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Author: Subject: latest glassware purchase
Fyndium
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[*] posted on 23-3-2021 at 09:55


Deschem has served me great, too. They have improved their shipping recently, and shipments have been coming over pretty much consistently in 2-3 weeks, packed to withstand intercontinental damage.

I just received another order from them, nothing fancy, just a stock of some spare parts and an extra jack. Also I bought a short vigreux head to allow for better separation compared to straight distillation without greatly impeding flowrate.

The 50mL glass syringe is also fancy.

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arkoma
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[*] posted on 23-3-2021 at 13:39


300mm Allihn condeser, 100mm thermo well, couple flasks. From deschem.



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karlos³
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[*] posted on 23-3-2021 at 16:19


I have to say, deschem really improved their shipping times!
I had to re-order a few thermometers and simply bought twice as much... 7 working days only!
Impressive :)
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Fyndium
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[*] posted on 24-3-2021 at 03:12


Fastest for me has been 7 days too, exceptional. Usually it takes 2-3 weeks, or around 20 days.

At least for some parcels they have started using forwarding parcel services, which means faster shipping and they take care of importing. I would call that a great service.

100% of my equipment bought from them has been flawless. One shipment was smashed on the way, but it was not their fault - the parcel was just plain crushed with something HEAVY, and I mean it - I can stand on their parcels with no stress, they are so rigid so I believe something major fell on it. It was resolved in a very convenient manner.
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Phosphor-ing
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[*] posted on 28-3-2021 at 18:21


I recently received my 4th or 5th order from Dr.Bob. Hot plate/stirrer, condenser, long vigreux column and various flasks in 29/42. Love ordering from him. He Includes free stuff and packs it to survive whatever the shippers can dish out.



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earpain
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[*] posted on 11-4-2021 at 08:10


Quote: Originally posted by earpain  
So you guys probably saw these kits flood the Chinese shill vendors who may or may not have warehouses right next to you(but it always says they do).

Looks like the 'guild' has raised the price. My order went like this:
posted as ~$60 or best offer. Hmmmm, normally for $60USD i might get two of those items at best. So i went through his history for this item, and almost all the orders said "accepted offer". So brazenly, I offered $7 below asking. I said it was a great deal but i'm very poor. Response was warm and friendly. And discount #1: he countered at $3.00 below asking price. I said hell yes.
So then of course i get a tracking number that for over a week is stuck at "waiting for package to arrive at facility/" I know what this means. I sent him a message saying I thought that was a bit sleazy, since the marketing included a map of my country with regions showing either 1, 2, or 3 days! I was in the 2 day zone.
BAM: Instant Discount #2 - $10 refunded to my PayPal right away.

I kind of have to now confess that this is the best deal ever for glassware. It is branded, however the company's name is in Chinese characters. But the Glassware is up to par with Deschem if not better.
The cut out foam is now the 'case' for safe storage.
The leibig and the vigereux column are so much longer in real life than it looks like in the picture. This really makes a huge difference for distillations.
The addition funnel has some new design for its stopcock that I cannot explain. But somehow it allows both for perfect drip...drip.. control, and yet if a bunch of salt or gunk clog up the bottom, i can turn it and it all plops out. It's the perfect separation stopcock.
Yes I have enough 3-way adapters now to last me several life times.
Lastly: I was SURE i had received the wrong keck clamps at first, they looked like 19/x. Then I thought 'hmmm', with some extra thumb muscle, it snaps on, and it SNAPS on any joint. Like these keck clamps will hold big flasks and condensors while they patiently wait for me to find my support hardware(do not do that ever, so stupid)
(the thermometer went up to 100C and broke the first day. Nothing else has broken at all)







Update: too good to be true is just that. However, this remains to be a great deal. It almost feels as though the worst glassware was mixed in with the best, for obfuscation.

Edited image is self-explanatory.
worth a mention:
* Addition funnel works, though 24/40 joint is gone
Condenser and Vigreux column seem to be indestructible(famous last words)
Crossed out glass stoppers represent proportion of the total. As there were stoppers lined around the entire package.
I treat my glassware a bit rough, but I prefer that to a 'walking on egg shells approach'.
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My apologies for unintentionally misleading
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[*] posted on 23-4-2021 at 17:42


I'm excited because I finally bought a sep funnel, 1L Erlenmeyer flask and beaker (with some tiny air bubbles in the glass but whatever) and 500ml reagent bottle with PP lid

Any tips for using these without breaking them?
Should I boil water in a glass to get it hot before boiling sulfuric acid in it?
Is it better to heat the glass as slow as possible to prevent thermal shocks?
And is paraffin wax bath good for boiling sulfuric acid?
Oh and the air bubbles! Should I be worried?


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[*] posted on 23-4-2021 at 22:36


If the glassware is made of borosilicate glass you don't need to pre-heat it. It can withstand a significant thermal shock, so it will definitely survive some gentle heating. Do it slowly however and remember that boiling-hot sulphuric acid is known of violent bumping, which can lead to some damage to the glass and things nearby.
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[*] posted on 28-4-2021 at 16:02


yup. what's the brand? Esco labs? I never had any of there glassware but they seem very reputable.

Beakers, except maybe huge ones, are probably the hardest to break. Along with Erlenmeyers/conicals.

Thermal shock is nowhere near the top of my list of causes of broken glassware. It's definitely much more likely to occur upon cooling from a heated state, than from sudden heating. Reason being, since generally one heats the vessel from the outside, the outer portion of the glass wall will expand first, and there's nothing constricting it from expansion. However when cooling down, the innermost part of the glass wall will be in a hot, still expanding state. Dropping it in an ice bath will first cool the outer side, constricting the not-yet-cooled inside, and if the Delta(T) is severe enough, it has no choice but to crack.

Definitely don't heat up your beaker you intend to put H2SO4 in with water first. Better to heat it up with H2SO4 in it, ya know?

The mid 300's C, the BP of H2SO4, is childs play compared to the temperatures I deal with when I manipulate boro glass with a torch.

But yeah, i'm still watching that thing like a hawk anytime I'm concentrating H2SO4, and have some sort of plan B in mind if the worst happens.

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[*] posted on 28-4-2021 at 23:20


160C is the gradient for boro.

Although, when I cool down reactions that are hot, like 150C, I first use hot water, 50-70C, to bring it below 100, and then use cold water to finalize it to ntp.

I don't know if anyone has yet tested it, but I suggested using air pump and bleeder tube to agitate sulfuric acid to prevent bumping. Also, I would use flask that is worth losing, like cheap 2L rbf, and it also needs a lot of heat, so it likely must be heated directly with propane gas. I've noticed that for effective boiling, thermal gradient must be over 20C with water-CaCl2 bath, and 50C with oil bath.
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[*] posted on 30-4-2021 at 17:24


Estate sale!

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earpain
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[*] posted on 9-5-2021 at 13:20


Quote: Originally posted by Fyndium  
160C is the gradient for boro.

Although, when I cool down reactions that are hot, like 150C, I first use hot water, 50-70C, to bring it below 100, and then use cold water to finalize it to ntp.

I don't know if anyone has yet tested it, but I suggested using air pump and bleeder tube to agitate sulfuric acid to prevent bumping. Also, I would use flask that is worth losing, like cheap 2L rbf, and it also needs a lot of heat, so it likely must be heated directly with propane gas. I've noticed that for effective boiling, thermal gradient must be over 20C with water-CaCl2 bath, and 50C with oil bath.


Although almost all borosilicate scientific glassware proudly boasts of the 3.3 thermal expansion coefficient, there are still different types of boro, some more heat conductive, some more insulating. Some have a chemical treatment done onto the surface as a final step to make the glass hydrophobic - I've noticed this effect in some of the very high end brands.

H2SO4 - hmm, I see your logic there. But on the flipside, I might say that such times call for the best, most durable of my glasswares.

Although I'll admit it's been years since I've had oxy/propane and worked wall thickness in the scale of most scientific devices, I routinely work test tubes, thinner parts of broken devices etc. over open atmospheric propane.
Unless I'm aiming for a complex spot, I've never had an issue with going directly to open flame. Not with boro.

Having the container filled with H2SO4 should even further fortify the thermal structural integrity. What I don't do is put a beaker on metal grill over open flame, such as on my stove. I put a frying pan on the metal grill parts, beaker on the frying pan.

One of my longest lasting and most abused, 1L erlenmeyers was routinely heated that way for like a year. And then one day it cracked, from sudden heat.


So my observation for thermal gradient, is that it depends on the vessel, and the glass. If I have a specific pan with sand in it I plan to reuse, and a specific flask, first time I bring something with a high BP to a boil, with two thermometers.

A tiny 50ml RBF will have a far more dramatic temp difference, as well as thermal latency effect, as compared to a 2L RBF.
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[*] posted on 12-5-2021 at 23:08


I feel this counts, or close enough. I ordered a few Geiger–Müller tubes from GSTube.com and they came the other day. Total 2 months in shipping lol, Mar 2 - May 6. But intact they were :) box was in great shape.


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