Don Stephan
Posts: 825
Joined: 2003-07-18
Location: Cincinnati, Ohio
 User Profile |
Don
As best I can tell, all four of your posts are identical, so I will reply only to one.
I have only done two large starbursts, quite a few years ago. I did not notice any problem with expansion due to contact with urea formaldehyde glue, and I was working alone. One starburst was a 4" diameter, the other a 4' x 5' oval.
You didn't mention how many leaves will be in your pattern. You might find jumps helpful with pattern shifting, although this may not be a problem with a slip match - mine were bookmatches.
I taped together the two halves of each starburst, then trimmed the common diameters in a single cut and taped together. I'm not sure where you saw a suggestion to glue down each half and then join, and I cannot envision how that would be done.
At the time, I did not know the benefits of making two ply assemblies, and glued the starburst and backer veneer to the core at the same time. It is recommended that the same number of veneers be applied to each side of the core, so if you make a two ply for the starburst ideally you would make a two ply for the other side as well. For that side I would simply tape two sheets of slip matched veneer, with the grain of one sheet perpendicular to the grain of the second, just like the plies in plywood.
Two ply is an excellent way to minimize telegraphing of a seam in the core through the veneer. Two ply also is recommended for marquetry, where grain of different pieces may run in different directions, so in your situation I would make a two ply for the starburst (and the other side of the core). For the lower layer under the starburst I would also simply tape together an assembly of slip matched veneer, ideally something that comes in wide leaves for faster assembly.
Unless you have two large vacuum bags, you'll have to glue the two ply assemblies one after the other, then the two to the core. Perhaps Darryl will chime in with timing recommendations so the glue in the first two ply doesn't become too rigid.
As you just joined the forum today I'm not sure your veneering background. Even if you are comfortable assembling sheets of veneer, and using a vacuum bag and urea formaldehyde adhesive, you might consider making a first practice starburst and running through all the steps you will use with your walnut burl, including making two two-plies and gluing to a core.
One final observation, I'm surprised you will be using a slip match with walnut burl. The figure in walnut burl is very strong and slip matches will be very noticeable for their lack of continuity. Is there a particular reason you will not be using a bookmatch?
|
