While spending some time on the internet, I came across several discussions about BLO. The pros and cons. They addressed the issue of solvents and chemical driers added to make the BLO and how it has a negative effect on wooden surfaces and skin...darkening, mold, dangerous to skin over time, etc...so I searched and found a few 100% pure, no chemicals or solvent BLO's, but they were expensive! So I was wondering...what do you guys use? Regular big box store brands, make your own? or is it just talk and is really a non-issue....???
Boiled Linseed Oil
- Thread starter macchips4
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Cherrybrook
Member
I never use it. If you decide to use 100% pure, it will take forever to dry.
Cherrybrook
Member
It is my understanding that "boiled" linseed oil isn't actually boiled. It just means that they added driers/chemicals to increase the dry time even though it still may take 24 hours for it to "dry". Raw linseed oil will take weeks to dry. If you want to do an "oil" finish, there are better products on the market to use instead of boiled linseed oil. I only use an oil finish if my client requests it and that's been one client since 1998.
Mark Maleski
Administrator
I'll confess that when I used BLO (which isn't that often), I usually use the regular stuff from the big box store and have at it. But Steve Voigt has been publishing some articles recently that have me thinking about a different way. His article in the most recent Mortise & Tenon mag makes a compelling argument that the stuff from the big box is low quality oil, made by mashing and squeezing every last bit of oil from the flax seed. He has a recent blog post (http://blackdogswoodshop.blogspot.com/2022/09/refining-oil-making-varnish.html) that describes how to wash the high quality (and pure, non-"boiled") linseed oils to refine it; this has two effects: it makes it faster to dry (surely not as fast as BLO though) and less likely to darken over time. I haven't given any of this a try, but Steve surely has, and his findings are meaningful to me.
As always, hobbyists like me are better able to go down these rabbit holes; if I were building furniture for a living I doubt I could find a customer willing the pay the extra amounts needed to explore this area.
As always, hobbyists like me are better able to go down these rabbit holes; if I were building furniture for a living I doubt I could find a customer willing the pay the extra amounts needed to explore this area.
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Mark Maleski
Administrator
Originally, I believe it was truly boiled - the heavy metal driers are a more recent innovation to speed the drying. I believe Tried and True "original" oil is polymerized through heating and, though slower to dry than modern BLO, does not take weeks. I'd probably use that myself, rather than the pure linseed oil.
I have heard a great deal of commentary re: BLO and it's generally from folks with minimal experience in actually using it or repeating quotes from others. I started my professional career as a woodworker/finisher at the Kittinger furniture company in Buuffalo NY in the early 70s. Kittinger reproduced the furniture seen at Colonial Williamsburg and also Historic Newport as well as a great deal of furniture at the White House. We used BLO as a step in virtually everything that wasn't a painted surface. The key was we THINNED it, as best as I remember, at least 50% with lacquer thinner. Many thousands of pieces had this step with none of the issues described by previous writers I have a 50 year old piece from there that hasn't darkened and is as good as the day it was made. I continued to use this step on premium pieces over the past nearly 50 years with no ill effects. As with anything in the industry, there is no right or wrong, just what works for you!
Cherrybrook
Member
So you basically use it as a wash coat?
No, I never looked at it as a "coat" at all. After your water based aniline stain is applied, we would remove
parts of the stain to highlight the natural wood grain with fine (320 grit) paper which also creates a more interesting color, not just (brown) and then apply the thinned BLO. I in fact use it yesterday and preferred a 2-1 ratio of thinner. VMP Naptha can also be used, as both solvents have a fast "flash point" meaning the solvents evaporate quickly. The BLO in this case seems to bring out the depth of color and by using the thinned mixture, it enables you to proceed with the next step which would then be the wash coat. After the wash coat you are able to add more thinned layers of color and paste wood filler. Clearly this isn't the format to describe the many steps we used, but trying to clarify our use of BLO! To be sure I can see where using straight, uncut BLO, would cause problems in subsequent steps as oil repels shellac or water based finishes and would lead to a problem called "fish eyes". BTW, the thinned BLO is able to penetrate the wood more deeply just as your initial coats of thinned shellac wash coats do the same.
