01-28-2011 04:42 PM
Hi. I just finished a breadbox of red oak. We like boiled linseed oil, and I plan to use that. Should I use a grain filler first, if so what is a brand name? Can you use boiled linseed on top of a grain filler? Can I use a polyurathane over the linseed, and is there any food safty problem using this sequence? Thanks for listening to all my ?`s-Jim
01-29-2011 03:30 AM - edited 01-29-2011 03:34 AM
……to the WOOD Magazine Forums, particularly to the Finishing & Refinishing Forum. I hope you will visit often. You will find a number of accomplished woodworkers and finishers here who stand ready to assist you with your finishing and refinishing questions.
I would suggest that you go very easy with the BLO on red oak. Not only is oak very coarse textured, but the cell structure is unique in that there are no blocking structures within the vessel elements. The cell structure of red oak can be compared to a bundle of open soda straws running the length of the tree. As a result, when you apply a slow curing finish like BLO, the oil runs into the “straws” where, kept from contact with oxygen in the air, it does not cure. As a result the BLO will continue to bleed from the surface for many hours (depending on how much oil is applied).
I would also take every precaution to avoid the possibility of any of the BLO getting to the interior of the breadbox. Oil inside the box will produce an odor that will permeate any bread stored within and will last for a very long time. Returning to the issue of the cell structure of red oak and the bleeding of the oil, it is possible for the oil to bleed completely through the red oak if an excessive amount is applied. The thinner you have milled the lumber the more likely this bleed trhough becomes.
Can BLO be applied over paste wood-filler? Yes, if the oil is allow to cure. (Opinion: Paste wood-filler on a bread box is a lot of effort with very little return.)
Can I use polyoneverythane over linseed (I presume again BLO and not raw linseed oil)? Again, yes; but, if you are going to use varnish on the breadbox why the BLO first, and why poly when there is absolutely no issue of abrasion resistance?
Is there any food safety problem using this sequence? All finishes, when fully cured are “food safe”. Returning to my first point, it will be the objectionable odor and unpleasant taste that results from any oil finish that reaches the inside of the box permeating the bread that will be the problem.
Given your stated intention to fill the grain I presume you want to achieve at lease a semi-gloss sheen. If so, you may want to consider shellac to finish your breadbox. It dries quickly and produces a warm, natural finish on red oak. If you want to fill the grain apply a “barrier coat”, perhaps from an aerosol, to make the excess filler easier to remove. When the filler is dry apply another coat or two, again from an aerosol. The shellac will accentuate the grain structure and will be completely odor free. It could even be applied to the inside of the box without problems.
For added contrast between the earlywood and the latewood you could use tinted paste wood-filler to fill the grain. Just be sure to remove all of the excess filler that is not in the open pores to avoid getting a “muddy look” in your finish…