Carbide Manometer - Simple DIY test for water in fuel

Collecting, filtering and dewatering of WVO SVO vegetable oil. For Biodiesel producers too.

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Carbide Manometer - Simple DIY test for water in fuel

Postby John Galt » Thu Feb 09, 2012 11:38 pm

Works accurately with VO, biodiesel, diesel, and fuel blends.

Simple U-Tube manometer: meter stick, 5mm tube, binder clips

Simple U-Tube manometer: 'canning jar' cap for carbide test, 500ppm & 1000 ppm calibration marks
Canning jar cap with screw ring fits a variety of jars for the carbide reaction chamber

Simple U-Tube manometer: 'zero' at 30cm, 500ppm calibration marks
binder clips allow easy 'zeroing'


Tube mortar for crushing carbide: 3/4 pipe 6", 2 end caps, 3" piece of 1/2" rod, 'tea' sieve, funnel

Finely pulverized carbide gives the best test results. Particles caught by the sieve are returned to the mortar for powdering. Powdered carbide that passes the sieve is stored in an airtight container for tests.


It's easy to dry 2 liters of BD on low heat at 100°C for one hour to ensure all moisture is out, [use hotplate outside for safety] Then add 1ml to one liter for 1000ppm, and finally mix 300ml each of dry and 1000ppm samples to make the 500ppm sample.

Masking tape was placed on the meter stick and the calibration levels marked on the tape.

The manometer assembly hangs from a hook and the 500 ppm calibration marks are a convenient go/no-go reference. A short piece of 6mm OD tube is sealed into the jar lid so the manometer is easily connected/disconnected.

The most important point for consistent results is to pulverize the carbide to a very fine powder.
John Galt
Posts: 526
Joined: Tue Mar 04, 2008 9:17 pm
Location: Coldest North America

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