I have purchased two different sets of Keck clips from eBay with average prices of around $1 a clip. Within about a week of use, almost off of the clamps have splits/cracks in them.

I am very careful with installation/removal, supporting both upper and lower portions, probably more so than most since I only recently stocked the home lab with ground glass. Running on 19/22 ST joints, which are tight and greased and apparatus is clamped securely with no flexing/etc. to put strain on joints.

 

What (if anything) am I doing wrong, or did I get bum/cheap sets of clips? Anyone else have these issues?

 

Thanks for any input.

Probably the latter: you got bad quality material (or the wrong size??).

No, definitely not the wrong size, 19/22 on 19/22 glassware. Much just be crap quality plastics as even the ones on the cold end of the apparatus are splitting, both top and bottom rings.

I'll break down and put enough money on some name brand ones, that should solve my issue. I wish I could understand why metal Keck's are in the $50 range for 5 of them, seems incredibly overpriced to me, even for laboratory ware which is always steep on the wallet.

The only other thing I can think of is that the plastic is affected by some solvent you might be using. Certain solvents can affect certain plastics.

 

There are also metal clips, for the same purpose.