I need more concentrated heat for soldering /melting than just LPG

[Andy Davies]

Hi, I have a Sievert professional LPG torch with a needle nozzle and whatever the next size nozzle up is and I'm struggling on some projects to get the heat that I really want. In the past I have used oxy acetylene in industrial applications and it was so powerful I could do anything with it. Whereas the LPG with the needle nozzle gives a much bigger flame (cone) than say a number 5 acetylene nozzle but the actual heat content is much lower.

To give you an example of my difficulty, I wanted to make earrings with glass beads sandwiched between two strips of 4mm wide silver and a 0.8mm diameter wire passing through the bead. I balled one end of the wire and passed the fee end through the silver then a bead and on through the second strip of silver. I cut the wire such that about 3mm of wire was left sticking out adjacent to the silver strip. The idea was to ball up the final end of the wire but the heatsinking effect of the strip was so great that I couldn't even get the end of the wire red hot.


You can see the balled end where I started at the top of the bead but I had to fold the bottom end of the axle wire to finish it off. To keep the heat off the axle wire from getting to the bead, I wound a 'spring' coil of silver wire that fills the hole in the bead while letting the axle wire pass through it. (that coil also filled the hole to stop the beads moving up and down)

I couldn't use the larger nozzle as the wider flame would have shattered the bead. I had been thinking of going for a Map gas and oxygen torch but is there a good LPG/Oxygen torch option that is even close to the performance of oxy acetylene or Map gas?

Any practical advice/recommendations will be much appreciated


Kind Regards . . . Andy (Aberystwyth)

[CJ57]

Hi Andy
My needle nozzle has never come out of its box in 40 yrs and isn’t much use for anything but soldering a jump ring or making granules. I’ve done everything I need to do in really complex pieces with the medium nozzle and on occasional the big one for a big cuff.
I’ve never done a silver glass combo and have no experience of oxyacetylene but there will be men on here who have!.
Caroline

[Dennis]

Hello Andy and welcome to the forum.
If your design idea does not work the way you envisage, dont overcomplicate. Just think of alternatives.
You can solder the wire ends using a tiny snip of extra easy soldier with much less heat.
If you like balls, solder on a 2mm one hole bead.
You can also use 1mm tube rivets, which can be spread with a scriber and light taps with a tiny hammer. Dennis.

[china]

Smiths Little torch use with LPG

[CJ57]

I’m with Dennis. An idea that seems great in your head isn’t always doable in reality. I learned a long time ago to go with the flow and achieve something that still works but differently to thr original plan. I put nothing on paper and it all evolves at the bench however long it takes

[Andy Davies]

Hi Caroline thanks for getting back to me. I’ve had a quick look at your work, I like it. The Sievert torch has been a disappointment in as much as my expectation was so high, in my naivety I was imagining that compared with my little crème brulee torch, which does a reasonable job, a ‘professional’ torch would be wonderful. Oxyacetylene is fantastic, for example you could easily cut through the handle of the vice in your video just using a simple ‘welding’ nozzle. You could cut the vice in half with a cutting head! the flame cone is very small so you have pinpoint accuracy. But the problem I have as a hobby maker is the rental charge on the bottles is over £300 a year plus gauges at ~£180 plus hoses and a troch and as I only make maybe a couple of pieces a month, I don’t feel I can justify the cost. I have been using hard solder but maybe I’ve got to work with easy and extra easy solder. Thanks again for the feedback and encouragement.

Regards . . . Andy

[Andy Davies]

Hi Dennis thanks for the welcome and the feedback. I understand you comments and I take them onboard, but I hate to be compromised by the technology. I've been looking into Mapp gas and Oxygen kits, the sort of thing that refrigeration engineers use. I've seen one kit for about £212 and another that uses rent free oxygen bottles and that comes in at around £420 But as yet I haven't had any feedback from Mapp/oxygen users. I'd rather spend £400 or £500 on something that I own than pay £335 to rent bottles for a year. Oh well, such is life.
By the way, nice work. I can see that there are some very skilled folks here. Thanks again.
Regards . . Andy

[CJ57]

Thanks Andy.
All the reservations you have and the examples you show don’t really enter my head as a jeweller though. Don’t think I’ve ever thought about cutting my vice in half with a torch! Why would I need to. I’ve used the sievert for 40 yrs and while I know the Smiths is probably a better option why change what works for me now.
Achieving my aims can’t only be dependant on the equipment I use otherwise I’d never be able to learn other skills or ways around a problem. We never stop learning and adapting otherwise what’s the point.

I never use my cooks torch for anything other than making granules or balling wires which is why my fine burner has never been out of the box

[Dennis]

I'm afraid that Caroline and I are rather ganging up on you, but jewellery making dos not need high performance torches. All I ever used for larger items was a modified plumbers torch. It will even hard solder belt buckles. Dennis

[Caro]

I've been using the Sievert torch for a couple of years now. Mostly I use the jeweller's kit nozzle which does most of what I need, occasionally I switch it out for the next size up which delivers 8x as much heat and is enough to cast reasonable amounts.

How on earth are you paying £300 a year rental for the gas bottle? I simply pay for the gas I use. No rental required. I think it was about £30-£40 the last time I bought a bottle which was about 18 months ago.