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Anodizing change??

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Would you rather have Type III anodizing even though it would cost you more?

  • Yes

  • No


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gorillamotors

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I have already changed the anodizing on my forward closures from the colored 'Green' Type I to a gray colored Type III mil-spec hard coat anodizing. The Type III is a far superior anodizing but cannot be colored green. Also, the cost of the Type III is more expensive than a Type I.


Would you rather have the motor 'case' Type III anodizing over the Type I even though it might cost more?

1. Yes
2. No
 
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cwbullet

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If it is more durable,, yes.
 

MarkM

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Absolutely! The green is cool, but a more durable coating would be worth the extra cost - to a point. How much extra, Jim?
 

Kaycee

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I voted no.

After many flights, I've never had an issue with degredation of the forward closure on my 54/1400Ns motors.

No doubt I'll lose the rocket and motor before I'd ever wear the forward closure out....
 

gorillamotors

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Don't know yet Mark. Just wanted to get an idea of what people wanted.

Kevin,

I've already changed the forward closure to Type III. The question was for the motor 'CASE'.
 
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Kaycee

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Don't know yet. Just wanted to get an idea of what people wanted.

Kevin,

I've already changed the forward closure to Type III. The question was for the motor 'CASE'.
Sorry for not reading the topic correctly. My answer is the same though.

After many flights, I've never had an issue with degredation of the casing on my 54/1400Ns motors.

No doubt I'll lose the rocket and motor before I'd ever wear out the case. :)
 

FROB

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If it ain't broke, don't fix it. especially if that makes it more expensive.
on the other hand, if you are getting customer complaints of the green anodizing not being durable enough, (or for example if liner burn through tends to happen in more than extremely rare, isolated cases) then by all means- but from what others have said, seems thats not likely the case, (pun not intended :)) so i vote no.

It would be interesting to do a poll on how many flights per case set people have managed to get with any reloadable motor before being lost or destroyed by crash, cato etc. or other cause not related to case "wear" or defect. the upper limit of the poll results plus some margin would give you a realistic durability target to design for. IMHO, once that goal is met, the priority should be to keep motors as affordable (and accessible) as possible.
The color of the anodizing is much more of an image branding "differentiator" for the manufacturer. It has no bearing at all for me as the consumer.
Just my 2-1/2 cents- but i believe that in general, the lower the cost of motors, the more people will be tempted to get into high power, and for those of us that already are addicted, the more motors & flights we can get for a motor "budget" that is usually limited by unrelated factors. thus, lower the cost, you sell more, increase it, sell less.
 

bobkrech

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The Type III is a far superior anodizing ...
Anodizing is a very misunderstood suface treatment for aluminum and aluminum alloys. Type I, II and III anodization processes all oxidize an aluminum surface to aluminum oxide to protect it from further oxidation. The ultimate difference between the three types of aluminum anodizing processes is the thickness of the protective aluminum oxide layer.

Type I anodization makes an oxide layer that is ~0.0001" thick; Type II anodization make an oxide layer that is ~0.0005"-0.0015" thick; and Type III anodization makes an oxide layer that is ~0.001"-0.005" thick. (The oxide layer thickness of a Type II and Type III anodization depends both on the alloy composition and the processing time.)

Type I anodization uses the lowest voltage and thus makes the thinnest oxide layer. It is primarily used when some surface conductivity is desired and little surface wear is expected. A good example is the exterior surface of spacecraft. The low process voltage limits the oxide layer growth to ~0.0001" which doesn't require changing machining dimensions to insure adequate thread clearances.

Type II and III anodizations uses a higher voltage than Type I and produces a thicker oxide layer that is an electrical insulator. The "as machined" dimensions of threaded parts must be modified (OD machined smaller, ID machined larger) to accomodate the expanded oxide layer.

The principal difference between Type II and III anodization is that a Type III process uses a higher voltage to obtain a thicker oxide layer and requires a refrigerated plating bath to accommodate the higher plating currents. Since aluminum oxide is not conductive, the oxide layer thickness is proportional to the applied voltage and to obtain a thicker Type III oxide layer the temperature must be lowered to prevent the finish from "burning".

Regardless of Type, the oxide layer is clear, however it is porous. To color the surface, the anodized part is soaked in a dye solution that fills the pores and immersed in boiling water to close the pores sealing in the dye. Type III processing is harder on dyes and thus is more restrictive in color choices than Type II anodization.

Also, the cost of the Type III is more expensive than a Type I.
Because it requires refrigerated plating tanks and uses higher voltages and currents, a Type III process requires more equipment and electrical power than a Type III process, and thus is more expensive than Type II precessing. You can reduce the Type III process time to obtain a Type II oxide layer thickness (which is what most rocket folks are doing), but why bother to use the more expensive Type III process to get an equivalent oxide thickness?

Bob
 

AndyC

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Great synopsis as usual Bob.

One of the things about type II/III vs I is that the final coating is tougher. The controlled oxide layer in all 3 versions is far harder, and thus much less prone to being scratched than bare aluminum (and of course does not get blotchy due to uncontrolled oxidation or surface modification). My poor man's understanding is that the thicker the oxide layer, the tougher it is to scratch it (not harder, just thicker).

While thicker oxide make the part less prone to mechanical scratches, how well does this carry though to damage caused by elevated temperatures, such as inside a motor? I have motor tubes with at least cosmetic damage on the inside (a couple with more) due I think to heat getting around the ends of the liners. Though maybe it comes back up around the outside of the nozzle as the nozzle is sealed with an oring to the liner, not the tube? Dunno if that made sense, but surely others have seen similar damage inside the tubes? How effective would thicker anodizing be at preventing this kind of damage, and since it is just enough to feel, how significant is it?
 

Mike Di Venti

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JIm,
I voted no . I have fown the snot out of your 54/2550 in one season. I had problems getting liners out and after all that, the ID finish was still in good shape.
that piece of hardware has flown 8x on your loads and 6x with the other guys loads.

The manufactors need to do their best to keep prices down. For new people coming in and existing customers.

as someone else pointed out.....if it's not broke, don't fix it.

my 2 cents
 

sandmantoy

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I like the idea of a stronger finish but agree with most of the guy's, to much cost makes my rockets get dusty. I voted no also.
 
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