Stuck on the Air Leak Test (MM-5)
Posted: Tue Oct 07, 2003 9:56 am
Hi,
My son and I enthusiastically assembled our first MM-5 coffee cup
engine and we were doing great until we got to the air leak test.
It failed. Obviously, we have an air leak. So we filled every nook
and cranny with silicon and it still fails. I used plumber's tape
to close up every possible gap, including around the brass crankcase
tube. We fail. I switched to our "spare" diaphragm. Fails. I am
at my wits end. It looks like most of you built these things in a
few minutes, with little trouble. So where could we have gone wrong?
Here are some questions I have: I am trying to understand how the
cylinder tube can be airtight if a wire moves freely up and down
through it. Obviously, that part is not airtight. So how could the
leak test possibly work? Also, the diaphragm is a bit wrinkled - no
matter how careful we are. And the brass ring easily bends when the
nuts are tightened. But I am not sure how to overcome these
problems. Any help would be greatly appreciated.
Thanks in advance,
Rick
My son and I enthusiastically assembled our first MM-5 coffee cup
engine and we were doing great until we got to the air leak test.
It failed. Obviously, we have an air leak. So we filled every nook
and cranny with silicon and it still fails. I used plumber's tape
to close up every possible gap, including around the brass crankcase
tube. We fail. I switched to our "spare" diaphragm. Fails. I am
at my wits end. It looks like most of you built these things in a
few minutes, with little trouble. So where could we have gone wrong?
Here are some questions I have: I am trying to understand how the
cylinder tube can be airtight if a wire moves freely up and down
through it. Obviously, that part is not airtight. So how could the
leak test possibly work? Also, the diaphragm is a bit wrinkled - no
matter how careful we are. And the brass ring easily bends when the
nuts are tightened. But I am not sure how to overcome these
problems. Any help would be greatly appreciated.
Thanks in advance,
Rick