Recommend a Torch

[Sparticusrye]

I am looking to get a torch, preferably propane, for silver soldering. There are several on the market and I don't have much experience with them, so I though I would ask here. Is there a torch that anyone would recommend that isn't going to break the bank?

I am looking to build a live steam engine eventually, one of Kozo's engines, in 3/4" scale and then possible in 1.5" scale. So It would have to be able to handle a project like this as well as smaller projets such as the Bill 1906 that I am working on now.

I have limited experience in this area so any information and/direction of where to get more info would be appreciated.

James

 

[sunworksco]

It depends on your budget and how long you are going to use the torch.
I use 3 different types, a MiniFlam propane/butane/oxygen pencil torch, a medium sizes propane/oxygen torch and a larger size oxygen/acetylene torch.
Regards,
Giovanni

 

[picclock]

I've only recently started silver soldering, but I've found a small propane torch more than adequate. My largest silver soldered piece to date is a 6" ring of 10mm steel. The torch kit I used was a Clarke pc109 which cost around £20 UK. They do a version with a higher heat output, a pc108.

http://www.machinemart.co.uk/shop/p...with-nozzles/path/gas-torches-soldering-irons

The trick that I found with silver soldering is that the fit between the parts is very important to maintain strength and to get the solder to flow well into the joint. Its very important to use refractory bricks to reflect the heat back onto the work. With the correct arrangement of bricks achieving the correct temperature is easy.

http://s917.photobucket.com/albums/ad19/picclock/Brazing 101/

Shows pictures of my very first braze (silver solder), warts and all. At the time I did it I was very mindful of burning off the flux, ultra cleanliness, and achieving the correct temperature. The fit of the test pieces is not as good as it could be because I didn't think it important at the time.

Flux used is Tenacity 5, got a tub which will last longer than I will, just mixed with washing up liquid and a little water. Solder is 842 alloy, the site I bought it from says :-

It contains 42% silver, cadmium and conforms to BS EN 1044 AG303
Melting Range 610 -620 °C
It is free flowing, offers excellent joint penetration and has the lowest melting range of all silver solders.

All I can say is it seems to work well. If you are silver soldering many parts on one assembly the trick seems to be use a solder with the highest melting point on the first part and one with a lower melting point for subsequent parts.

All the info says that stuff to be soldered should be super clean. I have not found this to be the case. I made up some small clamps to hold parts in position and to space the work off of the bricks to ensure even heating of the joint. You can see two of them in the picture link above. These were made of hot rolled steel, and deliberately left dirty and greasy so that solder would not adhere to them. Today they are covered in the stuff and the only way of removing it is to machine it off. On one it even penetrated the thread turning it into scrap.

A good trick I got from this forum is that if you are soldering two flat pieces together you need a small gap in between them. Dinging them with a centre punch raises the level of the metal allowing the solder room to penetrate.

Good luck with you silver soldering.

Best Regards

picclock

 

[steamer]

I have a large size "Turbo Torch" which I have used the heck out of...It works well for me. It hooks up to a 20 pound propane tank, and has interchangeable tips.

Dave

 

[Sparticusrye]

Thanks for the replys. This gives me somewhere to start.

Picclock, good amount of info there that should get me started. I'll see if I can get a torch for this weekend so I can get some practice before I need to do some actual parts for the engine I am building.

James

 

[sunworksco]

I've been using Turbo torch/Mapp gas for 30 years for sweating copper tubing at commercial projects but it is very slow for hard soldering.
That is just me in a hurry, maybe others like it slower but time has always been money for me.
It comes down to budget and time.
Regards,
Giovanni

 

[xo18thfa]

Here's the rig I use. It's a Sievert propane-air torch that use regular bar-b-que tank for the fuel. I have 3 tips, the #2942, #2943 and #2944. The #2943 will do a 3/4" Kozo boiler no problem. The #2942 is medium small, good for boilers up to 2.5" dia. The #2944 is a huge volcano.

Sievert is a bit pricey, well worth the investment. Don't scrimp on a torch, otherwise you won't get the project done.

Silver soldering needs a large volume of relatively low temp heat. 45% solder melts at around 1160F and the flux breaks down chemically at about 1400F. That's the kind of heat you need. 80,000 to 150,000 BTU, large diameter tip say 1.25" to 1.5"

http://ngtmodels.com/sievert-torches.htm

 

[arnoldb]

I have to second Bob on the Sievert. Pricey, yes, but definitely worth it. I had all sorts of problems with silver soldering boilers till I got the big torch - now it's easy-peasy and no-nonsense.

Regards, Arnold

 

[kwoodhands]

I use the Victor Turbo Torch, LP1-Proline Standard mapp and propane torch.Hooks up to a standard barbecue tank. Comes with T-2 burnrt tip .T-6 burner tip, regulator ,hose and torch handle.$218.00 at Build.com.
This is probably all you need for the A-3 Switcher.I use the smaller tip most of the time and the large tip for the boiler and any large work.
I asked a plumber friend for input on a torch.Tom told me he'll let me use his Turbo Torch to try it out. Bought mine online the following day.Very satisfied with the torch.
You may want to get a few firebricks , I had six hard firebricks that actually absorb heat rather than deflect it.I recently bought eight soft refractory ( insulating brick) from Sheffield pottery. Best move I could have made.I imagine I have saved a good bit of money just in propane because the work heats up quickly.I think I paid about $27.00 total for eight bricks.

mike

 

[tornitore45]

Second the soft brick idea. You can build a cozy hearth to reflect and hold the heat, also save burning something in the back of the table :-[
I have a Gross with pressure reducer and 2 tip, large and extra large for the big job. Use the barbecue size tank.
For small job the Bernz-O-Matic Propane/MAPP is quicker and alvays in reach.

 

[Sparticusrye]

Excellent help guys.

Tornitore45, Do you find that a MAPP Bernz-o-matic is enough for small quick parts? The engine I am making atm only has a couple of small bits that need to be silver soldered together. And the budget is tight at the moment as my wife is comming off maternity leave and will be staying home for a next while. I'm taking up some extra work which is slowing my hobby down in the mean time. I have access to acetyline at work but that is too much heat. Maybe I'll just get a buddy to tig weld the couple parts I have to do for now until I really need the torch. Since its just some 0.125" thick bar stock to make a base plate for an engine. (Building the Bill 1906, http://www.homemodelenginemachinist.com/index.php?topic=14214.0 )

But eventually the cylinder boss will need to be tacked on as well which is why I wanted a torch. If a simple MAPP torch will get me through this project then that might be what I will do until I get a little extra cash on had.

I like the Turbo torch and the Sievert. Its just coughing up $200 right now is difficult.

James

 

[shred]

I use a Bernz-o-matic for most all my silver-soldering (really tiny things I've done with the Creme Brulee' torch). For small stuff (everything through the Cracker boiler), it works fine with propane. I had to switch to MAPP for a 2.5" dia boiler I was working on though.

 

[tornitore45]

Sparticus, you do not say how wide and long is the 1/8" plate.
I would say that 1/8 x 1" x 6" can be MAPP brazed to the same but much wider and become tough.

If you can get the parts red you can silver braze.

Let's say a 3/8" bolt can be brazed to a nut with a MAPP + bernzomatic T7000

a 1/2" bolt will be taxing and 1" bolts a no go.

 

[Sparticusrye]

I checked my drawing again. Its 3/16 x 3 x 1.75 steel plate, butt joint to another piece of 3/16 x 3 x 0.5. I've got a MAPP torch not and will give it a go later tonight. I've got lots of material so I can try and see. All else fails I buy a Seivret in a few weeks.

 

[Omnimill]

Picclock, where did you get your insulating fire bricks?!

Vic.

 

[Sparticusrye]

I ended up getting a bernzomatic MAPP gas torch. It took me 4 attempts to get the piece of 3/16 x 3 x 1.75 and 3/16 x 3 x 0.5 inch to braze together. But I was able to do it. It took a lot of patience as the first attempts I got it red hot but not a bright red. Once I took enough time to get it to a nice bright red glow the solder wicked into the small gap between the two pieces and gave me a joint. Its a bit ugly at the moment but a little filing and some sanding and it will look half decent. I still need to join two more smaller pieces to the same part. So we will see how that goes. Once I get the last two parts joined then I'll post a picture. A lot more practice and I might even get decent at this.

James

 

[Orrin]

I have two Sievert torch sets and am pleased with them. About a month after buying one, new, I came across another one that was almost new for a price that was too good to be true. The used set had something I wouldn't have thought of buying: a U-tube that takes two torch heads. I used it for the first time, today, and it is the best thing since canned beer.

I was silver-soldering a long and heavy crankshaft and the twin torches were able to keep the entire length at soldering temperature. It worked like a charm.

Orrin

 

[sunworksco]

It is possible to use this Thermo Fix Soldering Clay heat shield under your work for a cleaner soldered part.
Saves silver solder waste, too. The ultimate in holding small parts together during soldering.
http://www.ottofrei.com/store/product.php?productid=8256&cat=1338&page=1

 

[picclock]

@ Omnimill

I ordered a load from a manufacturer up north (50 brick minimum I think). If you want some I think they cost me a couple of quid each. I live in Ashtead, Surrey so your welcome to pop round if you want some (PM me for address) or even if you don't ;D. Was planning to sell the rest on ebay but haven't got round to it yet.. .

Best Regards

picclock

 

[Omnimill]

Thanks for that, I've sent you a PM.

Vic.