Sciencemadness Discussion Board

250ml RBF with a bubble in the bottom?

WangleSpong5000 - 27-12-2017 at 23:54

I was looking around on ebay for 250ml RBF's and found this:


https://www.ebay.com.au/itm/262966431136



Is this a glass bulb in the bottom or a trick of the light due to the camera? I ask because I often place my flask on my magnetic stirrer hotplate and place a stir bar in the flask... obviously.

Sorry for the small picture. The other one was 1600 x 1600 and I believe this is too large for the forum.

Thanks

Sorry AGAIN i just realized as this is not an image file I couldnt use the img tags to display it... I really should now how to resize images by now I'm studying to be a programmer ffs


[Edited on 28-12-2017 by WangleSpong5000]

[Edited on 28-12-2017 by WangleSpong5000]

[Edited on 28-12-2017 by WangleSpong5000]

[Edited on 28-12-2017 by WangleSpong5000]

[Edited on 28-12-2017 by WangleSpong5000]

[Edited on 28-12-2017 by WangleSpong5000]

[Edited on 28-12-2017 by WangleSpong5000]

weilawei - 28-12-2017 at 04:19

It's hard to tell. I'm inclined to think it's the camera. That said, Deschem sells a lot of glassware, and you probably won't get that flask--just one like it. And lately, I've been disappointed with their quality. Their hose barbs were undersized by 0.5mm (on a recent order of stopcocks), leading to poor hose connections, and their stoppers were oversized (joint 2mm too tall, possibly an issue with the taper, but I haven't measured the angle. They stick way out the top of a 29/32 flask.). I've purchased a ton of glassware from them over the years, but in the past few months it's been mostly disappointing. I'm strongly considering not purchasing from them again.

20171228_073011.jpg - 1.9MB 20171228_073412.jpg - 1.7MB

[Edited on 28-12-2017 by weilawei]

Dr.Bob - 28-12-2017 at 06:46

I think the spot you are seeing is likely from the flash or other light source. I also agree that it is likely as stock photo, not a photo of the one and only flask for sale. Also, small bubbles are common in thicker walled flasks, and if small and contained, present little danger. I have used rbfs for 30+ years in the lab and never had one fail due to anything but dropping it, poking a spatula through it, or having it hit another flask in the sink, drawer or hood and get a crack in it. While bubbles and small chips are not bad or a serious danger, a star crack or line crack in a rbf or other labware should relegate it to only minor use, without heating or vacuum use. But I have had a few beakers with small cracks in them that I have used for collecting wash acetone, soaking small parts to clean them, or weighing out bulk solids for years, many doing a great job for many years after some people would toss them.

The quality of Chinese glassware is variable, but better than a few years ago, when I thought it was dreadful. I see more of it every day, with Fisher and VWR branded items often from China now, rather than Pyrex or Kimble as the supplier, and even they seem to be sourcing some stuff there now.

While I still prefer USA made glassware, which is getting harder to find each day (Chemglass is still mostly US made, but even Pyrex beakers and other labware mostly come from Europe nowadays), I have to concede that the Chinese stuff is catching up, and adequate for many tasks. I have heard many people who had good luck with Deschem, so I would perhaps try a small order first and make sure that you are happy with it. But that is likely one of the cheapest source of glassware in Australia. The postal rates make it nearly impossible to ship from the US to Australia now, but China subsidizes its postal rates, so they can ship nearly for free, thus the very good deals they can offer. They can ship a package to the US cheaper that I can mail the same item across the US.

[Edited on 28-12-2017 by Dr.Bob]

WangleSpong5000 - 28-12-2017 at 08:16

I have never bought anything off ebay that I would consider 'Primary' glassware. ie condensers, flasks, fractionation columns, sep funnels, still heads, claisin adapters, vacuum tae off tubes (or whatever they're called) as I've never needed to. I bought a distillation kit eons ago through an aussie lab supply company, filled the EUD and it sat in a box for 2 years. So over the last 2 months I bought everything else for the distillation kit (Thermometer adapter, tubing, aquarium pump, 2 retort stands that came with 2 clamps, 1 condenser clamp and 3 support rings) and the necacerry heating devices a hotplate mag stirrer with temp probe (the cheapest, shittest one that exsists the BT-1... i read a review by a bloke who specializes in electronics... i'll find it and post it... the review was not good) and a 250ml cheap mega cheap heating mantle which is actually pretty good for how cheap and shit it is. I bought ph paper, a set of beakers, a bunch of 3ml pippets, graduated cylinders, safety goggles and I'm waiting on a thermometer thats taken far too long...

Right now I am tring to find a seller, with cheap 250ml RBF + express shipping (just this once) for $20 AUD as thats all i have in my bank account and the express rbf will co incide excatly with a bunch of reagents that are due. I found one for
$24 AUD lol... so close

SWIM - 28-12-2017 at 19:29

Wow, they really screw you guys over on price down there.

I just checked Ebay, and I can get the same flask delivered to my place in California for $5.77 US.

Seems it ought to be cheaper with you being so much closer to the manufacturer.

Maybe you've got higher tariffs?

JJay - 28-12-2017 at 21:21

Deschem's quality varies... I think a lot of their items are seconds, but a lot of them are good quality. I recently got a reflux condenser from them, and the hose barbs are small, but I can just as easily use smaller hose. Their major pluses are price and packing, and they aren't scammers. Most suppliers will replace broken glassware, and those that won't can usually be required to issue refunds, but if you've ever had the same item shipped from China broken three times in a row with a month wait each time, you understand how important packing is....