Best oil to treat lumber with

Curious on what you guys use to preserve lumber. Ideally it wouldn't be harmful or toxic and even better would be an oil you could press your self out of something you could grow? Any tips greatly appreciated. Thanks

I have used raw pure linseed oil on my wooden tool handles and wood raised garden beds. It is pressed from flax seed. I have no idea how much seed is needed to make an appreciable amount. It dries very slowly, depending on the dryness of the wood can take days or weeks. But it usually takes a few days to dry. You can also make glazing putty by adding it to whitening. You can also add spirits of turpentine to penetrate wood better and dry quicker. Spirits of Turpentine is extracted mainly from pine trees so it "can" be natural as well. That being said, not all natural products are entirely safe and I would not use either of these without donning rubber gloves.

Both products have been used for centuries as far as I know. Maybe someone else will chime in on the safety and health factors. I do know that they can spontaneously combust and precautions must be taken, like soaking rags or brushes in water, etc.

There's an old saying that came from boat builders and dock builders way way back in the day... If it doesn't kill animals and small children it won't work. I want to defy that if I can. Limonene, a by product of making orange juice. Basically the oil from the peels is supposed to be a safe way to keep bugs away from things and since it's an oil I wonder if that would work. Its the best thing I can come up with so far.

Could any oil be used to preserve wood since it seals moisture and possibly air (depending on the oil) out? Does flax seed oil have problems because it doesn't penetrate well? If it were to have great penetration would it be a reliable way to preserve wood.

Tung oil is another one to consider for preserving wood.

I've used linseed oil with decent results.  You can also mix it with ground up charcoal and supposedly it will last decades:
Charcoal and Linseed preservative paint
I used this recipe on some wood I build raised beds out of 10 years ago and they are still in good condition.

Tung oil is supposedly better than linseed oil, but it's MUCH more expensive.  Plus it's hard to find these days, most of the so called "Tung oil" you find in hardware stores these days has little if any actual Tung oil in it.

That is good to know thanks for the helpful answers guys

The best oil for preservation of wood depends very much on what that wood is being used for.

If you are making flutes for example, you don't want to use linseed oil on them nor do you want to use Tung oil on them.

For flutes I use a mix of bees wax and lemon oil, it penetrates and is a non irritant to the lips.  

If you are wanting to use the wood for garden borders or raised beds then you want to start with a soak in Borax dissolved into water, once that soak has dried then you will want to use a mix of oils.
I like to use a soak of 2 cups borax per 12 Liters of water and follow that with a blend of tung, orange and lemon oils (3:1:1). I brush on the oil, using three coats with overnight drying between coats.
I've had good luck with wood treated this way lasting up to 5 years in ground contact.

If you are building a deck, once again you will want to use a fungus preventative/ insect damage preventative first then follow that with a wood conditioner oil blend.
For decks and tables I like to use a borax soak  and once dried I like  to use teak oil, it will soak in nicely and can be reapplied yearly to keep the wood looking good.
Tung oil needs more coats and a long drying time to be used outdoors.

Redhawk

Boiled linseed oil is pretty good for tool handles, fast drying window putty, paint...

Lumber is different. You would have to go old school and boil a vat of linseed oil and soak the lumber to get the oil to saturate and penetrate the wood enough to become more than a surface hardener/protectant. Linseed oil eventually dries, so you may be wanting a non drying oil like mineral oil (To keep wood from splitting on cutting boards, etc...) In the 1880's gardeners used this method to treat their lumber before they used it in the construction of their greenhouses... (One of their other treatments was two-three thick coatings lead white paint, and that was cutting edge technology back then).

For posts, the trick isn't so much about treating the wood, but tamping the soil enough around a post to prevent moisture from reaching the post for a long time, and then the species of wood can be important too. (Example; In Kansas, it's pretty typical to see a barbed wire fence with posts that are made from Osage Orange. Some posts have been in the ground since the days of Billy the Kid... All because, some farmer used a tamping rod around the fence post for half a day, maybe tossing in some lime as a soil binder, and creating rammed earth around the base of the post.)

There is a farmers treatment to treat lumber that uses mineral spirits, boric acid, and radiator fluid, but I have never tried the application, I read about it online (so, you have to know it works...) I 'may' have mixed some of this mixture up once to get rid of a termite problem in a rural building I had leased, and I could probably say that it works so good that the neighbors all had to call a pest control service... and even after that process of elimination happened I 'probably' never had termites again for the few years that I was in that building.  The great thing about that particular building was that the ground water was already contaminated from years of being a fuel pipeline area, and heavy agricultural run off from feed lots, and a major pipe line was laid not too far from that particular building, and a Titian II missile base that has been decommissioned since the late 80's was also within a mile or two...  I was really surprised that anything lived around the soil in that area. -Anyway, you are supposed to heat up the mixture of coolant and boric acid in a well ventilated area and then thin it out with turp/mineral spirits... Coolant is more of an oil-like product, and the spirits are more of a saturation type of chemical, and the boric acid is the magic dust that insects do not like... I think Diatomaceous Earth is the other one.

Real old school wood preservatives for interior furniture are beeswax, heat, and turpentine. I've seen furniture from the 1100's in German that looks as new as the day was made because layer upon layer of wax and stain was layered for days, months... and then set into the sun each day, then buffed out and repeated. (It looks highly polished when it is finished)

...so you're doing one of two things. Completely sealing the wood, or saturating the wood with a non drying oil that insects, fungus, etc do not like (This is why Cresote is popular with the Railroad... You are sealing off the sent of whatever attracts the insect/fungus to dine on the wood... So, you could use something more modern like two part epoxy like marine paint, or tar... (If I don't stop thinking about it it I will end up writing an essay...)

...

   

Boric acid may soak into the wood a bit better than borax.  You can buy it or you can probably make it by mixing borax with a mineral acid like muriatic acid.  

You can also use wood that is more rot resistant.  As i recall, Locust is used in permaculture for being fast growing, nitrogen fixing, makes good firewood, etc.  It has sharp thorns though.  

Creosote is supposedly a wood preservative.  Harvest your chimney.

Supposedly char also lasts a long time.  Would a fence post last longer if it was charred first?  

I guess to make turpentine, cut the bark off a pine tree, collect the sap, and distill it.  

Elmer, I like the way you explained the 2 main ways you can treat wood. Do you think you could completely or at least mostly saturate wood with an oil that does eventually dry?

Bryant, What is the purpose of using the borax soak or using borax on wood in general. The only time I've encountered borax is to wash oil and grease off my hands or to help with laundry. Don't really know alot about borax and what it's useful for or what it's properties are.

Hej!
If you have a woodlot with pine trees, and don't need the wood right away, there's a way to create your own naturally rot-resistant lumber/posts. Here in Sweden there's a tradition of going out with a barking spud (for those who haven't heard of them, they're basically enormous chisels-up to 10cm/4in or so wide) on a very long handle, and peeling 2 strips totalling 1/3 of the tree's diameter of bark off  opposite sides of the trunk of pine trees as far up as you can reach. A year later, you go out and so it again, stripping the bark either next to , or on either side of the existing stripped bit- if you do the strips on either side, make sure you only take another 1/3 of the diameter. Another year later, go out and strip the final third, and then in the fourth year you cut down the tree, and split/mill/ whatever your log. What happens is the tree floods the injured areas with sap, so after the third year, the whole tree if full of rot-resistant resin. One downside is that it's not a fast process, but if you can plan ahead a bit, it's the best wood in the world for door and window frames, and makes very long-lasting fence posts. Plus, the scraps left over can be cooked down to make pine tar, another great preservative.

Dylan Kirsch wrote:Bryant, What is the purpose of using the borax soak or using borax on wood in general. The only time I've encountered borax is to wash oil and grease off my hands or to help with laundry. Don't really know alot about borax and what it's useful for or what it's properties are.

Borax keeps boring insects and termites away from wood that has been treated with it, it also prevents fungi from gaining a foot hold so no fungi breaking down the wood.

A note on Boric acid and other acids, they will break down the lignin in wood. Lignin is what gives the wood cells their strength. enough said?

I've used many of the old world methods and as Elmer mentions heat is good for opening the pores of the wood cellular structure so your treatment can get in deeper than just the surface.
Mineral oil is a great thing, especially if you blend it with some bees wax at low heat, once it has cooled it will thicken and you then rub it into the wood with a pounce (a pad of felt covered with cotton cloth).

As I said in my first post, the proper treatments are determined by what your use of that wood will be. There are many treatments that will work, but usually only one or two are the best for what ever application.

(These days I use a heat gun to warm the wood before I apply my finish coats, except for the violins and guitars that get a French polish.

Redhawk

Hi this is my first reply/post on permies. Have you heard of Hempshield? It is a hemp oil based, eco-friendly, Penetrating Oil Wood Finish & Deck Sealer. I haven't tried it myself and I understand it is pricey yet may be what you need?

Linseed oil (flax oil) is good for coating wood because the high level of polyunsaturated oil (the omega 3 and 6 oils that nutritionists like, but which easily turn rancid if kept for too long) cure by polymerising into a dense (plastic like) coating which can protect the wood.  Oils that are more saturated do not have this feature and, as oils, can be stable for times approaching years.

Dylan Kirsch wrote:Elmer, I like the way you explained the 2 main ways you can treat wood. Do you think you could completely or at least mostly saturate wood with an oil that does eventually dry?

Hey Dylan,

I'm guessing that drying and then saturating the wood with an oil would be an option. So, say you have lumber that has already been cut, heating up boiled or refined linseed oil might be one way to get the wood to swell and open the cells to get it to accept more oil deeper... A mix of 1 part turpentine to one part linseed oil might also allow the oils to seep in deeper. You would probably have to make some sort of container that would hold enough oil to keep it warm and to hold the actual size of the timber... The only problem with this idea that I think you would run into is that the way lumber may bend twist, or buckle in the curing process because the lumber is being treated after it has been milled.

If you were to construct a Styrofoam box and steam the wood to heat it to a higher temp, or maybe a serious heat gun... Or somehow construct your own kiln or hillside fire pit to heat treat the wood to get the oils to seep in deeper. You start running into risks of messing up your wood when you start doing prolonged exposures to anything that will make the fibers in the wood separate.

Another thought would be in the way something is traditionally constructed... instead of trying to impregnate a 4"x4", why not engineer veneers so that you coat out side of two 2"x4"s and the inside is then technically treated. I'm constructing a greenhouse using appropriated locally sourced upcycled materials. Mostly pallet wood, RR timbers, and old glass window sashes... (One of the reasons I ended up on this site is because I was investigating the 'possible' dangers of Creosote) Since, I am limited to the scale of materials I can source, I have to re-think how things things are constructed and question things I may not have normally questioned had I just run to the lumber yard and purchased what I needed... So, yeah, linseed oil will harden and act as a binder (not a super strong one, but one like a flexible film) So, you could make laminated lumber that is treated all the way through (provided that you have the equipment to take the stock down to the sizes you want and the time a patients it take to do this). This is probably the most cost efficient method unless you are opening your own lumber yard.

If your lumber is over 2" wide, the process for treating the interior of the wood is probably going to have to be heat or pressure treated in some sort of a kiln. or vacuum chamber.    

(I really like Daniel's post from Sweden above that explains a 4 year process... If I only had a woodland forest in my backyard, I'd be set).

Let's not forget wood is already polymerized like plastic, so it is already highly stable.  It's just that fungi are also well adapted to rot wood in prolonged damp conditions.  As I understand it, talk about preserving wood, is primarily about how to keep water off of it so that it doesn't support fungal growth.  (Secondarily with wood preservation you're talking about fungicides - anything that inhibits fungi.  Some of these have issues with toxicity to varying degree.)  

There are many ways to repel water:  oil, wax, resin, tar, a roof, paint, stain, any sort of water-repellent coating including polymers like plastic or even more wood!  The main issue with these is that they breakdown with time, sun, heat, weather, abrasion, etc, and have to be reapplied/replaced.  When building something that will be exposed to the weather and susceptible to rot, it might be worth giving thought to ensure the waterproofing can be re-applied/refreshed.  If it is inaccessible then this may be where more durable treatments are needed.  A tar-coated railroad-tie comes to mind.  

Wood that is treated can last.  The problem is more with untreated wood, and treatments that wear out and aren't replaced due to cost, labor, and overlooked maintenance.  To address this, it seems worth talking about how to minimize these factors.  It seems to me that the more effective treatments are going to be not only the treatments that are durable, but especially the ones that can be applied with an economy of investment and an economy of labor.  

There's actually an enormous amount of paint that goes unused and discarded and is often available for free if you're not picky about color, or if you can adjust the color.  There are probably also easy and inexpensive ways to combine the process of the distillation of pine wood for making pine tar while obtaining the byproduct of a clean-burning charcoal fuel useful for cooking and heating and as coloring/pigment.  

Of course a lot of these methods were probably already developed and written about in old books.  Some might be available on google-books.  

P Mike,
when you say wood is already polemerized, are you referring to the naturally presant oils and saps and whatever else components of the wood? Or are you referring to the wood fibers themselves? Or both

Dylan,

I was mainly thinking of the wood fibers (cellulose and lignin).  

Waterlox is really nice to work with even though it smells like it contains solvents. They don't bother me. I won't be alive long enough to worry about any potential health risks associated with the fumes. It is food grade after it cures. If you are sensitive to that sort of thing then wear a good mask and gloves that can stand up to the solvents. I was doing floors and counter tops and wanted something easy to apply and maintain. Everything came out nice. Growing and producing something yourself is a cool idea but if you just want to get it done with a formula that has already been figured out and has a good track record then check this stuff out.

I've got pine cut offs from lumber mill i put on side of shop how can I keep the bark on ?

Tom fontanille wrote:I've got pine cut offs from lumber mill i put on side of shop how can I keep the bark on ?

I wouldn't. Leaving the bark on gives wood-boring insects the cover they like to nibble in peace. If you take the bark off, they feel exposed and generally find somewhere else to make their homes/snack bars. In a worst-case, I've seen woodpeckers making holes you could put your fist into, to get at insects that have taken up residence in house walls.

I would love to know if this would work for other trees like aspen

Dylan Kirsch wrote:Curious on what you guys use to preserve lumber. Ideally it wouldn't be harmful or toxic and even better would be an oil you could press your self out of something you could grow? Any tips greatly appreciated. Thanks

Pitch is wood's natural preservative and you can use it to preserve wood if you thin it out with oil. Start by harvesting it from a tree which is leaking. Put it in an old plastic container that you would have had to throw out or repurpose anyways, such as a sour cream container, with a small amount of oil. Heat it for 10 seconds at a time in the microwave, taking it out to stir it with a wooden stick. ​It doesn't take much heat to melt pitch, do NOT overheat it or you'll create a safety hazard, maybe even melt the container. When the oil and pitch are mixed together thoroughly, you're done. Use caution and common sense and you'll be fine, but you're doing this at your own risk. After the pitch has been melted and thoroughly mixed with oil, pour it through a cheap strainer (because you're going to have to throw the strainer away, you can't clean it). At this point you have a sticky oil which can be applied onto wood to preserve it. You can experiment with changing the ratio of oil to pitch but ideally you want to thin the pitch out just enough that it will soak into the wood. I did this with a tool and it seemed to work quite well.

Boric acid is great at protecting against termites. HOWEVER, it only works where it will not come in contact with water, which will wash it away.

It is being used for that purpose in Canada and with great success.

Mike Phillipps wrote:
Boric acid may soak into the wood a bit better than borax.  You can buy it or you can probably make it by mixing borax with a mineral acid like muriatic acid.  

You can also use wood that is more rot resistant.  As i recall, Locust is used in permaculture for being fast growing, nitrogen fixing, makes good firewood, etc.  It has sharp thorns though.  

Creosote is supposedly a wood preservative.  Harvest your chimney.

Supposedly char also lasts a long time.  Would a fence post last longer if it was charred first?  

I guess to make turpentine, cut the bark off a pine tree, collect the sap, and distill it.  

I buy pine tar pitch at horsey places [where they sell things for your horse].  Some places charge absurd prices, like $20.00 for a pint.  Another place sells it for $10.00 a quart.

I thin mine with turpentine and may or may not add linseed oil, but that leaves a surface coat and has no durability for outside projects.  

Non-hardening oils penetrate better, after thinning and tend to keep wicking deeper into the dry sections of the wood. The means they're cumulative penetrating finishes that increase in protection with future applications.  

Thinning is critical, to speed penetration.  

There is no silver bullet, so even this needs yearly maintenance. However, as noted, above, the penetration coats build, so aggressive applications early on will pay off in allowing you to coast later on.




Pitch is wood's natural preservative and you can use it to preserve wood . . .  You can experiment with changing the ratio of oil to pitch but ideally you want to thin the pitch out just enough that it will soak into the wood. I did this with a tool and it seemed to work quite well.

Being consumed with avoiding solvents can be counter productive to intent. For example, if the wood degrades prematurely, it will have to be replaced.

I am a HUGE fan of penetrating finishes. A common problem with surface coats is, they expand and contract at different rates than do the finishes, resulting in cracks in the finish. This lets water in, then the finish holds much of it in to do its dirty work.

Nautical finishs tend to have more [polymerized] oil in them than those used for your coffee table. This makes for a less durable, but more flexible one that tolerates the shifts in the wood better, as it looses and gains moisture.

For things like breadboards and cutting blocks, I ONLY use mineral oil, a non-hardening oil. You do not want hardening oils for such things. Even though it's said cured finishes, like polyurethanes, are food safe when hardened.

I bought a used butcher block on the cheap, because it was horribly cracked and split. The cracks and splits were caused by the wood drying and shrinking from the block being neglected.

I slathered mineral oil on and wherever it soaked in quickly, kept adding more. I did this throughout an entire day.  At the end of the day, I slathered on a generous coat and walked away. A few weeks later, the wood had absorbed the oil, swelling it to its original state (moisture content), closing up ALL the cracks and splits.

For fine exterior items, I like the Waterlox products, but am even more fond of Daly's Seafin and Profin penetrating products. Not cheap, but neither is replacing a door, or what have you.

Qualify my love for penetrating finishes with that I make routine exceptions (use finishes) regularly for interior projects.

Oil, hardening or non-hardening, is far from being the ultimate protection, BUT, sometimes old technology is the best technology.  Though oil may, generally, pale in protecting from abuse, it does have that advantage of penetration and flex. Other times, that surface coat, such as on a floor, is the best protection.

If you finish a wood floor with a poly, the trick to longevity is, scuff and add new coats BEFORE you have to. If you get down to the wood again, you'll have to take wood off. On the other hand, if you redo the floor when high traffic areas are showing signs of going south, you only have to scuff the finish to add more years.

DO scuff between coats or waste time and money. More than you'd expect, because you will have to remove the mistake you made by adding finish that did not adhere to the original coat.

Nathan Jarvis wrote:Waterlox is really nice to work with even though it smells like it contains solvents. They don't bother me. I won't be alive long enough to worry about any potential health risks associated with the fumes. It is food grade after it cures. If you are sensitive to that sort of thing then wear a good mask and gloves that can stand up to the solvents. I was doing floors and counter tops and wanted something easy to apply and maintain. Everything came out nice. Growing and producing something yourself is a cool idea but if you just want to get it done with a formula that has already been figured out and has a good track record then check this stuff out.

Walnut oil works pretty good for interior finishes, furniture, etc.

But like boiled linseed oil and tung oil, though a hardening oil, it does not provide a durable finish.

Abe Coley wrote:Walnut oil works pretty good for interior finishes, furniture, etc.

James Freyr wrote:Tung oil is another one to consider for preserving wood.

Humor: How many tongues does it take to make a quart of Tung oil?

Reading about Tung Oil's properties when applied to wood makes me list a Qt. of that on my shopping list to purchase for the shop.