Building a new copper boiler ..

[stubee]

Hey all,

About to embark upon a new project and I'd like to build the copper boiler myself (7 1/4" gauge 1366 PT engine) having being inspired by several threads on here I've been following.

Obviously I'll be needing the advice and support of my local clubs boiler inspector but in addition to this I wondered what tools one needs to complete such an exercise?. I'm specifically referring to the all important silver soldering stages and bending/shaping of the raw copper materials. So first off, I'm thinking perhaps a set of slip rolls ?? and also perhaps some decent heating equipment. I have a propane tank with large/small burners and consider myself competent in the art already, but was thinking of taking evening classes or such to enable me to use Oxy Acetylene for more localized heating jobs. I know other club members would put me to good use also with such equipment

So, what do people think? - cost is perhaps an issue ..

Would be grateful for peoples opinions on the subject.

Cheers,
Stu

[russell]

Oxy Acetylene certainly makes life easier. The kit, with bottles, is available in DIY stores here but I believe you have to hire the bottles in the UK and that makes it expensive if you only use it occasionally.

Russell.

[kwil]

I went to college and qualified at various levels to use Oxy Acetylene, Mig etc welding. I use it for steel. I have seen it used on copper boiler work and it is much too fierce generally. The other thread on the Brit boiler used propane, cannot see the problem with that, seems a matter of getting the right AMOUNT of heat and not just the temperature.

[Shawki Shlemon]

I use propane for heating the plates in order to form them and for shaping the wrappers . I make my formers from custom wood ( a sort of fine grain compressed wood ) . For the the assembly and staying I use Oxy Acetylene . I use a heating nozzle , a large one with 8 holes for the joints and a smaller one with a few holes for staying , one has to be careful not to overheat local areas or burning will result . I use a small step at a time ,clean , inspect , fix any fault if present , then go to next step .

[steam4ian]

G'day Stu

I am certainly no expert but did have a recent experience where oxy/acetylene was useful.

I decided to have a go at repairing a boiler where the flue to firebox tube plate joint had failed. I won't hijack this thread for a full description except to say that I enclosed the boiler in fire brick and I applied heat generally with a large propane torch. My friend used the oxy torch to heat inside the firebox and as the temperature rose to heat closer to the tube plate. All worked and the joints now look great. we were able to improve the firehole joint as well.

An oxy torch has the advantage that you can get heat locally. This would be particularly important in the firebox where propane torches blow back. However there is no substitute for getting everythink up close to soldering temperature before local heat is applied.

I can do better welds with Oxy than with electric glue, particularly on small sections.

To sum up. I would recommend getting an Oxy set if you are serious about boiler making. The other advantage is that it allows you to bronze weld reliably which is a requirement for throat plate to barrel joints on some designs, see a recent thread on a boiler which failed at the final soldering.

When I get my boiler past a successful hydro test I will write about what we did. I'm waiting on delivery of some 5BA studs to hold the regulator in.

Regards
Ian

[chiptim]

Hi Stu,
I've not tried oxy-acetylene but have use oxy-propane. On the assumption that it's similar but not as fierce (heat wise) I prefer step soldering with propane - lots of it and two torches with 50mm burners! I can imagine that oxy-acetylene could be a big benefit but a new skill to master and easy not to get the penetration required plus the risk of damaging the copper. You're unlikely to do this with propane.
You need a decent hearth and suitable bricks that you can arrange to suit the joint being soldered. I use Celcon blocks with a number of smaller refectory bricks. I've found the kaolin wool blankets very useful but they do disintegrate. I've used 3 for my boiler but they're in poor shape now.
Decent hand protection is a must - too chunky and you can't pick up or use the rods however in the latter stages the heat given off means you struggle to get close enough to it so you need something decent.
Good luck!
Tim

[russell]

Jul 23, 2010 7:50:01 GMT chiptim said:

Decent hand protection is a must - too chunky and you can't pick up or use the rods however in the latter stages the heat given off means you struggle to get close enough to it so you need something decent.

I bought a pair of kevlar oven gloves from Lakeland - they are excellent.

Russell.

[stubee]

Hi All,

Excellent and useful replies from all - many thanks.

I can see the many advantages of Oxy/A but as many have indicated it may be a little to fierce in the wrong hands.

Anyone had any experience of 'burning' the copper and was the situation recoverable?

Liking the oven gloves ;D

Stu

[mutley]

I've said it before, your home insurance company may not like oxy accet and the fire brigade certainly won't in a domestic environment. The fire brigade throw a 200m cordon around any fire involving ocxy acc. welding kit and it can be the quickest way to make yourself unpopular with the neigbours. If you want to use it make sure you follow all the storage guidelines.

Andy