On 28 Mar, 12:42, Ken Moffett wrote:
Robin wrote
ups.com:



I'm working on a little project (a spotlight) that is
basically a bit of aluminium tubing, 50mm ID, 5mm wall
thickness. I was wondering the best way to close the end of
the tube that doesn't have the light shining out. I'm
hoping to make it water resistant

a) Turn a round plate of 60mm diameter, drill and tap the
tube and screw the plate on - problem being the wall
thickness isn't that great so I'd be limited to about M3

b) Cut an internal thread in the tube and a threaded plug
to fit (probably a 1.5mm ISO thread) - would require some
form of sealant/ threadlocker

c) Cut a chamfered plug and bond it to the tube - not sure
what adhesive to use

Any other ideas? I'll be using my Myford Super 7 and
indexable tools

You didn't say what the enviornment is, but I frequently use
plastic plugs for steel and aluminum, round and square.

Like these:http://www.mcmaster.com/#tubing-plugs/=6ev3vm

Ken

The tube is basically a spotlight body, one which I'm hoping will be
waterproof. Since the bulbs (MR16) are halogen, they tend to generate
a fair amount of heat so I wouldn't be comfortable with a plastic
plug. Have always been tempted by the freezing/heating methods - I
suppose once joined, the fact the whole assembly is heating up should
stop it all falling apart although I'd be tempted to screw in place as
well.