How to cut a curve?

[modeng2000]

Wayne,


"i have heard of people using the high tem map gas"

What is 'high temp map gas' please?

John

[paul]

Ah well, I've just been and got some silver solder/flux/more gas! Looks like a big clean up job and some extra cursing is on the cards this weekend! Thanks all for the advice

[baggo]

Never mind Paul, these things are sent to try us Better safe than sorry though.

John

[wayne]

Hi John

Map gas from my memory is a mix of propain and butain sometimes on its own or with a second cylinder with oxygen it depends on the kit, both hwever are of the desposable type.

Its avalable from heating and refridgeration supplyers such as HRP. Refrigeration enginers use it in preferance to luging oxi acetaline bottles arround as it can be used for silver solder or easy flow brasing. I do not know what size work it will cope with as i prefer oxi acetaline.

Hope this helps
Wayne

[modeng2000]

Wayne,

Thanks for the explanation. I had not come accross the name 'map gas' before.

john

[Shawki Shlemon]

Hi Paul
First of all I admire your courage and drive to build a boiler with little know how as I gather from your thread. Now to the boiler silver solder for everything and soft solder if needed it to stop little pin head leaking holes . there are many books and articles in Me and AME about building boilers and this will be a very good investment in your hobby . God forbid if an uncertified pressure vessel explode and someone is injured ,the consequences could be unpleasant at the best.You must want to operate your boiler in front of family and friends at least. I am sure you want them to be safe . Talking about temperatures ,pressures etc.. is not enough .All clubs and other organizations test boilers to twice the operating conditions. this is done because the work may not be 100% , the materials may be less than 100% and so on .For what is worth my advice is to visit a hobby club and seek some advice from a boiler inspector, it is free and useful and you may even enjoy your day there .I am trying to be helpful rather than critical . I am a boiler inspector in our club and this is not up to safe standard and such boiler will never be allowed to be steamed in our club.It is true to silver solder the joints all traces of soft solder must be removed completely. Good luck .

[havoc]

On a secondary note dose any body Know why you can not use the Rothenberg Rollot s3 for jointing copper boilers. This stuff is brilliant, as its a copper based rod no flux for copper to copper joints, suitable for very high pressure and temp joints and its reasonably free flowing.

I cannot find any references to the product, but it looks like you are meaning one of the copper-phosphor based brazing alloys. I knew I had read something about them and suddenly remembered: "Soldering and Brazing" by Tubal Cain.

(in very short) Those alloys are only usable for copper and its alloys. (tungsten and molybdenum also, but I have never needed to use those materials in my workshop) They are plenty strong, but less ductile than copper. Only thing is, they can not be used in the presence of sulphur containing gasses at a temperature above 200°C: so never in coalfired boilers.

So it looks as if they can be used, but he advises against them as the savings on material and flux is neglible. I do have some of it but never used it.