Question 1

Do you have a metric version?

Accepted Answer

Not yet, because I don't know what the equivalent is to 3/4" EMT conduit outside of the US.  But I'm working on it and would like to have it soon, so if you can help with measurements of hardware outside the U.S., please get in touch at support@inventorevan.com.

Question 2

How strong is this system?

Accepted Answer

EMT pipe can hold hundreds of pounds - plenty strong for photographic equipment.  The limiting factor will be the plastic components.

When supported at one end, a typical arm (reaching out 2 or 3 feet, 50-70cm) should support a few pounds, the weight of an SLR or a reflector.  More than that would risk breaking the plastic of the pipe coupler.  
A camera arm supported at one end
https://static.wixstatic.com/media/7b82c0_e69dceb4fb2f4461a748a0b24598df3f~mv2.jpg

Supported at two ends, however, the system is much stronger.  If you build a frame with two supports, the system will hold at least 30 pounds  (14kg), and possibly much more.

A frame supported at both ends
https://static.wixstatic.com/media/7b82c0_0c64b4ff92ab4dd8a62dd0c65c62912b~mv2.jpg

If you need more strength than plastic components can provide, I suggest looking for parts from the fine folks at Maker Pipe,(https://makerpipe.com/) who provide a steel system also designed to work with EMT conduit.

Question 3

What filament should I print this in?

Accepted Answer

I print mine in Elegoo rapid PETG, because it's strong enough for my uses, less brittle than PLA, and inexpensive.  If you need more strength you could try ABS or PA -- if you do, please let me know how it goes!

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