Replies

1. 
   ErnieConover | Sep 18, 2006 03:40pm | #1

   Crotch Veneer almost always arrives a bit wavy due to the sheet alternating between plank grain at the edges and vertical grain in the crotch areas. If it is not too "wavy," spraying the sheet with a mixture of water, alcohol and glycerin before glue up will soften it and keep it more flexible. My mixture is about 60% water, 30% alcohol and 10% glycerin. A common spray bottle is the right delivery tool. The cheapest place to buy glycerin is a feed store as it is given to rumen animals with the colic. You can buy it at a health food store but you will pay many times more for the same thing. If you put too much glycerin in the mixture it will make the veneer slippery and a bit hard to glue down. A light misting from a spray bottle on both sides is usually sufficient. Whether it also affects the longevity of the glue joint, I cannot say? I have never had a problem with failure once the glue dries if the sheet was pressed flat in the press. This mixture will allow you to get the sheet flat by whatever pressing method you use without cracking it. A good press will flatten most stubborn veneers and I would experiment with that before going on to what I now describe because it is a real bother.

   If it is "wavy" to the point that it will not press flat you are going to have to thoroughly moisten the veneer with plain water (a bit of alcohol always makes it penetrate faster) or about five parts water (with a splash of alcohol) and one part glue. Yellow, or white cold glues are fine or you can use hide if you wish. (With hide you will have to warm the mixture in a glue pot.) You now have to press each sheet individually between boards with ample layers of newspaper on either side. A problem of modern newspaper with soy ink is that the print will transfer to the veneer. On some veneers this is not a problem but on most it is.(If you are a democrat and some republican triumph comes out in your veneer the sanctity of your shop is destroyed) Therefore you have to buy some plain newsprint like clerks wrap glass in at a housegoods store. I put one or two layers of this on either side the old newspaper to save cost. You have to change the paper two or three times because water evaporates out of pressed sheets very slowly. Vacuum presses are better in this situation. Once flat and dry the sheets should be kept between boards or heavy cardboard weighted with bricks until used.

   A very good veneering accessory is a common building brick wrapped in duct tape. It is a handy weight that does not scratch. I have six and use them for all sorts of things. They are the exact amount of pressure to hold something while glues dries and I have run out of hand planes as weights.

   With best regards,
   Ernie Conover

1. 
   hadley | Sep 18, 2006 06:08pm | #2

   Mr. Conover: Thank you very much for your helpful responce to my inquiry about flattening wrinkled crotch mahogany. 

         I am not an expert in these matters, but I characterize myself as a "serious" hobbist in that I work in my shop all day long. As yet I have not purchased a vacuum press because I simply do not know what to buy... and I have not been able to find a review or other writing to guide my purchase decision. Can you advise me in this matter also?  As always, thank you  ever so much for your assistance.

                                                          Kindest regards, Hadley

1. 
   ErnieConover | Sep 19, 2006 03:01am | #3

   Please call me Ernie. While I own a vacuum pump I do not own a vacuum bag. I have made a vacuum press by building a torsion box drilled full of evenly spaced holes in one side, and a vacuum fitting at one edge. I place my work on it and then place a heavy piece of poly over it and pull a vacuum. I have a gasket around the peripheries that seals when I clamp culls around the edges. The schemes works pretty well but not as well as a bag. I am reluctant to buy a bag on the sheer price of the things. I have had very good success on everything up to small tables by clamping the work between sheets of 3/4" MDF. You can accommodate pretty good size work this way and MDF is so cheep you get by nicely. I have toyed with the idea of building a traditional press from I beams and angle iron. A press is really the way to go for flat work as you get better clamping pressures. I also do a lot of hammer veneering and that can also do fairly good size work. For small panels it is the easiest way to go. It is a skill somewhat akin to French polishing and takes a certain knack. Once learned it is easy. For a good foundation in veneer techniques read Ernest Joyce's, Encyclopedia of Furniture Making. In short don't rush into the vacuum thing until you have explored clamping between sheets of MDF and Hammer Veneering.I have attached three photos. Two are of a small Victorian style writing desk I built. It is full blind dovetailed from walnut and then hammer veneered with a variety of woods. Dashboard burl walnut on the outside and bee's wing eucalyptus and madrone on the inside. The third is of my vacuum press described above. With best regards,
   Ernie Conover

   Edited 9/18/2006 8:04 pm ET by ErnieConover

   
2. 
   ErnieConover | Sep 19, 2006 03:08am | #4

   Not all my photos attached so here are the two of the writing desk.

   
1. 
   hadley | Sep 19, 2006 03:30am | #5

   Thanks Ernie!  Your work is beautiful and your counsel is much appreciated. I will take your advice to heart and proceed cautiously.

                                                        Kind Regards, Hadley