opinions needed on a shelf

[jaustin]

was asked to make a shelf, They wanted it as thin as possible with narrow brackets under it. and as thin as i can make it.

dimension are 12" deep by 36" long.

Plans are to glue up 2 pieces to get the 12"

wondering if there will be a warping problem and if there would be a better way to mount it on the wall.

brackets are for look only. wood most likely will be mahogany.

They want the shelf to be invisible as possible. They would like the items on the shelf to be the focal point and not overwhelmed by the shelf. The wall is also a Mahogany panels also.


http://i94.photobucket.com/albums/l89/gunracksonline/keyhole1.jpg?t=1188791685

http://i94.photobucket.com/albums/l89/gunracksonline/bracket.jpg?t=1188791644

 

[DaveO]

Warping shouldn't be a problem if you use well dried and stable wood. Mahogany is an excellent choice as it is very stable. I would consider attaching the support brackets with sliding dovetails. They would allow for movement across the 12" wide panel, but offer the most resistance to any cupping.
Dave

 

[jaustin]

how would you do the dovetail?

i have only done half blind dovetails using the porter cable jig.

 

[skysharks]

I took a look at your plans.
I was wondering about the thickness of 9/16 spanning over almost 3 feet, would probable be OK. However, you would have to watch how much weight that is to be put on the shelf.
I do remember another mounting technique, where as, there is a piece mounted on the wall with dowels sticking out, then the shelf is slid-over these dowels, corresponding holes are in the shelf, for the dowels to go into. So when you look at the shelf all you see is the shelf. You don't see any mounting brackets.

I have always wanted to try that.

What I would be concerned with though is:
1. 12" deep
2. 9/16" thick

 

[NCPete]

I would think edgebanded mahogany plywood....

 

[DaveO]

how would you do the dovetail?

i have only done half blind dovetails using the porter cable jig.

You do a sliding DT more like a dado. Start by cutting a dado with a router the minimum width of the DT slot to hog out the waste. The route the angle portion of the DT slot with an appropriate DT bit. Use that same bit, at the same depth to route the mating "pin" piece on the edge of your support members. At 9/16" thick it would have to be a very shallow DT with a wide angle. You might have to get a special roter bit or cut them by hand.

http://woodworking.about.com/od/joinery/p/SlidingDovetail.htm

HTH,
Dave

 

[rhett]

I would think edgebanded mahogany plywood....

I have to agree about using ply. More stable and lighter than real wood. You could opt for a small torsion box which would handle the length without sagging and would be even lighter than plywood. Leave the back support of the "sandwich" off and use it as your wall cleat. Then you have a floating shelf without any brackets.

 

[jaustin]

thanks dave

rhett, i don't think a torsion box would work, the guy wants his cars displayed on the wall but wants a shelf that is unnoticeable as possible.

 

[Mark Anderson]

a mahogony shelf on a mahogony wall isn't going to be that noticable....unless it's sagging in the middle:BangHead:

go with the edge banded ply ( 3/4 )

 

[jaustin]

made a proto type out of oak, i could not get the bow out of the front of it.
i emailed the guy that i won't be able to do it. I rather be honest than mess up $70 of mahogany.

I told him if he likes i will try and find someone who may be able to do it for him.

here is a couple of pics i did.

 

[jaustin]

couple more pics

 

[NCPete]

John, that certainly looks like a good start!

 

[DaveO]

John, I can't see how you could be having a problem. If the shelf stock is well jointed flat and glued together flat, it should remain flat at least for this time period (I am assuming that you made your prototype recently). If you use a mechanical attachment method for the bracket like the sliding DT, they would work to resist the possible warping forces as the indoor environment changes. If you are concerned with the shelf not sitting square to the wall, it might be due to the attachment method (again assuming you used the keyhole brackets that you inquired about earlier). You might have to make the shelf brackets at a angle slightly greater than 90º to counter act the stand-off created by those brackets, or find a way to recess them into the back of the shelf.
I believe that you can do this, you made it out of Oak and that is harder to work with and less stable than the Mahogany that is planned for the final work.

Dave

 

[jaustin]

Think my problem was using 2 pieces of wood to make the 12 in, and they where not perfectly flat. I am going to try 3 pieces then mill them down from 3/4. Instead of milling them down to 5/8 then joining them.

I used biscuits to joined the wood. I am going to try it one more time if i can't get it, is anyone interested in doing them for the guy?

John

 

[DavidF]

Under these circumstances, Mike's suggestion of glass might be better even if you make brackets rather than the pins he suggests, although I have mounted some pretty heavy shelves using that method.