Amperage & square inches

[vesatr]

Is the right amperage 1/10 or 1 amp per square inch for annodizing and what is the right way to figure square inches.I have a block of aluminum 2 x 3 x4 inches, some of the face has been machined away but not enough to really make a drastic difference in the square inches. Thanks. vesatr

[mcaswell]

0.1 amps per square inch.

To calculate the area of a part, break it down into individual rectangles. The area of a rectangle is Length x Width. Calculate the area for all the rectangles, then add them together.

Your 2 x 3 x 4 block has 6 rectangles.

2 with dimensions 2 x 3 = 12 sq in
2 with dimensions 2 x 4 = 16 sq in
2 with dimensions 3 x 4 = 24 sq in

Total Area = 52 sq in

[chromo]

Glad I read this one

I was about to figure cubic inches and screw something up

2x3x4=24. 00ps!

[vesatr]

I did the same thing and came up with 24square inches.What about a solid 4 inch round 14 inches long ?I have 2 steering cylinders off an oliver tractor that I am going to use the copy chrome set up on . New cylinder rods are 600.00 dollars apiece,I cant afford to make a mistake on them!! Thanks , vesatr

[gsw3]

Figuring square inch area for solid round parts:

(Part diameter in inches x 3.1416) x length = square inches.
in your case:
(4 x 3.1416) x 14 = 175.929 square inches

If the ends are solid and they will also be plated:
3.1416 x (radius squared) = square inches on each end of round parts.
in your case:
3.1416 x (2 squared) = 12.566 square inches (for (1) end)
12.566 x 2 = 25.132 square inches (for (2) ends)

175.929 (the "shaft")
+ 25.132 (the shaft "ends")
--------
201.061 total square inches


George W.

[24Seven]

another quick way to calculate area on flat circles is to remember that the area within a circle is very close to 3/4 of the area of a square or .75 so a 1" circle would be 3/4 sq. inch or .75 sq. inch likewise a 4" circle roughly = 3 square inches ....its so close its easier to calculate it this way unless you have to be absolutely dead on.

[24Seven]

correction a 4" circle would be roughly 3/4 of 16 square inches or 12 square inches as:

4x4 = 16
16 x .75 = 12

[24Seven]

likewise if we round off the 3.142 to just remembering 3 in our area of a tube equation you would come to within aprox tolerances in calculating your amps ...as a 4" solid round @ 14 inches long would be very simple to calculate it this way

(4 x 3) x 14 = 168 and then add the two flat ends or
( area of 4 x 4) x .75 = 12 x 2 two ends = 24
(add 1st line to second line) = 192 square inches and if each square inch = 1/10 of 1 amp then a total of 19.2 amps using this method which is off by aprox 1 amp or roughly 5% in this example which if I am not mistaken here, would be within tolerances for plating purposes. If so then this breaks the equation and figuring down to a minimum as all you have to do is remember a few easy numbers you can calculate in the noggen or a quick scribble without the use of a calculator.