Sciencemadness Discussion Board

Diy PTFE Boiling Chips

artemov - 8-9-2019 at 17:56

Bought a cheap ptfe rod, intend to cut it to small pieces to use as boiling chips. Wondering if they would be effective. Can they be washed and recycled for repeated use?

One thing I dun understand, ain't boiling chips supposed to be rough and porous? Ptfe is anything but, even those expensive ptfe boiling chips seem fairly smooth





Deathunter88 - 8-9-2019 at 22:43

Quote: Originally posted by artemov  
Bought a cheap ptfe rod, intend to cut it to small pieces to use as boiling chips. Wondering if they would be effective. Can they be washed and recycled for repeated use?

One thing I dun understand, ain't boiling chips supposed to be rough and porous? Ptfe is anything but, even those expensive ptfe boiling chips seem fairly smooth





Yeah all PTFE seems to have an almost magical effect in being able to facilitate smooth boiling. Most stir bars are smooth yet they are a good substitute for boiling chips.

markx - 8-9-2019 at 23:21

As far as I know solid PTFE parts are produced by pressing and sintering the virgin powder, so I guess at the microscopic level it is kind of uneven and perhaps also somewhat porous on the surface. It is a very slippery substance so this gives the illusion of it being very uniform and smooth.
Also it is for practical purposes pretty much indestructible by chemical means (apart from interactions with molten alkalies or media that require extremely high temperatures in excess of +300C), so yes, the chips can be washed and used indefinitely.


[Edited on 9-9-2019 by markx]

fusso - 8-9-2019 at 23:39

But will the smaller oligomer molecules leach out during boiling solvents?

Deathunter88 - 9-9-2019 at 00:02

Quote: Originally posted by fusso  
But will the smaller oligomer molecules leach out during boiling solvents?


Probably wouldn't be too big a deal as I doubt tetrafluoroethane would be very reactive.

teodor - 9-9-2019 at 01:46

I never tried PTFE rods, only pieces of PTFE tapes. I can say PTFE tape is not as effective as porcelain chips (also it is not sitting on the bottom but floating). I use porcelain chips made from a plate - I smashed a thick plate by a hammer. After boiling 85% H2SO4 and constant boiling point HBr with them the glaze was totally dissolved, so I got a totally unglazed chips. They work very well - I forgot about bumping at all.


[Edited on 9-9-2019 by teodor]

happyfooddance - 9-9-2019 at 22:49

Silica gel kitty litter works great and is cheap.

PTFE might look smooth and porous; the naked eye is a poor judge of such properties, however. Silica gel (or aerogels for that matter) look like perfectly smooth glass when carefully prepared, but air passes right throught them and they have more holes than they have solid space :o

[Edited on 9-10-2019 by happyfooddance]