Swede Posted April 25, 2008 Posted April 25, 2008 I will admit, I've always been kind of a dork when it comes to nice lab equipment. Becoming a Pyro gave me an excuse to buy a decent scale, and get rid of my old, inaccurate POS postal scale. The range of the scale, and the resolution, are both big deals. When working at the kilogram level, with rare exception, you don't need an accuracy of 0.001 grams, and besides, scales that can do 1 kilogram can't resolve to milligrams, with the possible rare exception of super expensive lab scales. I'm curious, what sort of balances or scales do you guys use regularly, and what resolution do you look for? For lighter weights, I'm thinking I'd like to resolve 0.01g, perhaps for testing very small batches or specific compositions. This one looks pretty decent.
justanotherpyro Posted April 25, 2008 Posted April 25, 2008 Yeah thats a more than decent scale. It definitely matters what your budget is. The 300g max capacity is a little low IMO. The question is if that extra decimal place is worth the extra $100 to you. Accuracy to .1g is good enough for pyrotechnics in general. It works for testing small batches. I test 1g batches of stuff all the time with mine which has a 550g capacity. If you want to do other chemistry related things with it then the .01g accuracy is nice. Also the cheapy one on the market that is popular is harbor freight's. It seems like this one is a bit more sensitive than the other one, but I like having the back light and use both equally.
Canadian_Pyro Posted April 25, 2008 Posted April 25, 2008 As justanotherpyro said, a 300 gram capacity is pretty low. I'd go with something that is capable of at least 500 grams. Precision to tens of milligrams is unnecessary, unless you are working with small batches of flash powder or similar. In that case, I would go for the additional precision, but if you are only measuring small batches, you can purchase 0.01x100g digital scales for about $30. They tend to stabilize exceptionally slowly however. My scale measures in 100 milligram intervals, and works just fine. It also cost about $130 less than the one you provided a link to.
asilentbob Posted April 25, 2008 Posted April 25, 2008 Its all dependent on the scale of things you do.(weak pun intended.) I use some mass produced knock off brand postal scale 4Kg capacity at 1g resolution IIRC... Nice for making decent sized batches of star comps. I'd like to have another balance for chemistry though with .01g resolution... just no money set aside for one.
TheSidewinder Posted April 25, 2008 Posted April 25, 2008 When I was flush with money a couple years ago, I ended up getting three: Ohaus CS200 - 200g x .001gA&D - 1kg x .01gOhaus EB30 - 30kg x 1g I've used all three fairly often, though I find I have little use for the A&D. (It's for sale, if anyone's interested, and comes with a seperate power supply.)
50AE Posted April 25, 2008 Posted April 25, 2008 I use a 1kg max weight scale, with 0.1g accuracy and this is enough for me. Sometimes is useful to have one with 0.01 accuracy, to make 1g batches for testing Scale
Swede Posted April 25, 2008 Author Posted April 25, 2008 Thanks for the inputs, that is the sort of info I need. Part of what I want to explore is alternate propellants for rockets and/or firearms (like Pyrodex) using KNO3 and various fuels, done on a very small scale, and in differing ratios. For this, I think the 0.01g resolution would be fine, while for general Pyro use, a 1 kilo scale would be desireable. It's amazing how cheap the smaller pocket scales have become. I call them "drug scales" because it seems many of them are designed to be disguised and used to sell drugs. You can buy a 100g X 0.01g jewelry/drug scale for $15 or so, while a better quality bench scale will run over $100. I wonder if this is a case where you truly do get what you pay for, or are the pocket scales in fact pretty decent and acurate devices? Here's a 100 x 0.01g scale for a whopping $12 + shipping... seems decent enough.
Frozentech Posted April 25, 2008 Posted April 25, 2008 Here's what I use. http://www.myweigh.com/scales/large-scales/triple-beam-scale
lnstantkarma Posted April 26, 2008 Posted April 26, 2008 I use a good old ohaus triple beam scale with a dial o gram, mine has this big scoop instead of the flat platform so it's great for measuring powders I got it off ebay.
JCrewPyros Posted April 29, 2008 Posted April 29, 2008 Scale What about this scale... lemme know so I can get it ordered asap... I thought I had one ordered but I guess I didn't...
due559 Posted April 29, 2008 Posted April 29, 2008 Scale What about this scale... lemme know so I can get it ordered asap... I thought I had one ordered but I guess I didn't...http://www.amazon.com/ZX-600-Digital-Pocke...09432617&sr=8-1 Same thing but 5 bucks cheaper at Amazon.
Swede Posted April 29, 2008 Author Posted April 29, 2008 I've got one just like that, and it's nice - works fine. Since I started this thread, I bought the fancy bench scale, the VMC-302b or something like that, with the "Deluxe German Load Cell," etc etc. This thread got me thinking... there is a reason a real lab spends what it does on a fine quality scale. They'll spend $1,000 on a good scale that goes 500g X 0.01, when they could buy an eBay drug scale that has the same range for $20, and I'm guessing it is durability, repeatability, and real accuracy. I put the drug scale next to my new quality bench scale, took two precision 50.00 gram calibration weights, and weighed them over, and over, and over. On the quality bench scale, it was boring. 50.00g, 50.00g, 50.00g, 50.00g. No variation. With the drug scale, it was more like 50.00g, 50.02, 50.02, 50.00, 49.97, etc. So there is definitely superior performance from the quality scale, but the cheap scale was within a few hundredths each time, if not dead on. If you are doing cancer research or something, then yes, the more expensive scales are necessary. For this stuff... I'm thinking the cheap ones will work fine. I will admit though, the VMC-302 is very nice to work with. It settles faster, doesn't dither once it is settled, and it is just a quality piece of hardware that I have complete confidence in. It's also nice because it's big; the platter is maybe 5" across. But with the money saved, you can buy a lot of other cool stuff! I like my fancy scale, but the cheap ones work very well too. One thing - be sure it doesn't have an "Auto Off" function. That makes me nuts! The stupid thing blinks off after I have "tared" a cup, while I fumble for some chemical, and being forced to rush is both annoying and dangerous.
justanotherpyro Posted April 29, 2008 Posted April 29, 2008 Yeah that is definitely frustrating. It was one of the things I took into consideration when I bought mine. I could have gotten the cheapo harbor freight one but I got the one that I did for $30 because of the warranry durability and I made sure it had a long auto off.
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