Replies

1. 
   rslatm | Oct 07, 2003 03:07am | #1

   First thing that comes to mind is to use channel and screw from the bottom. That way you can secure it in the middle and have slots on the ends for expansion.
1. 
   Sweejak | Oct 07, 2003 03:40am | #2

   Yes, that would be the clever way, like the edging on a drafting table, but i don't have access to the bottom, further it is a "L" shaped piece with both legs of the "L" exposed. The only means of mechanically attaching is to go thru a face, which I do not want to do,

   My current plan is to bore a shallow hole into the wood rebate where the channel is to be installed, then bore a roughly matching hole into the underside of the Aluminum channel.

   Put a healthy dab of whatever glue i decide to use into the hole in the wood add another dab to the matching barely scored hole on the underside of the aluminum.

   When mated these to blobs will form a little column of adhesive, little silicone fingers ... a rubber dowel.... that will function as semi flexible studs.

   That added with say a hard glue like epoxy in one location, ie center or show face front.

   The hard glue would function as a mechanical connector, keeping the stiff aluminum aligned, the silicone studs allowing the top to expand seasonally.

   Sounds good but has anyone tried it?

2. 
   JohnWW | Oct 07, 2003 04:57pm | #3

   Sweejak

   First of all, I'd never design for wood movement based on the idea that the piece will always be in a controlled environment.  At some point in the future it will be moved, or put into storage, or otherwise exposed to much larger humidity swings.  Furniture should be designed for reasonable worst case scenarios.

   Your idea of using dots of silicone sounds risky, I wouldn't use it for a piece being sold to a paying customer.  Edge treatments on the edges of tables are subject to a lot of abuse, they're easily snagged by people and other furniture being moved around them, especially if the edge sticks out beyond the side because the top has shrunk.

   Possible solutions: Build the top out of plywood, eliminating the wood movement problem or attach a conventional wood breadboard end to the table that allows for wood movement and then glue the metal onto to the breadboard.

   John W.

1. 
   Sweejak | Oct 07, 2003 05:26pm | #4

   Given the parameters I'm dealing with why is silicone a bad choice?

1. 
   JohnWW | Oct 07, 2003 06:17pm | #5

   Sweejack,

   If the corners of the aluminum aren't out in the open where they can be snagged or bumped hard, your idea will probably be adequate.  I have seen, and repaired, a lot of table and counter ends that had their end treatments torn off by wayward office chairs or from being snagged by someone's coat seam as they walked by.  In all of those cases the ends were more firmly attached than your aluminum strip would be.

   A second problem with your attachment is that it will allow gaps to open along the edge of the aluminum when the basically unrestrained edge of the wood top cups and shifts with humidity changes.  The silicone may not fail, but the joint between the edge of the aluminum and the wood will gap badly.

   I would suggest that you experiment with a mock up of the counter end before you try this out on the actual application.

   John W.

1. 
   Sweejak | Oct 07, 2003 07:05pm | #6

   I'm not worried about snagging things because the top is part of an entertainment system and not to be used as a table. Further I intend to set the aluminum slightly back from the front face, even if it were a table I have never been snagged by my drafting table which has a similar edging.

   In retrospect I should have used a U channel which allowed for proper attachment from below.... what can I say, I looked around the shop and there was this nice aluminum angle and not wanting to take a half day trip into town for supplies and the cost involved i decided that i would figure it out. Custom work often leads to such calculations and i think it sometimes takes some inventiveness to make a good job of it. I always tell myself "next time" but with one off pieces there is often no next time. The piece is the experiment.

   Anyway, the top is restrained with table top connectors and glue at the first four inches from the front edge back, this is why i cannot, or rather do not want, to remove the top and install a U channel. Lazy perhaps, and this brings up another calculation which is often made in custom one off work, when do you decide to back off a solution and revise the parameters? I guess it depends on budget, deadline, who the customer is, and personal makeup.

   It does keep things challenging..... next time.

   Anyway... from aluminum to philosophy.... I'm going to try the silicone solution, I'll let you know how it turns out but the final result could be a year or two off.

   Meanwhile since I appear to be hellbent any thoughts about the glue? What about the semi flexible construction adhesives, do they harden and become inflexible, i know from experience silicone stays flexible indefinitely, ask my wife. AHH! just kidding.