How to make table top dead flat for veneer replacement?

[Mike Dowell]

Just curious of your methods here at the creek. I've got a small table I replaced the veneer on the top of. It's about an 18"x18" or so. Anyway, belt sanded down to the poplar, then used Random Orbit to smooth out a bit, then used hand block. After the veneer is on and finished, there are a couple dips here and there in the surface. When you all do this, what methods do you use?

[John Lankers]

To get a small table top like this dead flat I would be very careful with the belt sander and use a straight edge to check for flatness often, use Bondo (wood putty) to fill small depressions and hand sand using an oversized sanding block.
If at all possible, I would discard the old table top, start with a new flat substrate and apply veneer to the top and bottom.

[Hoang N Nguyen]

This is were a drum sander or wide belt sander will shine. When I have table tops and panels that I can manage on my own, I send it through my drum sander. A few passes will make it dead flat and on I go.

[Chris Fournier]

Handplane.

[Mike Henderson]

If you can take the top off, take it to a shop which has a big belt sander and pay them to put it through a couple of times.

Mike

[Mike Dowell]

Good to know for the future. I didn't use any bondo because I though it might affect the glue adhesion in those spots. Hey, out of curiosity, what if this were not a small table, what if it were a 4x4 table? I don't think there's a belt sander for that.

[Robert Engel]

Good to know for the future. I didn't use any bondo because I though it might affect the glue adhesion in those spots. Hey, out of curiosity, what if this were not a small table, what if it were a 4x4 table? I don't think there's a belt sander for that.

What John ^ said applies to the 4x4, too.

Always best to just start with a new substrate if at all possible.

For a large top, it would have to either be in pretty good shape or be necessary to a restoration for me to re-use it. One possibility depending on application, is rip it down into manageable sizes, flatten and reglue, then tune up with a jointer plane.

They do make wide belt sanders with huge capacities.

You found out why my belt sander is collecting dust somewhere.

[Keith Outten]

This may be an odd solution but if there is a local CNC Router operator in your area they can surface table tops perfectly flat.

[John Blazy]

Pre-veneer onto 1/4" MDF or similar that is already dead flat, then glue the pc onto the table top. Pre-glue wood edges to the mdf, then sand flush prior to veneering if you want a wood edge.

[Mike Dowell]

John, I can't say I understand what you mean. Any chance you can elaborate?


The tables turned out pretty well because I wasn't happy with the finish/color, so I actually SANDED THEM BOTH BACK DOWN!!!!! In the process, I had a serious epiphany... I noticed that because the veneer was already stained, as I sanded into it with my ROS, I was able to see quite plainly when I Was totally flat, because the high spots sanded to clean cherry before the low spots. Absolutely amazing "why didn't I think of that?" palm/face moment. In the future, not only will I change my entire preparation, but once the veneer is glued, I'll sprits a bit of similar tone dye evenly across the veneer, then I can track my sanding perfectly.

When I sand a dining table, I draw all over it with a pencil, that way I can track exactly where I've been with the sander, but this method of using dye may be even more effective.

[John TenEyck]

Dead flat does not equal hand methods, at least not my hands. Drum sander gets close. Wide belt sander even better. CNC better still.

John

[Brian Holcombe]

Dead flat does not equal hand methods, at least not my hands. Drum sander gets close. Wide belt sander even better. CNC better still.

John

I can get a table top flat to .003" with hand planes.

[John TenEyck]

I can get a table top flat to .003" with hand planes.

I'm not sure how you measure 0.003", Brian, or how a wood top would stay that flat over time, but you have my respect. I'll stick with big machines.

John

[Chris Padilla]

John, I can't say I understand what you mean. Any chance you can elaborate?

If I follow what he said, he suggested you first apply the veneer to a flat substrate like some 1/4" thick MDF. Now the veneer is glued to a dead-flat surface with no hills and valleys. Next, glue that to your table top. The 1/4" MDF w/veneer is thick enough to not dive into the valleys and more smoothly ride over the hills and your surface will look much better. However, with this method, you now need to hide the MDF edge.

[Chris Padilla]

I'm not sure how you measure 0.003", Brian, or how a wood top would stay that flat over time, but you have my respect. I'll stick with big machines.

John

I think a nice straight-edge and feeler gauges perhaps? I, too, don't have that kind of skill, patience, or planes to do such a thing...nor interest. I'll stick to my tailed devices.