tbsteam
E-xcellent poster
Posts: 231
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Post by tbsteam on Feb 16, 2008 9:14:22 GMT
I am building a victoria steam launch but am looking for someone that could do the braising as i can't seem to do it. Any help will be appreciated. Thanks
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Post by ianengr on Feb 16, 2008 9:40:19 GMT
May I ask where you are generally located and what sort of trouble are you having?
Ian.
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abby
Statesman
Posts: 927
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Post by abby on Feb 16, 2008 18:01:10 GMT
Braising is very easy , you need an onion , couple of carrots and a stock cube ! LOL
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steam4ian
Elder Statesman
One good turn deserves another
Posts: 2,069
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Post by steam4ian on Feb 16, 2008 21:19:19 GMT
G'day TB I should add to Abby that you need a hot pan. Sorry about the group sense of humour. Seriously. You haven't told us what you are brazing (I guess it isn't lamb chops). Is it brazing or silver soldering? The techniques are the same but the heating equipment is different. I suggest you do read some literature by Tubal Cain e.g "Building Simple Model steam Engines" also if you can get hold of anything by LBSC. Send me personal email, my address is in the profile, and I will forward you some articles I have. BTW I am no expert and am still getting my silver soldering techniques refined. I was taught to braze many moons ago but always used an oxy torch. Regards, Ian
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paul
Member
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Post by paul on Feb 16, 2008 22:08:00 GMT
tbsteam: I'm sure there'll be someone nearby (unless you're in Tibet or something) if you need to find someone to do it for you. No doubt most will suggest you do it yourself though!
As Ian says, it depends what you are trying to braze(/solder) as to what equipment you need. I can manage silver-soldering small (less than a couple of inches sort of size) parts with a DIY type blowtorch, total outlay <£20 UKP, but if you want to silver solder big lumps of metal you'll need to get a 'proper' torch and some sort of brazing hearth (cost from say £75 UKP up).
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SteveW
Elder Statesman
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Post by SteveW on Feb 16, 2008 23:08:26 GMT
TB,
Classic brazing uses brass as the jointing material. This generally is OK until it comes to steam boilers. The zinc bit of the brass gets leached out and the joint is over, think Aero chocolate.
A similar joint is produced using a technique called bronze welding. This is like classic gas welding but uses a bronze filler rod/flux. Again anything in there that includes zinc will be a problem. This includes any fittings.
Silver soldering is just a bit down temperature wise from brazing. The big problem is the cost of the filler rod, it's beyond 'kin expensive and rising every day so the bigger joints (full size) can be prohibitively expensive.
You don't include the scope of your task, model or 12": foot.
Either technique will require an awesome amount of heat into the base material before the filler rod will flow. Bronze welding has the edge here because of the intense local heat available from oxy/acte.
Could you restate your question in the light of this and other contributions above?
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Post by Tel on Feb 17, 2008 10:04:36 GMT
Braising is very easy , you need an onion , couple of carrots and a stock cube ! LOL Doesn't hurt to 'ave a bit of meat as well
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Post by Tel on Feb 17, 2008 10:12:00 GMT
TB, Silver soldering is just a bit down temperature wise from brazing. The big problem is the cost of the filler rod, it's beyond 'kin expensive and rising every day so the bigger joints (full size) can be prohibitively expensive. Could you restate your question in the light of this and other contributions above? Still not too bad here - the 45% stuff is about 4 bux a stick from Ebay
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tbsteam
E-xcellent poster
Posts: 231
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Post by tbsteam on Feb 17, 2008 16:34:46 GMT
It is actually silver soldering.
i am north of manchester.
The problem is that when i go to apply the solder it starts spitting it everywhere.
I have got some lead free silver solder and a blow torch from b+q.
I wouldn't mind doing it myself but i will make a mess of it.
It is a 48 inch steam launch with a cheddar proteus and saito engine in it.
I want it to be ready before the 15th march as i want it to be finished as a suprise.
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Post by houstonceng on Feb 17, 2008 18:33:45 GMT
Lead free Silver Solder Are you sure we're talking real "Silver Solder" - ie copper+silver+zinc+a bit of cadmium (maybe) and somnetimes a bit of Tin ? Definitely no lead in "Silver Solder"! Or is it the colour of the solder that's silver ? How to use Silver Solder ? Firstly, clean all the joints with an abrasive (a good scrub with VIM powder was usually recommended) Assuming you have real silver solder and the appropriate Flux - such as Easyflo - you mix the flix to a thin paste (consistancy of single cream) and anoint all the joints you are soldering with this. Apply gentle heat with your Propane torch (or similar) to dry the flux in the joint, then heat the joint - quickly - to a hull red colour. Quickly because if you do it too slowly, the flux will cease to be active since it will have absorbed all the Copper oxide it can before you've had time to apply the solder. Dip the solder stick into the flame to heat it slightly, then dip it into some flux powder. The flix will cling to the solder. When the joint is at the right temperature, the flix in it will look like water. Now is the time to apply the solder (coated with dry flux) to the joint. It should immediately melt and flow into the joint. Redip the solder into dry flux and retouch to the joints as necessary. Ditto repeato as required. Let the assembly cool to black and dunk into a bucket of water. Most of the used flux will flake off - the rest can be coaxed off with a nail-brush - leaving a beautiful silver-soldered joint. The resty of the assembly will, usually, be black with copper-oxide and will need to be pickled in acid (dilute Sulphuric is my choice - others swaer by Citric Acid). A good wash and a bit of scouring (VIM powder used to be, again, recommended) and you have a completely clean assembly.
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Post by baggo on Feb 17, 2008 18:38:13 GMT
Hi tbsteam,
it sounds to me that what you have is actually lead free plumbing solder which is a soft solder with a melting point of about 240°C. It may contain some silver but it's not what we would call silver solder which has a melting point of over 600°C.
What exactly are you trying to solder? I presume it's not a boiler kit.
John
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tbsteam
E-xcellent poster
Posts: 231
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Post by tbsteam on Feb 17, 2008 18:57:25 GMT
I think that i have got the plumbers stuff. No, it isn't a boiler kit, it is just the pipework (soldering nipples onto pipe). I don't really want to do it myself as i have never done it before and would like a pretty good job which is why i am looking for someone to do it for me.
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Post by alanstepney on Feb 17, 2008 20:28:00 GMT
Although silver soldering isnt difficult, if you have no experience, getting someone else to do it makes sense.
I am sure there must be someone in Lancashire, or within easy reach, who can assist you.
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Post by chris vine on Feb 17, 2008 20:30:27 GMT
Hi Tbsteam,
if you are sure you have the right solder and flux, Andy has given you some good pointers. For small parts, I tend to cut a tiny piece of solder and sit it on the joint.
make sure you heat the metal and not the solder. It is the heat from the metal which must melt the solder and not the flame itself.
For just small parts like pipes and nipples this is quite an easy job. If you try a few test pieces first I think you will be surprised at how easy it is once you have the knack.
Chris.
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tbsteam
E-xcellent poster
Posts: 231
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Post by tbsteam on Feb 17, 2008 20:52:40 GMT
I was kind of hoping that there was someone who was in my neck of the woods that could do it for me but it seems that there aren't.
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paul
Member
Posts: 8
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Post by paul on Feb 17, 2008 20:55:20 GMT
A tip (if your application allows it) - to ensure a good square seating, make the nipple into a 'washer' that just fits onto the pipe and hold the pipe vertically (in an old vice or some form of clamp) to solder it. Once done you can cut or file away the surplus pipe leaving just the nipple at the end. Neat.
Why not just practice on some pieces of scrap?
PS I made the same mistake with solder - one of the DIY shops sells plumbers solder described as "Silver Solder"... which it ain't!
PPS I think you'd be shocked how easy it is to do following Chris's advice ^^^. Once the solder melts if flows like water into/around the joint.
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tbsteam
E-xcellent poster
Posts: 231
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Post by tbsteam on Feb 17, 2008 21:04:52 GMT
Which silver solder should i use??
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paul
Member
Posts: 8
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Post by paul on Feb 17, 2008 21:20:58 GMT
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Post by houstonceng on Feb 17, 2008 21:36:48 GMT
Ag 2 to BS 1845. That equates to :- Easy-flo No 2 from Johnson-Mathey. FSB No 2 from Fry's Metals. MX12 from Thessco Ltd.
Generally, it'll be sold described as Easy-flo 2 - even if it's not from J-M. Use it with Easy-flo Flux which is a white powder as I described earlier (complete with spiellung mistooks).
This is the lowest melting point S-S generally available but comes with a health warning. It contains Cadmium - which is carcinogenic - so should not be used in a confined space. Preferably, use it outside and stand up-wind.
If you are really worried, you can use one of the Cadmium free S-S BS 1845 No. AG 14 is recommended as a substitute for AG 1 and AG 2 Silverflo 55 from J-M FSB No 29 from Fry's M25T from Thessco
It's not got as low a melting point as Easy-flo and it's usually recommended that you use Tenacity flux rather than Easy-flo - although I've used the latter with success.
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tbsteam
E-xcellent poster
Posts: 231
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Post by tbsteam on Feb 17, 2008 21:47:07 GMT
I am not worried about getting diseases that will kill me.lol. I just want to get my boat finished a.s.a.p. I have ordered 1.5mm easy-flo No2 from chronos. Hopefully it will be here by tuesday and if it isn't i want my extra £6 back!!!
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