A lost method of finishing

[binarywhisper]

The page also mentions not heating the stuff.

I followed your links and it was an interesting read. It caused me to google the subject and there is no question

we should not be heating modern boiled linseed oil

Prehaps dad used raw linseed oil, no way to know now.
We will just have to have some fun and experiment but I'm going to start off following Pobah's advice.

 

[ezkcdude]

That probably also explains why your dad did the flaming, to make it cure faster. The "boiled" linseed oil appears to contain chemical activators which speed up the drying process, so there is no need for additional heat.

 

[Peter M.]

Linseedoil and linseedoil.
One very important thing about linseedoil is how it is extracted from the seeds. Coldpressing the seeds makes the best results, a bit wasteful but it is the only way to get a good product.

When you heat up the oil it starts to polymerize, the molecules starts to grow bigger. How much bigger depends on how much and how long it is being heated. Boiled oil hardens faster, but it doesnt penetrate the wood as well because of the larger molecules.

Today most linseedoil is extracted with heat and/or chemicals to get highest possible yield from the seeds. This oil will be full of nondrying ingredients and waxes that you dont want. If you want it to dry/polymerize at all you have to add chemical driers. But it will never be as good as the coldpressed variety.

Coldpressed raw linseedoil will dry, varmpressed raw oil will not.

The foodsafe variety is probably the good stuff.

Regards,
Peter

 

[binarywhisper]

That probably also explains why your dad did the flaming, to make it cure faster. The "boiled" linseed oil appears to contain chemical activators which speed up the drying process, so there is no need for additional heat.

I'm not suggesting that you specifically are confused but I am going to use your message to tackle it.

I think part of the confusion comes from the difference in heating the oil and boiling the oil. I believe that I am at fault for that confusion and at the least, I was confused.

I assumed that boiled linseed oil meant he boiled it. I now do not beleive that he boiled it and I beleive that it is likely that he used 100% pure oil. The process that I tried to recreate was from the memory of a 12 year old.

Dad heated it before use and flamed it when done. I am reasonably certain that he heated the oil to thin it and help it penatrate the wood. As I mentioned, wood that was left to soak in the pot of heated oil long enough took on a relatively colorless pale translucent appearance. THis was not an illusion, You could see quite deeply into the wood. I have a very clear memory of it as I had never seen anything like it before. It was the flame that brought back the color.

Polymerization, like any heat triggered chemical reaction, would occur within a specific definable temperature range. Once it hits the start of that range a chemical reaction begins that changes the essential nature of the oil. Up to that temp range it is likely that linseed, like most oils, thins with heat.

I agree with Poobah's original statement that surface depth is generally an illusion. As an artist I deal with that illusion all of the time. The peices that dad did using this method actually have some small degree of true depth though. That appearance of depth is greatly inhanced by the use of birdseye maple but there is more there then the natural illusion created by figured wood and a shiny finish..

I beleive that likely is the entire point of working the wood with the oil for such a long period. Within limits, the deeper the oil soaks into the wood the deeper the depth of the final finish. This could also be part of the reason for the great care given when using the flame. Prehaps we don't want to fully trigger the polymerization. Prehaps we want to trigger it in a controlled fashion keeping some of the translucence created by soaking the oil in to it. Purely speculation on my part.

There is no question the flaming is where the magic took place. Remember, this was before color TV's and fancy plastics. I watched that with great awe and my memory of this is very vivid. He would take a translucent relatively colorless peice of wood and wash it with flame and the grain and color would literally bloom under the flame like a CGI effect.

I am going to keep it simple to start and see where it takes me. Poobah has given some great advice and its the place to start. There is plenty of time for singed eyebrows and producing planks of $400 firewood.

I can just see it next year. A neighbor will ask how much it cost me in wood to heat my house for the winter and I will look him right in the eye and say, thousands, it cost me thousands to heat my house ... please just shoot me now.

 

[SCD]

figured grain and optical illusions

Hello Fellows:
Sorry I am so late in joining in on this thread. I have had lots of experience in playing with real wood and bringing out the grain patterns and the perception of depth in finishes. From my experience with oil finishes I agree with Poohbah the oil penetrates further when it is raw. It does not seem to stabilze or harden in the raw form. The heating process thins the oil and helps in penetration. I have used raw Tung oil and polymerized tung oil as well as linseed. I think the long term multi treatment of oil is ensure the wood is "preserved" to depth in order to protect against scratching and scarring from use. I also agree that the flaming process is a way of polymerizing the surface oils and harding up the surface. Without that treatment the surface would be sticky and pick up a lot of dirt. I also suspect if it is held for a long time it will pick up fingerprints as the acids in your skin oils will desolve the finish a bit and leave an impression. Just like your grandmothers dining room table.
These types of finish generally are not the best for horizontal surfaces as they tend to pick up dust,and crap, they usually end up quite dark over long periods of time. They require a lot of maintenance, not a big deal for a gun as the owner will oil and polish quite regularly, might not be the best for a speaker, unless of course you fancy rubbing and caressing your speakers on a regular basis. There are lots of ways to get a great finish on real wood speakers that are stable and low maintenance. the first place to start is with dry wood. I often use an oil finish to start as it helps stabilises the wood from changes in air moisture this is followed with an oil that contains polymers or has been polymerised, followed by multiple coates of eurathane for protection. A nice coat of paste floor wax for final finish puts the smiles on the faces.

Sanding to 320 grit or higher is the real trick here. You are managing the optical characteristic of the grain. The finer the sanding the more depth and lustre to the finish. A very rewarding and fun thing. Bringing a board to life is one of my favourite things. If you are interested in becoming a woodworker you pretty much have to like sanding it is the tought part but the finish makes it all worth the effort.

 

[binarywhisper]

Re: figured grain and optical illusions

Hello Fellows:
Sorry I am so late in joining in on this thread.

Your never to late and your opinions are very welcome

Not sure what to say about the long term maintence of the finish as it regards the method I've described. That gun stock I posted was finished 40+ years ago and has recieved pretty much zero maintence since then.

I've had it for 5 years and although I treasure it I have never looked after it in any way. I have never polished it including before taking the pic's I posted. It saw rough use in its life as a hunting rifle and lots of it. It appears to be impervious to everything including lots of blood over the years, sap, mud galore and a great deal of handling.

I wish I had more then memories to offer but I will be experimenting shortly and look forward to your advice and insights.

Thanks for joining in

 

[SCD]

good points:
I guess time and the effect of the flame have stabilized the finish nicely.
Most oil type finishes I have used take a long time stabilise and harden. which is the intent as it allows the wood to "breath" and change with humidity.

 

[Sheldon]

I've come recently to prefer tung oil. It's more expensive than linseed oil or linseed oil based finishes, but it's available in pure form (no accelerators), is easy to work with, hardens to a finish impervious to water and all common solvents, and doesn't darken with age.

Sheldon

 

[eLarson]

By darken, read also "yellow" with age. Tung seed oil is less prone to that.

However most of what is sold as tung oil is a combination of oils with some (usually not specified how much) tung oil in it.

I'll add the usual disclaimer about rags soaked with any of these oils: let them dry until they are stiff as a board before throwing them out. They WILL spontaneously combust.

(I'm sure it was back in there somewhere, but you can never be too safe)

 

[Sheldon]

By darken, read also "yellow" with age. Tung seed oil is less prone to that.

However most of what is sold as tung oil is a combination of oils with some (usually not specified how much) tung oil in it.

I'll add the usual disclaimer about rags soaked with any of these oils: let them dry until they are stiff as a board before throwing them out. They WILL spontaneously combust.

(I'm sure it was back in there somewhere, but you can never be too safe)

Yys, make sure it's pure 100% tubg oil.

Sheldon

 

[SCD]

Check out http://www.leevalley.com/home.aspx for tung oil.
This is a great woodworking catalogue.

 

[jdybnis]

I'm going to give this a shot on some baltic birch plywood. I'm going to try the "simmer in a pot for 3 days method" on a small piece. Is there a consensus on what type of oil to use? Linseed oil, boiled linseed oil, flax seed oil (i.e. cold pressed linseed oil, food-safe). Is this safe to do in a kitchen?

Linseed:
http://www.jamestowndistributors.com/find;a;1;ID;;eclDrill;1205

Flax seed:
http://www.a1supplements.com/detail.aspx?ID=1347

 

[Bare]

Been there tried that ... Tung oil makes a surprisingly mediocre finish.
Most any 'moderne' method is simply superior.
Do try for yourself though.. on a piece that you can easily throw away.

 

[pinkmouse]

Your comment might be more useful if you actually told us what it is you don't like about oiled wood.

Personally I much prefer an oiled or waxed finish to these modern high build lacquers that end up giving a result that looks like cheap and nasty plastic laminate.

 

[binarywhisper]

I'm going to give this a shot on some baltic birch plywood. I'm going to try the "simmer in a pot for 3 days method" on a small piece.

By all means give it a shot and let us know wht happens. I would expect from emersing plywood in heated oil for any length the plywood will delaminate.

I've only seen the the soaking in heated oil thing done with solid wood. My old man did it in the basement of the house and although I don't remember any odor myself I remember mom complaining.

I think we have covered in some detail that boiled linseeed oil is not to be heated in any inclosed space.


have fun

 

[binarywhisper]

Been there tried that ... Tung oil makes a surprisingly mediocre finish.
Most any 'moderne' method is simply superior.
Do try for yourself though.. on a piece that you can easily throw away.

ya I have to agree with pinkmouse. Could you tell us what it is that you don't like about it, what wood you have tried it on and prehaps how you applied it.

 

[infinia]

Hi All,
Really enjoing this thread on wood finishes.
I agree oil rub finishes look the best. This really brings out the grain and adds depth.
From an artist perspective we use stabilized linseed oil which is called "stand oil" Stand oil is made by heating the raw linseed oil in an autoclave under pressure. No chemicals needed.
Artists thin the stand oil with real turpintine (pine) spirits and add oil paint. You can get stand oil at any artist supply. I don't think it is very expensive and a lot less messy than boiling it yourself.
You can use "stand oil" by itself to rub the wood several times depending on how much gets soaked in the wood and let it set for a week. After that should be rubbed down with soft cotton rag. Then apply real oil based varnishes. The best varnish is called "Danmar". In the varnish you can also add small amounts of tint with certain types of paint pigments for a real translucent look. These processes are certainly tried and true.

 

[binarywhisper]

welcome to the thread infinia, good post!

 

[Sheldon]

Been there tried that ... Tung oil makes a surprisingly mediocre finish.
Most any 'moderne' method is simply superior.
Do try for yourself though.. on a piece that you can easily throw away.

Or surprisingly useful, depending on what you are after and how you apply it. Modern finishes give one look and typically have a single recommended application protocol. A tung oil finish is highly dependent on how it's applied. Just one example: if it dries in a fairly cool or environment, it will have a matte finish. If cured in a hotter environment (if often put small pieces in my car in the sun) it hardens to a nice sheen. Then there's the choice of thick coats, thin coats, prep coats like shellac, etc., etc., each of which changes the final outcome.

Tung oil when cured is highly crosslinked, so it's very resistant to moisture, solvents, etc.. I've also found it very useful in treating metal surfaces. I'll sand aluminum parts and coat with a very thin (wiped virtually dry with a bare hand) coat of tung oil and cure it warm. It bonds very well, doesn't chip or peel, and prevents finger marks and surface oxidation.

So good or bad? The answer is - it depends.

Sheldon

 

[jdybnis]

By all means give it a shot and let us know wht happens. I would expect from emersing plywood in heated oil for any length the plywood will delaminate.

I've only seen the the soaking in heated oil thing done with solid wood. My old man did it in the basement of the house and although I don't remember any odor myself I remember mom complaining.

I think we have covered in some detail that boiled linseeed oil is not to be heated in any inclosed space.


have fun

Submersing the plywood is just to test the technique quickly. If I use it on my speakers I won't be submersing them.

OK I'll stay away from the boiled oil and the chemical extracted stuff. This is what I'll use http://www.fromnaturewithlove.com/soap/product.asp?product_id=oilflax It's about $50/gal.

What would be a modern replacement for you're father's kerosene "tiger torch"?