more on paint/stain VOCs

This follows up a previous thread, "Recipe to restore VOCs?", in which I asked about improving the performance (water repellency, longevity) of the new low-VOC oil-based deck stains. I didn't get much back that was useful. I've looked online at a lot of MSDS (material safety data sheet) documents, and found that pure linseed oil (the traditional base of most oil paints and stains) is essentially ZERO VOC. Raw linseed oil takes a long time to dry (tung oil takes even longer), hence the addition of drying accelerants. "Boiled" linseed oil adds a broad range of solvents and drying agents to speed this up, and THESE are the things which determine the VOC level, toxicity, carcinogenicity, etc. It can STILL be VOC-compliant. THEREFORE, it should be perfectly legal ANYWHERE to add raw or (compliant) boiled linseed oil to any oil-based paint or stain, assuming no compatibility problems. (Does anyone have a serious objection?) The question I have is: HOW MUCH? Like, some fraction of a cup to a gallon? In comparison, the solvents turpentine and mineral spirits are essentially 100% VOC. Is there a good reason to add a solvent to this recipe as well? Does it further reduce drying time, or control the viscosity, or keep the additives/colorants/etc in solution, or maybe help soak the oil into the wood? If so, how much? Or can it be ignored? Has anyone experimented with this, successfully or not?

Reply to
jlfork
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Adding VOC's is not going to improve any product. In order to satisfy VOC regulations, products were reformulated which means that not only proportions were changed but different ingredients were used. You're wasting your time.

Reply to
Frank

snipped-for-privacy@aol.com wrote: ...

Yes, the coatings/finishes manufacturers have experimented w/ this extensively.

Look for some of the articles and/or responses in Q&A section of FWW and similar publications supplied by Chris Minck to learn a great deal about finish chemistry.

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Reply to
dpb

On 9/16/2008 12:28 AM snipped-for-privacy@aol.com spake thus:

That's probably true (that boiled linseed oil is VOC-compliant). Minor correction to what you wrote: the thing that makes boiled linseed oil drying is the addition of drying agents, which, as I understand it, are metallic salts. (Which is why one doesn't want to use this stuff on anything that comes in contact with food.) Really has nothing to do with the addition of solvents; after all, that's part of the vehicle, which doesn't affect drying (polymerization or whatever).

Reply to
David Nebenzahl

Frank - My purpose is to restore water repellancy to my deck stain. The new stuff doesn't do it. My comments were primarily about adding VOC-compliant boiled linseed oil. The solvent questions were posed only because I had seen many formulations for other purposes online (concrete, furniture, boats, etc) that used a mixture, and I wondered if there were good reasons to do so. I will repeat this: raw linseed oil is essentially ZERO VOC. Look it up if you don't believe me; the MSDS docs are online. It dries by oxidation, not evaporation. Same with tung oil. They actually increase their weight by 12 - 16% in the process, according to what I've read. If I chose to, I could mix raw linseed oil (zero VOC) with turpentine or mineral spirits (100% VOC) in a ratio of 2 to 1 or so and STILL comply with a 350 g/l VOC limit. Obviously, I couldn't "correctly" mix these solvents with boiled linseed oil if the latter was already at that limit. Wink, wink. You're right about formulation differences, which is why I brought up the compatibility issue and asked if anyone had tried it. I don't think I'm wasting my time yet.

Reply to
jlfork

On Sep 16, 11:39=EF=BF=BDam, David Nebenzahl wrote= :

Dave - The metallic salts part is true, but that's an issue of toxicity, not VOC compliance. And not all of them are dangerous. I'm still not sure about the solvent part, though. It IS a component in the various formulations, and I assume there's a good reason. Example: concrete treatment is 50/50 boiled linseed oil and mineral spirits. Why? I dunno. Maybe for penetration rather than drying. And if that's the case, I'd say it was a GOOD idea. That's another question that needs answering.

Reply to
jlfork

snipped-for-privacy@aol.com wrote: ...

As I said earlier, find and read stuff Chris Minck writes -- he's a professional finishes chemist and gives the reasons behind all this stuff in layman terms in articles and Q&A columns in FWW in particular that I'm aware of.

Reply to
dpb

On 9/16/2008 5:05 PM dpb spake thus:

I second that emotion. Haven't looked at FWW for a while (used to be a subscriber), but I remember that their writers were very good at demystifying and explaining whatever process, material or tool they were writing about.

And to answer the question before that, yes, pretty sure the solvent in deck coatings is for penetration and has nothing to do with drying (apart from possibly slowing it down).

Reply to
David Nebenzahl

David Nebenzahl wrote: ...

The solvent's purpose is what it says--it's what the rest of the finishes are either dissolved or suspended in. W/O the solvents, the can would be a bunch of other stuff w/ nothing to mix it up with. Kinda' like a cake batter w/o the milk/liquid.

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Reply to
dpb

Interesting note: I opened a new, customer-supplied can of oil-based paint a few months ago to paint a cabinet. (Sorry, but I don't remember the manufacturer.) The paint came out of the can in a big clump, almost like a can of dog food. Well, maybe not _that_ solid, but it gives you the visual. It bent and broke after a couple of inches of paint slid out.

I had to add a quart of thinner before I could brush it on, never mind spraying. They certainly solved the VOC issue!

On the plus side, I got two gallons of paint in a one-gallon can. :)

Reply to
SteveBell

I did. And that's MINICK. I went through all the articles, Q&A and letters at the Fine Woodworking site. I'm not a member, so I didn't read his featured article (was anything useful there?). I also GOOGLED "Chris Minick" and found several references to his recipes and info.

Examples:

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The entry about adding paraffin for posts was particularly novel.

But I found nothing about trying to boost the newer retail oil stains specifically (or, for that matter, paints); most of the above was from scratch or mixed with varnish. (Incidentally, most involved BOTH boiled linseed oil AND a solvent.) They made for interesting reading, but none actually answered my questions. Did I miss something?

Reply to
jlfork

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