Cyma AR Fifteen Metal blaster teardown

@Btnas and anyone that has one of these metal gearboxes noticed that there’s been specs of white rust/corrosion on and in their gearboxes?

@Ihobby
Can you confirm that your units are not being exposed to water during the manufacturing process or on its travel to Australian shores. I’ve serviced a few of your cyma blasters in recent weeks and noticed a recurring theme of said evidence of corrosion. This last unit being probable the worst of the lot that I’ve personally seen.

@Rattler I think you’d be much better qualified to say what exactly it is ect. If it’s weakening the structure ect. That is a little beyond me but I think it’s worth asking/mentioning.

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Wow, that is oxidation and a very bad case of it, I’ve seen light oxidation on aluminium but that almost looks like the amount you get on magnesium exposed to Salt water , or even electrolysis !

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Maybe it was a chemical that they have been washed with and it is still present and hasn’t been rinsed off properly in manufacturing 🤷

Normally all uncoated aluminium gets a light oxidation that coats the surface and protects it from corrosion but this is something else !

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The others I’ve done have only been light. I’ve brushed it down and oiled the area to prevent more. This one I’ve done the same. But do you think it would compromise the gearbox shell? Maybe something to just make the owner aware of sort of thing to keep an eye on?

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It shouldn’t compromise the box as long as the corrosion hasn’t gone too far

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Yeah I had a bit, mostly inside where the nozzle sits…I cleaned it up a bit, and oiled it.
Not particularly worried. If I remember my roof plumbing, fresh, fine cut metals actually react to the oxygen immediately, helping to PROTECT the substrate.
It’s why you should NEVER use a grinder to cut roof sheets, for eg.
Using a nibbler or tin snips creates a fine cut that seals itself, whereas a grinder just opens up the whole lot to o2 attack.
Fresh cast ally would also do that. Frankly, I’m taking it as a sign that the alloy/casting process is of relatively high quality…(don’t really have a choice!)
Happy to be told why I’m wrong, tho… But I’ve worked on boats, and have seen fully oxidised ally…It ain’t pretty!

No wire brushes, tho! Could potentially make it worse!!

Toothbrush I found was perfectly adequate for taking it off.

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Perfect!
Found this…

Yeah was just thinking they may wash/dip the castings in cheap acidic crap to clean post cast…
Maybe they test each blaster individually…then they get packed and sit in a humid cardboard box for a couple months…
That area is consistent with excess moisture hanging around (gels), so possibly another good sign of quality control???

The more I look at your pics, the more I’m convinced it’s from test firing gels…

This is my SS. Just wanna get a torch, then I’ll build up the MK gearbox.
I’m still admiring it, so didn’t want to pull it apart yet lol

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That looks awesome! Been thinking about one of those…
Too many! Send money!!

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Tbh I kinda wish I waited and got an ss instead of my mrt

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I dig the 'guard and gas block setup. Very ak…
Currently lusting after a metal one of these…not quite the same as the ss, but the handguard would suit both…
images (10)

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