Semi-gloss or gloss?
- Thread starter Izual
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Greg Nolan
enthusiast
It is mostly a matter of personal preference.
High gloss is the traditional and most commonly used. But lots of people like the look of semi-gloss. My eyes are unusually sensitive to glare, so I prefer semi-gloss because the sunlight reflections are easier on my eyes.
If you are doing semi-gloss, you need only do the last coat in semi-gloss; the earlier coats can be high-gloss.
High gloss is the traditional and most commonly used. But lots of people like the look of semi-gloss. My eyes are unusually sensitive to glare, so I prefer semi-gloss because the sunlight reflections are easier on my eyes.
If you are doing semi-gloss, you need only do the last coat in semi-gloss; the earlier coats can be high-gloss.
Greg Nolan
enthusiast
I don't really know. It seems to be the practice to apply semi-gloss only as the final coat. The contractor who refinished the oak floors of our house some years ago, for example, used a base coat of glossy varnish, and a final coat of semi-gloss. However, if you are only applying two coats, a base and a final, I would guess that you would be ok if both were semi. More than that, I would guess the finish might appear a little less transparent, or with multiple coats, perhaps even a bit cloudy -- there would be more of the solids that make the varnish semi-gloss present, and they would interfere more with the transparency of the finish. But I don't think I have ever applied more than 2 coats of semi-gloss varnish (which looked ok), so I can't really say.
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yeolwoodsman
Rolf Warncke
I recently had a couple of passing conversations about this that made sense and wil add to the discussion. The first was at the paint store where I was getting some spar varnish for my sons canoe. When the guy behind the counter saw that I was buying satin and semi gloss he told me to be sure that I stir the satin well before using. He then said they added silica to the gloss formula to get satin...makes sense. I once filtered some satin that had some skin in it and after brusng it on it was glossy...interesting. The second conversation was just yesterday. A friend was watching us put the outwale on the canoe when he started to ask some questions about finishing and if we would be using satin or gloss. He started to explain that guys building bamboo fly rods only use gloss varnish because "on the molecular level it's less porous, and allows for a better action on the fly rod". Again, makes sense but only to someone like me who tends to believe what he thinks makes sense. Not an expert by any stretch! Just though I would throw this into the mix. Interesting thread.
By the way I am of the habit of using gloss for the base coats and finishing with what I want the final surface to look like. I've always been told that gloss builds up faster that satin or semigloss.
By the way I am of the habit of using gloss for the base coats and finishing with what I want the final surface to look like. I've always been told that gloss builds up faster that satin or semigloss.
Greg Nolan
enthusiast
My understanding of UV protection is that it comes from chemical additives. For the same brand, I (not being a chemist) see no reason why the UV protection should be different in gloss and semi-gloss or satin. Every varnish maker makes a claim of "maximum" or "greatest" UV protection, but since I have never seen a report of any objective testing, I assume that such claims are puffery -- the sort of subjective claim that the law allows a seller to make on the assumption that no buyer is foolish enough to take such a claim seriously.
In an area such as this, where little or no objective information is available, myths based on unfounded opinion tend to grow and multiply.
I have read the notion that glossy varnish provides better UV protection because it reflects more light than semi-gloss or satin -- again, without any objective basis, and countering such a notion is the idea that the added silica solids in satin or semi-gloss block some light from passing through the underlying varnish. Which is correct? Don't ask me.
I find it hard to believe that there is any difference in porosity on the molecular level between gloss and semi-gloss -- I think it more likely that the base varnish stock is identical, with perhaps some adjustment of thinning agents to make the silica disperse more easily. I think that yeolwoodsman's paint vendor is correct that satin or semi-gloss is made from the same base stock as glossy -- so why would there be any difference in porosity on the molecular level. And anyway, how did the bamboo rod maker make that determination? Seems to me it would take a lot of time with an electron microscope examining a lot of different varnishes to com to that conclusion, and I am not aware that an electron microscope is part of the usual tool kit of rod builders. And in the limited amount of varnishing I have done, I have not observed any difference in the rate at which either builds up -- but I usually thin varnish a bit before applying it, and have little or no experience with how the stuff behaves right out of the can, so were I to offer an opinion on this issue, it would be worthless.
Some people will swear that the brand they use is best, but probably have nothing but very limited experience (that is to say, they have not done any controlled testing) for such a subjective opinion. Undoubtedly some brands have better UV protection than others, but there is no way to tell.
Some varnishes are thicker than others right out of the can, but they may be more difficult to apply, and may require more thinning.
What I think this all boils down to is that it is not something worth worrying about since there is no way for a consumer like you or me to judge -- so I just use the premium grade of a reputable brand to get the look I want. Even there, I can do no more than trust that the premium grade is actually better than the lower grade -- for all I know and can tell, the manufacturer slaps a different label on basically the same stuff.
In an area such as this, where little or no objective information is available, myths based on unfounded opinion tend to grow and multiply.
I have read the notion that glossy varnish provides better UV protection because it reflects more light than semi-gloss or satin -- again, without any objective basis, and countering such a notion is the idea that the added silica solids in satin or semi-gloss block some light from passing through the underlying varnish. Which is correct? Don't ask me.
I find it hard to believe that there is any difference in porosity on the molecular level between gloss and semi-gloss -- I think it more likely that the base varnish stock is identical, with perhaps some adjustment of thinning agents to make the silica disperse more easily. I think that yeolwoodsman's paint vendor is correct that satin or semi-gloss is made from the same base stock as glossy -- so why would there be any difference in porosity on the molecular level. And anyway, how did the bamboo rod maker make that determination? Seems to me it would take a lot of time with an electron microscope examining a lot of different varnishes to com to that conclusion, and I am not aware that an electron microscope is part of the usual tool kit of rod builders. And in the limited amount of varnishing I have done, I have not observed any difference in the rate at which either builds up -- but I usually thin varnish a bit before applying it, and have little or no experience with how the stuff behaves right out of the can, so were I to offer an opinion on this issue, it would be worthless.
Some people will swear that the brand they use is best, but probably have nothing but very limited experience (that is to say, they have not done any controlled testing) for such a subjective opinion. Undoubtedly some brands have better UV protection than others, but there is no way to tell.
Some varnishes are thicker than others right out of the can, but they may be more difficult to apply, and may require more thinning.
What I think this all boils down to is that it is not something worth worrying about since there is no way for a consumer like you or me to judge -- so I just use the premium grade of a reputable brand to get the look I want. Even there, I can do no more than trust that the premium grade is actually better than the lower grade -- for all I know and can tell, the manufacturer slaps a different label on basically the same stuff.
