19-03-2005, 03:01 PM
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Junior Member
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Join Date: Mar 2005
Posts: 21
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Quote:
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Originally Posted by Richard L
Quote:
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Originally Posted by hotrod
Also be advised that some of us have had problems with the shurflo pump at high alcohol concentrations. The pumps commonly sold with the santoprene seals do not like extended service with high concentration alcohol.
Mine lasted about 3 months before the santoprene seals began to leak fluid into the pressure switch.
Shurflo sent me viton components but due to cold weather I have not run the system in several months.
We will find out here in about 8 weeks if the viton is adequat to the task of running >75% alcohol mixes for extended periods.
Larry
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Thanks for this vital information. I have checked chemical comatibility tables for viton - it came up with inconsistant results- Vital's resistance to methanol is worse than natural rubber (NBR) but according to Dow Corning who holds patent right for viton, there are many types of vitons - one particular one suite methanol. It is just plain confusing. EPDM appeared to be simple and more generic and straight forward and very resist to methanol. I hate trade names especially there are many variations on viton.
I have search many sites for nitromethane compatible seals and came up with three suitable rubber materials PTFE and two others in "trade" name. The cost .... you have to see it to believe it:
PTFE: $1.20 dollars each
Trade name 1: $3.50 each !
Trade name 2: $5.85 each!
The size: 3/16"x 1/16" o-ring - standard imperial size. So we decided to machine our own PTFE seal. Cost is less than $0.1.
Some one is playing silly games. |
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