BLO vs Tung Oil

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Jmaxcy

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I'm sure this has been discussed here before but curious anyone's thoughts on BLO versus tung oil? I have both, I got tung oil because I noticed BLO was making some of my woods amber colored which I didn't love. Are there certain woods that work better with one versus the other? Just curious everyone's thoughts on this. Thanks!
 
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leehljp

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So far as "working" it is up to each individual and the brand of BLO or tung oil.

But, as to the amber color - it works well (IMO) with blond, tan and brown woods, but not with white wood or bright red woods. These are just my personal preferences as other may like it. Amber can turn some white wood into an ivory color and in a few cases it may be desirable. I have some bright maroonish-red bloodwood and the amber colored oils makes it a bit burnt orange-like in color, which I don't particularly like.
 

jttheclockman

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OIL is the key word and either one will turn wood yellow or tint it. Now others will jump in here and ask is it true tung oil you are using?? There is a difference from what manufacturer calls tung oil as opposed to another. So my question is what are you using the oil for?? Not enough info supplied.
 

Jmaxcy

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OIL is the key word and either one will turn wood yellow or tint it. Now others will jump in here and ask is it true tung oil you are using?? There is a difference from what manufacturer calls tung oil as opposed to another. So my question is what are you using the oil for?? Not enough info supplied.
Thank you. I typically use it after I sand to 600 to bring out the grain. Let it cure for 24 hours then finish with my typical CA finish. So really just to bring out the grain, not as a true finish.
 

jttheclockman

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Thank you. I typically use it after I sand to 600 to bring out the grain. Let it cure for 24 hours then finish with my typical CA finish. So really just to bring out the grain, not as a true finish.
Then all oils will do that and not much difference between either of them. One is more waterproof than the other.

https://www.popularwoodworking.com/flexner-on-finishing-blog/comparing-linseed-oil-and-tung-oil/#:~:text=The primary differences between linseed oil and tung,to two or three days for tung oil.
 
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leehljp

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I do occasionally use BLO or even a different amber oil to accentuate the grain on tan, beige, blond, brown grains. I don't use it for the purpose of curing the CA. For myself, I am not a big fan of additives for quick/instant curing. Patience is my "additive". ;)
 

monophoto

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To John's point - its important to understand exactly what you are using. You mentioned Watco - I believe that Watco Tung Oil (WAT-09) is more correctly described as a 'long-oil alkyd varnish' with a Tung oil base, and the label on the can clearly says 'Tung Oil Finish".

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To clarify - pure oils are just that - oils that are expressed from the seeds of plants - flax in the case of BLO, the Tung tree in the case of Tung Oil, walnuts in the case of walnut oil, etc. Those are the three most common 'drying oils' - that is, oils that will polymerize (combine with oxygen in the air) to create a plastic-like finish. Oils penetrate into the fibers of wood such that the polymerized oil finish is actually within the fibers of the wood. Both linseed oil and Tung oil polymerize naturally, although the polymerization process takes much longer with raw linseed oil. The product sold as BLO is treated with additives to make it cure faster. The main difference between linseed oil and Tung oil is that polymerized linseed oil is more amber in color than polymerized Tung oil, while polymerized Tung oil is more water resistant than polymerized linseed oil. Walnut oil is less amber than Tung oil but not as water resistant. A cured oil finish leaves the wood feeling like sanded wood, and will have very low lustre. The truly pure version of these oils are all 'food safe', but that is not the case if metallic dryers are added to make them cure faster (as is the case with BLO). That said, some people may still have allergic reactions to the original nut or seed from which the oil was expressed.

Any of these oils can be combined with a solvent such as turpentine or mineral spirits to make a 'Danish oil'. The Watco product uses 'Stoddard Solvent' which is a less-flamable form of mineral spirits. The main advantage of Danish oils is that because they are thinned with a solvent, they penetrate better (further) into wood fibers. A cured Danish oil finish will have slightly more lustre than a pure oil finish.

When varnish solids are added to Danish oil, the result is a 'long oil varnish', or 'wiping varnish' The varnish solids can be alkyds (as in the Watco product) or polyurethane (as in Minwax WOP). While varnishes can penetrate into the wood fibers so some degree (less than with Danish oils), the main claim to fame is that they cure to form a skin over the outside of the wood. As a result, a varnish finish will be harder than a pure oil or Danish oil finish, and can take on various degrees of sheen from matt all the way to very glossy.

I keep both BLO and pure Tung oil in my shop. I make a utility finish (for tool handles etc) by thinning ordinary paste wax with turpentine, and then blending in some BLO. I make a fancy finish for bottle stoppers, bowls, and boxes by blending pure Tung oil, turpentine, and a commercial spar (Tung oil and alkyd) varnish. And I make a similar finish for items such as walking canes that require a finish that can withstand more physical abuse by combining pure Tung oil, turpentine, and a Tung-oil-based polyurethane varnish. And from time-to-time, I also use a Danish oil made from either BLO or Tung oil as a finish - for example, its easier to soak some Danish oil into an item with a captive ring than it is to try to apply a wiping varnish on that loose ring. And for pens, I make a friction polish by combining pure Tung oil, lacquer, and lacquer thinner.
 

penicillin

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I like and use oil finishes for many woodworking projects, but not much on pens. Here are a few comments:

There are two types of oils for finishing wood:

Non-drying oils like mineral oil. Mineral oil (or mineral oil with additives such as beeswax or carnauba wax and sometimes orange or lemon oils). These are commonly used on cutting boards and sometimes food bowls. Mineral oil finishes are colorless and do not "amber" the wood. They are absorbed by the wood and provide some moisture resistance for products like cutting boards. Mineral oil finishes must be renewed periodically. Mineral oil finishes are never used on pens.

Drying oils like tung oil, linseed oil, and walnut oil. Drying oils are the type that some people use to finish pens.
-> The rest of this post refers to drying oils.

All drying oils amber the wood. They all "pop" the grain and give the wood that warm, amber look. Walnut oil is somewhat lighter, tung oil is in the middle, and linseed oil is somewhat darker. Note the word "somewhat." They all amber the wood and look similar.

As noted above, many oil finishes are not 100% pure oil. WATCO Tung Oil Finish is not 100% pure tung oil. It has various solvents and additives. You can buy 100% pure tung oil from various sources, and they should all be the same. If it says anything else, like "Tung Oil Finish", then it is NOT 100% pure tung oil.

Oil finishes cure at different rates. When oil is applied to wood, it soaks into the surface of the wood. As it dries/cures, it "polymerizes" (hardens). Different oils have different curing times. 100% pure tung oil can take days, up to a week or longer.

"Boiled" linseed oil has chemical additives, including metallic driers, so that it cures faster. It isn't actually "boiled" - that's an archaic term. Boiled linseed oil is not food safe!

You can also buy food-safe linseed oil finishing products that have been specially heat-treated to speed up the curing process. They tend to be "boutique" oil finishes, such as Odie's Oil and Tried and True. Because of the special heat treatment, they cure in about 24-48 hours.

Some people try raw pure linseed oil from the grocery store, commonly used for cooking. That can work, but the cure time is very long, and the oil may go rancid in the process. If you try it, keep the oil in the refrigerator to slow it from going rancid, and experiment on scrap wood first. (I use raw linseed oil to season new cast iron cookware after I grind it smooth with an abrasive wheel.)
 

jttheclockman

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Well a couple members took this much further than I did but you got some info and hope it helps to make your mind up as to what to use. To me popping grain is best done with BLO. Danish oil is basically the same but has poly in it and is used more as a top coat/ grain popping oil. If you are CA user than that is not needed. You do not want to pop grain on maples or holly or aspen type woods. You want the natural beauty. Good luck.
 

penicillin

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P.S. When using any oil drying oil finish whether pure or not, be sure you properly dispose of your oily rags.

-> Oily rags can and will catch fire. They can burn down your home or your shop!

Some people put them in a water-filled jar. Others take them outside and allow them to dry safely, disposing of them when they are hard and dry.

I used to put rags on a paving stone on the concrete, with the corner of the rag held down by a rock. These days, I use a water-filled jar.
 

jttheclockman

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P.S. When using any oil drying oil finish whether pure or not, be sure you properly dispose of your oily rags.

-> Oily rags can and will catch fire. They can burn down your home or your shop!

Some people put them in a water-filled jar. Others take them outside and allow them to dry safely, disposing of them when they are hard and dry.

I used to put rags on a paving stone on the concrete, with the corner of the rag held down by a rock. These days, I use a water-filled jar.
Always a good reminder.
 

donstephan

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My understanding of danish oil is that it contains varying proportions of three ingredients: oil, thinner, and a varnish. If that is true, combining oil and thinner does not make danish oil, just a thinned oil.
 

jttheclockman

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My understanding of danish oil is that it contains varying proportions of three ingredients: oil, thinner, and a varnish. If that is true, combining oil and thinner does not make danish oil, just a thinned oil.
Danish oil is a combination of BLO and poly with driers added.
 
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