| Pages:
1
2 |
Little_Ghost_again
National Hazard
Posts: 985
Registered: 16-9-2014
Member Is Offline
Mood: Baffled
|
|
Cheers I will go have a look 
|
|
|
j_sum1
Administrator
Posts: 6326
Registered: 4-10-2014
Location: At home
Member Is Online
Mood: Most of the ducks are in a row
|
|
Oil of Wintergreen by MrHomeScientist
|
|
|
Little_Ghost_again
National Hazard
Posts: 985
Registered: 16-9-2014
Member Is Offline
Mood: Baffled
|
|
I forgot to come back to this, I now have aspirin (not that much, 70 350mg tabs. Buts its enough to mess with), I got some in the end from a
supermarket, I found the home brand ones that were silly cheap had little in the way of added crap in .
The only trouble is in the UK you are only allowed to buy a max of 32 painkilling tablets from a supermarket in one day! Its to stop you
overdosing!!!! Obviously those that try and kill themselves with tablets havnt worked out there are other ways to do this.
Oil of wintergreen was a great write up and I will be doing this next week
|
|
|
chemrox
International Hazard
Posts: 2961
Registered: 18-1-2007
Location: UTM
Member Is Offline
Mood: LaGrangian
|
|
Don't buy used electromechanical balances unless you can find the service manual for the model listed. I have several that are DOA because the
manufacturer switched to using transducers. So-called modern balances are in reality "scales." They work on transducers instead of weights. Anyway
after an accurate balance has been moved or shipped it needs service. I bought a set of calibration weights to no avail-no manual available. Only
thing I can add is please boycott Metler!
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
|
|
|
Little_Ghost_again
National Hazard
Posts: 985
Registered: 16-9-2014
Member Is Offline
Mood: Baffled
|
|
I have a couple of cheap scale that are electronic. One measures to a max 300 grams and can measure to 30mg. Above 30mg it has 10mg resolution.
The other has a maximum of 5kg and a minimum of 100mg. Its resolution is 100mg. No idea just how accurate they are. I will at some point get decent
pharmacy scales probably mechanical and very old. I will then invest in some decent masses and have them calibrated.
Or buy a decent set from a uni second hand but in calibration. What ever path I take I want scales that will last. That way at least my results will
be constant.
I sort of prefer the large wood and glass case types from long ago. With decent masses they are hard to beat.
Also because I have so much contact with a good hospital I have made friends there that have said they can check my weights with there pharmacy
scales, so I should be able to make a calibration curve.
LG
|
|
|
arkoma
Redneck Overlord
Posts: 1763
Registered: 3-2-2014
Location: On a Big Blue Marble hurtling through space
Member Is Offline
Mood: украї́нська
|
|
one cubic centimeter of water = one gram. I use an insulin syringe marked out to 100 units per CC to determine small bits of mass with my "ghetto"
balance.
For instance, 5 "units" of water is 50mg. Of course, I am disallowing slight variations in density due to temp.
"We believe the knowledge and cultural heritage of mankind should be accessible to all people around the world, regardless of their wealth, social
status, nationality, citizenship, etc" z-lib
|
|
|
Little_Ghost_again
National Hazard
Posts: 985
Registered: 16-9-2014
Member Is Offline
Mood: Baffled
|
|
I forget the simple ways! I have pipettes etc that hold 1ml with 100 units marked. Also have access to RODI water. So mechanical balance would be
ideal. Volume wise I can measure accurately down to 1um as I have some old glass disposable pipette things with micro bore glass tubes.
Easy to get to hung up on accuracy. For most things 10mg is plenty
|
|
|
arkoma
Redneck Overlord
Posts: 1763
Registered: 3-2-2014
Location: On a Big Blue Marble hurtling through space
Member Is Offline
Mood: украї́нська
|
|
SI units were figured out by the French in the midst of a bloody revolution---well before "modern" gizmos.
"We believe the knowledge and cultural heritage of mankind should be accessible to all people around the world, regardless of their wealth, social
status, nationality, citizenship, etc" z-lib
|
|
|
deltaH
Dangerous source of unreferenced speculation
Posts: 1663
Registered: 30-9-2013
Location: South Africa
Member Is Offline
Mood: Heavily protonated
|
|
Little_Ghost_again, if you're planning to use the salicylic acid in soap, why not just crush up aspirin tablets of the required
amount and mix it in with your lye when saponifying. The acetlysalicylic acid will hydrolyse under the extremely basic conditions quite rapidly. Base
catalysed hydrolysis and saponification are very similar (the latter being a 'special case' where the ester in question is a lipid or ester of a fatty
acid. Acetylsalycilic acid is also just an ester and will hydrolyse with lye. What you're left with will be sodium salicylate and some sodium acetate
and the inert fillers used in tablet making. At the concentrations you intend to use it in the soap, these minor and harmless impurities will really
not matter.
acetylsalycilic acid(aq) + 2NaOH(aq) => sodium salycilate(aq) + sodium acetate(aq) + H2O
[Edited on 15-11-2014 by deltaH]
|
|
|
Little_Ghost_again
National Hazard
Posts: 985
Registered: 16-9-2014
Member Is Offline
Mood: Baffled
|
|
Quote: Originally posted by deltaH  | Little_Ghost_again, if you're planning to use the salicylic acid in soap, why not just crush up aspirin tablets of the required
amount and mix it in with your lye when saponifying. The acetlysalicylic acid will hydrolyse under the extremely basic conditions quite rapidly. Base
catalysed hydrolysis and saponification are very similar (the latter being a 'special case' where the ester in question is a lipid or ester of a fatty
acid. Acetylsalycilic acid is also just an ester and will hydrolyse with lye. What you're left with will be sodium salicylate and some sodium acetate
and the inert fillers used in tablet making. At the concentrations you intend to use it in the soap, these minor and harmless impurities will really
not matter.
acetylsalycilic acid(aq) + 2NaOH(aq) => sodium salycilate(aq) + sodium acetate(aq) + H2O
[Edited on 15-11-2014 by deltaH] |
Really sorry I seem to have a habit of causing utter confusion!
The aspirin isnt for soap or soap related.
Some of the things I do are simply for learning or doing and this is one of them. Having said that....Hmmmm aspirin soap!!! Now theres a thought
|
|
|
| Pages:
1
2 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
