Info on Tung Oil

[Chris Townley]

I am building the wood bed for an old pickup.
I have oak ready to put a finish on. I believe it is red oak.
I sanded it with 80 grit and then finished it off with 220.
I want to use 100% tung oil but don't know much about it. SO I guess I need someone to tell me some about it.
From some info I "read" you can put the first couple coats on with it thinned 1:1. (I assume with it thinned it will penetrate the wood better??)
I have no clue if the tung oil will color the wood or how much. I assume the more coats = the more color. True??
SO there you have it - that's pretty much the limit of my knowledge.

I want to use tung oil to avoid using any sealer that may chip / peel off later on in years to come forcing me to have to take the whole bed off and refinish it.
I heard you can keep adding tung oil to put moisture back into the wood (as years go by) rather than having it dry out?? True??
I'm working on making a street rod / show truck and want a super finish on the bed and something water proof.
Also I was thinking about actually using some sort of sealer (instead of tung oil) on the bottom of the boards that will be exposed to water; mud; grime, etc. I thought maybe it might help prolong the life??

There you have it - feel free to correct any of my misconceptions and add any info I need.
THANKS

[John K Jordan]

Chris,

I've never heard of adding more polymerizing oil/finish adding more moisture to the wood. Doesn't make sense to me.

I haven't used tung oil for things in the weather but I have used "boiled" linseed oil. I slather it on wooden boards on my trailers, barn doors, and garden and farm tool handles. Several coats provides good protection but I don't know how long it will last. I reapply every couple of years. I also don't care what these things look like.

For the oil finishes like BLO and "danish" I think more coats just builds up more on the surface. The first coat soaks in and changes the appearance. I use maybe 8-10 coats of danish oil on woodturnings and see no change in color or darkness after the first coat.

Assuming the boards are well dried to start with, it is an excellent idea to put finish on the bottom and sides of the boards as well as the top.

I have no experience with using oils for waterproofing. It seems to me polyurethane or marine varnish with UV protection would be better for that. You might google waterproof finishes or ask on the boat building forum here: https://sawmillcreek.org/forumdispla...-Boat-Building Those guys know how to waterproof wood.

JKJ

I am building the wood bed for an old pickup.
I have oak ready to put a finish on. I believe it is red oak.
I sanded it with 80 grit and then finished it off with 220.
I want to use 100% tung oil but don't know much about it. SO I guess I need someone to tell me some about it.
From some info I "read" you can put the first couple coats on with it thinned 1:1. (I assume with it thinned it will penetrate the wood better??)
I have no clue if the tung oil will color the wood or how much. I assume the more coats = the more color.
SO there you have it - that's pretty much the limit of my knowledge.

I want to use tung oil to avoid using ant sealer that may chip / peel off later on in years to come forcing me to have to take the whole bed off and refinish it.
I heard you can keep adding tung oil to put moisture back into the wood?? True??
I'm working om making a street rod / show truck and want a super finish on the bed and something water proof.
Also I was thinking about actually using some sort of sealer on the bottom of the boards that will be exposed to water; mud; grime, etc. I thought maybe it might help prolong the life??

There you have it - feel free to correct any of my misconceptions and add any info I need.
THANKS

[David Utterback]

My sole experience with pure tung oil was years ago. I went different directions due to it's odor and long cure time. As John suggested, BLO is easier to work with. Additional coats will help prevent the wood from drying out and weathering but will not add moisture to the wood. Good luck!

[Chris Townley]

Chris,

I've never heard of adding more polymerizing oil/finish adding more moisture to the wood. Doesn't make sense to me.

JKJ

I read a couple different places this worked.
Perhaps I should have said it was more of a "maintenance" type thing. I read (like any natural process) when the wood dries out; when applying tung oil it sucks it in and helps keeps it from being dry / brittle.
Kind of makes sense - When you sand the wood and first apply tung oil; it is drawn into the wood for protection. So I can see dry wood pulling moisture back in to help protect it.
I've done a lot of work working in my days - just never used tung oil and not familiar with it.
The color change; cure time; etc are things I am curious about also. It'll be a few months before I mount the wood. SO the cure time isn't a issue right now. But it's nice to have folks say it does take a while and it's not wise to rush the process.

[Steve Schoene]

Lets start with the wood itself. Red oak is not a good choice for the truck bed. It has open pores that can extend deeply into the wood, with the consequence that it is susceptible to rot. It's hard to fill those pores sufficiently to stop the moisture. The oak you want is white oak, which has its pores filled with tyloses so water doesn't penetrate very far into the wood. You can make water tight barrels from white oak but not from red oak. White oak is much more rot resistant.

I'm not a fan of pure tung oil as a finish since it dries slowly and is only a little more moisture resistant than boiled linseed oil. It should have several days to cure between coats, assuming that temperatures are at least into the 70s. If coats of pure tung oil are applied to quickly, you run the risk that the finish could develop a whitish blush after time. That blush would have to be stripped off to remove. If you want the "in the wood" look on the wood I strongly recommend an oil/varnish mixture. It will look virtually the same, but have much more water resistance.

Thinning oil does not make for deeper penetration. It's the size of the oil molecules that determine the ability to penetrate. Thinning doesn't change molecular size. The thinner itself may penetrate more deeply, but it still has to evaporate for the finish to dry. When it does evaporate, leaving the oil behind, it has just leaves the oil molecules more widely spaced, but no more deeply penetrated. Thinned oil or oil/varnish may well be easier to apply, but it takes more coats to protect the surface with the cured oil and/or varnish molecules.

[John TenEyck]

I am building the wood bed for an old pickup.
I have oak ready to put a finish on. I believe it is red oak.
I sanded it with 80 grit and then finished it off with 220.
I want to use 100% tung oil but don't know much about it. SO I guess I need someone to tell me some about it.
From some info I "read" you can put the first couple coats on with it thinned 1:1. (I assume with it thinned it will penetrate the wood better??)
I have no clue if the tung oil will color the wood or how much. I assume the more coats = the more color. True??
SO there you have it - that's pretty much the limit of my knowledge.

I want to use tung oil to avoid using any sealer that may chip / peel off later on in years to come forcing me to have to take the whole bed off and refinish it.
I heard you can keep adding tung oil to put moisture back into the wood (as years go by) rather than having it dry out?? True??
I'm working on making a street rod / show truck and want a super finish on the bed and something water proof.
Also I was thinking about actually using some sort of sealer (instead of tung oil) on the bottom of the boards that will be exposed to water; mud; grime, etc. I thought maybe it might help prolong the life??

There you have it - feel free to correct any of my misconceptions and add any info I need.
THANKS

Steve is correct. Red oak is a poor choice if you want rot resistance. Second, no oil finish is waterproof, at least not for very long. If you want a truly waterproof finish you need a film finish like marine varnish, better still when you apply an epoxy sealer first, or something like a two component polyurethane. For any of those choice to work long term you would have to apply an equal number of coats to all surfaces, and be prepared to do routine maintenance.

John

[Chris Townley]

Steve is correct. Red oak is a poor choice if you want rot resistance. Second, no oil finish is waterproof, at least not for very long. If you want a truly waterproof finish you need a film finish like marine varnish, better still when you apply an epoxy sealer first, or something like a two component polyurethane. For any of those choice to work long term you would have to apply an equal number of coats to all surfaces, and be prepared to do routine maintenance.

John

Yeah hear what you are saying.
Mainly I just want a deep rich glossy finish. As far as "waterproof";.. of course the more water it sheds the better; but for the most part the truck will be kept in a garage and not exposed much to the elements (other than road trips; etc). But it'll stay in a temperture controlled garage most of the time. I hear bad things about polyurethane. etc splitting and cracking and then lifting off the wood after a few years and I want to avoid all that refinishing mess.

[Steve Schoene]

Pure tung oil will never, applied properly, yield a glossy finish, satin is the best to be expected. For that matter oil/varnish mixes don't do very glossy very easily. The reason film finishes fail is mostly a matter of sun light. A good marine spar varnish, over a epoxy sealer (for the varnish think Epifanes, or Pettit Captain's, or Interlux Schooner.) The epoxy I am familiar with is Smith CPES, though there are other brands of low viscosity epoxy sealers. The combination, of varnish over the epoxy should last quite a long time if the truck is kept garage most of the time. By the way, none of the good varnishes are single part polyurethane.

Interlux does make a two-part polyurethane finish that would be good choice and be very durable. It's pricey, and directions must be followed meticulously. It's called Perfection Plus.

[Wayne Lomman]

Chris, you will never get a maintenance free timber finish. Oils are not waterproof and need to be re applied regularly. Film finishes can crack and let water underneath the film if they are not touched up regularly.

As Steve says above, you don't get a good single pack clear finish to do this job. Given that you want a glossy, full bodied finish as well, a two pack polyurethane is the way to go. No oil based coating will do this. 2 pack polyurethane is tough, resilient rather than brittle, and can be purchased UV stabilised. For timber work, I avoid epoxy sealers. Compatibility is fine but they tend to be a bit more brittle and therefore a bit more likely to crack with timber movement. For steel work I use epoxy primers and high builds under polyurethane every day.

I recommend using 2 or 3 sprayed coats of 2 pack polyurethane. Steve has recommended International's Perfection Plus. It is an excellent choice but to avoid the price, look for Interthane 990 instead. Its the version sold to industrial applicators rather than yacht owners. Neither product will cause any colour change as both will be water clear.

As others have said, coat the boards all over to the same standard. Maintenance will be checking periodically for chips or similar damage and touching it up regularly. Cheers