Jump to content
APC Forum

Scales. What kind do you use and why?


CaverCork

Recommended Posts

I have searched through the topics on scales and have not really found anything definitive here. Most left with more questions than I started with. My kitten decided to to try and weigh herself on my cheap Chinese "good?" pocket scale and it is now non functional. My other cheap Chinese scale is just that. So I am in the market for a new scale, preferably under $100. I am leaning toward a triple beam, as I am tired of having the scale shut down in the middle of mixing a complicated formula as well as tapping the platform to register minute additions or subtractions of chemicals. I would also like something that is good for research, as my main hobby is micro blasting, so I am constantly tweaking formulas for gas production and velocity, as well as whipping up a pound or two of stars or BP or a pound of ground meat. What I would like to know is what scales do you prefer and why? Digital or analog? Brands? Those types of things. As far as a T beam, I was looking at this, but I don't know anything about the brand. I am also dubious about the "magnetic dampening". Is this a standard feature now?

http://www.oldwillknottscales.com/adam-equipment-tbb-2610t.html

Edited by CaverCork
Link to comment
Share on other sites

The resolution on that scale would not lend itself to research. I like to do that in small batches so it's easy to dispose of if it doesn't work, or doesn't maim and injure if it works too well. I need something with at least a 0.1 gram resolution that is reliable and durable. But thanks for the reply. I was beginning to think maybe I had asked a not so intelligent question.

Edited by CaverCork
Link to comment
Share on other sites

Caver,

There are lots of digital scales available in the range of $150-$200 USD that can have 0.01g resolution -- but further, the 'better' ones have 'crash stops' so that when an errant cat steps on the pan, it doesn't deform the load cell.

 

I'm partial to the EJ-200 model of the A&D scales for precision work, working to 0.01g. They cost just short of $200.00 USD. They have ones in the 0.1g range for considerably less. All their models have pan-stops to prevent load cell crashes, and over several years of using their various models, I've never had one fail, except when I dropped one from table-top height to concrete floor!

 

Keep in mind that even a pan stop wouldn't prevent inertial damage of the load cell if a very heavy weight were dropped onto the pan from a good height.

 

LLoyd

  • Like 1
Link to comment
Share on other sites

I can recommend these scales:

http://www.dx.com/p/pocket-precision-digital-scale-300g-max-0-01g-resolution-15764#.VtJGUOa33wo

 

I'm on my third in 10 years, and they've always performed flawlessly until electronics failure. I've checked them against quality calibration weights and they've all been reliable and accurate. And for 10$ you really can't go wrong, just buy two of them so you have a spare.

  • Like 1
Link to comment
Share on other sites

Lloyd, really nice scale, but a little out of my price range. I have a crisp $100 bill that my wife and daughter haven't found yet, and is pretty much the extent of my current funds. Fulmen, these scales look good, but have the one fundamental flaw all of the little scales have, the auto off feature. My life tends to be chaotic, I have a teenage daughter, and usually get distracted at the most inopportune moments. I also tend to mix chemicals by weight in one container. This is a personal character flaw coupled with an appalling short supply of glassware. The auto off feature gets me every time. Can't beat the price though.

Link to comment
Share on other sites

Marine, though I'm leaning toward analog, if these were not sold out, I would probably be ordering one. Is it really .01 gram resolution? The last scale I purchased on Ebay said as much, but was only .1. And does it have the auto off feature, or at least something programmable?

  • Like 1
Link to comment
Share on other sites

I use digital scale of capacity upto 5 kg and precision 0.5g....
Link to comment
Share on other sites

I recently got this one and so far it's excellent

http://pages.ebay.com/link/?nav=item.view&id=381074268730&alt=web

 

The addition of the calibration weights is a nice addition, but, are they accurate, and can the scale actually be calibrated, or just "tested" for deviance? Ideally you can calibrate to multiple points, and assign the "points" yourself, around the weight you will be working. But that takes a bunch of weights that are not identical, yet, very specific to the stated weight. But it gets worse. You really need a way to confirm those weights, and the weight they are supposed to be at. Bleh.

 

I use a big old square kitchen scale, (Inca) that somehow seams to have survived, and still is reasonably accurate. That is, if the calibration weights i got, cheap of eBay, is worth the time it takes to use em, even knowing it wont provide great results.

 

I really should get updated to a "better" (as in reasonably accurate, and calibration adjustable) digital scale. But the ability to ignore the need for a battery, or a power-source is nice.

B!

Link to comment
Share on other sites

I've tested a few 20/0,001 and 300/0,01g scales against lab-grade control weights, and they've all shown good accuracy, linearity and stability. For our line of work they should do just fine without multi point calibration or certified control weights.

Link to comment
Share on other sites

MrB, the scale has a calibration mode that allows you to adjust within .01 grams. So far it matches the reasons of my two small pocket scales. Readings that small are inconsequential to me but they could be a cumulative problem if using the counting function I reckon.
Link to comment
Share on other sites

As Fulmen mentioned, most digital balances are 'accurate enough' for pyro work. Some folks even continue to use sliding-weight beam balances, quite successfully.

 

But if you're going to the trouble of calibrating your scale, then get one that permits span and linearity adjustments as well as 'max weight' adjustment.

 

Lloyd

Link to comment
Share on other sites

I bought this scale based on the recommendation by a friend at the county Ag extension office. He uses one for soil sample testing and states it's accurate enough for use in the field but iffy for the lab.
Link to comment
Share on other sites

MrB, the scale has a calibration mode that allows you to adjust within .01 grams. So far it matches the reasons of my two small pocket scales. Readings that small are inconsequential to me but they could be a cumulative problem if using the counting function I reckon.

 

Yeah, i'm quite sure that "any" scale is good enough for pyro, as long as they generate repetitive results. Anyway, thank you for the info.

 

 

As Fulmen mentioned, most digital balances are 'accurate enough' for pyro work. Some folks even continue to use sliding-weight beam balances, quite successfully.

 

Yeah, i do. That was sort of what i was trying to say with the description above. I just had no idea what they were called.

 

But if you're going to the trouble of calibrating your scale, then get one that permits span and linearity adjustments as well as 'max weight' adjustment.

 

Indeed. If your going to pick up a "good" digital scale, one that can be calibrated to a few different data points, preferably in the area of where your going to end up measuring things, is really what you want. But again. It's pointless unless you have weights that actually weigh what they say they do, and most the time we don't have the ability to verify that. We just have to take it in good faith, and hope we are ok. We had a couple of calibration weights "back when" where out of the 4 sets only 25gr 100gr and 450gr actually were consistent between the 4 sets.the other 7 weights to each set all disagreed with one and other... Using the ones that agreed with one and other, we were able to "calculate" the error on each weight, but it was still all in good faith, since we didn't really have a way to test the "good" ones. (Back in school. Feels like a 100 years ag.... Feels like yesterday, i mean.)

 

Anyway. I WANT a good scale. I'm pretty sure i don't actually NEED one. But there is a lot of things i don't really need, yet own, if for no other reason then to own them. I cant even see a scale of that dignity to be any more useful in future (per)chlorate making projects, then a cheap run of the mill one.

 

B!

Link to comment
Share on other sites

I was hoping for a few more folks that still use analog (triple beam) scales to chime in. I glean from the information provided, and correct me if I'm wrong, most of you use digital, for price and ease of availability. If I could find a deal like Marine was able to get, that little scale would serve all of my needs for quite a while. But the only ones I can find like it, and that fit my strange lifestyle, are over $200, so those are out. Another thing I am concerned about is accuracy, which has been discussed. At least one of my LE blasting mixtures is potent enough that two grams can obliterate a 70 lb chunk of concrete and shatter a truck windshield 60 feet away. The only things in my arsenal more powerful are HE. So naturally, I like to make this in small batches and it has five different components, which requires a fair degree of low weight accuracy. I also own a ranch, and like to cut and grind my own meat, and my little scale was perfect for this. So I'm looking for something that will do fireworks and kitchen duty on a shoestring budget. Plus I'm leery of Chinese electronics, which usually find their way to the dead electronics shelf in my barn within a month or two, though I did get lucky on the one the cat killed. It will be a few days before I make a final decision, so keep the suggestions and advice coming. Thanks!

Link to comment
Share on other sites

At least one of my LE blasting mixtures is potent enough that two grams can obliterate a 70 lb chunk of concrete and shatter a truck windshield 60 feet away.

----------------------------------

Please -- excuse me for laughing in your face over such a statement. I operate a licensed facility in Florida. In Florida, among other things, one must have a blaster's license in effect in order to run a fireworks manufacturing facility.

 

The old Dupont Blaster's Manual just might have a few arguments with your claims.

 

Now... I will allow that if you had a 3/8" thick sheet of concrete large enough to weigh 70lb, a 2g flashcracker could break it. "Obliterate"? No.

 

And similarly, if you fired a projectile from a 2g cracker at a windshield 60 feet away, it would break it.

 

AND, 2g of smokeless powder in a high-power rifle could do that.

 

But your claims were intended to make the user think you were talking about a fireworks device, of a solid block of concrete, and only the blast itself being responsible for breaking the windshield at that distance. Your claims are pure BS, and I will be glad to 'take you to the bank', if you desire it to be proved that you're lying in a public setting, with fireworks-knowledgable onlookers.

 

Why not give us this miracle low-explosive 'blasting mixture' formula, and let us confirm your results in a scientific way?

 

LLoyd

Link to comment
Share on other sites

One other thing -- I have and use two beam balances. One is an OLD Fischer two-pan balance from my college days, and the other an Ohaus 'dial-o-matic'. Both work fine, but I don't like the dial type, and very much do like having the two-pan arrangement for taring bowls, etc.

 

Lloyd

Link to comment
Share on other sites

Well Lloyd, thank you for stating you have triple beams and how they compare to any digital devices you may employ. The info on the dial type is very helpful. As far as my blasting agent, it was discovered in lab accident involving overuse of a solvent while making another formula. Perhaps "obliterate" was a little strong and my wording about the windshield WAS vague. A quarter sized piece of debris that penetrated the blast shield did that little number. Let me repeat, through a blast shield, traveled sixty feet, and still had enough inertia to break safety glass. And how about the "block" being reduced to penny and fifty cent pieces in size. Is that descriptive enough for your runaway imagination? And I see you imagining this charge lying on the concrete and once again, you would be wrong. You think I'm a fu**ing idiot? That would be doable with 120 grams of ANNM correctly placed. The charge was placed in a bore hole several inches deep and contained with bentonite clay plug. A mere "flash cracker" or "smokeless" wouldn't do that with two grams, I know from experimentation. And if you think I am just going to give you, or anyone else on this forum, the formula and manufacturing details of a substance almost as fast as flash and gassier than nitrocellulose, well, I'm just not that crazy. Your baseless attack was unwarranted and unwelcome. My "brief and less than detailed" description was to emphasize my desire for consistent accuracy, not "bragging" or "claiming" anything, as most of you could care less what I do for a hobby anyway. And I could not care less about your license or manual because innovation and experimentation are done outside of the "shell". Fireworks device indeed. So you can either accept my word, or you can continue to be an ass. Makes no difference to me. In the future, if indeed I'm even inclined to want your opinion or "expertise?", I'll be sure to include every minute detail, making the read tedious, so your little mind doesn't have to go off an a ranting tangent irrelevant to the discussion at hand.

 

Caver

Edited by CaverCork
Link to comment
Share on other sites

Heh! Yeah... so the story changes when challenged. I'll bet the 'concrete' was just a bag of concrete mix that had become solidified with humidity!

 

I do this for a living, Caver, and I have in my repertoir a 'bursting' composition that will explode with a report - uncontained - in sub-quarter-gram quantities.

 

Having also some blasting knowledge from both the military and civilian work, it's a hard thing for my tiny 'ass' to conceive without some sort of proof.

 

Not only the gas volume, but the velocity of the gasses have much to do with how much 'shattering' damage an explosive might have.

 

Regardless of how 'powerful' an explosion of a substance might be, it cannot possibly create more mass of gasses than the original mass of the charge. Consider that for a moment.

 

Even at 100% conversion of the original explosive into gas, you'd get 2 grams of gas, or 1.6 liters. That's at STP. At 117.6 psi(abs) (only 8x atmospheric), it would be only 0.2 L.

 

And a _relative_ pressure of 102psi (117.6-1atm) is unlikely to reduce a 70lb block of concrete even into two pieces, much less 'fifty-cent pieces'. Even halfway decent concrete has a tensile strength of around 300psi (300-700). So, raise the relative pressure to 300psi. That's about 20atm. At that pressure, you now have only 10ml of gas. About two teaspoons full. Hmmm....

 

Claims abound in this medium. Proofs are a bit more scarce.

 

And I care a great deal about what you do for a hobby, if it involves explosives. Because even if I make my living working with them, it's also my hobby!

 

Lloyd

Edited by lloyd
Link to comment
Share on other sites

Turning big rocks into little rocks isn't the fun it used to be. The only "high" explosive I care to mess with now is a shell or rocket header!
Link to comment
Share on other sites

First, the story did not change. Second, it was a solid block of cured concrete. Third, what happened, happened. Perhaps there was a flaw in the block? I did not do a detailed hardness analysis or x-ray the damned thing to look for existing micro fractures. I obviously do not have your resources so I use what is available. I have several of these from the same slab that I use for testing purposes. I do know the stuff works very well breaking dense Arbuckle limestone, upon which mere crackers, BP, and smokeless have no effect other than to blow the bentonite plug. This dense limestone is why I pursue making fast, gassy, and relatively easy to handle deflagrants. I can break concrete with mere home brewed BP or smokeless. I don't "play" with flash very much, too volatile. It was never intended to be a detailed account, just a "short" illustration of why I wanted accuracy. You sir, are the one that incorrectly read between the lines. I personally don't know of any deflagrant, in an amount that would fit comfortably on said block, that would even dent it just being ignited from without. Seriously, quit making assumptions. And yes, I can make your novelty bursting comp as well. It's not a safe practice, and has no use in the real world. At least my explosive is not a composition, per se. There is a manufacturing process to be followed and it won't explode just looking at it, but 0.2 grams will pop open air. Why would you even want to make that dangerous comp? Or I am reading too much between the lines now? All I wanted was a cogent discussion of scales, not this berating bullshit.

Link to comment
Share on other sites

"And yes, I can make your novelty bursting comp as well. It's not a safe practice, and has no use in the real world"

000000000

Oh, quite the contrary!

 

"Perhaps there was a flaw in the block? I did not do a detailed hardness analysis or x-ray the damned thing to look for existing micro fractures."

 

It would have to be more than just "a flaw" to be reduced to particles of the size you claim!

 

But nonetheless, this was not "berating bullshit". You made claims that cannot be upheld if you do not support them. I deny your claims based upon experience -- practical experience with such explosives.

 

"At least my explosive is not a composition, per se."

 

For clarity -- I say you cannot accomplish what you claim with any low-explosive composition/compound/mixture that you choose to name.

 

The only way you can refute me is to prove your claim.

 

'Simple as that! I'd probably drink a beer with you in a social situation and just say "bullshit", and leave you to show me. We have a lot of such conversations in the amateur fireworks world, and everyone learns from them.

 

You don't even have to give us the 'formula'. Just prove the claim that your - um - substance has the properties you claim.

 

Lloyd

Link to comment
Share on other sites

Lloyd, had you approached me with tact, I would and could prove it, if you would accept the evidence. A simple video would clear it up, or would it?. But your viciousness leaves me inclined to let you you believe what you believe, and me to know what I know. Your opinion of me and my "substance" is of little concern to me. As a matter of fact, your opinion on anything related to this forum has been rendered null and void to me. I have no more need to defend myself to you. I'm sure that until you get the formula and process, little I could do would be any proof for you anyway. And since you are a licensed business owner, and I'm just a lowly farmer, you have far more knowledge of the patent process. And I'm happy to hear that you don't play with what I surmised you were playing with. Body parts work best when still attached to the body. Have a wonderful life!

 

Caver

Link to comment
Share on other sites

×
×
  • Create New...