Hello there,
This is my first post on this forum. I’m a woodworker from Brussels, Belgium.
I have a few questions about finishing.
I would like to use a natural finish that doesn’t form any film on the surface. I want to still be able to touch and feel the wood once my piece is finished with a satin look. So i think tung oil or Boiled linseed oil would be the best choice for what I’m looking for. I’ve had no experience with BLO. My experience with tung oil is that it never really cured and stayed kind of greasy (on solid wenge). I’ve also used “Rustin’s Danish Oil” and really liked the satin look and the way it “popped” the grain but it’s not durable enough for a table top, it’s not waterproof at all and you can immediately see stains if you spill water on it.
My questions are:
1 Does adding a solvent to tung oil helps it dry quicker?
2 What kind of solvent should I use (preferably something not toxic, citrus solvent?)?
3 What kind of dryer should I use? Not toxic if possible.
4 Should I add a resin to make some sort of DIY danish oil?
5 Do “oily” wood species (like Wenge?) prevent the tung oil from drying? Do i need to use a solvent on the wood before applying the oil?
Thank you for your help.
Clément
Ps: I join an image to give you an idea of the kind of look i would like to achieve, I’m aware that tung oil is not the most durable product but I don’t mind putting a fresh coat every now and then.
Replies
Let me ask first, what is it you are finishing?
>>>> 1 Does adding a solvent to tung oil helps it dry quicker?
No
>>>> 2 What kind of solvent should I use (preferably something not toxic, citrus solvent?)?
See above
>>>> 3 What kind of dryer should I use? Not toxic if possible.
Do not use a dryer. It can cause tung oil to not cure at all
>>>> 4 Should I add a resin to make some sort of DIY danish oil?
What you want to use is what is known as an oil/varnish mixture. That is what Danish Oil generally is. Here in the US most commercial "Danish Oils" are almost totally thinners. To get the best finish, it's best to mix your own. Mix equal parts of an oil based varnish, real tung oil or boiled linseed oil and mineral sprits. This is an in-the-wood penetrating finish that will leave the look and feel of the wood. The varnish adds quite a bit of protection and durablity to the finish. Do not use any of the so called "non-toxic" thinners such as citric products. They do not mix well with the oil you use or the varnish.
Apply by wiping or brushing on a full coat. Let it set--keeping the surface wet if it looks "dry"--for about 15-20 minutes. Then wipe off all the excess with a clean rag. Wipe it dry. Let it fully dry overnight and apply another coat just like the first. Two coats are enough. Because of the high oil content, more than two coats can cause a sticky surface that will never fully dry.
A couple of notes. Be careful of the rags you use to remove the excess. They can easily burst into flames if they are put into a confined space. It's best to hang them on line or fence until they harden completely.
Second, I much prefer boiled linseed oil instead of tung oil. Boiled linseed oil dries much more quickly.
5 Do "oily" wood species (like Wenge?) prevent the tung oil from drying? Do i need to use a solvent on the wood before applying the oil?
Thank you Howie for your useful answers!
My goal is to find a good finish that I would use on most of my projects, right now I'm working on a dining table in european walnut (BTW here in europe, european walnut is ironically harder to find than american walnut...) so I want it to be durable enough for a daily use without having to use costers all the time. I tend to read two opposite opinions regarding the protection that tung oil offers against water, some people say it's waterproof and some say it has no protection at all.
Now I have more questions:
1 I wil try to make a few experiments of home made danish oil like you suggested but : from what I understand an "oil based varnish" is a blend of drying oils with resins and a solvent so isn't it weird to mix one part tung oil + one part oil/resins/solvent + one part solvent? (I'm not sure if this question is relevant...)
2 I often read that a heat process helps tung oil and BLO to cure faster (by polimerization) but I didn't find any "recipe" for that. Can this process be done at home? I think the heat should be between 140 °F and 170 °F, but for how long?
Thank you again for your help.
Clément
Clement, shor of encapsulating a surface in epoxy, no finish will totally exclude water and water vapor. Coasters, placemats and trivits should always be used to protect a finished surface. An oil/varnish finish is excellent for walnut. In fact, it's the preferred finish for most woodworkworkers. It is easy to apply, reasonably durable and easy to repair.
Tung or or linseed oil are both the worse two finishes for protection and/or water or water vapor resistance. You can go to the US Forest Service site and look for the "Wood Handbook". One section lists the protective qualities of various finishes. The only "finish" less protective and durable is paste wax. Tung oil is slightly more water resistant than linseed oil--particularly if 10 or more coats are rubbed in--but both are poor.
I don't know if it is "weird" to mix up the home brew I suggest. If you buy a "Danish Oil" and check the ingrediants you will find that the Danish Oil is made up of the same components. It's just that commercial Danish Oil has a higher proportion of thinner.
Heat will not affect the drying/curing time of either linseed oil or tung oil. Both cure by absorbing and reacting with oxygen. Heat may slightly speed up the process but only by a small amount.
Thank you Howie for your useful answers!
My goal is to find a good finish that I would use on most of my projects, right now I'm working on a dining table in european walnut (BTW here in europe, european walnut is ironically harder to find than american walnut...) so I want it to be durable enough for a daily use without having to use costers all the time. I tend to read two opposite opinions regarding the protection that tung oil offers against water, some people say it's waterproof and some say it has no protection at all.
Now I have more questions:
1 I wil try to make a few experiments of home made danish oil like you suggested but : from what I understand an "oil based varnish" is a blend of drying oils with resins and a solvent so isn't it weird to mix one part tung oil + one part oil/resins/solvent + one part solvent? (I'm not sure if this question is relevant...)
2 I often read that a heat process helps tung oil and BLO to cure faster (by polimerization) but I didn't find any "recipe" for that. Can this process be done at home? I think the heat should be between 140 °F and 170 °F, but for how long?
Thank you again for your help.
Clément
The information Howard gave you is sound Clément, but you may not have heard of 'mineral spirits'. Mineral spirits is white spirits, turps, or turpentine substitute here in the UK, but I'm not sure what that's called in Belgium, depending I suppose on which language you prefer to work in or use.
Pure tung oil really won't give a great deal of protection against water, water vapour or any other liquids unless you apply many coats: twenty or thirty. Even then it's not a particular water resistant finish. When cured it's also relatively soft and doesn't generally offer much protection against heavy objects, scratching, scrapes, etc.
Water spillages work their way through the dried oil very quickly and will leave a white ring in the wood, usually with raised grain. You will generally need coasters and the like over a pure tung oil finish to keep it looking attractive, unless you are meticulous about wiping spills immediately.
Anyway, much along the same lines that Howard gave you, you can make a fairly decent finish by simply buying a can of oil based matte, gloss, or satin varnish (depending on your sheen preference) and thinning it down about ±50% with white spirits. You thin it down to make it workable as a wipe on varnish-- too thick and the stuff is too hard to work. You wipe or brush this mix on resonably generously and let it sit for a while and then wipe it off with clean dry clothes following the long grain direction. You gradually build up the film thickness you want with successive coats. Going by your description of what you are after I think you are likely to apply between three and five coats before you are done.
Take note of the warnings Howard mentioned about rags and their disposal and, finally, do remember this mix and method I've suggested is really just a variation on the mixture and methods Howard described. In any case, both the suggestions made by us will give you significantly more protection than pure tung oil alone, and without a thick build-up of film. Slainte.
Thank you both for your comments.
I'm gonna try to make a few experiments with what you suggested, on scraps of course.
I also want to try a product from the German company "Biofa" which is supposed to be non toxic, durable and leaving a natural look to the wood. I hope it works because I'm getting tired of buying 20€ cans to find out it doesn't fit my expectations.
White spirit is called white spirit in Belgium and tung oil is called "huile de bois de chine" (Chinese wood oil).
I knew about the rags and spontaneous combustion but it's never a bad idea to repeat it.
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