Thread: Loudspeakers (Tung Oil finish)

Hi gainphile,
What kind of hardwood is that? It looks like a Jarrah, but it's a bit light. Is there any stain under the Tung Oil?
Whose Tung Oil did you use and did you sand between coats? With what grit did you finish sanding before you oiled and what grit between coats. How long did you let the oil sit before wiping it off.
The failure of the grain to show under the lights in your house could be due to several things.
The strength of the light could be inadequate to allow differentiation to the eye. The wavelength of the globe/element might be reacting with UV dampeners in the oil to either quench part of the overall spectrum, or to highlight other parts, such as far reds.
If you have a good finish in natural light, i.e. good grain differentiation, good colour, satin finish, then the cause of your problem must be environmental. Perhaps a down light with a broad spectrum globe over the speakers will help this. You might also consider using a UBeaut Traditional wax finish on the timber. This will definitely give you a good satin lustre. (and it smells even better than Tung Oil.)

Hope this helps

Regards,

Rob

Yes there are issues with solid timbers warping and moving, but it varies on the spicies, moisture content and how the timber has been cut.

many people do sucseed in making speakers out of solid timber without advent.

but a couple of precautions.

1. build the speakers is such a way that the panels tend to be held flat.

2. treat both sides of the panels the same way..smart people do this with table tops and other flat things....this way moisture transfer will be equal on both sides of the penel and will tend to warp less.

3. keep em out of the sun and be carefull about sudden climatic changes


as for the finish and appearance.

Ring pourous woods (hardwoods) can have different lights and hues depending on how the light strikes the surface, the character of the light and the angle of viewing........rosewood that can look fabulous in the right light and can present gorgeous flickering colours and lights and it is moved in the light, BUT can look dull and dog $##t on poor light.

Its all baout the thousands of little trnaslucent tubes that make up the wood structure.

I have not had much to do with oiled finishes, but it is well knwon that to get the best finish out of oil can take a long time.

There is the old adage that with tung....a coat a day for a week, a coat a week for a month and a coat a month for a year........yeh, probaly a bit over the top, but ya get the idea.
Oil takes time to absorb into the timber then takes time to polemrise or "go off".

good work.

cheers

Originally Posted by soundman

as for the finish and appearance.

I have not had much to do with oiled finishes, but it is well knwon that to get the best finish out of oil can take a long time.

There is the old adage that with tung....a coat a day for a week, a coat a week for a month and a coat a month for a year........yeh, probaly a bit over the top, but ya get the idea.
Oil takes time to absorb into the timber then takes time to polemrise or "go off".

good work.

cheers

Hi Soundman,

I can prove to you that Tung Oil and its "clones" can be polymerised in wood using heat generated by friction during sanding, thus "going off" in minutes rather than months.
I also have heard the adage you quoted, but I heard the oil as being Linseed Oil. Usually you only need about 3-4 coats of Tung Oil to get an excellent finish. The timber, once the oil is dry, can then be coated with wax, shellac or Poly. Have a look at this thread by JillB.
She used Wattyl Teak (Scandinavian) Oil, which is a Tung Oil hybrid. Four coats and let it dry then it's ready to wax.

Regards,

Rob

Sorry you can prove nothing of the sort, unless you have some very funky scientific equipment.


There is no such thing as "clones" of tung oil, either it is pure tung oil or it has been added to, blended or adulterated which is more often the case.
If it has been added to, blended or adulterated it is a very different product and very likley behaves very differently than the pure oil.

Yes heat may accelerate polimerisation in oils, but claimimg that effect happens any deeper than the very surface is drawing a long bow.

You may burnish oils, and that may achive what appears to be a hard surface, but it will still take time for the whole of the applied oil even the very surface to react fully and cure properly.

Some will claim reasonably that burnishing particularly with sandpaper does not produce the best clarity and light from timbers because it is grinding a slurry of wood dust and spent abrasive into the grain of the timber along with the finish product.

As for linseed oil... in its unaltered form it reacts and dries exceedingly slowly, the the "boiled form"(which by the way is not boiled, but modified by addition of driers) it may dry faster but it also takes quite some time to react completly and does not go off nearly as hard as tung.

The old addage I quoted, has probaly be spouted in realtion to just about every oil used with timber.

Putting other products over various oils is certainly nothing new, AND it does not change the facts about how oils behave and cure.

BUT none of this helps the original poster.

cheers

Originally Posted by mrpedersen

Outside you have the nature of the sun in full spectrum that catches the grain and reflects it as it is. Whereas artificial light has a subset of the true spectrum. If I want to find any tiny scatches , flaws from the 220 / 320 g sanding I'll take my project into the sunlight - sure does reveal !! The Ott lights are near natural by pricey.

They'll look good in any light, nice work.

glenn

Interesting. I never thought of that before.

I will try different light bulbs to investigate the effects.

Originally Posted by boneaus

It is just that natural timbers tend to move around as they dry out or absorb moisture. In a cabinet, the bracing effect of the glued up pieces holds everything tight. If you left a piece of timber standing upright like your baffle I wouldn't expect it to stay straight for long. It would depend on the timber moisture content and the enviroment. When hardwood beams are joined to make a frame they usually stay straight. With wooden instruments it is the joinery and glue that holds everything straight. I thought I could already see a crack in one of your pictures, or was it just a grain effect? Not trying to be negative because I would love to use timber in my speaker projects.

That's not a crack, just the grain.

What if I brace the back of the hardwood with alumunium bar for example? Or glue an MDF board at the back (like 'layering')...

I did some more reading and the one that I have is "backsawn" which have the risk of warping more than "quartersawn" ?

Originally Posted by Lignum

Very impressive gainphile. They look (and no doubt sound0 superb.

Thanks Lignum!

Sonically they are like my crappy old prototypes which I made using Pine wood. But having a properly made cabinet made me want to spend even more time with them

Originally Posted by LGS

Hi gainphile,
What kind of hardwood is that? It looks like a Jarrah, but it's a bit light. Is there any stain under the Tung Oil?
Whose Tung Oil did you use and did you sand between coats? With what grit did you finish sanding before you oiled and what grit between coats. How long did you let the oil sit before wiping it off.
The failure of the grain to show under the lights in your house could be due to several things.
The strength of the light could be inadequate to allow differentiation to the eye. The wavelength of the globe/element might be reacting with UV dampeners in the oil to either quench part of the overall spectrum, or to highlight other parts, such as far reds.
If you have a good finish in natural light, i.e. good grain differentiation, good colour, satin finish, then the cause of your problem must be environmental. Perhaps a down light with a broad spectrum globe over the speakers will help this. You might also consider using a UBeaut Traditional wax finish on the timber. This will definitely give you a good satin lustre. (and it smells even better than Tung Oil.)

Hope this helps

Regards,

Rob

They are not Jarrah, but Mahogany ("Eastern Mahogany?"). The oil is Feast and Watson "China Oil". The sanding from memory simply 220 (?) grit using orbital sander than 280 grit. 4 coats in total.

I did not sand between coats (should I?) but let them dry for 24 hrs. Basically one coat every time I go home from work

Originally Posted by soundman

Yes there are issues with solid timbers warping and moving, but it varies on the spicies, moisture content and how the timber has been cut.

many people do sucseed in making speakers out of solid timber without advent.

but a couple of precautions.

1. build the speakers is such a way that the panels tend to be held flat.

2. treat both sides of the panels the same way..smart people do this with table tops and other flat things....this way moisture transfer will be equal on both sides of the penel and will tend to warp less.

3. keep em out of the sun and be carefull about sudden climatic changes


as for the finish and appearance.

Ring pourous woods (hardwoods) can have different lights and hues depending on how the light strikes the surface, the character of the light and the angle of viewing........rosewood that can look fabulous in the right light and can present gorgeous flickering colours and lights and it is moved in the light, BUT can look dull and dog $##t on poor light.

Its all baout the thousands of little trnaslucent tubes that make up the wood structure.

I have not had much to do with oiled finishes, but it is well knwon that to get the best finish out of oil can take a long time.

There is the old adage that with tung....a coat a day for a week, a coat a week for a month and a coat a month for a year........yeh, probaly a bit over the top, but ya get the idea.
Oil takes time to absorb into the timber then takes time to polemrise or "go off".

good work.

cheers

Thanks for your great tips!! For one I had made the mistake of only coating the back once (no one will see....)

The appeal with Tung Oil for me is all the saying on the Internet that they will get better with time and very easy to fix !

Hi Gainphile,
Sorry to be so long responding. I would expect F&W China Wood Oil which is I believe one of the pure Tung Oils available, to give a fairly flat finish. 240 grit final sanding is, in my opinion too low. I would advise a minimum of 400g and 600 if you can get it between coats. I think this will bring up a satin lustre for you. Probably another couple of coats using this method will work.

Regards,

Rob