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Aluminum or brass end plugs

This is the place to post your submarine build- ups.

Postby Skip Asay » Fri Oct 30, 2009 3:53 pm

Each has its pros and cons. While aluminum will corrode in chlorinated water, it is much lighter than brass. Brass doesn't corrode, per se, but it is far heavier than aluminum. This weight might end up hurting you, though. This is because you'll need to keep your weight as low as possible to maintain stability (mostly surfaced) and with big blocks of brass as end caps, your weight will be pretty high. Virtually all model submarines require weight to be added with the keel the most obvious place. Using brass, your boat's overall weight will reduce the amount of weight you'll need in the keel. This can be offset to a large degree by the use of foam, however, but you'll probably need quite a bit and you'll still have to add weight in the keel.

Realizing the faults inherent with acrylic, I've been very successful using 3/8" thick acrylic as end caps with zero ill effects. The thicker the piece is, the better (to a point, anyway. Use a very sharp tool and leave a small radius instead of sharp corners and you'll be home free.

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Postby Sub culture » Fri Oct 30, 2009 4:00 pm

Why metal endcaps when plastic works well and is lightweight?
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Postby Sub culture » Sat Oct 31, 2009 6:59 am

Well, you go with what you think is best then.

Most people make endcaps out of plastic, because it works, is cheap and easy to machine. If you need a new one, just machine another out of blank stock, doesn't take long to machine an endcap if you have a lathe.

If using metal, then you can make the face of the cap out of sheet stock and solder it onto a brass ring. It will probably still be heavier than a plastic endcap, but not by much. If you domed the endcap a little too, it will be very strong.
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Postby Ramius-II » Sun Nov 01, 2009 1:21 pm

Just something to consider, electrolysys. You are talking about working with metals in water. Brass is considered electrically "neutral" when mixed with most other metals and most items you would use would probably be brass such as screws, tubing, etc. thus you would have more flexibility in uses and designs. While there is aluminium solder available, silver and even lead-tin solder are more common.

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Postby Ramius-II » Sun Nov 01, 2009 4:15 pm

Hi John! :D
Again you are absolutely correct and when I read that you were bolting 2 electric motors directly to the end cap the first thought was that the motor bodies are most likely steel and would be in direct contact with the aluminum (as you wrote) for cooling. It is almost impossible to know the extent of someones range of knowledge and to me I would not be a good friend if I did not at least ask if such factors had been considered. It is also easy to imagine that you might be using the end plug as a grounded plate to reduce EMI and RFI by running a heavy wire back to the batteries negative so as an electronics person it is the way I think. I would love to see pictures of the completed assembly!

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End caps

Postby Mike Dory » Sun Nov 01, 2009 5:23 pm

John - My friend, Your whipping a dead horse. While you might get away with Aluminum end caps in a 4" inch tube (mounted in a large hull) Like a 1/32 scale Type 1X U-boat You would have a time dealing with that much weight up high in smaller hull boats, like say a 1/32 scale Type XX111, the hull is just to narrow. You can get plastic any way you want it from Mcmaster-carr, The cost isn't outrageous, it machines well and it's light weight. As someone already pointed out " Why change" In addition It has stood the test of time my friend. You pointed out that by mounting motors to it, you could use it as a heat sink. I'll give you that, but if your having that much heat. You might consider gear reduction or water cooling to take care of the problem. Weight up high is hard to overcome. Look at What do you gain Vs. what problems they create. Call me we'll chat about it. As always, all my best....... Mike Dory
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Postby Sub culture » Mon Nov 02, 2009 6:41 am

Most people use plastic sheet if machining endcaps. You get a little wastage, but not much.
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