Open Segmented Bowl – Gluing the Segments

The assembly of the segments is where all the careful, accurate construction of the jigs comes together.  This is a fairly small bowl, it is only 4” tall and 6” wide but still has 74 individual pieces in it so if you are not careful there is plenty of room for error.  Here I have the 12 pieces cut and numbered for layer 1.

Layer 1 Segments Ready to go

First I mounted the three jigs to the lathe and made sure the Index Wheel is aligned to the top of the Alignment Guide and clamped in place.  Now everything is ready to go except for one last setup measurement.

Lathe Jigs Set in Place

I need to set the stop on the top aluminum angle to the proper radius.  It’s back to my cut list sheet where for layer 1 the dimension is 2.903”.

Using my digital calipers I set the stop at 2.903” or according to the photo 2.9035”.  Being .0005 inches off falls in the splitting hairs category so I am calling that good.  Next is to make sure the stop is at 90 degrees to the base aluminum angle and clamp it in place.

Setting the Stop Block

Now I can start the glue-up.  I take the piece numbered 1, apply glue to the back, set it on the aluminum angle, rub it back and forth against the base maybe an eighth of an inch each way a few times, adjust it in position snugly against the stop then hold it with my fingers in place pressing firmly towards the base for a minute.

First Segment in Place

Now that the piece in place I have to clean up any glue squeeze out from where the long edge of the segment meets the base.  The area circled in red shows where the glue needs to be cleaned up on the top side.  The similar bottom joint needs to be cleaned up also. 

I tried several different things to clean the glue off with; a wood chisel, an X-Acto knife, a dowel pointed in a pencil sharpener, small pieces of wood of different shapes and none of these worked very well for me.  The steel tools were all too hard and left scratches at the joint while the wood was too soft.  

Glue Scraper

What worked the best was a small piece of the plastic left over from the alignment guide cut narrow enough to fit between the segments.  When filed to a skew edge it cut away the glue and did not scratch the cherry.  Mind you there are a couple of things to consider.  First, the glue squeeze-out needs to be kept to a minimum so you are not trying to remove big blobs and second there is a window of opportunity to get the glue removed while it is rubbery.  Let it go too long it cures and the only resort to remove is with sharp steel tools.

With the glue removed segment number 2 can be added.  The sequence is to advance the Index Wheel by 30 degrees, clamp it in place, glue the piece on and clean up any squeeze-out just like with piece 1.

Two of 12 Segments in Place 

Do the whole process 10 more times and presto one layer glued up with only 5 more layers to go.

Layer 1 Adding Segments

Now on to layer number 2.   First go to the cut sheet and check out the requirements for layer 2.

Same sequence of events, rip enough blanks at the 1.012” width then set up the jig on the table saw for an Outer Face Length of 1.068” and cut 13 pieces.

Layer 2 Segments

With the pieces cut I need to set the Radius for layer 2, checking the cut sheet it’s 3.074”.  Out comes the digital caliper so I can set stop at the correct distance 90 degrees to the base aluminum angle and clamp it in place.

Layer 2, Setting Stop Block

Now I can slide the jig up close to the first row, set one of the pieces in place and check to see if everything looks good.

Starting Layer Two Glue-up

Here is how I have things set up for gluing the segments on.  The segments to be glued are on the jig in the order I will use them.  Next to the Gluing Jig I have a scrap piece of countertop that has a snap off trim knife, a wet cloth, my glue syringe and the plastic glue removal tool.  

I tried all sorts of methods to apply the glue starting with straight out of the bottle but I did not have enough control that way.  I also tried using a wood sliver, an artist’s brush and a metal pallet knife.  They all applied the glue OK but the problem was with the glue.  I had squeezed out a dab of glue to pull from but with the low humidity here it skinned over in just a few minutes and became unusable.  The glue syringe works very well since only the tip is exposed to the air.  Loading it up with 1cc of glue gives me more than enough to do a full layer.

Where to Apply Glue to Segment

Before actually applying the glue I took a test piece the same size as the actual piece and drew the glue line limits on it.  The entire glue surface of the piece is between the outer edge and the line.  Any glue squeezed out beyond these lines needs to be removed.   Using the test piece as a visual guide I carefully applied the glue so by eyeball it looks to be just shy of the test piece lines.  I also swiped my finger down the outside to remove a thin strip at the edge.  When rubbed into place the glue will cover the area but the squeeze-out will be minimal.

Repeat the glue-up sequence 12 times and layer 2 is done.

Layer 2 Segment Glue-up Progression

Joint with Glue Cleanup Needed

If you look carefully at the last segment I glued on you will see where there is just a little glue squeeze-out that has to be removed.  Having just a little to remove is OK as it confirms I have full coverage on the joint.  One just has to remember that there are 4 edges to remove the glue from; the one shown, its counterpart now setting on the aluminum angle and the two edges under the piece.  It’s easy to miss the two underneath leaving you with hardened glue to remove – been there, done that, no fun.

The third layer glue-up is a repeat of the second layer, so no need to go into details.  With the third layer glued up the bottom half can removed from the lathe and set aside until later.

Glued up Bottom Half of  Bowl 

Next Up – The Top Half & Lathe Turning