MB65E Posted April 20, 2015 Report Posted April 20, 2015 Ok, now my intrest has gotten the best of me.. I knew they were more than 35¢.The Champion box of 100 is $66.75 However, A box of 100 Tempest gaskets is $39.65 from Spruce... Individually they are 35¢... If purchased individually in a lot of 100 Spruce offers a 20% discount off the 35¢... They all have the M674 and U674 p/n's I'm done with my torch, and Champion! -Matt
PTK Posted April 20, 2015 Report Posted April 20, 2015 Ok, now my intrest has gotten the best of me.. I knew they were more than 35¢.The Champion box of 100 is $66.75 However, A box of 100 Tempest gaskets is $39.65 from Spruce... Individually they are 35¢... If purchased individually in a lot of 100 Spruce offers a 20% discount off the 35¢... They all have the M674 and U674 p/n's I'm done with my torch, and Champion! -Matt So they go down to 28¢ a piece if buy 100! http://www.aircraftspruce.com/catalog/eppages/spgaskets2.php
DonMuncy Posted April 20, 2015 Report Posted April 20, 2015 I will probably get flak for this, but it would appear that the only reason to not to reuse spark plug washers is because the temperature they have been subjected to makes them incapable of properly conforming to the two surfaces they are supposed to seal. And properly annealing the used washer reconfigures its molecular structure to that of a new one. Thus, the only reason to use new ones would be if you do not have confidence in your ability to properly anneal them. From what I read, it is not rocket science to anneal them. With that being said, I have several I have annealed, but have always used new ones. Does anyone here have sufficient metallurgical knowledge to confirm or refute this information.
Hank Posted April 20, 2015 Report Posted April 20, 2015 Don, they are crush washers, and deform when properly torqued. But copper work-hardens, so if simply reused, they will be harder and wil. It deform properly to make a tight seal. Each subsequent use, hardness will increase and seal will degrade. At some point, they will be hard enough to split when torqued. That's what I remember from my Material Science classes. --BSME, MSE
carusoam Posted April 21, 2015 Report Posted April 21, 2015 Just like freezing water to make ice... But, in this case you start with heated copper that is already solid and by cooling it rapidly, it gets it's molecules locked into the preferred arrangement. There is a really cool phase diagram that will indicate the phases you get by traversing the metal through temperatures... The nice thing about new ones is the surface finish is fresh and ready for use. Nice to know, in a pinch, the old ones can be resurrected... Hank has the coolest degree, MSE... (In Kerville, that stands for Mooney Special Edition) Engineer/CB, -a-
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