Hey guys,

I am bidding on a job that I was approached on to supply Macassar Ebony panels for a retrofit for 2 matching elevator cars.

I have specified FR Flake as the core material.

As it stands my estimate is specifying ME for the back side and the face.

I was wondering if there is a suitable wood species to veneer the backside with that is cheaper as it will never be seen in order to tighten up the price point for the panels.

It will have to be the same thickness of course, but I worry about the density of what that species is and the MC%. I was looking for wood types that are within a 10% density range or less of the Macassar.

My experience tells me not to do it and if they want ME on the face, they're getting it on the back side also from the same log.

Have any of you guys ever tried balancing the sheet with two different woods that are close in density? What were the results? Did they end up cupping/warping out?

As a matter of fact I have pressed Macassar ebony on FR Pcore with a cherry reject back for elevator cabs! (hey quit mowing my lawn)! :)
I didn't have any problems with the panels staying flat. If you are working with FR board be aware that it reacts with PVA in funky ways. I was cold pressing and I had to extend the press time by another 30 minutes. Do a test! My feeling is that most warping issues are caused in the hours immediately after pressing. Balance the panel's exposure front and back. Support them on a level flat surface etc

We have done a lot of Macassar panels. We use maple when the panels do not require Ebony. Similar density stiffness etc.
If you are using plain sliced face use the same on the back; same goes for qrt cut, match the cut on the back. I would also suggest hot pressing if you can, it will set the glue up before it is absorbed by the core. As TG suggests, do a test.

Hey guys,

Interesting. That cuts my bid price considerably into what I felt was more reasonable for the work.

If I get the gig I will be pressing in the Hofer 5 x 10 top/bottom heated press.

I was planning to use Urea Formaldehyde Resin at about 120-130 degrees.

I have never actually pressed macassar ebony as of yet. I am curious to see if I get grain saturation with the rigid glue.

I will need to make up approval samples anyhow so I was planning to try it at 120-130 degrees and another at 190 to liquify the resin.

In your experience do you guys wipe the sheets with acetone or similar prior to gluing down to drive out some of the oils?

I have heard conflicting opinions on wiping with acetone. Some say it just brings fresh oils to the surface.

I have come to believe that water base glues are better with dry, non-oily woods, and solvent based glues are better with oily woods. And TB III is good for just about nothing.

I'm in the no wipe camp for ebony. I have hot pressed with UF and PVA, cold with PVA and had no adhesion issues either way.

Right on. My gut feeling on the approach was to just run the veneers dry with no acetone spray/wipe.

It's .5mm veneer, I was thinking the UF from Spectrum should saturate the grain.

The samples I'm pressing in the next few days will tell.

And agreed... More and more I am staying away from aliphatic glues. I no longer even consider using it for veneering anything.

With laminates I use PVA glue. To hell with contact cement.

As far as a lot of the woodwork, I've started to just use UF for assembly. Doors, stave cores, counter top edges, panel glue ups, etc, etc. With flat panels and doors I find it's not that bad in terms of wait time because I just throw everything in the press and use the heated plates to kick the glue. And everything comes out dead flat which is nice.

This just occurred to me...

Have any of you guys tried polyurethane glue for veneering?

I recently veneered a table top with two layers of 1.5mm QS cherry using polyurethane glue from Spectrum.

It worked really well for that project due to our inability to calibrate the core prior to veneering. The top was too wide for our sander. We calibrated the 1.5mm veneer first and taped the cross band and face sheets together. In order to negate any inaccuracies in the flatness, we relied on the Polyurethane's glue line expansion to fill those defects.

I'll add that to the list for samples with the Macassar and see how it turns out.

I appreciate the advice and wisdom gents!

Something to think about with PU glue - when the glue foams into a gap it has little to no bond strength. I would prefer a depression in the face that can be sanded back to an unstable pocket beneath the veneer.

Regarding veneering with poly glue - I have been there.....
We vacuum bagged a walnut job with "The Black Hand" glue, and had more bubbles than Sally Rand. Trouble was, there was so much glue that it accumulated and then swelled as it came out of the press and cured. Once swelled and cured, it was trash.
Since then, we have found that clamping single faces with perfect cauls will put it down well. Lots of pressure from handscrews, etc. Toothed spreaders used to spread the glue.

I hear you on using polyurethane glue in a bag being a pain.

I use it only in the Hofer veneer press for those very reasons. The glue expands and spreads out to the edges of the panel which gets cut off anyhow.

In a veneer bag this makes one hell of a mess without the proper precautions in place.

However, the glue simply can not move the platens of the hydraulic press and we typically run somewhere around 60-80lbs per square inch.

The cherry table top that I tried this on came out perfectly.

My only issue with it is if there is glue squeeze out at the leaf seams. While the press keeps it super flat and it dries as a thin film on the surface of the veneer, it is much harder than the wood.

This was fine on 1.5mm veneer that I could sand those harder spots down and then evenly sand the entire top. I checked it with a precision straight edge as I went to make sure of flatness, but this is not going to work with .5mm veneer. I'll burn right through it.

I think it's going to be Urea on this one.