This follows the threads "recipe to restore VOCs?" and "more on paint/
stain VOCs." It's my experiment on "doctoring" deck stain to get
better performance. This is Episode 1.

I bought a pint of Klean-Strip boiled linseed oil (BLO) and a gallon
of Klean-Strip 100% mineral spirits paint thinner, and intend to use
them to modify my new reformulated retail oil-based semi-transparent
deck stain in the hope of improving its durability and water
resistance. Because I'm adding linseed oil, I'll also add some
mildewcide.

The BLO says ZERO VOCs on the label and in its MSDS (online), which
presumably means no solvents added. There is no info on the label or
in its MSDS about ANY additives, like metal salts, and the MSDS lists
no concerns of carcinogens. (Other manufacturers' MSDS sheets list
things like cobalt as a hazard...) I HOPE there's something added to
speed up drying... It's somewhat thicker and more yellow than cooking
corn oil.

If VOCs were the only concern, it would appear that anyone, anywhere,
is perfectly free to add as much zero-VOC BLO as they like to any oil-
based stain or paint, assuming chemical compatibility, without
violating ANY VOC regs. But there's more.

I assume that there are good reasons to add a solvent as well as the
BLO to my deck stain, since just about every recipe I've seen for
other applications uses both. Maybe it improves penetration. I assume
that lower VOCs were obtained primarily by reducing or replacing the
old solvents in paints and stains, which may account for the poor
performance. So I figure I'll restore 'em.

The mineral spirits label says 791 g/l VOCs, while its MSDS says 815 g/
l VOCs. I don't quite know how to reconcile this; maybe I got an old
one... The MSDS bulk density of this product is 6.380 lb/gal.
Multiplying that by 120 gets 765.6 g/l, which is LESS than either
listed VOC content! I can't resolve that one, either. (That conversion
factor should really be 119.83, but everyone uses 120...) Any way you
do it, though, it's 100% VOCs.

The questions remain: how much shall I add, and in what proportions,
to a gallon? And can I do it without violating the VOC regs? (I really
don't care about the latter, but I'll play the game...)

I have several cans of stains, some new and some old. The VOC numbers
range from 250 to 610 g/l. I will assume that it will be perfectly
legal to add stuff as long as I don't exceed the original VOC number
on any given can. So how do I do that? Easy. All I have to do is mix
the BLO and mineral spirits separately in a proportion that produces a
mix with a net VOC content less than or equal to that number. Then, no
matter how much of it I add to the stain, the original VOC density
will not be exceeded.

Let's say the stain label says 350 g/l VOC. I have BLO at 0.0 g/l VOC
and mineral spirits (MS) at 791 g/l VOC. Let f be the fraction of BLO,
and (1-f) the fraction of MS. The proportions to match this number are
found from:

350 = f * 0.0 + (1 - f) * 791

which reduces to f = 0.558 BLO, (1 - f) = 0.442 MS. Since the MS is
the VOC source, that 0.442 is the MAXIMUM fraction of MS allowed. So I
could use anywhere between 0.0% and 44.2% MS, with 55.8% to 100% BLO,
as long as the sum was 100%. To make things simple, I'd probably go to
a 40% - 60% mix, or 2 parts MS to 3 parts BLO, as the max.

If that number were 100 g/l VOC, as has apparently become the limit in
southern California, the result would be only 12.6% MS as the max,
with 87.4% BLO, or a ratio of 1 part MS to 7 parts BLO.

So now I have a guideline for satisfying the VOC regs. The next
questions a Is the mix compatible with the new formulations? Do I
want the MAX MS mix, or something less? And then, how much of the mix
shall I add to a gallon of stain? More to come.

On Sep 19, 2:50*am, wrote:
This follows the threads "recipe to restore VOCs?" and "more on paint/
stain VOCs." It's my experiment on "doctoring" deck stain to get
better performance. This is Episode 1.

I bought a pint of Klean-Strip boiled linseed oil (BLO) and a gallon
of Klean-Strip 100% mineral spirits paint thinner, and intend to use
them to modify my new reformulated retail oil-based semi-transparent
deck stain in the hope of improving its durability and water
resistance. Because I'm adding linseed oil, I'll also add some
mildewcide.

The BLO says ZERO VOCs on the label and in its MSDS (online), which
presumably means no solvents added. There is no info on the label or
in its MSDS about ANY additives, like metal salts, and the MSDS lists
no concerns of carcinogens. (Other manufacturers' MSDS sheets list
things like cobalt as a hazard...) I HOPE there's something added to
speed up drying... It's somewhat thicker and more yellow than cooking
corn oil.

If VOCs were the only concern, it would appear that anyone, anywhere,
is perfectly free to add as much zero-VOC BLO as they like to any oil-
based stain or paint, assuming chemical compatibility, without
violating ANY VOC regs. But there's more.

I assume that there are good reasons to add a solvent as well as the
BLO to my deck stain, since just about every recipe I've seen for
other applications uses both. Maybe it improves penetration. I assume
that lower VOCs were obtained primarily by reducing or replacing the
old solvents in paints and stains, which may account for the poor
performance. So I figure I'll restore 'em.

The mineral spirits label says 791 g/l VOCs, while its MSDS says 815 g/
l VOCs. I don't quite know how to reconcile this; maybe I got an old
one... The MSDS bulk density of this product is 6.380 lb/gal.
Multiplying that by 120 gets 765.6 g/l, which is LESS than either
listed VOC content! I can't resolve that one, either. (That conversion
factor should really be 119.83, but everyone uses 120...) Any way you
do it, though, it's 100% VOCs.

The questions remain: how much shall I add, and in what proportions,
to a gallon? And can I do it without violating the VOC regs? (I really
don't care about the latter, but I'll play the game...)

I have several cans of stains, some new and some old. The VOC numbers
range from 250 to 610 g/l. I will assume that it will be perfectly
legal to add stuff as long as I don't exceed the original VOC number
on any given can. So how do I do that? Easy. All I have to do is mix
the BLO and mineral spirits separately in a proportion that produces a
mix with a net VOC content less than or equal to that number. Then, no
matter how much of it I add to the stain, the original VOC density
will not be exceeded.

Let's say the stain label says 350 g/l VOC. I have BLO at 0.0 g/l VOC
and mineral spirits (MS) at 791 g/l VOC. Let f be the fraction of BLO,
and (1-f) the fraction of MS. The proportions to match this number are
found from:

350 = f * 0.0 + (1 - f) * 791

which reduces to f = 0.558 BLO, (1 - f) = 0.442 MS. Since the MS is
the VOC source, that 0.442 is the MAXIMUM fraction of MS allowed. So I
could use anywhere between 0.0% and 44.2% MS, with 55.8% to 100% BLO,
as long as the sum was 100%. To make things simple, I'd probably go to
a 40% - 60% mix, or 2 parts MS to 3 parts BLO, as the max.

If that number were 100 g/l VOC, as has apparently become the limit in
southern California, the result would be only 12.6% MS as the max,
with 87.4% BLO, or a ratio of 1 part MS to 7 parts BLO.

So now I have a guideline for satisfying the VOC regs. The next
questions a Is the mix compatible with the new formulations? Do I
want the MAX MS mix, or something less? And then, how much of the mix
shall I add to a gallon of stain? More to come.

Use Cabots, it works for alot of folks

I can answer the MSDS question as I write a lot of them. Most likely the
technical/marketing folks did not tell the MSDS writer that they had a
new VOC number. The MSDS should still be good for the intended users of
the material if it satisfies OSHA's HAZCOM requirement.

As for you becoming a paint chemist - you are terminally stupid ;(

On Sep 19, 8:13�am, ransley wrote:

Use Cabots, it works for alot of folks


Maybe next time, Mark. I have new cans of stain left over from last
year, so I'm going to experiment with them.
What better comparison could there be than the same deck with the same
stain, one version original and the other doctored up?

On Sep 19, 10:01�am, Frank frankdotlogullo@comcastperiodnet wrote:

I can answer the MSDS question as I write a lot of them. Most likely the
technical/marketing folks did not tell the MSDS writer that they had a
new VOC number. The MSDS should still be good for the intended users of
the material if it satisfies OSHA's HAZCOM requirement.

As for you becoming a paint chemist - you are terminally stupid ;(

Why, thank you, Frank, for your comments. What a helpful fellow.
I don't need to be a chemist to determine proportions. I'll find out
soon enough if it's compatible.
What the hell do you care? It's my deck, my stain, my money, my labor,
and I'm not violating ANYBODY'S regs. If it fails, I'll sand it off
and go with the conventional approach (i.e., a better stain). If it
succeeds, you can bet I'll let everyone know about it. I'll report on
it every once in a while. First will be after it's mixed, applied, and
allowed to dry. Assuming that goes okay, it'll be every 6 months or
so. If it fails, I'll report that, too.

Episode 2: deck prep, mixing, and application.

We had a good rain, which was a good time to clean the deck (16' x 16'
redwood). I used a deck wash, following the instructions. As usual, I
wasn't impressed with the results, but that's what everybody
recommends... Let it dry for 6 days. Weather note for my location: at
this time of year it's usually dry with low humidity, daytime highs in
the 70s and nighttime lows in the 50s.

I started with Behr semi-trans oil-based deck stain from Home Depot,
exactly the same stuff I had used in 2007 (after sanding the whole
deck down) with unsatisfactory results (see previous threads). The
label says it has 550 g/l VOC. This seems pretty high, considering the
VOC limits elsewhere (especially in California). But it produced
almost no water repellancy, even with a 2nd application 2 weeks later,
and pretty much just disappeared from the heavy sun & traffic areas of
my deck after only 1 year. I've re-stained the deck every 2 years
since it was built, so I know what it should look like.

Using my proportion formula from episode 1, with zero-VOC BLO and 791
g/l VOC mineral spirits (MS) and the 550 g/l VOC target, I got
proportions of 0.695 MS and 0.305 BLO. That's more than 2 - to - 1
solvent to BLO as the allowable max. This seems higher than necessary,
judging from the recipes I've seen for other applications. So I went
with a 50 - 50 mix. Pure guesswork.

Next question was how much of this mix to add to a gallon of stain. A
gallon is 16 cups. I guessed that half a cup would be a conservative
starting point. That's only a hair over 3% of a gallon. By comparison,
a lot of applications are ALL BLO and MS, so maybe I'm being too
timid...

Compatibility: it mixed in perfectly, as far as I could tell. No
visual indications of any separation, even after several hours of just
sitting.

Separate issue: I also added a packet of mildewcide. Krud Kutter from
Ace Hardware was the only one I found locally, at least in the 1-
gallon size. Its online MSDS says it's a viscous liquid; what I got
looked like something between toothpaste and putty. Maybe it was just
very old... I squeezed it into the mix and it didn't dissolve or
disperse, even though the label says it's good for ANY paint. I
stirred the hell out of it, but only managed to reduce it to very
small blobs. So this part was probably a waste of time and money. I'd
try another brand if I ever do this again.

Application: with a long-handled 1/2"-nap roller, making sure that the
stain filled any cracks and screw holes completely. I only did the
horizontal surfaces at this time; I'll get the verticals and in-
between the deck boards later. The verticals merely dry and fade with
time, and I only do those every 2nd or even 3rd staining. For in-
between the deck boards, I've found that the fuzzy paint pads WITHOUT
the holder fit nicely, although it can get messy. If I'd been thinking
better I would have done that first, but I was eager to see how the
main flat area would do...

My deck has areas of different combinations of traffic and sun
exposure. Some sucked up the stain immediately, others probably could
have been skipped altogether. I did the whole thing anyhow. So on day
one there are dull areas and glossy areas. I'm not too worried about
that; blowing dust and/or rain will take care of the shine eventually.
From previous experience, these areas will dry at different rates. If
I recall right, it'll be about 5 days before there's NO perceptible
stickiness anywhere, even with an un-doctored stain. We'll see how my
modified version does. Stay tuned.

Episode 3: Drying time and appearance

It took about 7 days before I could no longer find any sticky spots
anywhere on my deck. I had estimated 5 days from previous experience,
but that was only to the point of being able to walk on it in the
usual traffic areas. This time I actively searched for sticky spots,
so it's not really a good comparison. My experiment of adding 1/4 cup
BLO and 1/4 cup MS to a gallon of Behr stain DID dry okay, but I can't
say if it took any longer with certainty. It obviously wasn't less.
The fastest drying areas were those with the highest traffic, most
sun, and heaviest sanding (last year). These absorbed the stain
quickly, felt dry within a day or two, and have a flat appearance. The
shaded areas and those with little or no traffic had retained the
previous stain and came out fairly glossy, certainly moreso than with
previous unmodified applications. The accumulation of stain on these
areas makes them look more solid than semi-transparent, but that
always happens. The glossy areas cause water to bead very well; the
flat areas bead less. I'm tempted to brush some additional stain onto
those flat areas to get more consistent protection and appearance. I
expect the gloss to disappear over time with age, dust, wear, etc, but
we'll see what happens. I also want to see how long the water beading
lasts and if any separation occurs between the new (modified) and old
(unmodified) stain layers.
Incidental note: I had added a packet of mildewcide to the mix and was
disappointed that it did not disperse/dissolve well. (I do NOT believe
it had anything to do with my addition of BLO and MS, which are both
traditional paint ingredients.) But I don't see any little globs of it
on the deck; I assume that the roller "smushed" them, mixing and
spreading them out.
So now we wait to see if my experiment improves anything. I'll report
here if I notice anything happening, good or bad.