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Forum topic by hObOmOnk posted 05-16-2010 09:36 PM 2143 views 0 times favorited 48 replies Add to Favorites Watch
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hObOmOnk

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05-16-2010 09:36 PM

...

-- 温故知新


48 replies so far

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trimmer

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#1 posted 05-17-2010 03:30 AM

a.

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DaleM

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#2 posted 05-17-2010 03:45 AM

C. 1.66 lbs.

-- Dale Manning, Carthage, NY

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Scott Bryan

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#3 posted 05-17-2010 03:52 AM

I am with Dale.

-- Challenges are what make life interesting; overcoming them is what makes life meaningful- Joshua Marine

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TopamaxSurvivor

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#4 posted 05-17-2010 05:39 AM

a

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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DrB

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#5 posted 05-17-2010 01:23 PM

C

-- Something like a swiss army knife..that's my life. JB

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Dan Lyke

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#6 posted 05-17-2010 02:37 PM

C

-- Dan Lyke, Petaluma California, http://www.flutterby.net/User:DanLyke

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hObOmOnk

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#7 posted 05-18-2010 12:47 AM

The answer is, of course:

C. 1.66 lbs.

-- 温故知新

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TopamaxSurvivor

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#8 posted 05-18-2010 02:34 AM

I would have said, 1.6 #, but I do not know how much the dry shellac changes the weight of the liquid as it dissolves since I have never done it. If a pint is a pound the world around, the answer shouldn’t be 1.66 ;-)) But I don’t know the weight of a gallon of alcohol.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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Sawdust4Blood

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#9 posted 05-18-2010 02:58 AM

a 2 lb cut is by definition 2 lbs of shellac in a gallon of alcohol. However, the mass of the shellac would displace some of the alcohol in a 1 gallon container. Therefore, if then end result of the mixture is a ratio equivalent to a 2 lb cut in a 1 gal container, then the original weight of the shellac would have to be a number less than 2 (though probably not all the way down to 1 lb). I don’t know the weight per gallon of alcohol or the displacement value of shellac in alcohol to say what the exact number is…I’m good with 1.6

-- Greg, Severn MD

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Dan Lyke

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#10 posted 05-18-2010 03:04 AM

Since it’s been a day or so and people are asking for spoilers:

WARNING: SPOILERS

It’s not the weight of the alcohol, it’s the volume of the shellac. A 2lb cut means that 2lbs of shellac flakes have been added to 1 gallon of alcohol. The only way the resulting solution would have 2 lbs of flakes in a gallon is if the flakes were infinitely heavy and thus took no room (I’m no chemist, but there may be things in full solution that do this).

So, falling back on our high school SAT test options, we know the answer is less than 2, so it’s not A or B. D seems unlikely, whence my C guess.

Working backwards from that, now we want to find the volumes of shellac flakes and alcohol in the final solution. If we take 1 gallon of the final solution of a gallon plus 2 lbs of shellac flakes we end up with .83 of the shellac flakes, so we end up with .83 of a gallon of alcohol, and .17 of a gallon of shellac flakes.

If the answer is correct, this also means that 2 lbs of shellac flakes occupies 0.2125 gallons of space, or about 9.4 lbs/gallon (weighing a gallon of flakes will give you a much lower number because of packing).

Unless I made some boneheaded arithmetic error somewhere up there.

And the net assures me that alcohol is about 6.5lbs/gal, although that doesn’t really come into this problem. But that would explain why you need to stir your shellac before you use it.

END OF SPOILERS

-- Dan Lyke, Petaluma California, http://www.flutterby.net/User:DanLyke

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TopamaxSurvivor

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#11 posted 05-18-2010 03:36 AM

I’m no chemist either and I have never made my own shellac. As it disolves, does the volume of the liquid increase? If it does not increase, then the answer would be 2 and the total weight of a gallon of 2# shellac would be aproximately 8.5 #.

Bullseye Shellac says their 2# cut is 7.25 pounds per gallon. Therefore, it appears the correct anwser is some where in the neighborhood of 1.8 # of shellac in a gallon which is slightly closer to 1.66 than it is to 2 ;-))

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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TopamaxSurvivor

17677 posts in 3143 days


#12 posted 05-18-2010 04:45 AM

We are all shellacked in unknowns ;-))

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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hObOmOnk

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#13 posted 05-18-2010 05:15 PM

Many thanks…

-- 温故知新

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PurpLev

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#14 posted 05-18-2010 05:33 PM

A 2 pound cut shellac formula is 2 pound shellac flakes per 1 gallon of alcohol.

The resulting mixture is more than 1 gallon in volume (since it’s 1 gallon of alcohol + the shellac flakes), and thus if you take 1 gallon of the total mixture to fit into a 1 gallon container, you’ll be left with slightly less than 2lbs shellac in the container but not so much that it’s half (1lbs). therefor the 1.66 would be the closest answer, but may not be exactly precise.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

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TopamaxSurvivor

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#15 posted 05-18-2010 11:52 PM

hobomonk, Why did you add the last .06 on 1.6 in the original question?

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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