[RASMB] torque strength

[Ariel Lustig]

Hi Karen and colleagues,
I can tell you only from my own experience how  I treat this  problem. First of all  I use  only sapphire windows,
since  at the end  they are  cheaper then many broken quartz windows. Why broken ? my cell-stuff  is very  old so 
Epoxy centerpieces (alum-filled and  charcoal-filled) swell slowly and became a bit  convext on both  flat side , so I
even  install (not too  easy) in case of the  bad once DS-window gaskets between the  window and  the  centerpiece.
as it is obligatory for  metallic centerpieces!! 
Sure that in case of metllic centerpiece the  torque  strength is more  crucial  since  lack of elasticity you break easier 
the  window just during  closing the cell (not  the  centerpiece as you wrote ,Karen ! ) so 130 torque -units should  be  enough. A probleme  may be  the  temperature, I torque  the cell at the (coldest) temperature  the run is planed , independend if  I fill the  cell at room temp.( if the sample allows it). The idea is to prevent  shrinking later of the  centerpiece....and leaking. A bit tolerance for higher  temp. is still  given  with  130 t.
The Epoxy once  "suffer" more tolerance, so 120 -140 is  OK.
With time usually one gets the feeling witout looking on the torque dial especially  using Epoxy once , according  the
flexibility.
 I don't believe that the torque  instrument is a so precise instrument  and unic by all users !!!
It may happen (I believe  at most of you) that the screw-ring -gasket  do not lie properly on top of the upper window- holder (catched in the winding or an alien element is between)  breaks , and as response you may read  a high  torque 
dial but in realty the centerpiece is not pressed to the  windows.

Just returning to  centerpiece break  during a  run , usually happens with  quartz  widows. First you  have  a leak
in one  sector (may be evaporation true the filling screw), the filling hight liquid  remain much  higher as in the other sector, then the midle strap breaks and also
mostly the quartz window. (Saphire  even at  max.speed never  break.)
                                                                                                           yours...ariel

!
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