mig welding tips

i was looking at bodgeit's blog and i noticed he was using a MIG welding tip for his extruder, how many people have done this and how has it worked out for them, have they had to modify it in any way.? other than the heating element on the out side of it,

i was also looking at plasma cutter tips too they could work but i think they would need to have the hole drilled out in them too. and they would need some way of holding them on, seeing how there are no threads on them.

but i wanted to know what other people have tried and worked out for them when it comes to the mig tips, what size have people used.

i do like the idea they are fairly cheap 5 for about 8 dollars CAD some are more. the plasma cutter tips are less 2 for about 5 dollars CAD.

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[mike-mack.blogspot.com]

You have to drill the Welding tip out to 3.5mm I have left 4mm at the bottom leaving 4mm of 0.6mm hole to extrude through the shorter Tips are 19mm long.

As they are copper you can drill them out on a pedestal drill I have done before.

Its better to drill the o.6mm hole out with 2.5mm before drilling the 3.5mm.

This stops unwanted deviation of the bigger 3.5mm drill.

It certainly extrudes OK I just don't know if my tiny stepper has enough umph to extrude through the 4mm length of 0.6mm hole.

I'm sure you could calculate the force required. I will be doing an empirical test later today by attempting to measure the the pull I get with 11 splines on a 5mm shaft.

As nophead says untill I get gearing this will only be a low res extruder. That I hope will be easy to improve on.

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Bodge It [reprap.org]
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ah thank you, i may end having to pay some one to do that for me though, seeing how i do not even have a drill press, but i was thinking i will go with a .8mm welding tip, though, that and i am planning on using a geared extruder, though i am stil trying to figure out how to build my repstrap. i rather do like your setup there, with your extruder tip and barrel. how much would you wand for a peek barrel ?

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[mike-mack.blogspot.com]

One option to do reduce some of the friction is to drill out the backside
of the tip as well. I've used the welding tips for other extrusions and
found that I could use a dremel 30 degree conical tip to clear out and taper
the inside of the tips a bit more. You do need to leave a millimeter or two
that is untapered at the tip to get a clean extrusion. The trick is figuring
out how much untapered section to leave to get the lowest friction and still
get a clean extrusion.

I wouldn't think you'd need a drill press - a hand drill and a table vise should do the trick.

Mounting the tip in the drill and the drill bit in the vise would probably work best... If the sides of the tip are all slanted, the drill chuck may not get a good enough grip, I suppose.

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