Timber Table Top Gaps

[hap97]

Restoring an old tasmanian oak timber round table (1200mm dia). The top boards have a 3mm gap between them and I wish to fill them. One option is a commercial wood filler, but this will tend to crack in time with the timber movements.
I have seen a table gap filled with a black compound and the finished table looked quite unique.
Any ideas on what could be used?
How does PVA and wood dust work? Will the PVA be hard enough?
Thanks

[Chipman]

Depends on what you want to do... Pictures are very helpful!

Generally a filler looks exactly like that... a filler. I prefer a thin strip of wood or veneer and the very minimum of filler. Yes you can mix sawdust with some glues or commercial fillers or even varnish. Others people can advise you on this. None the less, their are some really good comercial fillers available and you can usually tint them to the right colour.

Is it a clean gap... ie straight sides or a split with ragged edges?
Are you trying to keep the current finish or are you planning on sanding it back and refinishing it?


If it is a clean straight sided gap, cut a thin strip of wood and glue it in (may need to do it from both sides)

You could cut the gap to an even width and push the two pieces together snd reglue it (could even use biscuits) or if you don't want to take the planks off the table, you could once again use a thin wooden strip.

I have recently repaired a silky oak chest with a split join on top with veneer and am currently working on a round Red cedar table that belonged to my Great great granparents. (really only firewood but I am giving it my best shot)

Chipman

[BarFly]

Hi your photo looks like the splits are straight along the joints, I would be inclined to take the top off and re-plane the joints and then glue it up, this would help you to get the best finish and you will have no trouble with filler shrinking or splitting. Alternatively builders bog with some pigment colour will work well.

[Claw Hama]

I think BarFly hit the nail on the head with, lift the top off, plane the joints with a nice sharp jointer plane, at least a 6 and then reset the top back on. Usually only a dozen clips/screws at best holding a top on those. I had one almost the same except it was extendable (My X now has it)

[hap97]

Thanks for the suggestions.
I agree that planing and re-gluing the joints is the best option, however in this case the top was originally pocket screwed and later nailed around the edges. The top is very well fastened to the frame.
I have already screwed a batten underneath to support the centre of the table panels.
I am interested in the options for filling the gaps.
Option 1: Router groove along joints and glue in 3mm veneer.
Option 2: Fill with coloured builders bog, how does black go?
Option 3: Fill with commercial filler, I like Cabots wood filler or TimberMate filler, any comments on these?
hap97

[mic-d]

It sounds like the table was made without accounting for wood movement, which might well be why it has gaps, if the timber shrunk after it was made. If you now fill those gaps with something inflexible, like veneer or timber putty and do not account for timber movement, you run the risk of the table top buckling when the humidity increases. Your best bet would be to route out the gaps using a straight edge and fill with a flexible filler like black Sikaflex or one of the deck caulking compounds from a chandlery. You woouldn't need to route out the full depth of the top, just enough to give a good depth of filler - say 5-10mm.

Cheers
Michael

[hap97]

The black Sikaflex was the material I had in mind in the initial post, as I know the wood will move and the joints will crack again. The table is over 1oo years old.
Lets talk Sikaflex. I bought a tube to try it out (Sikaflex-11FC) and it cures fast and is sandable and very tough but dries soft to the touch. Has anybody actually used it for table joints?
The table will be finished with Wattyl Teak Stain
Is Sikaflex suitable for old cypress pine flooring?

[mic-d]

I've used it for decking not table tops, it is paintable and will stick to anything - even cypress.

Cheers
Michael

[Chipman]

Hi Hap97,

Now I have finally seen the picture of your table, I would strongly recommend you take the boards of, joint then to get the edges straight and glue them together (suggest biscuits or splines)

Then when you reattach the top, make sure you allow for movement. Otherwise it will break apart again.

I would suggest that if you just use a filler, it will crack out too. As for a flexible filler... I can't see it looking really good doing it that way. Pardon the pun...it is only a stop gap measure.

The method I first suggested, (veneer) only works if the joints are not moving, clearly this is not the case with yours.

I would have to agree with barfly and claw hama

Too many choices!

Regards,

Chipman

[weisyboy]

i would rout 3mm groves along the cracks then rout matching groves at 90* to the others and fill with tinted resin or glue in veneer. would give a nige pattern and fix the pronblem.

[jerryc]

Recently I had to restore a cedar desk circa 1900, where the top had divided into it's three planks because the glue had failed and each plank had cupped slightly. Claw Hama and Barfly are correct in their advice. My only disagreement with Chipman is in the use of biscuits or other means of "registering". Clean matching edges and a rubbed joint properly clamped are all that is needed.

Make sure you have enough clamps so you can equalise clamping above and below the table and that you also place cauls above and below the table surface. To stop the cauls sticking to the wood I use packing tape to cover the cauls but in the past I have used newspaper as a glue barrier. Personally I would not rout away any of the wood or introduce flexible adhesives.

Jerry

War does not decide who is right. War only decides who is left.

[Clinton1]

I would not bog it up, for the reason you suggest and it also looks crap.

Sanding dust and PVA is basically the same as bog, good in some places, but not anywhere big and visibile.

Sikaflex... not my preference... won't it just look like black bog stuffed in the gaps?

Preferably:
Undo the pocket screws,
Gently lever the table top up to create a small gap between the underside of the top and the supporting frame... use small wedges or a 'restorers bar'.
Slip in a hacksaw blade and cut off the nails.
Remove nails, fill the nail holes (with your pva/sawdust! )
Joint the top boards and reglue.
Refinish the top while it is off the frame, seal the whole thing to limit moisture exchange with the air so you limit wood movement in the future.

[munruben]

I agree with Clinton anything you fill the gaps with is going to look exactly what it is...Bog or filler. If you are serious about restoring this piece then the only way to do a decent job is to remove the top and do what the other guys suggested. A piece of craftsmanship that is a hundred years old plus deserves better treatment than filler or Bog. It will take away from its originality and totally spoil it in my opinion. Take the extra time and effort to do the job properly. Its worth it.
That table will come up beautifully if you do it right.