[Oscar]

I want to make a nozzle for flux core, only because I have a Smithy Midas 1220LTD lathe-mill-drill and no current projects for it. So it basically just "something to do" to practice/learn machining. So the question is: what material should I be looking at? I've seen some that are a hard black plastic, but I have no idea what it could be. Is brass an alternative?

[Demented]

I'm pretty sure the plastic ones are just some form of Nylon. PEEK would probably be better but it can be pricey for a plastic. PTFE should also work. I like machining plastic so I'd go with some black PEEK.

Brass would be an ok alternative. I've had good luck making gas nozzles out of 360 brass.

If you really want to get fancy McMaster has some machinable alumina ceramic rods. Only around $400 a foot

[Poland308]

The one that came with my 210mp was just black plastic. I got it hot enough that it melted. Just from welding.

[PeteM]

Since you're doing it yourself, you can pimp it out with something shiny like aluminum or brass!

Of course, it wouldn't be very shiny for too long.

[noddybrian]

If you mean by " nozzle " ( which is termed here a gas shroud ) I think most common plastics would melt being that close to the arc - I have one odd spool on torch which I use just for odd job repairs in the field where material is too thin for stick ( but runs from a stand alone converter plugged into the stick set ) & wanted something just to insulate the contact tip so also being a machinist I turned up a replacement brass neck / tube for the torch & threaded the end to accept standard 17 series Tig ceramics ( thinks its a 5 that is closest fit around contact tip so gives best access in corners ) works fine - not broken one yet & though splatter builds up it scrapes off with care.

[Otto Nobedder]

If you mean by " nozzle " ( which is termed here a gas shroud ) I think most common plastics would melt being that close to the arc - I have one odd spool on torch which I use just for odd job repairs in the field where material is too thin for stick ( but runs from a stand alone converter plugged into the stick set ) & wanted something just to insulate the contact tip so also being a machinist I turned up a replacement brass neck / tube for the torch & threaded the end to accept standard 17 series Tig ceramics ( thinks its a 5 that is closest fit around contact tip so gives best access in corners ) works fine - not broken one yet & though splatter builds up it scrapes off with care.

This^^^^

This was what I was envisioning, but hadn't the words to explain it yet. The TIG ceramic prevents you shorting the tip and gives you an edge guide. Done right, it gives you adjustable "stick-out". I would expect frequent cleaning so spatter doesn't create a short-circuit path, but on the whole it sounds like a brilliant idea. Kudos to noddybrian for putting it in to practice and explaining it well.

Steve

[noddybrian]

Thanks Steve.
The splatter is'nt that bad depending on the wire used - some is dirtier than others - the splatter comes off fairly easily but if you forget to clean it occasionally shorts across to the work - if it's not too thick & the amps are'nt too low it will momentarily flash over & burn off - I can move the contact tip to ceramic position slightly - normally keep contact tip just shy of level - I made this up out of necessity as I have never found anything ready made ( plus I have numerous lathes / mills etc )- in the UK very little flux core is used so very few related parts exist - unless you jump up to the serious size cored wire units found in ship yards or repairing mining buckets etc - but this is typically running 2mm minimum on a boom with God knows how many amps ! I nearly bought recently a Hobart suitcase that would have made my lash up redundant but it was in terrible state - very hard life & looked like it had got wet which is a shame as i think it may have been compatible with my Thermal arc 400 - this has similar looking plugs to the Millers & will do CC or CV - unit had been on an XMT but that had died - I often make hard to find bits or one offs as an experiment - it's only my time so no worries if it does'nt work out - mostly it does even if some would say why not just buy stuff - well we don't have many weld supplies around here & I like making things.

[noddybrian]

Update on the nozzle - initial trials with a new ceramic in the workshop on clean(ish) metal were good - the splatter would come off easily often with just a rub with welding glove - however I took this setup out yesterday & spent most of a day repairing gates & handrails on a beach - material was a mix of scaffold tube & 1-1/2" Sch40 - some was black - some galvanized - all had been painted many times over many years service - all was rusty inside & out ! the splatter built up quicker than expected & after an hour or so of welding was hard to remove - material condition did'nt help as it boiled & gave off a lot of splatter - could'nt clean too much due to thickness left after rust - by the end of the day I had trashed the nozzle but got job done - not sure if contact tip to nozzle distance is important as I've not experimented much yet - I may have run a bit too close on stickout & I may try a larger ceramic next time - due to getting into tight joint shapes I had gone with a 5 this time which was a close fit on the tip which may not have been the best idea - overall it works & I'm not unhappy using this setup & if need be I'll just change nozzles frequently as they're cheap enough - but if anyone finds a better material to use I'm up for testing it.

[Poland308]

I’ve used wire brushes for cleaning up copper connections to clean off spatter from the ceramic cups. I just cut off the handle and chuck them up in a cordless drill.

[Oscar]

I received some Acetal rod aka: Delrin to make a GAS SHROUD for flux core. I should be able to whip something up on the lahte Saturday and try it out. I definitely don't want to do ceramics because I know that thing will be in pieces in no time flat.

[noddybrian]

Assuming " Delrin " is the same both sides of the pond I don't think it's a good candidate for this - I've used it a lot but it's really only noted as a bearing material - it does not like heat that much & flux core generates more than solid wire - in plastics I think PTFE is higher temperature rated & even that I doubt will survive that near the arc - I do agree the ceramic is a bit fragile - if it's your own though there is no need to use a Mig torch as a hammer to align stuff ! please share your experiment & if anyone else has thoughts on material I'm interested.

[Oscar]

You're probably right, but it was free, so we'll see.

[Demented]

Yeah, the delrin wont last long with the heat, but it's quick, cheap, and easy for making a cover, especially compared to the commercially available plastic ones. Short of ceramics, exotic metals, and grahite, there's not much out there that will handle the heat and not have shit stick to it. Even graphite wont last with heat; it can handle it, but it oxides at 600*C and flakes off.

[Oscar]

Special thanks to JohnT for sending me the Delrin. Took me two tries, but here it is:




I machined the main ID a little too big, so I need to run and get a spring clamp and cut some slits to make sure it sits secure on the neck. The taper was simply ground down with a 3/4" air belt sander, obviously not machined.

[Demented]

Glass filled delrin, or did you do something to get the matte finish?

[Oscar]

I don't know, I simply turned it in the lathe.

[Oscar]

Delrin will NOT hold up. This was just a couple minutes with some small coupons about 3"x3"x3/16" (couple inches of weld, intermittent stops), about 350ipm x 22V, 0.030" E71T-11, with about 7/16"-1/2" CTWD.

[Poland308]

My factory one from Lincon looks the same and only lasted about as long too.