I'm just about to start making a set of shelves for my CD/DVD colection. I'll be using pine and will finish it by staining and varnish. The question is do I need to use 'knotting' to seal the knots? I suspect not as the varnish/polyurethanne shopuld be sufficient to prevent bleed through.
On the off chance I should seal the knots should I do this before or after staining?
I would - for the sake of a few seconds work why take the risk? I've certainly seen varnished timber trashed by bleeding knots.
Before - and make sure it's transparent knotting fluid, as it often isn't, and would otherwise show through the varnish and looks horrible (as it does on my bannisters, courtesy of the previous owner. One day....)
David
My first purchase from a timber yard (a very long time ago) was wood to make some shelving. They supplied parana pine which is, substantially, knot-free. A jolly effective answer to your problem.
(Environmental issues were not in vogue in those days...)
Interesting - I wonder whether temperature is a key component to this. I replaced all the skirting and the facings in a hallway recently - 5 doors and 10m length so there is a fair length of stained and varnished pine and not one knot has bled. I never thought of stopping as I've never ever had any problems with white/red pine - it would have been a major task for that amount of wood. Temperature? - as a hallway it is run quite cool, 16C. Oh, yes and there's French pine shelving along the length too, and that's remained clean.
The only place I've ever had bleed is in a small area of douglas fir that my kitchen units are made of and that's t&g panelling above the stove - so is it the douglas fir or the temperature ?
I'm not saying, don't do it, but with all the timber facing that I've got in this house and only the smallest area of trouble, I for one will continue not bothering.
Rob
Luck of the draw with softwood. IME one stick in a pile will bleed all over the place, and the rest will be fine. Kilning can cause the resin to gush out of the end grain, so heat makes a big difference. Knotting is alcohol soluble (usually shellac) so clear French polish would probably be the thing to look for. Pine resin will bleed through most other finishes
I've made a fair amount of furniture out of cheap pine in the past & it never occurred to me to use knotting. I've varnished it, used Danish oil & wax and not had any problems - maybe I was just lucky?
Varnish will usually stop it..it's paint that is the issue.
AIUI it bleeds through any sealer that's soluble in white spirit, but not those soluble in alcohol.
Thanks for all the advice. I guess sealing the knots is the prudent course. On that subject if the knots are sealed before staining I would expect the stain not to 'penetrate' the sealed area which may prove to be tricky. Perhaps sealing after staining may be the best course as I assume stain will not penetrate the knots anyway.
It's all pretty academic for a clear finish because the resin is the same colour as the wood. As NP points out, it's when it bleeds through white paint you have a problem.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.