Hi all
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From: <[log in to unmask]>
> I would like to ask if they are so easy to make that buying them is
> unecessary, then how is it done?
I have clipped most of this from a page of notes that I made with a view to
writing a web page about the subject.
Use German "green band" capilliary tube.
A laboratory clamp stand can be utilised with a fixed clamp and a
sliding one to grip the two ends of the capilliary.
The lower sliding clamp can have various weights hung on it and the drop
height adjusted
using blocks.
The melting is provided by a small coil (6 mm - 8 mm dia) of NiCrome wire
heated from a 12volt battery or a battery charger. The connections to the
coil can be made via "chocolate block" connectors (the coil is arranged
concentrically with the tube).
Thin brass tubing (available from model shops) can be
threaded onto the coil leads for rigidity and to concentrate the heat
within the coil itself. The precise form of this coil can have a marked
effect on the shape of
the finished tip.
The coil melts the glass and the bottom weight draws the the melted portion
into a thin neck.
A guage wire is fed down the tube until it stops in the narrow portion.
The position at which the guage wire comes to rest is "nicked" and the tube
snapped.
A tungsten carbide scraper or planer blade can be used to nick the
surface of glass to provide a "notch" that facilitates cutting.
Polishing can be achived using many items from the Dental
Laboratory...Pumice powder...diamond impregnated rubber discs (used in
a Dremel Tool).
Final polishing should be achieved using a flame.
http://website.lineone.net/~dave.cushman/tipshape.html
gives ideas on the shape of tips.
Regards From:- Dave Cushman, G8MZY
Beekeeping and Bee Breeding, website
http://website.lineone.net/~dave.cushman
Archives of IBList, website http://website.lineone.net/~d.cushman