Saturday, 12 August 2017

Back to the maths

Yesterday I purchased a metal file which enabled me to do some ‘fine tuning’ on the cheap snow foam gun bought on eBay and sent from China.  The recommended gun cost approximately $100 and the supplier was in the UK.  However the Chinese replica was $20 and I’m hoping it will do the same job.  This morning was all about the maths in calculating the ratios for car wash mixture in the snow gun bottle.

The first step was to fill the snow gun bottle with water.  When using the gun this will be a mixture of car wash and water, but it’s the ratio I wanted to calculate today.

I also need to use two buckets to catch the water that passes through the gun in order to calculate the total amount of water passing through the gun until the snow foam bottle is empty.  We have two new buckets but there is nothing on them to indicate capacity.  So my second step was to fill one of the buckets with water using a container with a known capacity.  The capacity of the buckets was calculated at 15 litres.

The third step was to empty the bucket and then refill it I used the pressure washer and snow foam gun.  The purpose of this was to establish the volume of water that must pass through the pressure washer to empty the snow foam bottle.  Actually this turned out to be a relatively simple task resulting in the snow foam bottle emptying at the same time the water filled the bucket.

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So the total water usage was 15 litres.  The snow foam bottle has a capacity of one litre resulting in a 14 to 1 ration.

Things became slightly trickier with the car wash.  It’s American and the ratio was provided in US imperial.  1oz to 1gal.  (Actually the instructions stated 1oz or 1 cap) This was converted to metric

1oz = 0.284131 litres

1gal = 3.785 litres

Calculate number of gals in bucket = 3.69 (14÷3.785)

Therefore the correct ration is 3.69 caps or 105mm of carwash to be added to the water in the 1 litre foam gun.

Why be so precise?

Using less than the required amount of car wash is likely to result in an inadequate density and coverage of foam on the vehicle.  Using too much is a waste (and the car wash is expensive).

Having completed that task I went on to crimp the terminals on the 12V fuse box I purchased from China.

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There are a total of six fuses divided into two banks of 3.  The box has two 12V supply input cables and six output cables.  I crimped male spade connectors onto the input cables and female connectors onto the output cables.  The logic behind this was I wanted to ensure any “live” terminal had an insulated female end. 

I think I might have found a location for this fuse box under the 4x4 steering column.

Another small task was to assemble the switch assembly which has been made up of very cheap components purchased from China via eBay.

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The three switches will be for the LED Light Bar on the front of the vehicle; the Tyre Pressure Management System and the Two-way radio.  The Dash Cam will be permanently on and therefore won’t require a switch.  I think I’ve found a location to hide these switches.  There is a small, flat cabinet with a lid on top of the dash.  Each switch has an LED which will illuminate when on but because the switches will be inside the cabinet almost no light should escape.

1 comment :

Marilyn McDonald said...

AAARRRGGGHHH!!! I am having a meltdown ... TMI, TMI, TMI