I have a drum of raw tung oil that I would like to polymerize to use on teak flooring and furniture...
I have searched the net up and down and the most I can come up with is that it needs to be heated to 240�C in an inert atmosphere... Anyone have any more info, tips? I have a university lab that would like to help but they also have not been able to dig up any info... Does anybody know where I could find this information?
Thank you VERY BIG in advance... ;-) Dennis Linkletter
>If raw tung oil is pure tung oil, I use 50% tung oil and 50% mineral spirits for the first 2 coats waiting at least a day in between, prefferably 4 days. Then the last coats [at least one] should be pure tung oil.
>I have no idea how tung oil is polymerized other than through some sort of chemical "cooking" process which I'm sure is complicated and expensive. However, it seems to me that additives and driers are what pure tung oil needs in order to provide a good protective coating that will penetrate/bond/adhere to a surface, hence the addition of varnish and turpentine. Beyond this, I dunno.
I don't understand why you would want or need to do anything to the Tung Oil. It is a perfectly good finish by itself. Tung Oil will self-polymerize in the presence of Oxygen. The addition of a thinner will make it happen faster.
The thinned Tung Oil will polymerize overnight, by itself. Are you looking for something faster than that? Add more available Oxygen in the form of Japan Dryer?
Have you tried this and it didn't work? Then I would suspect that the Tung Oil is old, and in that case, there is nothing you can do to it to make it polymerize.
Are you looking for a harder surface? Add varnish resins for a surface film that is harder than that of the cured Tung Oil.
Are you trying to make your own product such as the Partially Polymerized Tung Oil products by Sutherlin-welles and others? Call and ask them what they do to the oil. Or, find a finishing chemist. They will describe the process for you, but I would expect that you would have to pay for the information.
Both non-conjugated and conjugated drying oils like linseed and tung can be polymerised by heating in an inert atmosphere. These polymerised oils are then referred to as bodied oils. To achieve the higher viscosities of bodied oils, non-conjugated oils are heated up to 320�C and conjugated oils to 240�C.
This increase in viscosity, or 'body', is caused from thermal decomposition of naturally-occurring hydroperoxides. This decomposition yields free radicals that contribute to a limited amount of cross-linking.
Tung oil heating must be carefully controlled, or the polymerisation will lead to gelation of the oil. The viscosity can also be increased by passing air through the oil (called blown oils) at high temperatures - up to 150�C. Reactions like those seen in crosslinking cause oligomerization of the oil.
Polymerised tung and linseed oils dry faster, and are harder and more durable than raw oils. They also produce a smooth, glossy finish, whereas raw oils produce a matt sheen, a result of the natural expansion that takes place during polymerisation. This expansion creates a finely-textured surface that appears to the naked eye as a matt finish.
>Polymerizing causes the oil to flow better, dry quicker and harder. If you don't have a method of heating I guess you need to buy a 55 gallon drum of varnish and a 55 gallon drum of turpentine. Then get a 165 gallon tank to mix it all.
One thing I learned a long time ago is to ask first, then act.
>I read all of that and still don't have a clue what he is talking about.
The simple facts are still what I said in my post. Thinned raw Tung Oil will cure overnight. The partially polymerized product will cure overnight. So what is the deal with boiling it. Add some varnish resins if you want a harder surface film. Either is a better alternative than trying to boil a 55-gallon drum of Tung Oil in the back yard.
Boiling finishing Oils is an industrial process, not something that anyone should be doing. I would doubt that the College lab would be prepared to handle quantities large enough to consider using it as a finish.
If you are still intent on blowing yourself up, ask Steve Russell how to go about it.
>I just realized that I did not mention that I'm in Surabaya, Indonesia and it's just not cost effective to purchase and ship a drum in from the States. Especially considering the prices companies are getting for the finished product.
My drum of Chinese raw Tung was only $540. Look at commercial oils prices and do the math.
I�m hoping to be processing about 1,200 sqft at any given time. I�m going to use citrus oil solvent as not to fill the factory with toxic fumes� I�ve written to Steven Russell twice and have yet to receive any response. I�ve thought about heating the oil in small aluminum containers with out any air inside using a pre heated ceramic kiln. The university has a reactor that can heat the oil in an inert atmosphere.. I don't know why should this be so difficult.. I just don't know about heating times and cooling schedules... The oil is not going to boil I'm told... Thanks again for any ideas...
