Replies

1. 
   creekwood | Nov 27, 2007 02:37am | #1

   Why are you going to use African Mahogany?

   I'm not sure, but I think the rosewood is oily, and should be wiped before gluing to negate the oil film.

   Jerry

1. 
   tomsellars | Nov 27, 2007 03:17am | #2

   The mahogany yielded the 2" net.. The real issue is whether veneer can be glued over a solid wood substrate with the grain parallel and not crossbanded as we usually do...

1. 
   user-83153 | Nov 27, 2007 03:33am | #3

   I wouldn't risk it. If you are worried about the extra layer of veneer exceeding your 2" net couldn't you plane the mahogany down to the correct thickness?

              Rob

2. 
   EarlKelly | Nov 27, 2007 04:12am | #4

   Tom,

   Certain Rosewoods by themselves can check when glued with a PVA type glue. I have some samples I did in a hurry with Titebond on 1/4" ply and they checked badly and others that didn't. I have had complete success gluing Karelian birch(single layer) over soft maple with the grain on 4/4-8/4 stock.

   That said, gluing veneer over solids can be done safely. Maybe not 100% trouble free but I've had quite a bit of success doing it. First, I would use a rigid glue such as PPR or Unibond 800. Pretty much any urea resin glue will yield a rigid glue line.

   I would crossband, in effect making a 5 ply sandwich. I use a veneer similar in color to the face used, that appears to become part of the face veneer on the edge. I have pieces 10 yrs and older done with this technique without failure. Let me qualify this by stating I would be very hesitant to send one of these pieces to the Southwest or Northeast because of the radical humidity difference from this area on the Gulf Coast.

   Just be forewarned that rosewood veneer "can" be troublesome even under the best of circumstances.

   Earl

   Furniture...the Art of a FurnitureMaker
1. 
   tomsellars | Nov 27, 2007 06:04am | #7

   What is PPR? I've had extensive experience with the titebond "extend"... It has more solids than regular PVA ... It seems to be less plasticky, therefore less creep in the glue line? It has performed very well with my vacuum pressing...Tom

1. 
   EarlKelly | Nov 27, 2007 06:20am | #10

   PPR= Powdered Plastic Resin made by Dap and Weldwood. It's a powered urea resin you mix with water.EarlFurniture...the Art of a FurnitureMaker

1. 
   tomsellars | Nov 27, 2007 06:37am | #12

   Thanks... I haven't used that glue in 20 years...Still good!Thank you

3. 
   mwenz | Nov 27, 2007 04:30am | #5

   I understand the desire.

   You don't mention the final width of the glue-up of the African Mahogany (AM). If the AM is flatsawn and 20" or more in width, I think that even though it has little movement in service, the Rosewood (RW) veneer will eventually fail. Could be wrong, hope so.

   If the AM is flatsawn, consider ripping and flipping 90 degrees and glue it back as QS and do the cross banded core. If for no other reason (assuming the final width is very wide) there will be a far greater chance of longevity of the show veneer and there will be far less risk of possible glue-joint telegraphing (regardless of whether you do a CB core).

   I also wouldn't choose to use anything but epoxy for the glue-up of the AM (whether left as 4" boards or CB strips) and PRG or epoxy for the RW.

   Take care, Mike

1. 
   tomsellars | Nov 27, 2007 06:08am | #9

   What is PRG? Do you recommend epoxy to avoid creep or in case the RW is oily?  The boards to be veneered are only 4" wide X 2" thick.. They are mid-century style. Thanks Tom

1. 
   mwenz | Nov 27, 2007 06:28am | #11

   Epoxy for the glue-up of the boards to eliminate the potential for the glue lines to rise or fall. But I also use it for veneer quite often.

   PRG - plastic resin glue.

   Both PRG and epoxy are a rigid glues that themselves do not remain "plastic" like PVA glues (both regular Titebond and the coldpress glues).

   Rob M.'s recommendation of hot hide glue is spot on as well for all the reasons he mentions, but especially the saturation aspect. The others (PRG/epoxy) have longer open times and if you haven't used hot hide glue, I would practice before using it on a larger surface. But it is an excellent choice as well.

   Regardless of glue choice, prior to gluing RW n a larger surface, it is a good idea to wipe it with acetone to both remove wood dust and remove any inherent oils. Having never used RW veneer on a large area, there may not be a risk of the oils.

   Take care, Mike

4. 
   RMillard | Nov 27, 2007 05:09am | #6

   Tom,

    Under certain circumstances, I have veneered over solid wood without crossbanding and I have not had any problems, but more information on exactly what you are building would help.

   Rosewood is a very brittle wood prone to checking, so it may check no matter what you do; maybe not today, next year or while you're alive, but more than likely at some point it will.

   I personally wouldn't use any kind of PVA glue for veneering, and I'd be especially concerned using it on rosewood. I have no experience with epoxies or urea resin glues. I use hot hide glue/ hammer veneering, and while my use of rosewood has been limited, the results were excellent. The hammer veneering process, completely saturates the veneer with glue and I think this may lead to it controlling checking.

   Rob Millard

   http://www.americanfederalperiod.com

5. 
   KeithNewton | Nov 27, 2007 06:06am | #8

   I have done this with lots of kinds of veneer without any problems, but I always use epoxy.

   I would not think of using a glue which contains water. When you apply a water-born glue, the veneer instantly expands. As soon as both the veneer and the glue dry, both try to contract to the original size. This is what causes the checks.

   If you use a rigid glue which contains no moisture and a veneer which is at or near EMC, there is no reason for the veneer to check, because there are no built-in stresses.