Is there a scanner that can work out cubic centimetres?

[Charlie J]

To give a simpler example and always remembering that Volume = Mass/Density

Take a ball of dough which will have a given mass and density and therefore volume. If you rolled it out as flat as you can it would still have the same mass, density and volume as the ball but a much larger surface area.

[K2-K6]

Trying to visualise it. And so if I had that notional 1cm cube in steel and milled a V shape into one surface, then mass is reduced but surface area changes by the difference between that one face being removed, plus the two triangles missing from the other two faces affected and compared to the two newly made facet of that V ? Maths should prove or disprove that.

If that's true, wouldn't the displacement method be more accurate, and certainly close enough for the purpose calculations needed for the original question.

[Charlie J]

Rather than trying to visualise it. Try this exercise.
Take a steel cube 100mm x 100mm x 100mm and work out the surface are and volume.

Now slice the cube in half to give two pieces 100mm x 100mm x 50mm and now work out the total volume and surface area of the two pieces.

You will find that whilst the volume remains the same, the surface area will have increased by over 30%. So the displacement method for determining surface area isn’t remotely accurate even for non complex shapes.

I’ll let you do the actual maths which will clearly demonstrate the point

[Oddjob]

What have I started 

[K2-K6]

  interesting though.

Thanks for input from other posters,  certainly makes you use your thinking power to try and figure something out.

Apologies if it's diverting your thread Ken 

[SteveD CB500K0]

Well you did ask for cubic centimetres (volume) and then went on to talk about square centimetres (surface area).

You are clearly a man of many dimensions.


Sent from my iPhone using Tapatalk

[Charlie J]

  It can get quite complex, even more so if you put rugosity (surface roughness) into the equation.

But here’s a link to a useful guide and calculator from Caswell Plating that may be of help.

https://caswellplating.com/surface.html

[JamesH]

Rather than trying to visualise it. Try this exercise.
Take a steel cube 100mm x 100mm x 100mm and work out the surface are and volume.

Now slice the cube in half to give two pieces 100mm x 100mm x 50mm and now work out the total volume and surface area of the two pieces.

You will find that whilst the volume remains the same, the surface area will have increased by over 30%. So the displacement method for determining surface area isn’t remotely accurate even for non complex shapes.

I’ll let you do the actual maths which will clearly demonstrate the point

An alternative approach to visualising this is to consider the 10 x 10 x 10 cube (in cuboid form), then visualise yourself smashing the living sh*t out of it with a 10lb club hammer (repeatedly) and imagine the surface area of the resultant, flat, but larger surface area object. Simples.

[Charlie J]

Now why didn’t I think of that

[philward]

Ken, I have found that the plating area only has to be approx. My instructions from the kit state:- (for example)

'Current approx 0.5 Amp - Plating area 2.5 - 5.00 square inches (optimum 4 square inches) - Typical part: Bolt 19mm dia x 50mm long'

This gives you some wiggle room - its other factors like temperature and mixture condition that have made the difference in finish in my experience.
I have made rough calculation on the area by breaking the object visually into sections and applying an area calculation to each section and adding together.
Always had reasonable results over several projects

[Oddjob]

The owner of Gateros told me in a conversation that a 6mm x 50mm bolt would be 1/3 of an amp for 20 mins, plating companies only plate for 15 min he said so the extra 5 mins gives you a better coating whilst only being a few more microns thick. If the part isn't a critical fit part you can leave it for a good while and really pile the plating on but not if you have threads etc.

Getting ready for my first attempt this weekend I reckon. Some of the parts I'm going to plate are unusual, we'll see how they come out.

[Sesman]

Hi, Ken.

Screws arrived thanks.

[AshimotoK0]

I have always worked  on 100mA /square inch of surface area for BZP. I got that figure from a 1943 Canning book.

One of these days I am going to make a DIY mini barrel plater as loads of tiny bits are a PITA using the wire 'hanging' method.

You basically have a little plastic barrel with lots of holes in it rotating slowly at an angle in the electrolyte and metal cathode 'danglers' strategically placed to contact the steel parts as they rotate.

I have discussed this with PM 's with Ken but I made a big mistake and tried out 'YouPlate's' ready mixed chemicals as opposed to the 'Gateros' stuff I have used for ten years. I got a really dull finish with the Youplate stuff and no amount of   playing around with settings/brighteners will achieve a bright finish ... so voted with my feet and gone back to the Gateros stuff. Well we all make mistakes 

[Moorey]

 
  Just to throw another spanner in the works with the water displacement method. When measuring the surface area of the water you will
  get vastly different results just by adding a drop of soap to break the surface tension of the water yet still have the same volume of
  water.