Questions on Tung & BLO

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Firefyter-emt

Firefyter-emt

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Hello all, I am very new to pen turning and my finish has all been Shelacwax so far. I have used BLO many times to pop the grain of wood, but then you have that long wait for it to dry. What is the effect on wood with BLO?? I mean it is a lot thinner, how fast does it dry out? What finishes would you put over a blank that has been given a coat of BLO? Next, one of my favorite finishes, Tung oil.. I am sure someone has used this on a pen.. How good is it as a pen finish, what procedure would you recommend if I used the Tung.

I am not trying the CA finish yet, Maybe later on, but not yet.
I have a redheart blank glued up drying and was thinking about the BLO, but I would hate to wait a week before I finish it.
Thanks guys!
 
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I have never waited for the BLO to dry on a lathe. On of the advantages is you can dry it really quick by spinning the blank really fast while wiping with a rag. Get the blank pretty warm and it will dry. Not a good thing to do with crack prone wood like ebony. I've done this on pens and bowls. Can't help ya with the tung oil.
 
BLO is a reactive finish-- it never "dries", it "cures" by reacting with oxygen. Just as Jim said, heat it up. If you have an air compressor, blast it with the air chuck and about 50-80 pounds of air to get the O2 going and it will cure fast enough.


Tung oil is a different animal altogether. The question is, is true tung oil that you have--- which I'm willing to bet a pen blank it ain't true tung oil nor will it actually have any tung oil in it.

What you have is likely an oil-varnish blend that is labeled "tung oil" which will cure faster than true tung oil, but still PAINFULLY slow compared to lacquer and CA. Not much different than "Watco Danish Oil". Both are mixes of linseed oil and/or soya oil, and various varnish resins (usually polyurethane or alkyd resin). Basically they are thinned polyurethane with some gilsonite (aka, fiber-free roofing tar) added to give them that dark color many people love. Great finish for decorative shelf-sitting items (for those that like that look).

True tung oil is very slow drying, so I've heard, as I've never used (nor even seen) it before. It is a rare animal in most shops and stores.


If you want to see some color pop, try BLO under Deft cellulose lacquer, available in spray cans. Lots of info on this site on using lacquer as a finish.
 
Oh I dobut it is pure at all.. I use Flombsby (SP?? Tung oil. I use it here and there, I have maybe 6 coats on my workbench [:D]

Question with the speayed lacquer, do you guys spray it on the lathe?? If not what method do you use to hold the pen blanks to spray. Also, how well does the lacquer hold up? I don't really want to be spraying clear all over my lathe when I get the old girl all set on the new stand. (see photo below)

You see, the old girl is 67 years old and just got restored... [:)]
Gonna be doing some light duty turning in her old age, kinda like retirement.. This one is getting set up soley for pens and small things like that. I will use my larger lathe for other turning.

lathe-a31.jpg
 
You are correct that Linseed and Tung Oils are used to "pop" the grain in furniture. This works because of the different amounts of the oil that is absorbed into flat, side, and end grain orientations on the surface.

The difference in oil absorbtion is required for furniture because it is not sanded to anything finer than 280 or 320 grits. Sanding to finer grits closes the wood to penetration, but furniture folks say they prefer to leave the grain "open" for better penetration of dyes and stains.

The same grain "pop" effect can be achieved with other finishes if the wood is sanded and polished to 2000-grit or finer, such as the equivalent 12,000 Micro-Mesh. Lacquer is particularly good for this.

For finishing a pen, we are using the oils strictly as a lubricant to allow us to apply more volatile finishes such as lacquer, shellac, or CA-glue. The effects of these oils on the finish is that, in simple terms, any oil that gets into a lacquer or shellac will act as a plasticiser. That makes the finish softer than if the oil had not been there. We could use a "non-drying" oil such as Mineral Oil, Olive Oil, or Motor Oil as the lubricant, but these will stay as a liquid form that is captured in the finish and have a greater plasticising effect than those oils that we consider as "drying" oils.

For a CA finish, the BLO acts as a mild accelerator. We use a thick CA to give us more working time and it will spread out into a thicker film, and then we apply Boiled Linseed Oil over it to keep the applicator from sticking while accelerating the curing of the CA glue. The BLO is not absorbed into the CA glue. therefore it has no effec on its hardness. This can also be done with a thin CA glue, but we would have to work faster and apply miore coats.

If this isn't confusing enough, I will try again.
 
No, that helped quite a bit.. I have to look into the CA finish, but it is interesting about the oil not mixing with the CA. I take it that is will stay on the top and the CA will cure allowing you to wipe it off later. (any quick good links to the CA procdure?)

BTW, Your site is very nicely laid out. I had it bookmarked from before when I was doing some research into pen turning. One question, you use polyurethane glue which I believe is what "gorilla glue" is (although I can not find a positive on it) What about using that for blanks? Just wondering, I have been using the 2-part epoxy which is a pain to mix when needed and dry time is not a huge deal to me.
 
I usually apply the spray lacquer on the lathe while the pen is turning then turn the lathe off immediately after spraying. Just lateky since I dug up an extra mandrel I remove the tube/mandrel assembly and spray it while holding it vertically. The I stand the assembly in a corner of the cabinet to dry.
 
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