Veneer Problem as a 2 page pdf
When gluing segments together, it is usually unlikely, at the least, to have cut them accurately enough that the pieces will fit together without gaps. Small errors, multiplied by six add up. Even blade deflection can be too big of an error. One way to over come this problem is to glue up two halves of the assembly, flatten them, and then glue the halves together as described in 6 Window Ornament. However, if you want to add veneer in between the segments, flattening would essentially erase the veneer. This is what I call the Veneer Problem.
This mini-article will discuss the plan that worked best for me, after trying several different approaches, when adding veneer in between the segments of the 6 Window Ornament. Instead of turning the ornament, assembling halves and flattening them, the segments are temporarily glued up into halves and flattened. Then they are separated and the veneer glued on. Next they are turned, and then glued together, in the original order, all at once.
This article assumes you've read the 6 Ornament Article.
The Veneer Problem
Start by wrapping the six triangular segments into a hexagonal bundle with rubber bands and numbering the segments in clockwise order from one to six. Place a "v" (for veneer) on the left inside face of each segment as in Fig01.
Unbundle the segments and set segments 3 and 6 aside. Place segments 1,2,4 & 5 on newspaper or other disposable backing. Spray the faces that were interior but not marked for veneer (place the segments with the V face down and the numbered end to your left) with spray adhesive such as 3M Super 77 as in Fig02. Give the glue a few minutes to set (or follow the directions on the can).
Being careful to keep them in the numbered clockwise order, glue up into halves pieces 1,2 & 3, and 4, 5, & 6. As spray adhesive is a contact cement and does not easily allow for repositioning, orient the pieces carefully before bring them in contact. I found that if I brought the corners together on a flat surface and then rotated them together as in Fig03, that I usually got good results.
Flatten the two halves, then separate the segments. Remove the residual spray adhesive from the segments with mineral spirits and a paper towel as in Fig04.
Cut veneer segments, apply glue to the veneer, and tape the veneer in place so it doesn't shift when clamped as in Fig05. You can clamp all the veneer to the segments at once by sandwiching all the pieces between two pieces of plywood (or other sheet good) as in Fig06. The sandwich layers, from the bottom are 3/4" plywood, waxed paper, veneer, triangle segment, plywood.
After the glue the glue has cured, remove the clamps and trim the veneer flush with the base of the triangle. Bundle the segment together with the veneer layers out, being sure to preserve the clockwise order of the segments, as in Fig07. It will help prevent veneer chipping if you wrap blue masking tape around the area to be turned. Fig08 shows the bundle mounted for the first turning.
Complete the first turning as described in the 6 Window Ornament article, then remove the bundle from the lathe. To avoid removing veneer with the tape, pull the tape to the side, rather than up, as shown in Fig09.
The re-bundling and second turning should be done as described in the main article. Glue-up should be done all at once. Spread glue on all of the segments and bundle them together with rubber bands to hold them in position until you can clamp them. Remember to keep the clockwise order and face orientation the same as it was in the flattening step (Fig01). Cable ties, with the aid of a tie gun, as in Fig10, make excellent disposable band clamps. After glue-up proceed as in the main article.