brazing/siversoldering

[david simmoParticipant @davidsimmo]

 

    hi can any body suggest which propane torch is best to buy for a beginer

   I have brazed in my apprenticeship but that was along time ago,I have never siliver soldered before but we all have to learn some time, thanks dave

[david simmoParticipant @davidsimmo]

help

[David Clark 13Participant @davidclark13]

Hi There

Depends on the size of the job.

For very small jobs, you can buy a torch from B&Q that runs on propane but with something added to make it burn hotter. I think the fuel is in a yellow can, could be called knap gas or similar I think. The can has a threaded end to take the torch. Basically it is a blowlamp.

I think that would comfortably handle up to a gauge one boiler.

regards David

 

[JasonBModerator @jasonb]

If you are going a bit larger then the next step up from MAP gas would be a torch that is run from a propane cylinder. Machine Mart do a couple of reasonable ones and the Bullfinch range are OK as well. Silvert have a larger range of burner sizes but they do cost a bit more.

 

As David says an idea of what you want to do would help with suggesting nozzel sizes etc.

 

Jason

[david simmoParticipant @davidsimmo]

 

 thanks david and jason I am building 3 1/2 gauge boiler I hope ? read all the books on the subject but they old books, maybe some one could name a moden book thing have change alot in the last  20 year in engineering some good some bad, I will do test peaces first to learn the skill required as the old boy who tort me when I was apprentice

           thank again dave

[JasonBModerator @jasonb]

I’m sure David could point you in the right direction for the back issues that featured Julia Olds boiler build, It shoul dgive you a good idea of whats involve in building a boiler to teh current regs, unfortunatly she does not have anything on her web sites about the boiler project.

 

Jason

[WearyParticipant @weary]

I find that Bullfinch nozzle 4104 running off 6kg Propane bottle is fine for Tich boiler and general brazing.  4105 nozzle is next size up, and whilst I have a 4103 (next size down) it is no real use for copper work, but OK for brazing small steel items.

 

I also have an Oxy-acetylene set but find it difficult to use for boiler work and so would be interested to hear what size nozzles others are using for this equipment.

 

Phil

[BoldminerParticipant @boldminer]

Hi Dave, when you do your test pieces try adding the tiniest drop of washing up liquid to the flux,this breaks the surface tension and the flux will then wet the job and stay put. As the piece heats up watch the flux closely and when it appears to turn to a liquid then is the time to apply the solder. The solder should be melted by the job not the flame. Place flame onto the job infront of the solder and it will run along the joint. ( It goes without saying that both parts of the joint should be clean before any flux is applied).

Regards Colin

[John Wood1Participant @johnwood1]

Hi David, I use a Sievert entry level torch kit which came from Chronos (it was a present)http://www.chronos.ltd.uk/acatalog/

It seems a very good system for general use and does everything I need. There are other, more comprehensive sets available as well so at least have a look see.

As Jason suggests they are a bit expensive but for decent and versatile equipment I reckon it’s worth it, especially as safety is a significant factor when dealing with Propane.

 

Hope this helps.

Regards, John

Edited By David Clark 1 on 08/06/2009 13:02:13

[david simmoParticipant @davidsimmo]

 

     hi sorry to take so long replying [work] thanks for the tip colin

[mgjParticipant @mgj]

If you are going the Sievert route (which is probably the best) the trick is to get the right regulator.  They do an adjustable one at 4?bar. Anyway the high pressure one – unfortunatlely not the one in the entry level kit! You can always turn it down when changing the nozzle for a small job, but if you have a lower pressure regulator you can’t turn it up if you need more heat, or buy a big nozzle.

 

My Calor kit with their biggest nozzle and medium pressure regulator wont silver solder (with AG2) a 3″ traction engine towbar – well not without doing it in several steps, lots of burned out dead flux etc, several pickling stages to get all clean again. General cartwheels and handstands.

 

So I wish I had bought the regulator with a bit more shunt to start with, because they are quite expensive.  

 

 

[Kieran SparksParticipant @kieransparks65317]

Exellent information which is free, about topic………

 

http://www.pollymodelengineering.co.uk 

Go on the Technical notes…..Basic silver soldering.

 

which covers……

joint design

flux choice

hearths and heating

pickling

temprature chart which implies job type and flux.

 

Or visit a very helpful chap which is specific in the field. and will help you ever step of the way. Everything you ever needed to know is on this site…..

http://www.cupalloys.co.uk

 

You can also purchase everything you will need from here…..

including starter packs, torches, fluxes, solder sticks of all types non toxic cleaning salts, refractories.

My favorite, Kaolin Wool (insulation blankets) exellent for lagging boilers and forming quick hearth setups instead of heat sink bricks.

 

Hope this helps everybody

 

 

 

[the artfull-codgerParticipant @theartfull-codger]

Hi, I’ve used sievert for years, it’s quality equipment but not cheap, if you can get hold of a ”flamefast” brazing hearth 2nd hand( it has it’s own built in  air blower) they are really good for brazing & silver soldering, & I use pieces of” thermalite” building blocks from building sites, the lightweight ones, they are super for reflecting the heat back into the work, far better than firebricks & free if you’re a skip rat, almost as good as ceramic blanket without the cost.

[David Clark 13Participant @davidclark13]

HI There

I have bought new Seivert at very reasonble prices on Ebay.

I have a patio gas container which has a regulator built in to the cylinder connector.

Does anyone know if this is ok or will I need a separate regulator?

regards David

 

[mgjParticipant @mgj]

David, as far as I can see, the answer is “It all depends on the pressure and volume of gas that the burner can take compared with the amount delivered by the regulator”

 

For instance, my self blown calor nozzle will blow itself out, because not enough air is getting into it at the back. Thats with a 2 bar regulator. So there is no point it putting it onto the high pressure 4 bar job.

 

On the other hand, the bigger Sievert nozzles, to reach their ful potential, will handle and need the 4 bar. 

 

The likelihood is (depending on the nozzle) is that it will work, but you won’t get full throttle out of it. Whether that matters depends on the size of the jobs you want it to do. So much gas  is so much heat capacity, even if the nozzle can handle more.

 

I guess you’ll need the bigger regulator in the end – the test will be if you can heat work up without cooking the flux?.

 

 

 

[Colin ReedParticipant @colinreed51485]

I’m also wanting to set myself up to do some silver soldering etc. and noticed that Machine Mart do this Sievert torch kit for £57.48, or if you can wait till one of their VAT free days for £49.98. The ad also says that the regulator is adjustable 1 – 4 Bar, which was mentioned earlier in the thread.

 

Sievert PMPX Professional Torch Kit 

 

Is this a good starter kit or am I missing something and need to be spending more money for something more suitable?

 

Colin

[Bryan RozierParticipant @bryanrozier80712]

Hi,

 

The PMPX starter kit is good value (especially if you buy it off ebay!) but the nozzle will only be good for fairly small parts.

 

For making a small 3.5inch boiler I used two Sievert torches. One has a 2944 burner for rapid heating. The other has a 3525 Cyclone burner which is great for close up work and inside fireboxes. You will need a extension neck for the 2944 burner as it puts out a massive amount of heat.

 

Cheaper kits are available from Machine Mart etc but they don’t have the heat output required for boiler work. One of the biggest mistakes beginners make is not enough heat.

 

The Sievert option is not cheap but compared to the cost of a professional boiler maker it’s great value.

 

Cheers

Bryan

[Michael GrayParticipant @michaelgray16785]

For your big boilers I’d take a look at the Mini-Mongo and Mongo style burners designed for foundry work and described on the Internet (Google is your friend). I built one of these for my foundry which was capable of pumping out almost 1M Btu’s per hour.  Melted 9 lbs of aluminium in under 15 minutes.  It can be adjusted for the diffuse kind of flame needed for silver-soldering.

HTH, Mike in BC

[Norman BarberParticipant @normanbarber28134]

Hi David,

I have used Sievert equipment for many years and although expensive it is very good.  You get what you pay for.  I now have a range of nozzels fromthe smallest to the largest.  If you are building boilers a cyclone burner is essential – the ordinary nozzels blow themselves out in confined spaces like the inside of fireboxes.  I agree with other contributors that an adjustable regulator is essential.  It is worth while buying a handle for the torch which incorporates an economy trigger.  More expensive but worth while in the long run.  Make sure that you buy a long neck tube – the job gets very hot!  In this connection, I have found the use of a ceamic blanket to minimise heat loss from the job is well worth the modest cost.

 

Weary mentions oxy-acetylene.  There is no doubt that the use of  an oxy-fuel gas system is ideal for stays inside fire boxes and other similar features (see Alec Farmers book “Model locomotive boiler making”.  Be very careful however.  An oxy-aceylene flame is very hot (3000 degreed C) and in the hands of an inexperienced operator can do a lot of damage.  I use an oxy-propane torchfor this sort of work.  The flame temperature is lower than oxy-acetylene and less likely to cause local burning ofthe copper although care is still needed.  It will still melt the copper and, more important, damage the silver solder.  In any case, the oxy torch should only be used to add the final touvh of local heat once the whole boiler fabrication has been raised to almost siver soldering temperature with the Sievert burner.

 

Regards, Norman

[Mark Smith 3Participant @marksmith3]

Very good book by Tubal Cain Soldering and Brazing, all you need to know.

[Ian S CParticipant @iansc]

If you’v got oxy-propane, you can hook up a cutting torch,and cut steel too,gives a softer edge than oxy-acetylene.I had to build up a damaged gig axle with bronze filler,an the cutting torch was the only thing available,it worked well. Ian.S.C.

[Ian S CParticipant @iansc]

If you’v got oxy-propane, you can hook up a cutting torch,and cut steel too,gives a softer edge than oxy-acetylene.I had to build up a damaged gig axle with bronze filler,an the cutting torch was the only thing available,it worked well. Ian.S.C. PS,Is there a system that uses compressed air and LPG?

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