Blowtorches – bullfinch 1210 & 1240

[pgk pgkParticipant @pgkpgk17461]

I was given these from a barn clearance. A chart tells me that the smaller one has 1.2KW and the larger 8.3KW outputs.

Is the larger torch adequate for my adventures in 1" minnie boilermaking? 8KW ought to be a lot of heat output if losses avoided…?.. apparently requires a minimum 13kg cylinder.

[pgk pgkParticipant @pgkpgk17461]

[Simon Williams 3Participant @simonwilliams3]

PGK-

My central heating boiler is rated at 17Kw, runs about 7/24 of the time. Sounds to me like 8 Kw should be plenty for a bit of silver soldering, provided you can direct it into the metal and not lose a significant proportion on global warming.

Simon

[Philip RoweParticipant @philiprowe13116]

I'm not saying that it is absolutely necessary but when I made my Minnie and Rob Roy boilers I used a 2943 burner which has an output of 43.5kw.

Maybe you don't need such a high level of heat but I do seriously doubt if you would have enough heat at just 8kw.

Phil

[JasonBModerator @jasonb]

Yes 8kw would be about the minnimum for general soldering, I would be looking around 25kw for boiler work which would be around a 30mm dia burner.

Also make sure you have a HP regulator, 2-4bar so it flows enough gas

[Neil WyattModerator @neilwyatt]

My 17mm burner struggled with a short 3 1/2" diameter vertical boiler.

Neil

[CotswoldsPhilParticipant @cotswoldsphil]

My attempts at a Minnie boiler some years ago, even just the firebox, following Mr Mason's instructions, failed miserably with a 38 dia. Bullfinch 1250 12.6kw torch. My next attempt will be with a Sievert 45kw power burner at a minimum.

Another problem I had was the flame going out at critical moments through lack of oxygen in the work area.

Phil H

Edited By CotswoldsPhil on 31/03/2016 18:58:34

[pgk pgkParticipant @pgkpgk17461]

That's some serious heat…no wonder this is done outside the shed!

Thanks all,

pgk

[Dave HalfordParticipant @davehalford22513]

If you can find some rock wool insulation it will help a lot being as it doesn't melt at 700C. Or you can try vermiculite or perlite from a garden center. Any of will beat a barrel of coke.

Edited By Dave Halford on 31/03/2016 20:14:12

[DMBParticipant @dmb]

Thats right pgk, dont use Sievert torch in shed, not even with door open or all the plastic bottles on the shelves will develop new shapes!
Don’t ask…..

[Ian WelfordParticipant @ianwelford58739]

Dave

does the vermiculite break down in use? Never thought of using spare rock wool as heat lagging !

[Steve WithnellParticipant @stevewithnell34426]

I've got both those burners and I can't imagine soldering a boiler with either of them. Copper boilers are just big heatsinks.

[pgk pgkParticipant @pgkpgk17461]

Posted by DMB on 31/03/2016 20:23:46:
Thats right pgk, dont use Sievert torch in shed, not even with door open or all the plastic bottles on the shelves will develop new shapes!
Don't ask…..

It'd be even worse here..upvc double glazing and the whole shed clad in upvc shiplap. I experienced the potential with my OH's best chip-pan fire before she was banned from destroying kitchens.. and that was heat and smoke rather then the fire spreading…everything plastic melted.

[WearyParticipant @weary]

To give you an idea…..

I silver-soldered a 3.5" Tich boiler with a 6kw Bullfinch burner (4105, 15mm approx' diam.) without any problem. Though admittedly it was not my first locomotive boiler. Even silver soldered all the stays inside the firebox etc., using this burner. Plenty of vermiculite and very careful packing to minimise heat losses is essential.

Tich is a little smaller than Minnie. Tich = 60mm o/d boiler, 180mm long.

Regards,

 

Phil

Edited By Weary on 31/03/2016 22:30:34

[Dave HalfordParticipant @davehalford22513]

Posted by Ian Welford on 31/03/2016 20:24:34:

Dave

does the vermiculite break down in use? Never thought of using spare rock wool as heat lagging !

Ian

It's already been burnt once.

The rock wool worked for my mini boiler with above small burners – noticeable difference.

[Brian HParticipant @brianh50089]

Although I have built copper boilers using a large Bullfinch burner, I would additionally use a small oxy-acet nozzle for stays inside a firebox in something like 3 inch.

Although its a mistake to use too much localized heat, it is difficult using too little heat.

The flux is also important; I always use Tenacity No 5 because it is made to withstand prolonged heating.

I was interested in the suggestions to use Vermiculite and rockwool, I've always packed jobs with firebricks, broken ones are especially useful for filling in small gaps.

A good source is firms with heat treatment facilities, especially ones doing aerospace work because they have to reline their ovens frequently and the scrapped bricks are useful.

[julian atkinsParticipant @julianatkins58923]

Hi pgk pgk

I would endorse Steve and Philip's views.

You need to get a decent Sievert set for propane. Boiler making is quite tricky at various stages doing the silver soldering, and the last thing you want to worry about is lack of heat.

If you overdo the insulation/firebricks due to inadequate burner/torch you also make life very difficult, with heat throwback and moving the boiler around in some stages of silver soldering.

Cheers,

Julian

[WearyParticipant @weary]

@ Brian Hutchings

For years I used firebricks. However I switched to Vermiculite as an experiment, and found it so much easier that I almost never use my firebricks nowadays. The main exception is usually when I want to retain heat in an area when I usually use the broken firebricks as 'packing', much as you seem to do.

Regards,

Phil

[pgk pgkParticipant @pgkpgk17461]

I have 8 vermiculite bricks and a bag of coarse vermiculite on order as well as a 25KW burner and supplies. I need to pop down to the yard and pick up some thermolite blocks and dry them in my shed. Whether I have the talent/ability to do the job is another matter…

I'm also debating brick acid v sulphuric.. leaning to the latter as cheaper and the trip to get it gives me the chance to buy a deep lidded (nappy) bucket.

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