I have Zinsser Seal Coat (2# cut) and I want to cut it to 1# and 1/2# (for wash coats). What is the ratio of alcohol/shellac to reduce the 2# cut to these cuts? Thanks.
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I have Zinsser Seal Coat (2# cut) and I want to cut it to 1# and 1/2# (for wash coats). What is the ratio of alcohol/shellac to reduce the 2# cut to these cuts? Thanks.
2# to 1#: 50% 2# + 50% DNA
2# to 0.5#: 25% 2# + 75% DNA
Shawn,Quote:
Originally Posted by Shawn Patel
Thanks. That's what I tought but I wnated to make sure before I mis-mixed a whole gallon! :eek:
While this is likely close enough it is not exactly true. It is true that if you were going to make a 2# cut that you would take 2# of shellac flakes and add to one gallon of DNA and 1# of flakes to one gallon DNA for a 1# cut. However, one gallon of the pre-mixed stuff in a 2# cut has less than a gallon of DNA - it also has the volume of the shellac in there.Quote:
Originally Posted by Shawn Patel
So, if you simply add another gallon of DNA the mixture will not be a true 1# cut .. but it should be close enough.
Actually you are right. I just got a response from Jeff Jewitt at Homestead finishing and he said for a 1# cut, mix 1 part shellac to 2/3 part alcohol. So for a 1# cut it would be 32 oz shellac and 21 oz of alcohol. To get a 1/2# cut he said to add 1 part shellac to 2 parts alcohol. Again, for 32 oz of shellac I would add 64 oz alcohol. For me, these ratios can really be confusing. I wrote this information down in my shop notes!:DQuote:
Originally Posted by Larry Fox
I apologize; I've been doing it 'wrong' all this time. I thought a 2# cut meant 2# shellac per 1 gal of finished product; it's PLUS 1 gal alcohol. And to think I'm an engineer....
You should be ashamed of yourself. NONE of the rest of us have EVER been wrong :D:D:D.Quote:
Originally Posted by Shawn Patel
Seriously though, I am now confused. Is it safe to assume that since the question originated with Zinsser's 2# cut Seal Coat that this is what Jeff is calling "shellac" in his answer? That is; for a 1# cut you add 1 part Zinsser's Seal Coat and 2 parts DNA? It seems funny to be discussing all this as I just mix shellac till I have the consistency I am after without much consideration to actual "cut" but now you've got my curiosity up ;).
I'm with Glen. I keep a can diluted for use on different shop items and as sealer. When the mix gets low or thick, I will pour in some more DNA and keep going. I'll usually add a little DNA at the start to make up for evaporation during the previous use.
I am still using the same uncleaned brush after 5 years that I squeeze out the shellac mixture with a paper towel, then wrap it with a fresh paper tower, pour a little DNA on it and then insert into a newspaper plastic bag and twist. After a month or so, the bristles do get stiff, but soften right up when put into the mix for use. Of course, this is not for "FINISH" work but works great for sealing.
Yes, his answer is based on the Zinsser product.;)Quote:
Originally Posted by glenn bradley
This is what I typically do as well but thought I would point out that the straight dilution method would not yield the exact result.Quote:
Originally Posted by glenn bradley
I very often use the "eh, close enough" measurement system when it comes to these types of things. :)
You are supposed to measure? ;)
I just mix until it looks like what I want.
If we're really trying to be ultra precise about it, something about that just doesn't ring true if we're talking parts by volume. ("oz" could be weight, but when referring to liquids, "oz" usually means "fluid ounce").Quote:
Originally Posted by Byron Trantham
Admittedly, I've never mixed shellac from scratch, but as a reality check, for those of you who have mixed a 2# cut from flakes and DNA, is the volume of the resulting mixture actually 50% more than the volume of the DNA that you started with? Intuitively that seems high.
Where did I get that 50% figure? You start with some volume of 2# cut mixture of shellac and DNA that contains a given weight of shellac and a corresponding volume of DNA. Turning that into a 1# cut means you double the volume of DNA with the same weight of shellac. If you do that by adding 2/3 part of DNA by volume, that means the volume of a 2# cut mixture is 1/3 shellac by volume and 2/3 DNA by volume.
It also means that when you mix a fresh batch of 2# cut using 2# of shellac and 1 gal of DNA, the final volume of the mixture will be 1 1/2 gallon. If 2/3 of the final volume is the 1 gallon of DNA, the final volume must be 1 1/2 gallons, a 50% volumetric increase.