boiler leak

[Bill DawesParticipant @billdawes]

The continuing saga of my Emma Victoria build (now 12 years in the making)

Some time ago I reported that the boiler failed a pressure test, just a couple of tiny leaks, one on the outside of the firebox at a joint the other inside the fire box between inner wrapper and end plate.

Hate resoldering but eventually gave it a go which cured the problem but created two others inside firebox. (liberally coated all joints and rivets with flux) Now dreading even more the thought of another reheat.

I am wondering if Comsol might be the answer but concerned about two things, is melting point of Comsol high enough for use in  the firebox and as it contains lead will that prohibit any future silver soldering exercise.

Bill D.

[Nick HughesParticipant @nickhughes97026]

Hi Bill,

the answer is Yes to both questions.

[noel shelleyParticipant @noelshelley55608]

I would not use comsol or a soft solder on a boiler inside or out. IF there has been ample flux then several causes come to mind, both involve heat, or the lack of it. Either the heating was to slow and the flux became exhausted or that there simply was not enough heat to allow the solder to flow properly. Once partly soldered the joint will need more heat and lots of it quickly to repair the joint. This is where oxy fuel equipment comes in handy. A bigger burner and a good brazing hearth may be needed. Packing round the boiler to conserve heat with ceramic fibre or charcoal will help. Good Luck. Noel.

[duncan webster 1Participant @duncanwebster1]

Unless you have enough heat to get the whole boiler pretty hot, trying to repair silver soldered joints can be a nightmare. Uneven expansion can cause more leaks. Don’t ask how I know. Alec Farmer’s book recommends Comsol for situations like yours as long as the boiler is structurally sound, just a small leak. Most important, discuss with your boiler inspector first

[Dave HalfordParticipant @davehalford22513]

You can also cause leaks by cooling too quickly.

[Clive Brown 1Participant @clivebrown1]

Silver soldering inside the firbox with air/propane isn’t really a runner without a very large amount of heat and insulation and, even then, probably will result in chasing leaks as you have found. That leaves oxy/gas or comsol as possibilities.

[Bill DawesParticipant @billdawes]

Thanks for replies guys.

I have found that over the years varied opinions exist on the suitability of Comsol, the majority opinion seems to be against so I will go with that.

When I first started this silver soldering lark on my boiler I had a purchased a standard Sievert kit with, I think, a 2941 burner, quickly finding that did not produce  enough heat I bought a 2943 burner which has about 40+ kw of heat from memory, that was much better, even so seemed to take an eternity to heat up, what on earth do you guys do on a big boiler, mine’s only 4″ diameter by about 11″ long.

Not long ago I bought a Turbo Oxy Propane set hoping it would work on a small area such as a leak but the heat just soaked away, I then tried getting  the boiler hot with my propane torch and then attacking it with my Oxy propane, no success there either, probably need more practice but the oxygen cylinder on these doesn’t allow much time for messing about experimenting. I do pack around the boiler to retain heat and I let it cool naturally before pickling.

I guess you’ve either got the knack or not.

Think I will have another go with pre heat and then oxy propane torch.

Bill D.

[Clive Brown 1Participant @clivebrown1]

Should have mentioned in my earlier post that Sievert Cyclone burners can be useful for working in the firebox. Their air is drawn from the base of the burner which helps avoid the “flame-out” tendency of normal burners working in the confined space of the fire-box. Still need plenty of general heat and insulation though I’d expect.

[noel shelleyParticipant @noelshelley55608]

Several things come to mind on this matter ! In heating there are 2 values that are NOT the same, the first is the temperature the second the amount or volume of heat. So an oxy fuel heater will have high temperature but not nescessarily high heat volume, a 2943 will give volume of heat but normally a lower temperature. People go out and £1000s on tools Etc but gripe at £140 rental for a BIG bottle of Oxygen for the year. I don’t like it but it is part of having the right gear for a job and avoid the distress of running out at the crucial moment. The rental is by the month so if you get the job done quick it may not cost much. One can avoid the need for 2 propane bottles by fitting a Y fitting if one is using oxy- propane and air – propane at the same time, a 19Kg is a good size. If one uses the Saffire type of oxy torch then one now has the facility, with a cutting head, to cut steel and in skilled hands the cut can be as clean as a hacksaw, well almost.

The right gear will include a brazing hearth, plenty of material to keep the heat in and of course the right flux. General heat and spot heat along with slow cooling is a good plan.

An already built boiler with even tiny leaks may prove a challenge to repair with out the above type of equipment.

Good luck. Noel.

[Nigel BennettParticipant @nigelbennett69913]

One thing to consider with this job is the flux. You’ll be messing about with some fairly high temperatures for some time if you’re having to heat up the whole boiler. In these circumstances, standard Easyflo flux won’t cut it; you’ll need something better such as JM’s Tenacity 5 or CuP Alloys’ equivalent, which I think is HT5.

[Tim StevensParticipant @timstevens64731]

It might help – for the flux – to have some way of adding more flux as the heat destroys what you start with. You might try with some dry flux powder in a tube, and blow it into the area of interest while diverting the flame briefly. And whatever you do, be careful not to suck under any circumstances. The flux won’t be pleasant but the heat will be a disaster.

And of course, the more flux you add, the longer it will take to remove the residue.

Tim Stevens

[Bill DawesParticipant @billdawes]

Thanks guys for your help. It seems I am doing the right things, big enough burner, insulate around boiler (I use aerated building blocks), I do use HT5 flux when i think it needs it, is there a time when using HT5 rather than Easyflo is detrimental rather than useful?

I feel I should have achieved a better standard of silver soldering by now but being fair to myself this is the one and only boiler I have made, plenty of smaller stuff which is always successful now.

Bill.

[bernard towersParticipant @bernardtowers37738]

Dont  put yourself down, making a boiler at home is not for the faint hearted and you are almost there , there are a lot of people with locos and traction engines but the boilers are bought in so well done.

[bernard towers]

On bernard towers Said:

Dont  put yourself down, …

I agree!  Bill’s tackling a difficult job.  My experience is with much smaller objects than a loco boiler, and the secret seems to be plenty of heat and a flux that lasts long enough to protect the melt.   Noel and others have already covered the point.

My collection of insulating bricks and a small cartridge powered Sievert torch will only braze or silver solder dinky little parts.  Nowhere near good enough to tackle a boiler.   I can’t pump heat into anything other than tiny jobs fast enough.

I dunno if this helps, but I recall reading an early LBSC article in which he describes how he did it.   His torch was a big 4-pint paraffin blowlamp, I guess a couple of kilowatts out, so not impressive.   The torch wasn’t the main source of heat. For that, the whole boiler was placed on top of a coke brazier, where the coke inside was at bright red heat, but the boiler was protected from high temperatures by a thin layer of unburnt coke on top.  The coke brazier warmed the whole boiler to something below brazing temperature, which reduces the risk of breaking existing joints with unequal thermal expansion, and means the torch only has to provide enough extra heat to make the joint in hand.   LBSC made it sound easy…

Dave

[noel shelleyParticipant @noelshelley55608]

Bill, As others have said, your dealing with a difficult task, I have never built a boiler, though I have done a lot of brazing and welding.

To add to Daves comments about LBSC, the idea of surrounding the boiler with coke or charcoal is that it will burn, adding heat indeed the air movement caused by the torch will fan the fire. One might even use a small blower to aid burning and considerable heat, it is a clean fuel with almost no ash. Once the job is done leave the boiler to cool in the charcoal. Charcoal will melt steel if blown !

If your using oxy fuel for spot heat then do NOT use it to raise the general heating as it is to intense. Only use it on a job like this once the whole boiler is up to a good heat, you can then melt the areas you need with your spot heat.

Any job where heating is done it is always useful to know the temperature, it will improve the success rate no end ! I use dip pyrometers for molten metals. A non contact thermometer that could read to say 800c or so might be a handy gadget to give an idea of your heating ? Once again, Good luck. Noel.

[Bill DawesParticipant @billdawes]

Thank you for encouragement guys.

Wow, heating up with a paraffin blowlamp and a coke hearth, now that sounds scary.

Reminds me of when I started my engineering apprenticeship in January 1957 at a Birmingham company called Alldays & Onions (established about 1650) they manufactured at that time, industrial fans, furnaces, pneumatic forging hammers and foundry equipment including blacksmiths hearths so I know what temperature they get up to with the blower on, I see from time to time examples of these in various museums. Some of you might have heard of Alldays cars which they made in the early 1900s along with push bikes, motor bikes, stop me and buy ice cream and hot pie trikes. I worked next to a guy in the machine shop who had a large envelope stuffed with pics of all those, wish I had asked him if I could have some, guess they were binned when the place closed down. I do have however an old catalogue dating back to the 1800s with blacksimith equipment in it, descriptions in those days seemed have liberal descriptions such as ‘New Improved’ and ‘Patent design’ On the cover was an artists impression of the Alldays works which was situated on the Grand Union canal but looked more like the Manchester ship canal in the drawing!

Part of my apprenticeship did not involve brazing unfortunately. after 5 years on shop floor I was sent to the drawing office much to my dismay as I loved it on the shop floor, 5 years in D.O. and I joined another company a junior technical sales engineer finally finishing up on the engineering side in which I still ‘do a bit’ part time at 82 years (83 next month) earns a few bob and keeps my brain active.

Will keep you posted.

Bill D.

[noel shelleyParticipant @noelshelley55608]

Happy Birthday as of next month Bill. I have an allday and onions hearth blower, hand cranked, just the job for an apprentice on a cold morning . Noel.

[Bill DawesParticipant @billdawes]

One of the first jobs I was given when I started in the machine shop was drilling cast iron gear box casings for hand driven fans, they were generally referred to as field fans and the army used a lot.

Some of the holes were straight through for a nut and bolt, others drilled with a blind hole and then tapped.

One those tapping attachments that reverse when you lift the operating arm was used, trouble is it was on a pillar drill that even on the slowest speed it was far too fast for tapping, several broken taps later and in a cold sweat (remember I was only 15 then) the foreman came over and asked what the problem was, “remember son, he said, don’t be afraid of your machine” waving me aside he proceeded to show me how it was done, bang, broken tap. ” Carry on son you’ll soon the get the hang of it” he said as he walked away puffing his pipe.

Bill D.

[Bill DawesParticipant @billdawes]

Thought I had sent this a few days ago but got lost in the ether.

Anyone know where I might get a gas torch holder, something that clamps on and with articulated arm is what I had in mind.

Bill D.

[MichaelRParticipant @michaelr]

Have a look at this site https://www.aliexpress.com/item/1005003908690157.html?src=google  may be something to meet your needs.

Michael

[WearyParticipant @weary]

Maybe try ebay search +++   Laboratory Stand  +++?

Phil

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