Thanks for this, have been after some for a while, but they are not that common down under. So ends up being pricey to buy some from overseas, will be making some of these this weekend I think, nice tutorial! Only place local I found was NZ$45 for 8 of them. $5 should cover the parts I don't already have 






) but can you weld to a magnet? if so couldn't you weld two magnets to a slider to shorten or widen the gap between the two pieces to be welded then you don't have to worry about retrieving anything afterwards.
[Unless I've misunderstood your intent [which is quite likely....
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