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Discussion => Drug safety => Topic started by: quinone on October 10, 2012, 06:49 am

Title: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: quinone on October 10, 2012, 06:49 am
So title say's it.

Most people seem content on here with a '0.001g' $100 jeweler's scale and if that's how they wish to weigh their mg magnitude compounds I have no interest in stopping them.

I'm looking for a REAL (aka scientific) analytical balance though and scientific quantitative balances are at the ABSOLUTE MINIMUM $500, but I would never pay that, for that cheap it would likely be an unreliable balance.

Basic (yet accurate) balances run about $800 without all the bells and whistles.

Does anyone have any input on preferred brands and model's of quality (but priced appropriately) scientific analytical balances?
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: Ben on October 11, 2012, 01:30 am
If you are looking beyond the $1000-ish "consumer" quality there is not that much difference anymore.

At the high end of the market manufacturers will provide datrasheets on what accuracy to expect at certain weights, and those specs are always met or exceeded.

 I used to work with Perkin-Elmer gear in the lab, using equipment that can measure accurately down to the microgram (not milligram!). Such balances do cost tens of thousands of dollars each though. I'm not sure what level of gear you are considering, but if you need anything that measures in steps of 0.1 milligram or smaller to be very expensive.
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: quinone on October 11, 2012, 04:38 am
If you are looking beyond the $1000-ish "consumer" quality there is not that much difference anymore.

At the high end of the market manufacturers will provide datrasheets on what accuracy to expect at certain weights, and those specs are always met or exceeded.

 I used to work with Perkin-Elmer gear in the lab, using equipment that can measure accurately down to the microgram (not milligram!). Such balances do cost tens of thousands of dollars each though. I'm not sure what level of gear you are considering, but if you need anything that measures in steps of 0.1 milligram or smaller to be very expensive.

I to have used microgram balances, it's the essence of this post and why i won't use those joke jeweler or sub $100 balances, specifically in that they're not designed to measure powders with high surface area.

Every 'jeweler' balances i've used, it won't even register the mass until a whole bunch has been dumped onto the balance and then all of a sudden it changes from 0.000g to 0.016g ... wtf!!!!  I can obviously have no faith in such a measurement. 

But if there's some magical sub $100 scale that actually is reliable i'd be grateful to hear it's name, this does not include the most favourite one which requires the user modify the balance by adding washers and other stupid things to the underside ... how can you even call such a device a scientific instrument?

Apparently i'm the only one though who want's a real balance cuz you're the only one who responded and took a day or more lol.  I've NEVER seen or used a scale outside of the lab that doesn't just report strange values when used and I actually feel more comfortable eye-balling a balance that jumps from 0.000 to 0.016g ... and continue registering 0.000g even when there is powder on the scale, it just jumps to 0.016g uh ... when it wants to lol, sometimes the amount i've added looks more like 100mg too before the balance changes from 0.000.

I just need a good balance cuz i've several sub 50mg entheogen's i'd like to try but cant.
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: gestaltassault2 on October 11, 2012, 04:59 am
use the liquid measuring technique:

---CLEARNET LINK---
http://www.erowid.org/psychoactives/dose/dose_info1.shtml
---CLEARNET LINK---
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: quinone on October 11, 2012, 05:13 am
use the liquid measuring technique:

---CLEARNET LINK---
http://www.erowid.org/psychoactives/dose/dose_info1.shtml
---CLEARNET LINK---

No thanks.

I'm looking for an analytical balance, hence the title of the thread.
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: goldfibre1 on October 11, 2012, 07:01 am
not a direct answer to your question, but as a matter of technique that I've found useful.

I don't tare the balance.  I think this adds alot of rounding error.  It's one of those cheapie jeweler balances.  The max weight capacity is 10g.  I use vessels that are between 5g and 10g.  I find that contact lens cases are perfect.  They usually weigh about 7g and have two sides to store different things.  It's also a very inconspicuous object.

I measure the weight of the container with your product.  Weigh an empty container that you will place your dose into.  Remove your dose from the main stash.  Place in empty vessel.  Reweigh both containers. Subtract the weight of the main vessel from the post dose removal main vessel.  Subtract the weight of the vessel with dose from the weight of the empty vessel.   If you're careful, those numbers will be within 1 or 2 mg of each other.  I usually do all weight measurements twice or thrice.  I've been surprised that the numbers were the same many times.

If the measurements are not close, I start over.  Anything can alter the weight measurement so I make sure they are in the same configuration when I measure (same direction and placement).  The air conditioning is not blowing.  And I place some shielding around three sides of the scale to prevent breezes.
 
For doses around 20 to 30mg, I have some confidence that it will be within a couple mg of what you want.  Now, these little scales are not very accurate, but they might be precise.  Meaning the measurements I get are repeatable.  The scale came with a 5g and 10g calibration weight. 

I've used this technique to measure molly doses around 100mg and bumps around 50mg. 

Try it, tell me what you all think.

thanks, G
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: goldfibre1 on October 11, 2012, 08:40 am
that being said, Sartorius and Mettler make excellent analytical scales.  You can get a used one for around $600 on ebay.  But then, if you go that route, you should have a special table for the scale.  Usually very heavy and stable to compliment the accuracy of the scale.  And then you should have a special room to put it so it will not be moved, temperature controlled, sound proof, etc. 

Seems like a little overkill to measure out exactly 50mg.  Unless you're doing a research study.  And then other factors are really critical, time of day, meals ingested, mental state, setting, etc, etc.

I ran into that problem with the jeweler's scale of starting off at 0mg, using a light-weight weighing vessel or paper, and trying to weigh 50mg.  You'll be off +/- 50mg.  It'll say 0mg or 100 mg.  But if you start heavy and DON'T tare, measure the contact lens case weighing about 7g.  Then you add 50mg.  It'll be close.  It might say 7.052g.  And then when you weigh your stash, it'll start at 7.191 and go to 7.140g after you remove 50mg.  I've done this several times now and they've always been within 2mgs +/- of each other.  The differences of the two vessel weighings that is.  I'm not saying it's totally accurate. 

If it isn't a big deal to you if it's 52mg instead of 50mg, I think the jeweler's scale is fine.  If you've got money to burn, get the analytical scale.  I'm a nerd so I'd love to get the scale, but it's probably not practical for me.

Hope this helps,
G
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: quinone on October 12, 2012, 04:46 am
not a direct answer to your question, but as a matter of technique that I've found useful.

I don't tare the balance.  I think this adds alot of rounding error.  It's one of those cheapie jeweler balances.  The max weight capacity is 10g.  I use vessels that are between 5g and 10g.  I find that contact lens cases are perfect.  They usually weigh about 7g and have two sides to store different things.  It's also a very inconspicuous object.

I measure the weight of the container with your product.  Weigh an empty container that you will place your dose into.  Remove your dose from the main stash.  Place in empty vessel.  Reweigh both containers. Subtract the weight of the main vessel from the post dose removal main vessel.  Subtract the weight of the vessel with dose from the weight of the empty vessel.   If you're careful, those numbers will be within 1 or 2 mg of each other.  I usually do all weight measurements twice or thrice.  I've been surprised that the numbers were the same many times.

If the measurements are not close, I start over.  Anything can alter the weight measurement so I make sure they are in the same configuration when I measure (same direction and placement).  The air conditioning is not blowing.  And I place some shielding around three sides of the scale to prevent breezes.
 
For doses around 20 to 30mg, I have some confidence that it will be within a couple mg of what you want.  Now, these little scales are not very accurate, but they might be precise.  Meaning the measurements I get are repeatable.  The scale came with a 5g and 10g calibration weight. 

I've used this technique to measure molly doses around 100mg and bumps around 50mg. 

Try it, tell me what you all think.

thanks, G

Thanks for advice, it's actually not always necessary to tare your balance against a known weight, esp. if that weight is near the upper limit of the balances max weight.  Taring is for the actual container the compound will be in (like a contact lens case).

TBH I actually never saw a set of 'taring weights' in any lab we worked in. We'd put the weigh boat on the scale, TARE THAT, add compound close balance shield and weigh.  For particularly sensitively necessary weight's we'd work through the premise of subtraction (which I .... think is what you are trying to explain).  You open the shield, remove a tiny bit and put it .. somewhere lol and calculate the difference btwn the original measurement (higher #) and the difference in the newly displayed weight (lower #), is the amount removed and the amount contained in the ... somewhere you put it.

The most annoying thing's about analytical chemistry is that you'll sometimes spend quite some time opening the shield again, adding some of the removed compound, calculate the new mass of the compound you put in ... something (take the difference in mass when you added to the balance and that's how much more you've taken from the ... something container).  There's times you have to leave and go do something else for 10 minutes cuz your fucking frustrated (which doesn't mix well with high ACCURACY measurement), only to come back and get the proper mass on the first try lol.

I have less interest in PRECISION, it only show's that the balance is consistently weighing the same mass of the container.  It's more about ACCURACY because you want the right mass of compound, but you can't be accurate if your balance isn't precise either.

Thanks for the advice/input goldfibre1
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: quinone on October 12, 2012, 05:01 am
that being said, Sartorius and Mettler make excellent analytical scales.  You can get a used one for around $600 on ebay.  But then, if you go that route, you should have a special table for the scale.  Usually very heavy and stable to compliment the accuracy of the scale.  And then you should have a special room to put it so it will not be moved, temperature controlled, sound proof, etc. 

Seems like a little overkill to measure out exactly 50mg.  Unless you're doing a research study.  And then other factors are really critical, time of day, meals ingested, mental state, setting, etc, etc.

I ran into that problem with the jeweler's scale of starting off at 0mg, using a light-weight weighing vessel or paper, and trying to weigh 50mg.  You'll be off +/- 50mg.  It'll say 0mg or 100 mg.  But if you start heavy and DON'T tare, measure the contact lens case weighing about 7g.  Then you add 50mg.  It'll be close.  It might say 7.052g.  And then when you weigh your stash, it'll start at 7.191 and go to 7.140g after you remove 50mg.  I've done this several times now and they've always been within 2mgs +/- of each other.  The differences of the two vessel weighings that is.  I'm not saying it's totally accurate. 

If it isn't a big deal to you if it's 52mg instead of 50mg, I think the jeweler's scale is fine.  If you've got money to burn, get the analytical scale.  I'm a nerd so I'd love to get the scale, but it's probably not practical for me.

Hope this helps,
G

O  and i've had prob's (like I said in my first post) about the 0.000 to 0.0015 so much that's why i've lost faith in jewerler's scales.  Using paper specifically is the absolute worst for making mistakes in measurement, the starting mass is too close to the balances lower detection limit.

I'm lazy and not particularly creative so i've never found a small container to use for measurement's, but your suggestion of using a contact lens case sounds perfect and i'll try it.

Problem is I have NO scale right now, so if anyone has any favourite brands/models of these cheapy jeweler balances i'd appreciate the input.

PS:  All measuring i've ever done in my life has been for research, so i'm probably pretty jaded in my measuring demands.  But like you said, the difference between 50mg and 52mg makes no difference when weighing to consume, but when doing a research study the difference between 50mg and 52mg = failed experiment.
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: goldfibre1 on October 12, 2012, 11:51 am
that's right, like being graded on "efficiency."  2mg is 4% which is like going from an A to a C.  check out ebay, found one for $13usd, shipped from china so took like 2 weeks.  came with two calibration weights.  sorry if I called them "tare" weights which I don't think I've heard of. 

you can get a 6 pack of color-coded contact lens cases at Walmart for $4.  what a bargain!

I'm trying to come up with a design for a good "snuff" dispenser.  I'm not satisfied with the ones available out there.  If anyone's got any clever ideas, pls pm me.  Or if you know of one off the shelf that you like, pm me as well.

thanks guys,
G
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: quinone on October 12, 2012, 08:31 pm
that's right, like being graded on "efficiency."  2mg is 4% which is like going from an A to a C.  check out ebay, found one for $13usd, shipped from china so took like 2 weeks.  came with two calibration weights.  sorry if I called them "tare" weights which I don't think I've heard of. 

you can get a 6 pack of color-coded contact lens cases at Walmart for $4.  what a bargain!

I'm trying to come up with a design for a good "snuff" dispenser.  I'm not satisfied with the ones available out there.  If anyone's got any clever ideas, pls pm me.  Or if you know of one off the shelf that you like, pm me as well.

thanks guys,
G

No, you're right, their called calibration weights.  I was just wracking my brain for the word calibration and was pretty fucked up at the time lol so ijust called them tare weights.

I bought one of the lower end jeweler's scales and it was pure unadulturated garbage lol.  Moreso looking for the 'high end' jeweler's balance.  There's been a brand/model kicking around here whose name I just cant track down, one of them required you add a washer to the underside (that's why i was making fun of balances that require the user make modifications to them, blasphemous) and the other I just can't remember.

Sorry I don't have any ideas on a snuff dispenser, kind of against them being carried around with ppl all day  when they should be sober at work anyways.  Playtime is playtime, worktime is responsibility :).
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: Ben on October 13, 2012, 01:06 am
Problem is I have NO scale right now, so if anyone has any favourite brands/models of these cheapy jeweler balances i'd appreciate the input.

Well, if you are looking to get a scale that is really really cheap, check out the ones at dealextreme. These aren't that bad in design really, but there are some that come off the production like miscalibrated/defective. One way to quickly test this is to use a known weight such as a coin (all modern coins have well defined weights) to see if its way off or not. Obviously these scales aren't -that- good, but a model under $50 can actually weight something like 20 mg with an error under 10% reliably. The 10% error may sound horrible for research purposes, but could be good enough to measure amounts of substances that needn't be -that- accurate.
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: quinone on October 13, 2012, 01:22 am
Problem is I have NO scale right now, so if anyone has any favourite brands/models of these cheapy jeweler balances i'd appreciate the input.

Well, if you are looking to get a scale that is really really cheap, check out the ones at dealextreme. These aren't that bad in design really, but there are some that come off the production like miscalibrated/defective. One way to quickly test this is to use a known weight such as a coin (all modern coins have well defined weights) to see if its way off or not. Obviously these scales aren't -that- good, but a model under $50 can actually weight something like 20 mg with an error under 10% reliably. The 10% error may sound horrible for research purposes, but could be good enough to measure amounts of substances that needn't be -that- accurate.

I'm not looking for a scale that's really really cheap, the title of my thread even says that lol.  I'm looking at this point for a high end jeweler's scale (vs. an analytical balance).  I'm looking for the BEST jeweler's scale that is out there.

Thank you for explaining to me how to calibrate a balance lol (wtf?)
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: Ben on October 13, 2012, 01:52 am
I'm not sure what the difference between an jewelers scale and an analytical balance should be.

If you know the weight range you will need to be measuring and the accuracy you require, you can select a model from any major supplier that exceeds those requirements. Many vendors of lab equipment have these available, and it really doesn't matter that much if you get perkin-elmer, fisher, ohaus, mettlab or other A brand product.

Perhaps the idea of veryfing a balance using a coin sounds stupid, but it actually has merit. If i want to see if a balance is not defective, i throw on a 1 euro coin, and expect a result that is in the order of 7.5 grams. Obviously a circulated coin is not a reference weight accurate to 7500 milligrams at all, but if the balance shows a result under 7.4 or over 7.6 grams for that coin, it is a good reason to no trust it any longer.
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: quinone on October 13, 2012, 07:15 am
I'm not sure what the difference between an jewelers scale and an analytical balance should be.

If you know the weight range you will need to be measuring and the accuracy you require, you can select a model from any major supplier that exceeds those requirements. Many vendors of lab equipment have these available, and it really doesn't matter that much if you get perkin-elmer, fisher, ohaus, mettlab or other A brand product.

Perhaps the idea of veryfing a balance using a coin sounds stupid, but it actually has merit. If i want to see if a balance is not defective, i throw on a 1 euro coin, and expect a result that is in the order of 7.5 grams. Obviously a circulated coin is not a reference weight accurate to 7500 milligrams at all, but if the balance shows a result under 7.4 or over 7.6 grams for that coin, it is a good reason to no trust it any longer.

I meant the better (more expensive) jeweler's scale's.  I agree fischer, perkin-elmer etc. are all just as good :)
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: PharmerBob on October 13, 2012, 08:10 am
the smallest chem i'll be dosing is 2cb in the 30mg range at it's lowest. Also 30mg doses for DMT at its lowest. I can be + or - 5mg on the accuracy without problems. I'd like to keep the maximum the scale can be off to 5mg in either direction if possible. Can any jewelers scale be accurate within 5mg over or under?
Title: Re: Suggestions on REAL Analytical Balances (Not Jeweler or $100 Balances)
Post by: Ben on October 14, 2012, 02:32 am
Any decent milligram-resolution scale will be able to measure 30 mg with less then 5 mg error. Even very cheap scales will easily be that accurate as long as they are not defective.

I tested the very cheap 1 mg resolution, 20 gram capacity scale as sold on dealextreme against other scales with reference weights. It actually is remarkably accurate for its price. Measurements over the entire range have never been off by more then 1 percent, and most of then are within 0.2% except on the very low end of the range.

The downside of these cheap scales is that you need to keep an eye on them constantly, verifying with a reference weight every single time you use them. A proper analytical balance will not need such scrutiny since it has a built in system that diagnoses large (say, >1%) errors every time you power it up. Considering the dx one costs $30 or so, where the proper balances costs several thousands, i would not advise against using the cheap ones as long as you frequently re-assert their accuracy.

Once these things go off they tend to go way off though, indicating double or even tenfold the weight actually on them, so you're probably notice fairly quickly.