Applying pure tung oil to hardwood floor WITHOUT solvent. Am I mad?

[grapeseed]

I know the most common way to finish a hardwood floor with pure tung oil is the thin it with a solvent (e.g. turpentine) for easy penetration.

I'm pretty eager to buck the trend and avoiding using thinner of any kind if I can. So far I've found very little on the internet about doing a floor like in this manner. It seems that occasionally people will apply pure tung oil to pieces of furniture without a thinner, but I don't read about anyone attacking a floor in this manner.

Can it be done? I expect it will take a lot more "elbow grease" to do this without a thinner...but is it achievable do you think??

According to this website, the procedure is basically
1) put oil on cloth
2) rub into the floor boards
3) wait half and hour
4) rub off excess with a dry cloth
5) wait 24 hours
6) start again

The timber is grey iron bark and there will be about 140 square metres of floor to do.

[Skew ChiDAMN!!]

It will work.

140m²? You're dead right about it taking a lot of elbow grease!

[Enfield Guy]

There are products available that are far easier to apply with far better results out there. Why make life so hard for yourself for a lesser result? Try OSMO. I have recently finished about 25M2 of cork tiles with brilliant results. I can't speak highly enough about the product.

Cheers
Bevan

[ian]

I know the most common way to finish a hardwood floor with pure tung oil is the thin it with a solvent (e.g. turpentine) for easy penetration.

I'm pretty eager to buck the trend and avoiding using thinner of any kind if I can. So far I've found very little on the internet about doing a floor like in this manner. It seems that occasionally people will apply pure tung oil to pieces of furniture without a thinner, but I don't read about anyone attacking a floor in this manner.

Can it be done? I expect it will take a lot more "elbow grease" to do this without a thinner...but is it achievable do you think??

According to this website, the procedure is basically
1) put oil on cloth
2) rub into the floor boards
3) wait half and hour
4) rub off excess with a dry cloth
5) wait 24 hours
6) start again

The timber is grey iron bark and there will be about 140 square metres of floor to do.

on the basis that the finish MUST be tung oil ...

What you propose is really a two person job
-- person one applies the oil and maintains the wet edge
-- person two follows along wiping off the excess oil
with your 140 sq,m floor, one person working alone would have to work on small areas to ensure they get back to mop up the excess oil whilst it's still wet.

BUT
to quote from Lee Valley

Pure or Polymerized Tung Oil
Unless you are finishing a food-contact item like a salad bowl or spoon, your choice should be polymerized tung. Not only does it dry much faster, but you can use it to create finishes that range from nearly matte to high luster.
Tung oil cures by polymerization (molecules combining to form long chains) and oxidation (combining with oxygen from the air). Polymerized tung oil has been heated to complete the polymerization half of the process. Polymerized tung cures by oil oxidation and evaporation of thinners after application, so the curing (drying) process is faster than that of pure tung.

Pure Tung
For non-food contact use, always thin with 50% mineral spirits for the first coat. Subsequent coats can be full strength, but must be wiped down after 15 minutes. Always allow ample drying time (48 hours+).

Use
Since tung oil may raise the grain of the wood, you should moisten the surface to make any fiber ends stand up, and once dry, use sandpaper or steel wool to remove them before oiling. Alternatively, you can lightly sand the first coat before applying the second. Any filling, sealing or staining must be done before the oil is applied.

The first coat should be a liberal one, and you can rub it over the wood with your hand, a soft rag, or #000 steel wool (#0000 deteriorates badly). Allow this application to sit for 5 to 10 minutes so the oil can soak in, then remove any excess with a clean, soft rag or steel wool. Check after about a half-hour for any seeping, and rub this off as well. Let dry completely (24 to 48 hours) between coats. For woods with very open pores, allow an extra 24 hours drying time.

For me there would have to be a very compelling reason not to use thinned polymerised tung oil.
sensitivity to mineral turps, would not, for me, be a compelling reason. I'd engage a contractor and leave the house for a week to allow the solvent to fully evaporate.

[grapeseed]

Ok thanks folks for the replies. It sounds like I should probably let go of the idea of doing what I intended.

[grapeseed]

For me there would have to be a very compelling reason not to use thinned polymerised tung oil.
sensitivity to mineral turps, would not, for me, be a compelling reason. I'd engage a contractor and leave the house for a week to allow the solvent to fully evaporate.

What happens if I use pure (non polymerised) tung oil and thinner on ironbark floorboards? I ask because I already have a heap of the non polymerised stuff sitting here...

[ian]

When you say "a heap of the non polymerised stuff" how much do you actually have?

I've found a source which suggests that coverage is about 9 sq.m per litre, so for your 140 sq.m floor your "heaps" would need to be about 16 litres just for the first coat.


some application instructions from https://www.canadianwoodworking.com/...ebunking-myths

raise the grain before you apply tung oil. Raise the grain with a rag soaked in warm water, sand, and then begin.
Bob Flexner says that applying oil is simple, “wipe, wait, sand, repeat.” Apply the oil liberally with a soft cloth or brush and then wipe it off like you mean it. Check after an hour or two, and if extra oil has beaded on the surface, wipe it away.
Don’t forget that rags used to apply drying oils are highly combustible. When you’re finished with your rag, hang it outside to dry. Be careful disposing of them.
When using pure tung oil, you need several coats. It’s very important that you thin each coat with the first coat being the thinnest (I recommend 70 percent solvent). Each successive coat should be thicker (less thinned), and the last coat must be the thickest. Your thinner needs to be an organic solvent, one that is carbon based like turpentine, mineral spirits or the newfangled “citrus solvent”.

Every layer except the last must be sanded, so the next layer of tung oil will bond to the previous layer. Three hundred and twenty-grit sandpaper creates the “tooth” that grips the next layer. When sanding between coats, you have to go lightly or you will suddenly sand through one or more previous coats and you will have dreaded witness lines.

Getting good results requires using the right techniques and not being in a hurry. I would allow at least a week between coats, although I have heard of people doing it faster with good results. There are many other finishes better suited to a tight schedule; varnishes, lacquers, and even BLO. However, if you want to use oil, and you have some time to devote to the finish, pure tung oil is in a class by itself. There is no other drying oil that has the same resistance to water, mold, bacteria, yellowing, darkening, but offers strength and flexibility.

This lot Pure Tung Oil Wood Finish & Protection recommend a minimum of 6 coats

The surface should be dusted to remove all loose particles. For better penetration the oil should be thinned one to one with natural Citrus Solvent. Using the Pure Tung Oil straight from the bottle would only be for the most thirsty surfaces like old weathered wood, 100 year old wood floors that were never finished or concrete. For the majority of all projects you will thin 50% with thinners for the entire finishing process. The first coat of thinned material should be a liberal one. Apply with a natural bristle brush or sponge brush. Allow this application to sit for a minimum of 40 minutes so the oil can soak in. When it soaks into the wood, apply another coat immediately. Continue to apply coats, one after another, until wood is saturated and stays glossy for a minimum of 40 minutes but can be 1½ hours. If eighty percent of area stays glossy the wood cells are saturated. Then wipe down the surface with clean rag material. Continue to check for any seeping in the next few hours, and rub this off as well. Let soak in completely over night between applications. Do not allow standing oil on the surface overnight. Any standing or puddles oil should be wiped away with clean rags. Hang oil soaked rags up separately to dry. For woods with very dense pores like Teak wood (and possibly Ironbark), thin with two parts Citrus Solvent to one part oil will help it absorb better for every coat. Pure Tung Oil will take 7 to 10 days for a minimum cure and 15 to 30 days for a full cure.

Tung oil can be applied pure to very porous surfaces or with Citrus Solvent added if a non-toxic finish is required. Thinners can accelerate the drying process and greatly improve the penetration by cutting the first coat of oil with Citrus Solvent, mineral spirits or turpentine by 50%. Do not use the “Green” thinners now being sold. They contain water and will not mix with the oil.

The number of coats of oil to be applied will be determined by the intended use of the piece. Surfaces that receive moderate to heavy use or handling could need up to six coats for maximum protection, plus a light renewal coats a couple of times a year. Apply till the surface reaches the saturation point. This will be evident as the surface will not absorb more oil. Renewal and building coats are quickly applied with cheese cloth, a lint free cloths (old bed sheets work well). This process will give you a surface that will stand up to vigorous use and spills: water will bead on the surface. Do not get hung up on the number of coats, let the wood tell you when it has reached its maximum saturation. Pure Tung Oil will be in the wood up to the surface not on the wood like varnish or Poly urethane top coat.

I don't suggest you try polmerising the oil yourself, because the process involves heating the oil to about 260°C in an oxygen free environment. A process that is probably not covered by your home insurance.

[grapeseed]

I don't suggest you try polmerising the oil yourself, because the process involves heating the oil to about 260°C in an oxygen free environment. A process that is probably not covered by your home insurance.

Haha I suspect you are right!

I've got 10L of it here already, but it sounds like I am going to need more.

The Tung oil I have is Sceney's and appears to be NOT polymerised. You mention earlier that I should be using polymerised on the floor. Will it be quite problematic if I don't?

Ian it sounds like you're not great fan of finishing an iron bark floor with tung oil...I'm interested in what you would finish it with if it were up to you?

[justonething]

Raw oil, be it Tung or linseed, has both advantages and disadvantages in comparison to the polymerised or boiled version.
The disadvantage is generally well understood, it is extremely slow to cure, But because it is slow to cure. It also means that it has more time to be absorbed or to sink deep into the grain.
You should first try it on a piece of scrap timber (of the same kind), But the basic process is to brush it on quite liberally and leave it for a couple of hours and see how much of it is absorbed and wipe off any excess if there is any. Leave it overnight and repeat the process again the next day. If you touch the surface the next day, it should feel fairly dry but a tiny bit greasy. If you apply boiled oil it would have cured overnight which means it won't absorb much anymore and you need to sand the surface to open up the pores again. With raw oil, it doesn't dry, your timber is ready to take on more oil the next day, day after day. This mean the grains in the wood are far more pronounced after a few days of application.

The disadvantage of slow drying is inconvenience. You could try and speed up the curing process by mixing the raw oil with polyurethane and turps in the final two/three coats in the ratio of PU: oil:turps of 40:20:40, apply it with either a brush followed by rubbing in with a rag, or wiping it on with just a rag. Leave it to dry overnight and sand between coats with 400 grit sand paper. Once again, try it on a scrap piece to see if you like the looks of it.

[ian]

Haha I suspect you are right!

I've got 10L of it here already, but it sounds like I am going to need more.

The Tung oil I have is Sceney's and appears to be NOT polymerised. You mention earlier that I should be using polymerised on the floor. Will it be quite problematic if I don't?

Ian it sounds like you're not great fan of finishing an iron bark floor with tung oil...I'm interested in what you would finish it with if it were up to you?

Reading that link, I'd be surprised if your Tung Oil is not polymerized. For me the tip-off is "For larger areas such as floors, white spirits is a more economic solvent" unpolymerised oil takes so long to dry -- days to weeks -- and requires so much labour to apply that I can't imagine any reputable paint supplier recommending it for a floor.

From what I've read, polymerised tung oil dries relatively quickly, but the usage is typically much smaller scale than your 140 sq.m floor -- largish projects finished in tung oil seem to be about 1/100 the area of your floor

as to floors, I think a polyurathane / tung oil blend is superior both for application, maintenence and durability