Extruder nozzles

Has anyone thought about using gas jet nozzles? (As in cookers)
I don't know what size they are, but might they be small enough to use as the extruder nozzle? And they come in brass.

What else has been considered already? I know about welding tips, propelling pencils, drilling your own hole in the heater brass threaded rod.... is there anything else that's been tried?

Hazel.

Flicking through ebay for gasjet and other nozzles, I found an oil burner nozzle:

[cgi.ebay.co.uk]|66%3A2|65%3A12|39%3A1|240%3A1318|301%3A0|293%3A1|294%3A50

I also found some 'tattoo tips'. They look about the right size to be useful, and they're sold pretty cheaply on ebay.
[www.tipsandgrips.co.uk]

However, I'm not that familiar with tattooing, so I'm not sure whether they're similar sizes or not.

I've tried:
The BfB 'proper' machined nozzle with 0.4mm hole
Welding tips (migmate) 0.6mm holes, drilled out to 3mm (halfords) - 5/£5

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Reprapping blog and other rants: [renoirsrants.blogspot.com]
My Reprap: [sites.google.com]

tattoo needles seem to range from 0.25 to 0.4mm, so some of the larger sizes might be the right size for a nozzle. The're also not too expensive.

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Reprapping blog and other rants: [renoirsrants.blogspot.com]
My Reprap: [sites.google.com]

Yes, I'd read your welding tips work.
I had thought about syringe needles,as I have a ready supply of these, but how would you connect to a heater section? I think you'd have the problem of a gap, again, between one component and the next.
Any ideas?

Hazel.

Re the oil nozzle, erm, might have some problem taking the sintered bit out of the oil nozzle!
Also, do you happen to know what the range of orifice sizes is?

Hazel.

I think the high pressure nozzles are too small, but if there is a pressure regulator after the supply, then they may be big enough.

Another option that might be a lot more practical, is many motorcycle engines are fittes with "jets", that are available in a number of sizes, to control the fuel flow. Not sure if they go down to the 0.5mm size, but they do have a range around 1mm and under in diameter. I think they are contoured for minimal length of the constriction, and easy flow in, so they could be near a near perfect "hack" for the task !

Graham

I did try and look up fuel injection nozzles for engines, but the high precision leads to higher cost. I didn't look for motorcycle engines, though.

The reason I mentioned tattoo 'tips' is that they seem to be a shield around the needle, a few mm at one end (the grip end is 8mm outside diameter?) narrowing to a needle diameter at the other - and a '13' needle size is 0.4mm, the same size as the BfB nozzle.

The needle is solid and long. It fits down the center of the grip and tip and is driven by the motor at one end, and the other end uses the tip to accurately guide the needle.

possible issue: There is a big hole in the side for the ink. outside diameter seems to be 8mm
[www.ecvv.com]

Initial thoughts :

Tap the tip to 6mm, screw in a standard reprap drilled rod/bolt, use the hole for a thermistor to place against the bolt and wind the heater directly round the tip/shank of the tattoo tip.

OR,
I've got some thin brass and Aluminium tubes from a modelling shop that accept a 3mm filament. (imperial dimensions but the ID is 3.1mm)
Use a length of tube, insert down the tattoo tip, use a grubscrew or high-temp solder to fix. wind heater directly around nozzle. Add heatsink directly above heater to reduce high-temp zone to a minimum. the remainder of the tube acts as a temp insulator to the drive system (no PTFE/PEEK insulator)

Good photo:
[yilongtattoo66.ecvv.com]

Edited 2 time(s). Last edit at 05/22/2009 07:00AM by David Reynolds.

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Reprapping blog and other rants: [renoirsrants.blogspot.com]
My Reprap: [sites.google.com]

I have asked Indesit for the dimensions of their LPG nozzle. I have already tried asking a spares supplier, but kept getting customer service on autopilot: "please tell us the model number of your cooker and we'll see if we've got anything...."

I haven't checked motorcycle jets yet, but have also asked some eBay sellers about burner nozzles used for model steam engines. At least they may be more used to getting individual queries!

We'll see.
Hazel

I used to carry a selection of main jets (nozzles) around in my wallet for my old XR600, and change them as needed. Some drawings here:

[www.motorcyclecarbs.com]

All the motorcycle main jets I've seen have a countersunk exit hole, which would smear out the filament during extruding, so that wouldn't be any good. It would be possible to mount the jet in a hand drill chuck, and sharpen it on a file to remove the lip around the jet; but if you're going to do that, you can also just drill yourself a nozzle if you've got some appropriate drill bits, via Vik's Afghan Lathe technique. I've made one that way, it was actually pretty easy. Not the most accurate technique in the world, but it works.

I don't know the length of the hole in a motorcycle jet, but it's probably fairly long; I think the ideal setup on a RepRap is to have the 3 mm hole go as close to the tip as possible.

You could also look up Brian in the For Sale section of the forums - he made a series of really nice nozzles on his lathe; I've got a couple and they're quite good! Still using my original 0.6 mm brass cap nut though; haven't got around to testing the new ones yet.

Wade

Making them is actually pretty easy, once you've bought some small drills. Any nozzle more than a few quid is probably easier to make than buy.

The 0.6mm welding tips have been easiest so far, almost the right shape and size, just needing a little alteration.

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Reprapping blog and other rants: [renoirsrants.blogspot.com]
My Reprap: [sites.google.com]

I have been using welding tips for a while. They are easy to get hold of and easy to modify. There are 2 sorts that I have found so far, small ones from halfords/screwfix with a 5mm thread and larger ones from B and Q witha 6mm thread.(both come with 0.6 and 0.8 mm holes)

I have now got a set up which seems to work well with the larger ones drilled out to 3.5mm with a heater in a block of brass powered by a resistor.This is the only set up that I have got to run without jamming so far although I have only run it for 18 hours so far so not a realistic test. When I do get reliable results I will post more details.
Andy

Hi Andy,
Yes, I think I've been reading your blog, too.
Thanks for offering to explain further - I'd love to see more details when you're ready.

Cheers,
Hazel.

Hi Andy

Where's your blog? have I missed one?

I didn't know that b&q did welding tips - I've destroyed a couple of the halfords ones by drilling them out too large. An M6 thread would be a lot more useful.

Thanks for the tip

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Reprapping blog and other rants: [renoirsrants.blogspot.com]
My Reprap: [sites.google.com]

Hi Dave, re Andy, I am assuming he's the EMC Reprapper.[http://emcreprap.blogspot.com/]

Nophead thanked him, in the hydraraptor blog (Feb), for his welding tip work.

Hazel.

Ah, thanks.

I use google reader to keep up-to-date with all the reprap blogs.
Here's my list of blogs: (google reader will import an xml file

I've managed to include Faith, Hydraraptor, and EMC

If I've left you off, let me know!

Dave R

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Reprapping blog and other rants: [renoirsrants.blogspot.com]
My Reprap: [sites.google.com]