Needle flame gas torch

[GoCreateParticipant @gocreate]

Hi everyone

I have a couple of questions concerning needle flame torches

I am looking for a needle flame torch that uses propane and compressed air for precision silver soldering of small parts. I want to avoiding having to heat a large area to get sufficient heat, I want to try and keep the required heat localised, so I believe I need a flame temperature higher than that obtained from a normal propane/atmospheric air torch.

There seems to be plenty choice for needle flame propane/oxygen torches at reasonable cost however, I want to avoid having to use oxygen cylinders. Is it possible to convert these to operate with compressed air rather than oxygen?

Is there any information or plans for building a needle flame propane/compressed air torch?

One UK supplier does supply what I am looking for but at over 200 GBP for a torch, micro compressor and gas regulator the cost is quite high. A propane/oxygen needle flame torch is available at around 50 GBP but of course an oxygen cylinder is required.

Thanks in advance for sharing your own experience and/or suggestion.

Nigel

[GoCreateParticipant @gocreate]

Propane + comp. air torch availability

[JasonBModerator @jasonb]

Depends what you term a small part, the jewelry trade use a torch with gas and then blow down the other pipe to get the compressed air part of the equasion.

But I suspect you are looking for something larger.

Any reason for not wanting the Oxy cylinder, there are several companies that do rental free bottles now.

J

[Michael GilliganParticipant @michaelgilligan61133]

It may be worth talking to Sutton Tools [website here]

They have an excellent showroom, opposite the Jewellery School on Vittoria Street, Birmingham.

MichaelG.

.

P.S.

If you do go to Birmingham Jewellery Quarter; find time to visit this amazing Museum.

 

Edited By Michael Gilligan on 19/09/2012 08:08:43

[Michael GilliganParticipant @michaelgilligan61133]

Posted by tractionengine42 on 19/09/2012 05:25:40:

Hi everyone

Is there any information or plans for building a needle flame propane/compressed air torch?.

Nigel

Nigel,

I think there was something by Duplex, in Model Engineer … many years ago.

… any offers from our Index experts?

MichaelG.

[AndyPParticipant @andyp13730]

I use a Smith Little Torch daily for jewellery work and it is a lovely piece of kit. I am using oxy/propane in common with most smiths but they list compressed air tips on the website.

I bought mine years ago from the States but some of the UK jewellers suppliers like Cousins or HS Walsh or Sutton Tools mentioned above may now stock. If you do get it from the states the bottle fittings don't fit.

Andy

[dcostaParticipant @dcosta]

Hello MichaelG!

A search using criteria words torch or flame or Duplex in the article title field and not having the word electric in the category field retrieved a list of 202 articles, which are too long and impractical to post here.

Looking at the data found I see the criteria used is too vague.
Can you, please, give me some more clues to use as criteria for the search?

Obviously I can send the found data to anyone interested.

Best regards
Dias Costa

[GoCreateParticipant @gocreate]

Hi Everyone and thanks for the quick responses.

Having considered everything I think it boils down to whether or not a softer comp.air/propane needle flame torch will be better than a higher temperature oxy/propane torch, when silver soldering thin sheet brass/copper and small brass parts onto much larger brass parts .

What ever I use it's a skill I will have to learn and experiment with, but what's the best equipment.

Jason,

My main concern is that maybe an Oxy Propane could have to high a temperature just for silver soldering such parts as mentioned below however, maybe this idea, with reference to AndyP's reply, is misplaced.

I am thinking of fine scale model cars 1/15th scale, so parts from say 3mm to 10mm cubic size would need silver soldering onto much larger pieces without heating the whole piece and upsetting previous work.If you know the work of Gerald Wingrove then you will have the idea of what I am aiming at. In his book he uses comp.air/propane.

In addition very small diameter tube down to 0.5mm and thin brass/copper sheet/strip down to 0.15mm could need silver soldering in longish lengths.

I have no real objection to the oxy cylinder if that's the best way to go and at reasonable cost. Living in a remote area mail order would be needed and may suppliers won't dispatch to my post code, arranging a courier can be expensive. But then again I guess a 9L oxy cylinder will last a good while.

 

Michael, Andy – Thanks for the website's, some interesting option to look at there and at more competitive price.

I had forgotten about H S Walsh, an obvious supplier to look at but, for some reason, I seem to be locked out of their website, maybe because currently I am in Asia.

Dias, thanks for your search, I should have thought of that. I think maybe adding micro, micro flame, miniature, needle flame may improve search focus. Now that you have mentioned it I can do this my self no problem. Thanks again.

Andy, Smiths do list a comp. air/propane tip for a softer flame so that's interesting.

Looking forward to hearing any further suggestions and/or experience.

Cheers

Nigel

 

Edited By tractionengine42 on 19/09/2012 13:58:27

[Sub MandrelParticipant @submandrel]

For 1:15 cars I assume you mean things like brass bodyshells or chassis members?

Don't forget remelting silver solder takes more heat than the first time, so its not difficult to add extra bits as long as they aren't right on top of wht you are working on.

For small stuff I use an ordinary 'cooks blowtorch' also sold for Model Engineer's use at ~4 times the price.

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Apologies for the delayed follow-up

The "article" that I mentioned before actually appears in Ian Bradley's book The Amateur's Workshop [Chap. 27 in the 1999 edition] and is described as a Self-Blowing Blowpipe.

Unfortunately, he acknowledges that it only appears to work with Coal Gas.

Presumably there is someone ingenious who could re-design it to suit Propane, but not I.

MichaelG.

[GoCreateParticipant @gocreate]

Thanks again for your posts.

Niel, yes typically body shells and chassis in brass or copper. As your suggestion is so cheap I will try out a 'cooks torch' and get some experience and see how it goes. From the sound of it my idea towards a propane/air torch may be over skill. I think only experimentation with lead the way to what is right for me.

MichealG, thanks for the info. It would be nice to be able to build a torch but any good knowledge re. propane/air seems thin on the ground, best left alone until something can be found.

I will let the forum know how I get on.

Nigel

[Michael GilliganParticipant @michaelgilligan61133]

Nigel,

There is another way … which you might consider.

Resistance Soldering/Brazing

MichaelG.

[GoCreateParticipant @gocreate]

Hi Michael

Thanks for the link, USA is still the place to get that less than usual item.

I think Resistance soldering will not be known by many in model engineering but I understand it's used a fair amount in electronics. I only discovered it reading Gerald Wingroves book, The complete car modeller', he build his own and had it professionally tested.

Actually, I looked at these while visiting the USA a few weeks ago with a view to buying one and cutting carriage costs etc. Just at that time a unit came up on ebay in the UK, (a rare event I think), although not particularly cheap for an oldish piece of equipment much cheaper that a new one though, maybe a bit out of date as compared to those shown on your link. It was in 'buy it now' so I took the plunge.

I have not tried it yet as I am still on my travels and now in Asia. Won't be home till xmass .

I would still like a gas torch, I think these 2 methods will compliment each other and give greater flexibility in building miniature replica cars. experience will tell.

Building a resistance soldering machine would make a great MEW article for someone with the knowledge to do it. There is information on the web where people use car batteries in quite a crude way, I discounted this approach in favour of a proper unit with variable power setting levels.

Cheers

Nigel

[Sub MandrelParticipant @submandrel]

I found an ancient (1946) copy of 'Mechanics' today. There's a design for a town gas blowtorch in it. This may work on propane/butane but you would need to experiment with the jet size. and it may just blow out when you blow.

The old way was a spirit lamp and you blew into the flame througha blowpipe to get a hot jet out of it. The cook's blowtorch type have a mixture ring to go from soft yello flame to intense blue flame about 2" long but pencil sharp.

Right click the picture and choose 'view image' to see it full size.

Neil

[GoCreateParticipant @gocreate]

Hi Neil

very much appreciate the info you posted. Looks quite simple to make and it would be easy to experiment with different nozzle sizes and gas pressure.

Some commercial units use an aquarium air pump to provide air supply, maybe one could also be used here and experimentation with varying air flow.

maybe i will give this a try, it will be an interesting exercise.

Cheers

Nigel

[Michael GilliganParticipant @michaelgilligan61133]

Nigel,

I just located this YouTube video about Resistance Soldering

Definitely worth a try for the size of work you mentioned.

MichaelG.

[GoCreateParticipant @gocreate]

Michael, thanks for that resistance soldering link, looks a very useful and precise soldering technique.

For fine precision silver soldering I will try the suggestions above but I though I would play around a little with a propane / air design based on the info provided by Neil. This is what I came up with, any comment good or otherwise appreciated. Not all details worked out yet, just playing around with ideas.

Nigel

[Michael GilliganParticipant @michaelgilligan61133]

Nigel,

That looks very tidy

When you get the various dimensions and pressures sorted; please share [either via the forum, or it would make a good article for MEW].

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Nigel,

For very small work, I always fancied a torch shaped more like the classic Airbrush

… any offers ?

MichaelG.

Edited By Michael Gilligan on 07/10/2012 17:16:46

[GoCreateParticipant @gocreate]

Michael

Some fascinating air brushes there.

Hmmm….. Now you've got me thinking.

Thanks

Nigel

[joegibParticipant @joegib]

Actually, the Flamefast Adapto Needleflame torch illustrated here is quite similar to an airbrush:

**LINK**

It's about the size of an airbrush and is handled in much the same way as a pen. The dual gas/air supply pipes make it a little more unwieldy but not markedly so. The air supply is provided by a fishtank aerating-type unit so I suspect this is the kit Nigel was referring to in his opening post:

"One UK supplier does supply what I am looking for but at over 200 GBP for a torch, micro compressor and gas regulator the cost is quite high."

If so, I'm astonished that the price should have risen fourfold since I acquired one in the mid/late 80s when Flamefast attended the ME shows. I can't have paid more than £50. No wonder the Chinese are 'eating our lunch'!

Joe

Edited By joegib on 08/10/2012 17:38:36

[Michael GilliganParticipant @michaelgilligan61133]

Joe,

Thanks for posting the link … Yes, I was aware of that Flamefast; but consider it a "near miss".

I was thinking [a fantasy, perhaps] in terms of something that handles like an airbrush.

i.e. Propane supply in place of the Paint

… With a variant of the airbrush's dual-action valve.

MichaelG.

[GoCreateParticipant @gocreate]

Joe

The flame fast torch is 130 GBP +vat

The portaflame kit (regulator) is 88 GBP + Vat

By the time you add the postage and the vat it's 270.6 GBP. 45.10 GBP vat is a killer

I could get a needle flame propane oxy kit for less than 50 gbp + purchase of a 9L oxygen cylinder & gas for less than 100 GBP.

Thanks to Neil's post showing the old ME article I am inspired to have a go at building one.

Nigel

[thepegParticipant @thepeg]

Hi, my 1st posting here.

tractionengine42, seeing your 3D CAD images for the propane/air torch reminded me of a similar torch my grandfather had. He was a dentist (actually a dental technician).

The torch was used on coal gas and air fed from a foot operated leather bellows. it was basicaly two tubes joining together where the top tube bent at 45degrees and then a single tube for about 2" before terminating with a jet screwed in the end. At this point another tube screwed on (about 2" long x 1/2" dia.) This, like in your CAD, also had an inward flare.

The big difference between the two torches is that your jet is flush with the end, whereas My g'dad's was inset 2".

I've just started playing with an Einhell Oxy Compact 600/15 with a view making it use compressed air / butane (or MAPPS). In standard form, the slightest amount of air introduced immediately extinguishes the flame. I've read that butane does not mix as readily with air as coal gas. But even my g'dad's torch has a couple of inches of tube for extra mixing.

The tip on the Oxy Compact is a "double" type with a small bleed hole on the side of the central tip tube. I'm guessing that the central tip at the end is using venturi effect to pull the overall flame shape in.

I did try taking off the outer tip and taping on a 6mm dia. tube instead. Extending just past the inner tip was better, but it still extinguished. Extended 2", I couldn’t blow it out! (too late to run the air compressor). So I get the impression that an inner tip flush with the end may be difficult to achieve, but I’d be glad to be proved wrong.

Also, I've read of a design which uses electricity to pre-heat air/butane to get a better mixture. So I'm thinking of perhaps a coil of tube through which the flame travels to pre-heat the mixture before arriving at the jet(s). And making the inner jet (venturi) adjustable in position (for testing purposes) to get the sharpest flame shape.

I think pre-heating will be a real asset because I have one butane burner nozzle which simply will not work until it is hot enough. I have to wrap my hand over the rear air holes, get a yellow flame going, then slowly open the holes as it warms up.

John

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