Have been lurking for some time checking out all the great work, and wonderful people. When I can get some pictures together I will try to post.
I am starting to try to turn again, and looking for some advice. I recently turned a couple of cherry bowls, sanded to 600, finished with BLO. I decided it was time to bite the bullet and purchase the beal system.
The directions say not to use with linseed oil, but I know others have.....
Does anybody have any input on the right/wrong way to use a beal system, and what finishes are safe and why?
This time I searched I found lots of great info in the archives on the beal system, but still can't find any hard evidence on why/why not the beal should be used on a BLO finish.
The closest I found was BLO is a soft finish, but yet it could be used.....
>I can't come up with any reason why a BLO finish would be any more problematic to buff than a PTO finish. Both will take a while to harden, and you would want to wait until they were thorougly hardened before buffing (well you should, anyway). I can't comment from experience because I never use BLO by itelf, although I have used and buffed Watco that I understand has a high percentage of BLO as well as some resins.
The key here is that both oil finishes are auto-oxidative which leads to polymerization. They don't so much dry (though even pro's often use this term), as just cure and harden into a slightly rubbery solid. Thus it is important to put them on thinned enough to let them maximally penetrate into the wood, and then give them time to cure, which is often days or weeks. The thinner the film applied, the less the surface of the film will block the underlying oil from the oxygen needed for polymerization, and so the shorter the drying time for that coat.
Anyway, I'm getting far afield. The point has been that BLO and PTO are very similar in most characteristics and as long as the finish has been allowed to fully cure, I am unaware of why buffing would cause problems with either.
For more on power buffing, it alternatives, and equipment choices go the link below and get by pdf of the article I did for More Woodturning on Power Buffing
>I vaguely recall reading that with the instructions for the wheels, too, but I decided to ignore it. I knew that several of my bowl gods, one of which included Mr. Grumbine, used Watco, which is a BLO derivative, with his buffs. I do as well, all of the time, but you have to make sure the product has fully cured. I wait at least two weeks from last coat to buff. You can "reactivate" uncured BLO from deep inside a bowl with the heat buffs can generate.
>Boiled Lindseed Oil, which in reality rarely is boiled anymore (it may be heated a little), but is Lindseed Oil to which chemical driers are added so as to produce some "pre-polymerization" which makes for quicker curing.
Also thanks for the great article Lyn. You mentioned thinning BLO. I assume the best way to do that would be with mineral spirits or turpentine? Would a 50/50 mixutre be adequate?
>I don't want to answer Lyn's question, so I won't, but rather add that you can also thin BLO by warming it. I have done this by boiling a pot of water and then immersing a container of BLO in the water.
You DO want to keep it away from any intense heat source or flame!
I love the smell of turpentine and always use it when it is an appropriate thinner, because it reminds me of working in the boatyard in the spring.
I have a shopmade SBS (sequenced buffing system). Without the Beal (Beall) instructions, I didn't know that BLO wouldn't work and wish you hadn't told me. I reckon BLO and DO (Danish oil) only STW (seemed to work) because I put off doing the FB (final buffing) for SL (so long). OW (Oh well), IGTK (it's good to know) that I'm CS (curing smart) instead of BL (buffing lazy) although I remain CS&F (childish, silly and foolish).
Speaking of BLO (being less organized) & PTO (power take off? parent teachers organization? whatever?): this great forum is growing rapidly with newcomers from different backgrounds. I wonder if it would benefit from its own glossary of jargon, acronyms and acrostics? MN! (maybe not) ;)
>Yep, either Mineral Spirts or Turpentine will work, though mineral spirits is cheaper and will evaporate a little faster. Both are toxic in the way that all petroleum solvents have some level of toxicity, so best to do you mixing with good ventilation.
How much you thin will depend on the absorbancy of the wood and how much of a coat you want to build. Most of the time, I use polymerized tung oil sealer, which is just PTO with lots of mineral spirits to thin it (over 50 percent). This is fine with me as for early coats I want maximal penetration, and for later coats I like faster curing of the coat, and don't mind the slow build.
I'd suggest you not worry too much about the specific ratio and take a more results oriented approach to determining the mixture best for the wood at hand. That said, I suspect a 50/50 ratio with "pure" BLO would likely be a good starting point. But again, I'm a tung oil person, so others with more experience with Linseed oid may have better adivce.
>In a crude analogy, the thinners create a swimming pool for the smaller molecules of the liquid oil to swim around in so they can link up to form the larger molecules of the solid. We refer to this linking together and subsequent evaporation of the thinner as "drying".
There is a balancing act going on. The ideal situation is when both the cross-linking and the evaporation take place at the same time. If the thinner evaporates before they can get together, we have a sludge of half cured oil on the surface of the wood. If it doesn't evaporate as the molecules of oil get together, they get tired and just lay there doing nothing, and curing can take a long time.
Ideal reaction of the oil and evaporation of the thinner occurrs within a defined temperature range. 65-70 degrees is ideal. Most finishes say right on the back of the can, "Do not use in wet or extremely cold or hot conditions." My definition of "hot" is when there is sweat dripping off the end of my nose, and "cold" as when I have to wear a jacket in the shop. Everything in between is OK.
In hot weather the the thinners evaporate too fast, and too slow in wet weather. The linking of the molecules creates heat, and if it is too cold, the heat of their linking is carried away before they can do anything.
We can improve the evaporation of the thinners in a finish that we make, by using Naptha in higher humididity because it evaporates faster, and 1K white Kerosene in the summer because it evaporates more slowly than either Mineral Spirits and Turpentine.
Adding these other thinners to a pre-mixed finish will aid penetration because it is thinner, but it will do nothing to change the evaporation of the thinners that were already in the finish. The only way we can do that is always let the wood sit overnight at 65-70 degrees after we have applied a finish.
Now that I have everybody thoroughly confused, I will shut up.
Use Naptha if you need faster evaporation because of lower shop temperatures.
Using white (1-K) Kerosene will work better in hot weather because it will evaporate slower.
Like I said I am a lurker, but view the site on a multi-daily basis. I am always surprised at how generous everbody here is with their knowledge and the amazing depth of knowledge availible.
I hope I can someday return the favor to the next generation of wood workers.......as I have a lot to learn before I spout off myself...
>Sorry Mike, I only make the snowballs, I don't throw em. A glossary wouldn't work anyway, too much for one guy to know, and for what a committee would come up with we don't need an acronym. ;)
