearrange quotes to tell a cohesive story on the subject that they are filed under.  Sometimes the "story" is from multiple threads so while I understand the context is only what it is filed under my notes can easily be taken out of context because they are not necessarily in chronological order or from the same thread.

I don't know the thread title, but this is the portion of the conversation I was referring to.  As a side note, I'd recommend searching for some of Melvin's writings on the topic of joining plates.  Again sorry, I only save the words not the threads so that I don't have to slog through the conversation to get to the point.

David, please let me know if quoting you from the past is not kosher with you.  I will happily make it disappear if you like.

 

David Burgess:

 The "Gluemeister"?
Gosh, it's great to finally have a title! I wonder if it would look like an impressive credential on a business card. Might I go so far as to be "Dr. Gluemeister"?

Speaking of titles, I haven't seen the article yet. What is the title of the article? Jeffrey suggested some really good ones, like "A Sticky Situation".

I use the same glue strength for tops and backs. This may result in a stronger joint at the back, because of less absorption, but I can't really be sure, because I've only removed one back from one of my instruments. The unfortunate owner was holding the cello backstage during an intermission, and a stage hand with a rolling cart of chairs used it for target practice.

Center joints:
I may have deliberately omitted this, because of the variation in techniques, such as "rubbed" versus clamped joints. I size first with a three minute gel, which is left to dry overnight, and then follow with about a 90 second gel, and clamp it. Without the initial sizing, the glue might need to be much thicker. It's amazing how much glue will soak into the wood on some highly figured maple.

JohnCee, on Jan 26 2010, 04:00 AM, said:

David, for center joints, do you clean up the edges with a plane after the initial sizing has dried, or go straight to final gluing?

David Burgess:

Generally not. Occasionally, cello plates will change shape a little overnight, and require a slight touchup. There have also been a couple of times with wild maple where parts of the grain were raised enough that I made a pass with the plane, only enough to remove some fuzz.  

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Yes.  I use word that way I can move stuff around as "new" information comes in.  I use highly creative titles like "glue".  Then I put related topics like "glue" and "joining plates" in a folder.  Then related folders get put into folders marked "construction", and so on...  My files are much more organized than my bench.  :D

-Jim

“I don’t need to know everything, I just need to know where to find it when I need it.”   -- Albert Einstein

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2 hours ago, Jim Bress said:

David, please let me know if quoting you from the past is not kosher with you.  I will happily make it disappear if you like.

No problem, Jim. In the future, if I can't remember something I've said before, now I know who to ask. ;)

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On 4/18/2018 at 5:18 PM, Michael_Molnar said:

I do a rub joint and find that when it's done wrong it's usually that the glue is too thick.

Exactly, or my technique has been a bit sloppy.

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I just rubbed it. I got sick of thinking about different clamping methods and suction gaps. I clamped my #5 into the vise and jointed it flat and true. Then I sized with dilute glue, then I cleaned up the mating surfaces and used a less dilute glue and rubbed them. 

Pictured is my 4 1/2, not my 5. 

IMG_20180419_162420.jpg

IMG_20180415_170810.jpg

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