# How to glue up 1/8" mahogany boards for a bar top?



## gkustas (Dec 3, 2011)

I am making a bar top for a back bar cabinet. It is going to be 20" deep x 64" long. I plan on doing the following: (2) 3/4" cabinet grade plywood substrate, with 1/8" x 5" mahogany boards glued to the top, and 3/4" x 1 1/2" mahogany boards on the edges.

I've never done this before, and I'm not sure the bast way to glue the 1/8" boards to the substrate, and to each other.

Should I edge glue them together first, and then glue them to the substrate, or just glue them to the substrate and press? If I edge glue them, do I do the full width at once, or do one row at a time? 

I plan on using Gorilla carpenters glue. I also plan on using a polyurethane finish.

I guess that's it. Any thoughts?


----------



## [email protected] (Dec 1, 2011)

I sure there will be a bunch of replies from folks with a lot more experience than me, but gluing the mahogany boards to plywood is likely to cause you grief. 

The plywood won't shrink or expand much at all, but the mahogany will be prone to humidity changes - which could cause the 1/8" mahogany to split or buckle. I know this can happen with thicker stock.


----------



## cabinetman (Jul 5, 2007)

gkustas said:


> I am making a bar top for a back bar cabinet. It is going to be 20" deep x 64" long. I plan on doing the following: (2) 3/4" cabinet grade plywood substrate, with 1/8" x 5" mahogany boards glued to the top, and 3/4" x 1 1/2" mahogany boards on the edges.
> 
> I've never done this before, and I'm not sure the bast way to glue the 1/8" boards to the substrate, and to each other.
> 
> ...


 





 
What are you trying to achieve...the planked look?












 







.


----------



## TylerJones (Dec 4, 2011)

Edge glue the solid stock first, then flatten with a hand plane. You can do to or three at once and then join the whole thing. Use a notched caul to hold the pieces flat while clamping. Glue the edge pieces to the ply and then glue the solid stock on top. If you have a vacuum press this is the time to use it, if not just make a bunch of curved cauls and get a crapload of c-clamps.


----------



## GeorgeC (Jul 30, 2008)

It all depends upon how much swelling and shrinking the mahogany does. I do not have any knowledge of this. I do like the looks of the planked look.

I tried this with 1/4" solid oak boards. Made the big mistake of not bringing the oak into the house and letting it thoroughly acclimate. I had an old birch desk that was made on Okinawa in 1961. It needed a complete refinish and I thought I would try recovering the top in oak. (Actually I recovered the entire desk in oak, but just the top in solid)

After a time the oak shrunk and I have a small space between adjacent board edges. I have been lazy. I need to take this desk out into the garage and route 3/4" grove between each board and inlay a contrasting color. Doing the contracting color just because I want to see how it looks. Will probable use walnut.

Anyway, after all of this rambling, my message is to be sure you know the characteristics of the mahogany before you embark on this project.


----------



## gkustas (Dec 3, 2011)

Wow - great advice guys, and quick too. Yes, I'm going for the planked look, but mainly because I don't want to use a thin veneer. I don't think I can get boards any wider.

The bar is going in my basement, which is a pretty constant humidity level. The boards have been sitting down there for weeks already.

I never heard of a caul before (told you I never did this), but I looked it up online and now I know how to make them. I'm psyched! Thanks again.


----------



## cabinetman (Jul 5, 2007)

For wood cut at 1/8" thick, the movement issue is negligible to none, if it's been acclimated properly.

I would first mark each section to be laminated and mark the mating edges. They need to be jointed to each other so they fit against each other tightly. You can lay one on the other with a small overlap...like an 1/8", and lay a straightedge down the length and use a utility knife and gently make several passes to cut both at the same time (several passes). Where the joints match make cross hatch marks so those edges line up when you laminate them.

Or, you can joint the edges on a jointer if you are careful. Or, you could get lucky making a pass on the table saw to get a good edge. Or, you can joint with a block sander or hand plane to get the edges to match.

Block sand the back of the 1/8" material to get it smooth and glue it down to the plywood, one at a time, you can use TB II or TB III. You could use cauls and/or weights. The next section (plank) gets fitted to the first, and glued down. You want a very smooth thin layer of glue on both the plywood and the back of the veneer. Wipe out the squeezeout along the joint line, as you need a very clean surface for the next section. When ready to lay the weight down, lay waxed paper on the joint line to keep glue off the weight.












 







.


----------



## [email protected] (Dec 1, 2011)

> For wood cut at 1/8" thick, the movement issue is negligible to none, if it's been acclimated properly.


Thanks Cabinetman. That's good to know. I guess once it's that thin it's more like "veneer" than a "board".

Good luck with the project gkustas!


----------



## gkustas (Dec 3, 2011)

Hey cabinetman, The 1/8 boards are pretty true as they came, but not not exactly the same widths (on some boards). So, I was thinking about clamping maybe 4 boards together (face on face) and running them carefully through the jointer on each edge to get uniform width and [hopefully] a tight edge.

See any problems with that? I don't feel completely confident with the knife method, and definitely not with the table saw. Thanks again for your help.


----------



## cabinetman (Jul 5, 2007)

gkustas said:


> Hey cabinetman, The 1/8 boards are pretty true as they came, but not not exactly the same widths (on some boards). So, I was thinking about clamping maybe 4 boards together (face on face) and running them carefully through the jointer on each edge to get uniform width and [hopefully] a tight edge.
> 
> See any problems with that? I don't feel completely confident with the knife method, and definitely not with the table saw. Thanks again for your help.


The boards (which actually are referred to as "flitches") don't necessarily have to be all the same in width, but do have to have straight mating edges. Some woodwork may looke "fakeish" if done in such uniformity to appear almost machine done. Some irregularities can add to the "custom" look, as in handcut dovetails versus machine made.

Cutting two mating edges at one time will produce exact mating deviations in the joint. IOW a gapless joint. The flitches can be cut on a table saw using a hold down board slightly narrower than the width to be cut, to hold the flitch flat to the saw table. A 60T blade should produce a joint ready edge. A light touch up to both mating edges with a block sander to check for gaps may be necessary.

If a group of flitches are clamped together to be machine jointed, both front and back boards used as clamps should be slightly proud of the flitches to get a flat run on the infeed table. To keep all the flitches parallel, I've left them in the clamp-up to run both longitudinal edges without unclamping the group. For that to work out perfectly, the clamp up boards have to be parallel, and the placement of the flitches have to be exactly even before making any passes.

Another choice would be to make a shooting board to be used with a hand plane. 












 







.


----------



## gkustas (Dec 3, 2011)

Ok, I think I get it now. I would need something (a spacer) to hold one of the flitches steady and level above the over for the overlap cut, right? Like this:


----------



## cabinetman (Jul 5, 2007)

gkustas said:


> Ok, I think I get it now. I would need something (a spacer) to hold one of the flitches steady and level above the over for the overlap cut, right? Like this:


Exactly...if you are hand cutting with a knife. You would take light passes so as not to have the knife directed by the grain.


----------



## TylerJones (Dec 4, 2011)

In my opinion, this seems like a lot of unnecessary work. Any pieces I have done with 1/8' veneer I have prepared the edges on a joiner or with a joiner plane, clamped the veneer, and the attached to the substrate. You have flawless joints and uniform bond to the substrate. It's how Krenov did it, it's how Rawlings does it. Attaching the pieces one at a time to the substrate is virtually guaranteeing problems. And I'm confused at to the reason for running the mating pieces through a table saw together. Thats much less likely to give you a fine joint than a joiner. Any deflection of the blade will mar or cut one piece and not the other, giving you a gap, if you block sand that edge after you risk sanding it out of square. What you are trying to do is get a joint ready edge on each piece, if you have a machine designed to do just that you should use it. The only thing that will produce a better joint than that is a #8 joiner plane. I apologize if I'm missing something here...


----------



## cabinetman (Jul 5, 2007)

TylerJones said:


> In my opinion, this seems like a lot of unnecessary work. Any pieces I have done with 1/8' veneer I have prepared the edges on a joiner or with a joiner plane, clamped the veneer, and the attached to the substrate. You have flawless joints and uniform bond to the substrate. It's how Krenov did it, it's how Rawlings does it.


Well, that's not how Maloof did it, or how Loriman, Holman, or Cascall, does it.



TylerJones said:


> Attaching the pieces one at a time to the substrate is virtually guaranteeing problems. And I'm confused at to the reason for running the mating pieces through a table saw together. Thats much less likely to give you a fine joint than a joiner. Any deflection of the blade will mar or cut one piece and not the other, giving you a gap, if you block sand that edge after you risk sanding it out of square. What you are trying to do is get a joint ready edge on each piece, if you have a machine designed to do just that you should use it. The only thing that will produce a better joint than that is a #8 joiner plane. I apologize if I'm missing something here...


I think you are missing something. I never said to run the pieces through a table saw together as a group. Cut one at a time should give you a nice edge...at least my saw provides that. When block sanding an edge, it's a light touch just to dress the mating edges together. Not all members here, and maybe the OP, may not be as an experienced expert with machinery and handplanes as yourself. So, suggestions that are performable and predictable with minimal room for error seem to be in order.

I've had very good results with my methods. They may be different than yours. I don't have any issues with _"virtually guaranteeing problems"_. For some applications, the flitches can be contact cemented in place. Here is an example:
.




















 







.


----------



## TylerJones (Dec 4, 2011)

All good points, thanks for clearing that up for me. You're correct that you can get joint ready edges off the table saw, I was confused about running the mating pieces together at one time. Seems to invite problems. I know a lot of people use contact cement but it does have a nasty reputation of delaminating, especially for a bar top. 

You are absolutely right about giving advice thats easily replicated, that's one reason I think it's always best to join pieces together first whenever possible. 1/8" certainly allows this. I have done the glue up the way you suggested and its really hard to get clean joints(edge not face), even for an experienced woodworker. Your way assures that each piece is well laminated to the substrate and thats huge, again especially for bar top. On the other hand if all of the pieces have dead flat joints then the likelihood of the piece delaminating is very slim; and you guarantee really clean, tight edge joints. Just goes to show that we all have different ways of working. 

Nice work in the pic by the way.


----------



## TylerJones (Dec 4, 2011)

Also as an afterthought, if the pieces were any thinner than 1/8" then the method you described would be the no contest way to go.


----------



## Midlandbob (Sep 5, 2011)

You seem to be making very thick veneer. 1/8 inch might be pushing your luck attaching to plywood. You would be wise to get it thinner to limit the forces. The glue has to overcome the expansion and contraction with moisture changes. The maximum thickness is more like a 1/16 th though mahogany is very dimensionally stable with maximum % change of only about 5% .
It is also important to put a similar treatment on the other side of the plywood and to make the new plywood layers at 90 degrees to the outside layers of the plywood.
Alternatively, You could glue the mahogany to a similar hardwood with which it could move.


----------



## moferg (Dec 11, 2011)

*Joining thin wood*



gkustas said:


> I am making a bar top for a back bar cabinet. It is going to be 20" deep x 64" long. I plan on doing the following: (2) 3/4" cabinet grade plywood substrate, with 1/8" x 5" mahogany boards glued to the top, and 3/4" x 1 1/2" mahogany boards on the edges.
> 
> I've never done this before, and I'm not sure the bast way to glue the 1/8" boards to the substrate, and to each other.
> 
> ...


Ihave built several guitars and the wood usally runs .090- .120, I would layout my thin strips on butcher paper or wax paper, making sure your joints are good and tight,clamp in place and then use thin viscosity super glue. If 1/8 is your finished thicknes then resaw your mahogany to 3/16 to be sure you have enough stock for sanding and cleaning, then I would find a good quality cloth tape to put on your substrate and tape aprox 6" apart and then glue your mahogany panel down with hot hide glue, then if you have humidity problems the panel will be floating on your substrate and not glued down solid. I hope this helps I have been woodworking a long time and ever time I start a project with wood I find that there is still a lot of trial and error because of the properties of wood. metal is a lot less forgiving.


----------



## gkustas (Dec 3, 2011)

Many thanks to all that helped me here. I thought I'd post a few pics now that it is done. Overall I'm happy with it, but I'm not sure how the Mahogany matches with the base cabinet veneer. I don't know what species it is, but as the Mahogany darkens, maybe it will look better on the base.


















http://www.woodworkingtalk.com/members/gkustas-25490/albums/mahogny-bar-top/12038t-bar-top-1.jpg
http://www.woodworkingtalk.com/members/gkustas-25490/albums/mahogny-bar-top/12039t-bar-top-2.jpg


----------



## del schisler (Nov 5, 2009)

gkustas said:


> I am making a bar top for a back bar cabinet. It is going to be 20" deep x 64" long. I plan on doing the following: (2) 3/4" cabinet grade plywood substrate, with 1/8" x 5" mahogany boards glued to the top, and 3/4" x 1 1/2" mahogany boards on the edges.
> 
> I've never done this before, and I'm not sure the bast way to glue the 1/8" boards to the substrate, and to each other.
> 
> ...


job done


----------

