Sciencemadness Discussion Board

Crooked Pyrex Glassware

malford - 16-8-2013 at 10:08

Hello, below is part of my distillation setup. You can see that I have two Pyrex adapters connected and that the fractionating column is terribly crooked due. Is this normal for high-quality glassware to be this crooked or does this indicate counterfeit products?

<img src="http://i.imgur.com/98LJvbB.jpg" width="800" />

<!-- bfesser_edit_tag -->[<a href="u2u.php?action=send&username=bfesser">bfesser</a>: reduced image size(s)]

[Edited on 16.8.13 by bfesser]

bfesser - 16-8-2013 at 10:12

It happens. Just because your joints are stamped Pyrex&reg; doesn't mean that the final product is manufactured by Corning. Your adapters may have been made by or repaired by another glassblower at one time. Also, I've seen original glassware where the angles are a bit off. It's usually not a problem.

[edit] To me, it looks like the distillation adapter on top of your Vigreux column was made by another glassblower.

[Edited on 16.8.13 by bfesser]

malford - 16-8-2013 at 10:27

So, let's assume that my products are stamped Pyrex because they were manufactured by Pyrex and not altered by a bad glassblower...

In such a case, can deviations this large be expected from high quality glassware? The first connector I purchased was off so I returned it, but not nearly this much. This is impardonably poor glassware.

watson.fawkes - 16-8-2013 at 10:38

Quote: Originally posted by malford  
So, let's assume that my products are stamped Pyrex because they were manufactured by Pyrex
[...]
In such a case, can deviations this large be expected from high quality glassware?
They're stamped Pyrex because standard taper joints, both male and female, are sold as pre-fabricated parts to glassware manufacturers. The stub on the joint is sealed to whatever ware the glassblower is making. A lot of glassblowers no longer even have the gear to grind a taper, not even to touch one up. The pre-formed versions are inexpensive enough that it's generally cheaper to cut off a damaged one and replace it.

It looked like you've mated a 60&deg; adapter to a 75&deg; adapter. It's hardly a wonder that the column is not vertical.

subsecret - 16-8-2013 at 12:38

Those glassware pieces shown are generally angle-specific. There are different ones made with different angles. Did you buy glass with the same/supplementary angles?

malford - 24-8-2013 at 20:30

Quote: Originally posted by watson.fawkes  
It looked like you've mated a 60&deg; adapter to a 75&deg; adapter. It's hardly a wonder that the column is not vertical.


I thought so too, but my 105 degree adapter does not align properly with what the apparent 75 degree adapter. My days of purchasing from ebay are finished.

How does Chemglass compare to LabGlass in terms of quality? My main concern at this point is everything lining up very close to perfect.