Anodizing question - Stripped upper surface area

[Leoshik]

Hello fellow Calgunners.

A question to whomever may be privy to this information:

Does anyone know the total surface area of a stripped upper for anodizing parameter purposes. I am assuming that the machinists in the crowd who have a blueprint can probably pull the number directly from CAD, Solidworks etc.

Specifics: The upper in question is, for all intents and purposes standard milspec. It is a 5.56 Armalite flat top (M15A4).

If anyone happens to know this it would be greatly appreciated. If not then my next step would be to contact Armalite, although I'm not sure if that's something they'd commonly help customers with.

Note: I've already got a generic and assumingly fairly accurate surface area for a stripped lower. The two receivers will be anodized together with the parameters (bath solution, cathode area, current, bath duration) adjusted for their total area.

EDIT: Apologies if this may have already been covered, my searches have turned up nothing.

[eaglemike]

You should be able to calculate it pretty close. If you're a sq in off or two it's not going to make a difference.

[jingerale]

I don't have solidworks at home, but on monday if you still need an answer. I can import the upper and look at the surface area property.

[Lostsheep]

Here are all of the "mass properties" courtesy of Solidworks.



Mass properties of AR15_Lower_Receiver ( Part Configuration - Default )

Output coordinate System: -- default --

Density = 0.03613 pounds per cubic inch

Mass = 0.19992 pounds

Volume = 5.53388 cubic inches

Surface area = 81.80518 square inches

Center of mass: ( inches )
X = 0.89611
Y = -1.17687
Z = 0.01727

Principal axes of inertia and principal moments of inertia: ( pounds * square inches )
Taken at the center of mass.
Ix = (0.11837, 0.99295, 0.00682) Px = 0.12582
Iy = (-0.99197, 0.11794, 0.04572) Py = 1.01552
Iz = (0.04459, -0.01217, 0.99893) Pz = 1.07880

Moments of inertia: ( pounds * square inches )
Taken at the center of mass and aligned with the output coordinate system.
Lxx = 1.00318 Lxy = 0.10461 Lxz = -0.00210
Lyx = 0.10461 Lyy = 0.13834 Lyz = 0.00679
Lzx = -0.00210 Lzy = 0.00679 Lzz = 1.07863

Moments of inertia: ( pounds * square inches )
Taken at the output coordinate system.
Ixx = 1.28014 Ixy = -0.10623 Ixz = 0.00099
Iyx = -0.10623 Iyy = 0.29894 Iyz = 0.00273
Izx = 0.00099 Izy = 0.00273 Izz = 1.51607

[kcstott]

It's nice to be exact with the surface area but not needed.

I use to do anodizing in a home brewed set up. You just need to get close.

[Leoshik]

Thnk you all for the input.

I guess I can treat the upper as a closely similar in size cylinder and get a rough area dimmension that way. Or maybe a parallelepiped (or rectangular solid, whatever) with the bottom side missing. In retrospect, I agree that considering I am doing a homebrew setup, a slight deviation in either direction will not spell utter failure.

[Lostsheep]

Thnk you all for the input.

I guess I can treat the upper as a closely similar in size cylinder and get a rough area dimmension that way. Or maybe a parallelepiped (or rectangular solid, whatever) with the bottom side missing. In retrospect, I agree that considering I am doing a homebrew setup, a slight deviation in either direction will not spell utter failure.

Ummm.......


Surface area = 81.80518 square inches

How many sig-figs does one need?

[isplice]

I thought OP was asking about the surface area of an upper receiver, but the data looks like it is for a lower receiver. I may be wrong though......

[Leoshik]

I appreciate the detailed response Lostsheep, but isplice has it right - The question (and thread title) is about an upper receiver's surface area.

My apologies if your selective reading caused you some agitation.

[Lostsheep]

I appreciate the detailed response Lostsheep, but isplice has it right - The question (and thread title) is about an upper receiver's surface area.

My apologies if your selective reading caused you some agitation.

HA HA HA.
Reading comprehension fail on my behalf, allow me to de-agitate myself.

[kcstott]

Leoshink
Just be sure to use distilled water for a preanodize rinse, anodize and after anodize rinse.

Don't cross contaminate, Change you glove often, and don't touch anything with your bare hands once the part is cleaned and ready to anodize.

Ask me how i know. All you anodize problems will come from two things. The anodize bath being to hot (above 70 degrees) or any minor contamination, lack of thorough cleaning. Cross contamination of rinse buckets, and just plain old dust in the air.