I added a gas spring from the boom to the stick. I only found the correct length, stroke and force on Aliexpress:
- 6kg (60N) gas spring:
http://www.aliexpress.com/snapshot/7601366858.html
The sleeves and spacers are cut from 8mm and 12mm stainless steel tubes. The pin is also gotten from Ebay:
- 8mm (ID 4mm) tube cut to 13mm length:
http://www.ebay.com/itm/121600172085
- 12mm (ID 8mm) tube cut to 4mm legnth:
http://www.ebay.com/itm/121762512929
- 8x30mm pin:
http://www.ebay.co.uk/itm/121851516316