OnLine Easy Answers - Surface Area Calculator

[charlton]

This may already be out there but since i couldn't find it.. I'm slapping this together.... I just started working on it so I'm not sure yet that the Bolt calculator is accurate.

Should be working by weeks end. In no way affiliated with Caswell. Use at your own risk. Let me know if it's off so I can fix it.

http://216.242.56.15/Plating/Plating1.cfm

[seanc]

Charlton:

Excellent start, nice to see a live one on-line!

Although, it appears you've forgotten to take into account the surface area added by the thread "grooves".

eg, take a cylinder of any arbitrary length & diameter, cut 60º threads all the way down the length, and it almost doubles the surface area.

I've been using my own calculations in a spreadsheet, and for a particular bolt I'm currently working with, I come up w/ 3.39 sq-in. Plugging the same numbers into your calculator gives 1.92 sq-in. If I double the shank length (my bolt is fully threaded) to accomodate full threads, it gives 3.12 sq-in., more in line w/my calculator.

I'm not convinced that taking ALL the threaded area into account is necessary, but considering how good zinc is at penetrating crevices, it would seem to be a significant factor.

Sean

[charlton]

Ok, good tip. In the Caswell manual they say consider the entire shank as a tube but obviously your method is more precise. Maybe I'll incorporate consideration for the threaded region eventually. That's a big difference.

Hoping desperately to find some Ammonium Hydroxide locally tomorrow. I've got a bike that's been down for over a month and it's begining to burn me to get it back together

I was hoping that the 6.6 pH of the reverse osmosis water I used to top off the solution would bring the pH back up but it would take a LOT.

Which brings up another question....how many times can you "Top-Off" the solution with distilled water until the solution is too weak to plate? How do you know when you need to change out the solution / bath entirely?

[seanc]

Charlton:

Hoping desperately to find some Ammonium Hydroxide locally tomorrow

While not ideal, household ammonia cleaner (eg Parsons Ammonia) is mostly aqueous ammonium hydroxide. It usually contains small quantities of surfactants (detergent) and "perfumes", and I don't know what effect those would have on the electrolyte. You might check in a good hardware store for more pure forms.

how many times can you "Top-Off" the solution with distilled water until the solution is too weak to plate? How do you know when you need to change out the solution / bath entirely?

The only answer I've ever seen to this question is "when it stops plating effectively". Most commercial platers either just change it out at regular intervals, or perform chemical analyses to determine depletion, which simply isn't practical for us.

Since last spring when I started out, I've added about a gallon of water to a 4-gallon tank, to make up for evaporation, and it's still working fine. Not being at all familiar with chemistry, I don't know the characteristics of the actual chemicals in the mix, but I don't believe they are volatile. ie, they don't evaporate off with the water.

I keep my tank tightly closed when not in use to minimize evaporation, but in use, it's inevitable.

Sean