Filling knots prior to finishing

[The Bear]

As per my other thread on this forum, I have some oak shelves i will be finishing with a shellac sanding sealer and then clear wax. A couple of the planks have some knots with fairly large cracks in them. Now i'm not at all bothered by how this looks, as they will be fairly well hidden when in place.

My question is what should I fill the cracks with before I apply the wax (and is this before or after the shellac)?

Mark

 

[laird]

PVA and sawdust (build it up and sand flat when set), before the shellac, would be one way.
Coloured hot wax with a bit of grain reproduction, again before the shellac, would be a better way if the cracks are visible.
Or really go to town, cut an area out clear of the crack and make a matching grain patch from another piece of timber. Glue in place, smooth of and shellac.

 

[Chems]

I used 2 part epoxy to fill a knot like that in oak, it was clear so took on the colour of what was behind it. Then applied a coat of Bison Wax.

 

[OPJ]

I'll second the recommendation for the use of a epoxy. I did this myself recently on a walnut-veneered top and also on a chair seat:

I actually used Araldite, which is affordable for small jobs like this, compared with the cost of the West Systems Epoxy range, for example! :shock:

To colour it, I bought a few 50g sample bags of "cement dye" off eBay for only £1 each! 8) There's enough in one of these bags to last you a fair while! :wink:

I'd always recommend applying at least one coat of finish (two is better) before attempting to fill something. The timber will always darken once you put the finish on and any coating will only help to prevent your filler from seeping in to the pores of the surrounding grain. I've since put several coats of oil over both pieces and the epoxy is holding in very well.

 

[Chems]

I actually used Araldite, which is affordable for small jobs like this, compared with the cost of the West Systems Epoxy range, for example! :shock:

Same here, just have to be careful to fully mix it or else it just turns into a gel and not a solid.

 

[The Bear]

Thanks guys, how well does the epoxy sand?

Mark