DiMethyl (Stranger)
02-27-02 08:19
No 274115
      RBF's and Magnetic Stirrers  Bookmark   

I've been looking around for a 3-neck 2000ml FBF.
Completely unable to locate one.
Plenty of RBF's though.
Does anyone know if the oval stir bars work well in the
RBF's?
I definitley need the magnetic stirrer working with this.
 
 
 
 
    foxy2
(Distinctive Doe)
02-27-02 09:04
No 274128
      Re: RBF's and Magnetic Stirrers  Bookmark   

Oval?
Do you mean egg shaped?
Yes those are designed for round bottom flasks.

I would suggest buying a heating and stirring mantel, if you can afford it.  But a good stirrer will stir thru one of the fabric heating mantels.

Speak Up(Action Alerts!) (http://www.drcnet.org/)
 
 
 
 
    pickler
(Greenhorn)
02-27-02 13:50
No 274259
      Re: RBF's and Magnetic Stirrers  Bookmark   

You must not be looking hard enough for that flask. Swim found on in five minutes. Look around they are out there!tongue

We'll soon FIND OUT if I'm a chemist or not!
 
 
 
 
    DiMethyl
(Stranger)
02-28-02 00:01
No 274484
      Re: RBF's and Magnetic Stirrers  Bookmark   

You must live in another country.
I'm pretty good with search engines and I've hit
every glassware site that I know of or can find and
still unable to find that item.
It must be an unusual item since most companies do not
appear to have it in stock.
 
 
 
 
    pickler
(Greenhorn)
02-28-02 00:03
No 274486
      Re: RBF's and Magnetic Stirrers  Bookmark   

Well what country do you live in? Does it really matter? Many places can ship things.

We'll soon FIND OUT if I'm a chemist or not!
 
 
 
 
    DiMethyl
(Stranger)
02-28-02 00:23
No 274503
      Re: RBF's and Magnetic Stirrers  Bookmark   

I live in the good ol US of A.
Yes, I'm aware that goods can be internationally shipped.
I have bought a few goodies from Canada and was really
pleased with how those transactions went.
 
 
 
 
    bucockey
(Newbee)
02-28-02 01:33
No 274533
      Re: RBF's and Magnetic Stirrers  Bookmark   

dja think of trying ta get used glass?
 
 
 
 
    RoundBottom
(Hive Bee)
02-28-02 03:17
No 274558
      Re: RBF's and Magnetic Stirrers  Bookmark   

as far as i know, FBFs are an oddity.  they aren't used anywhere near as often as RBFs.  in fact, one glassblower called them a specialty item.

so, owing to their rare nature, you will be less likely to find them at auctions.  also, you are less likely to find them in glassware catalogs (which is where you are most likely looking for them).  in fact, a HUGE glassware catalog has 5 FBFs, all 1 neck boiling type (only 1 had ST GG joints).  of the 8 multiple neck type, 0 were FBFs.  this is due to the fact they are classified as distillation flasks, which should NEVER be flat bottomed.

this leaves 2 options.  get a custom flask made, or get an existing RBF converted to a FBF (i believe baalchemist has some experience with this).  or stick to RBFs. 

the major disadvantage to RBFs is the increased problems with stirring.  a FBF distributes the weight of the Al foil over the flat bottom.  an RBF has more weight focused on the bottom and therefore the stir bar.  also, it is harder to get a larger egg shaped stir bar into a ST 24/40 joint.

the obvious advantage to a RBF is that it can double as a distillation flask, thereby eliminating the need for a 2L FBF and a 2L RBF. 

if you have a 2L RBF, try stirring the 27.5g Al foil in methanol WITHOUT Hg salt, ketone, or nitro.  if you can get it to stir, and can keep it stirring (very important, try keeping it stirring for 3h at least) then you have what it takes to do a AlHg Nitro.

i learned a thing or two from charlie dontcha know.
 
 
 
 
    Starkas
(Newbee)
02-28-02 05:21
No 274579
      Re: RBF's and Magnetic Stirrers  Bookmark   

Find a glass blower.  I get all my glassware from a glassblower.  If he doesn't have it he makes it.  It would take him about 5 minutes to whip up your flask for you.

I pay him cash and he looks after me.  His prices much cheaper than any Glassware or Lab supplier.

His next feat is going to be to stretch out a 10L RB flask into a 10L Sep funnel for me.  I don't really need a 10L sep funnel but my 2L is too small and his price difference between a 4L and 10L sep funnel is a joke.
 
 
 
 
    mottaman420
(Newbee)
02-28-02 05:37
No 274587
      Re: RBF's and Magnetic Stirrers  Bookmark   

Be wary of Glass blowers making lab equip. They r not trained to do so. Glass might not reach pressure requirements and could pop if you did something involving pressure, and furthermore if he whipped you something up in five minutes than your full of shit cause you have to anneal the glass to prevent stress cracks or else it will shatter very very very easily or more likely before it even finishes cooling down. Furthermore don't look for a Pipe/Bong Glassblower. They use hollow glass tubes to make their shit rather than molten glass from say a glory hole which is used to make large things like vases 2000ml flasks etc. I looked for 3 neck flasks and found them easily online i even found a 20,000 ml 3 neck flask (pretty cool huh) Just imagine how much shit you could make with some of those. So whoever said they had a glassblower whip them something out of his'her ass in five min. is either completely full of shit or is forgetting to add essential details.cool Check out www.artglass1.com to learn about blowing glass and about glass blowing equip. There are plenty of books on making laboratory  glassware just look around. You could probably start making your own glassware for around a total cost of about $700. The glass is dirt cheap its just the tools that are expensive. If you want ground glass joints you'll have to buy a glass grinder (expensive) which will increase your costs significantly. You might be able to buy that glass etching stuff to accomplish this though (your local crafts store) --This is just an idea so i don't know if the etching thing would work though.  smilelaughsmilelaughwinkcoolwinkcool

_.-==''SupaTokaBuDsMoka''==-._
'''''''GonnaGetHighTillIDie'''''''
 
 
 
 
    greeter
(Stranger)
02-28-02 06:43
No 274602
      Re: RBF's and Magnetic Stirrers  Bookmark   

>I've been looking around for a 3-neck 2000ml FBF.
>Completely unable to locate one.

Contact any outfit that sells glass lab supplies such as distillation kits, etc., many of them have online storefronts with "contact us" links.  Send them an email and say something along the lines of:

"Hello, I am interested in buying a three-neck flat-bottom flask with 24/40 joints at each neck.  Would you please email me a price quote?  Thank you."

Leave it up to them to figure out how to get it/make it, that's their job, they sell glass.  No one is going to look at you funny for buying a 2L flask, they aren't that big.  Go asking for a 10L+ and people might start asking questions.

These glass suppliers will not ask what you intend to use the flask for.  After all, they sell chemistry supplies so your plan is obviously to use it for chemistry.  What's more, they don't care.

Ask around if you like, get the lowest price, and buy it.  Be sure to send them a thank-you note when you get it and tell them you're happy with the quality (if in fact you are).

greeter
 
 
 
 
    noj
(Hive Addict)
02-28-02 07:35
No 274614
      Re: RBF's and Magnetic Stirrers  Bookmark   

Unless of course you just want to buy magnetic stirbar that will work in a RBF.


Chaque un son gout
 
 
 
 
    Starkas
(Newbee)
02-28-02 20:31
No 274840
      Re: RBF's and Magnetic Stirrers  Bookmark   


whoever said they had a glassblower whip them something out of his'her ass in five min. is either completely full of shit or is forgetting to add essential details




Hmmm... bit harsh.  I'm estimating the 5 minutes but that's how long its taken him to make most modifications that I've watched him do.  Now that I think of it, any flask modifications have been left with him overnight.  He whipped a Claisen up from scratch in less than 4 minutes.

 
 
 
 
    terbium
(Old P2P Cook)
02-28-02 20:54
No 274853
      Re: RBF's and Magnetic Stirrers  Bookmark   

Be wary of Glass blowers making lab equip. They r not trained to do so.
Eh? Just who do you think does make laboratory glassware?

furthermore if he whipped you something up in five minutes than your full of shit cause you have to anneal the glass to prevent stress cracks or else it will shatter very very very easily or more likely before it even finishes cooling down.
That is not true. Laboratory glass is made from a borosilicate glass like Pyrex or Kimax that has a low coefficient of thermal expansion and does not need as much annealing as a sodalime glass. When doing work on borosilicate glass, such as adding joints to a flask, the work can often be annealed sufficiently in a few minutes using the flame from the torches at the workbench. I have had work like this done for me many times (by professional, laboratory equipment glassblowers) while I stood next to him and waited. Putting the finished work between a pair of sheets of polarizing plastic will reveal any residual stress that was not relieved by the annealing.
 
 
 
 
    blaztoff
(Hive Bee)
03-02-02 09:59
No 275686
      Re: RBF's and Magnetic Stirrers  Bookmark   

5 minutes making a piece of glassware is full of shit. Yes for some glassware that has blanks that dont need a lot of shit like a 1neck flask yes to a point. They just cut off the neck and have a blank with the right joint put on. But after they have to clean it thouroughly and thenthey bake it in a oven at 1000C for 12 hours to get rid of any stress or fractures that can be invisisble to the nacked eye but weaken youre glassware. And Dont worry avout the glassblowers turning you in. But dont go in there not looking the part and asking for all this shit that obvious you dont know shit about. Most glassblowers are extremmely friendly helpfull nice people. And most dont make a lot of money either. They want youre busuiness but dont putthem in bad spot. Swim has built nice relationships with several glassblowers and they are great. They have taught him lots about glassblowing and even have let him fashion a couple of items under thier supervision. Ask questions with them pick a part and go by it. Desighn some things anddiscuss the item with them. They love talking techincal. Swimhad them researching and discussing all sorts of stuff for him after he had them blow a special high pressure vessel that he designed.  It involved electrical currents and they loved it. They wereintrigued by the special requirements needed and swim learned some that he had not thought of when he went into the desighning. Find out all you can about Borosicate glassblowing.[http://www.ecu.edu/chem/glassblowing/gb.htm#Introduction]
 
 
 
 
    terbium
(Old P2P Cook)
03-02-02 20:25
No 275824
      Re: RBF's and Magnetic Stirrers  Bookmark   

But after they have to clean it thouroughly
Dirty glassware will need to be cleaned before lampworking but there is no reason for cleaning after.

and thenthey bake it in a oven at 1000C for 12 hours to get rid of any stress
Pyrex glass has a softening point of 820C, if you put it in an oven at 1000C you will get nothing but a puddle of molten glass. The annealing temperature for Pyrex glass (Corning No. 7740) is 555C. Only something like Vycor 96% Silica Glass (Corning No. 7913) would require an annealing temperature approaching 1000C.
 
 
 
 
    PrimoPyro
(Hive Prodigy)
03-02-02 20:31
No 275826
      Re: RBF's and Magnetic Stirrers  Bookmark   

Damn terbium, you know your shit. That's impressive.

Wir pumpen..... (Klatschen) Sie oben!
 
 
 
 
    DiMethyl
(Stranger)
03-02-02 23:01
No 275907
      Re: RBF's and Magnetic Stirrers  Bookmark   

Yes, I did ask around and as a result found a company
that sold me the 2000ml 3-neck FBF for $100.
This was after I shelled out the $$ for a one-neck 2000ml
flask and a claisen adapter.
Oh well.
 
 
 
 
    Argox
(Hive Bee)
03-02-02 23:28
No 275920
      Re: RBF's and Magnetic Stirrers  Bookmark   

terbium, you are fucking amazing--I already told you privately, but I'll say it in public--is there ANYTHING you don't know?  The range of your knowledge is Awesome!

Dude, whoever you are, my hat is off.  Cheers.

Regards
Argox