Thread: Transperent 'plastic like' way to attach discs of wood

Shalom Eran,

You could try making a mould in the shape of the table top, then place the timber discs in the bottom and pour a clear epoxy/casting resin over it, them polish the surface after it's set. Something like this: https://www.youtube.com/watch?v=-37FeNedGd0

If you want extra strength, you can screw small metal plates between the discs.

Ensure the disks are suitably thick.
Cut each disk in half.
Route out the inside of each disk so that you can fit a 3mm thick steel plate and a steel bar inside each one.
Arrange all the disks into a suitably pleasing pattern, ensuring about 30-40mm contact area where they touch.
Using a 6mm thick flat steel bar, connect all the disks up, hiding the bar where it passes from one disk to another in the contact areas between each disk.
Weld bar and plate up, glue into disks, glue the backs on all the disks back into place.
Done!

Originally Posted by elanjacobs

Shalom Eran,

You could try making a mould in the shape of the table top, then place the timber discs in the bottom and pour a clear epoxy/casting resin over it, them polish the surface after it's set. Something like this: https://www.youtube.com/watch?v=-37FeNedGd0

If you want extra strength, you can screw small metal plates between the discs.

Isn't the epoxy just a filler? Is it strong enough?
As far as I know using this had to be done with really shallow layers (1/4 inch). In order to fill gaps between 3cm thick timber discs, I will need to use around 5 layers... no? isn't the time between layers should be around a week or so? 5 weeks for just this part seems a lot!

Do you have a suggestion on how to use the metal plates?

Thanks and Shalom

Originally Posted by Master Splinter

Ensure the disks are suitably thick.
Cut each disk in half.
Route out the inside of each disk so that you can fit a 3mm thick steel plate and a steel bar inside each one.
Arrange all the disks into a suitably pleasing pattern, ensuring about 30-40mm contact area where they touch.
Using a 6mm thick flat steel bar, connect all the disks up, hiding the bar where it passes from one disk to another in the contact areas between each disk.
Weld bar and plate up, glue into disks, glue the backs on all the disks back into place.
Done!

I didn't really get what you're saying.
Why should I cut them in half? You think I should leave only the bark and than some?
In order to ensure 30-40 mm contact area between two 'circles' I need to cut the edges too, and than lose the natural form of the timber, no?

My thoughts would be to make it using a combo of the above. I'm assuming the circles diameter are large, like 200mm, not slides little branches.

First, they need to be a reasonable thickness. Thin slices of timber are very weak and can snapped like biscuits. Perhaps 20mm minimum, but I'd do atleast 35mm or more.

Next, I'd arrange the slices in the final layout, then slightly flatten each side where they touch. Use a disk sander or hand held belt sander (carefully!). Two circles touching leaves little connecting surface, but take only a small edge off and you can get a flat 2cm touching.... Adjust to suit the aesthetic.

Draw a 15cm line between each of the touching pieces with a ruler. This line is where I'd drill a 12mm wide hole about 10cm deep. Into this hole I'd insert a metal rod.... Rebar from concreting would be perfect (it's available in many sizes, drill hole accordingly. I thought rebar as it has a textured surface). I'm thinking it wouldn't be a press-fit, but a snug one (reason soon)

Lay it all out in the final form. Mix up a batch of epoxy and pour it down the drilled holes. Insert rebar. You are looking to get squeezout.... Flow the squeeze out back into the container, but dont fiddle with it, you want those holes flooded with epoxy. Assemble table on flat surface lined completely with grease proof baking paper (it won't stick)

Leave for complete drying, then sand/flatten with the belt sander or other magic (such as a router mounted in a flattening jig).

Lastly, as pointed out, make up a scaffolding to surround your table (like a giant cake tin!) and flood fill with epoxy. Overfill it a bit and work that epoxy into every gap, nook and cranny. When it dries it will be very hard. Sand flat, sand smooth, fine sand then polish.

Easy!

I understand you are after a transparent look but I reckon too much filler on any furniture, even if it is transparent, looks very, very ordinary.
Most people also underestimate the mount of filler required to do these sorts of filling jobs.
If you use epoxy it will cost a heap to fill all those holes.

I think it might look better if the gaps were filed with a contrasting timber cut out to a close (nut not exact fit) with a bandsaw.

Then you could glue the whole lot together like jigsaw puzzle using epoxy onto a cheap hidden base of something like ply.
It will will still require a fair bit of of epoxy to do this nut nowhere near as much as filling all those holes.

If you are determined to go with the transparent look and don't care about the cost of epoxy they you could just epoxy thinner slices of the rounds onto a thickish sheet of safety glass?
It will be plenty strong enough and adding the epoxy and the wood will just make it stronger.

Originally Posted by ueran

Why should I cut them in half? You think I should leave only the bark and than some?
You want to hide the supports - so hide them inside the disks...your disk is (say) 300mm diameter, and 40mm thick...cut it so you end up with 2x300x20mm thick disks, which you then hollow out to create space to hide the steel plates and steel bars that will do all the support work, and glue the disks back together (giving you back your original 300x40mm disk) when the supports are done.
In order to ensure 30-40 mm contact area between two 'circles' I need to cut the edges too, and than lose the natural form of the timber, no?
Unless your tree segments are machined to be perfect circles, the areas where they touch will no doubt have a larger contact area, which, with a bit of creative fiddling, can be expanded further to hide the supporting steel. The actual amount of contact will of course depend on how big the top is - if it's just tiny (say 500 diameter) with a single center leg you could get away with using maybe 20x6mm steel as your structure; if it's a bigger - 1200mm with four legs - you might want to use a 40x6mm bar.

If you use an approach such as epoxy to bond all the disks together, remember that your timber is oriented in the worst possible way to take loads so you'd want to avoid too great a span.

...

Just a note of caution before you go ahead. Have you considered how the disks will behave. Rounds cut at only 3cm are likely to warp, depends upon timber species and how they are dried but generally once they start bending there not much you can do to stop it. Then they will probably split radially as they dry. Perhaps even a whole segment will pop out. Think of a pie with one slice taken out.

Then you have the problem that they have virtually no inherant strength across their width - certainly not enough for furniture. This is because you only have 3cm of long grain. Stick a fitting or metal bar in them and you hace even less. It will only work if all the strength is built into whatever the surrounding structure - which I dont think is the look you are after.

Google 'end grain veneers' or 'veneer oysters' to see how this was done in the past. I like this one http://scottbrogangroup.com/products-detail.php?id=634

Welcome to the forum Eran.