BOXHILL by Martin Evans

[jma1009]

despite the hot weather today decided to have a go at fitting the backhead to the boiler of STEPNEY, being the final silver soldering stage.

first job was to check that the propane bottle was still heavy!

then fluxing up the bits and fitting same to the backhead etc.

around 4pm it clouded over so lit the propane torch. after 10-15 mins of directing the heat on the firehole ring the job was up to heat then silver soldered up the backhead stays then the firehole ring then the backhead bushes and longitudinal stay ends, then the backhead to outer wrapper joint and water gauge top elbows and manifold bush, then the rear section of the foundation ring. all went ok and nothing missed.

before fluxing up the rear section of the foundation ring and backhead and outer wrapper were crosshatched with a triangular file.

anyway here's a few pics. the first pic shows the boiler fluxed up and ready for silver soldering with a piece of thermalite cut to size shoved up the inside of the firebox.

second pic is the boiler still hot after silver soldering.

the other pics are of the finished joints (which havent been cleaned up/tidied up yet) but the longitudinal stays have been cut to length, and the last pic ive filed the backhead phos bronze stays down.

i wasnt too impressed with the cupalloys supposedly 'same as easyflo 2' silver solder used on the firebox doorplate so decided to use same on the backhead etc to use some of it up rather than use what little ive left of genuine easyflo 2.

next job is to open out the threads on the boiler bushes to full depth and fit threaded plugs etc and the inner dome etc for my own hydraulic test. no celebrations till then!

cheers,
julian

[jma1009]

a few additional points...

the backhead and remaining joint on the rear section of the foundation ring were done with the rear of the boiler pointing upwards which requires directing the heat downwards. only apply the silver solder when the whole lot is up to heat.

LBSC and martin evans and others say peen over the edge of the firehole ring. this is stupid as prevents the silver solder flowing through this joint with the backhead and will result in just a surface flow of silver solder which has little strength. i added a chamfer to the edge of the opening to the firehole ring on the backhead and also on all the stay holes and edge of the rear section of the foundation ring.

the solid phos bronze longitudinal stays are silver soldered direct to the smokebox tubeplate and backhead which considerably simplifies construction plus saves time, and is also what the professionals do.

cheers,
julian

[runner42]

Hi Julian

great work, you must have lost a few kilos in sweat with all that heat and in a UK summer to boot. I note that the bushes are already threaded, you are not phased by the high temperature affecting the threads?

Brian

[arch1947]

Nice job Julian.
Cheers,
Arch

[Deleted]

stunning work Julian.... I bet you can't wait to do the hydraulic test although going by the quality of your work it's only going to be a total success... top job...

Pete

[jma1009]

thanks pete, arch and brian for your very kind comments!

brian, although you can see threads in the bushes, they are tapped only a couple of threads deep to full section with a taper tap. ive spent most of this evening tapping them to full depth with plug taps. however with hard drawn phos bronze i must admit ive never found any damage to threads due to heating and pickling. gunmetal might be different but ive never used gunmetal for any boiler bushes.

cheers,
julian

[Deleted]

I particularly like the two pieces of wood ---- they look as if many a blue overall have already sat there !!

[Deleted]

Brilliant Julian! Would it be possible to copy the whole of the boiler building part of this thread to another thread purely for how to build a boiler? Maybe have it pinned so as to be easily accessible?

[shooter]

Hi Julian,
Superb work as always. You are definitely the group guru on building boilers.
Have to agree with Ben on making your boiler build a separate thread. It needs keeping for posterity.
(and for the rest of us to learn from)

Cheers for now. Steve.

[Roger]

Absolutely superb, that's a brilliant build Julian.

[jma1009]

oh gosh, thanks for all your very kind comments!

ive no idea how to transfer all the boiler stuff to a separate thread or the boiler construction section on the forum!

ive been trying to work out how much the boiler has cost. the odd sized barrel seamless copper tube came from m-machine metals at darlington at £68, the other copper sheet and all other tube material was about £80 from macc models as was about £40 worth of silverflo 24. the large bushes are PB1 cored and cut nearly to size in slices from C. Rees (previously fromstock) in cardiff for £10. there is probably £100 worth of silverflo 55 and easyflo 2 silver solder. hard drawn phos bronze for the smaller bushes i already had in stock. in addition to the above ive used half a tub of 500g thessco F flux powder, and 2 bottles of sodium hydroxide from wilkinsons to remove the flux after the silverflo 24 joints.

so say £310 for a fully silver soldered complete small 5"g boiler with all stays silver soldered with propane, that anyone should be able to do without resort to oxy-acetylene.

im currently making all the gaskets for the regulator bushes and inner dome - a bit of a change! i will make plenty of spares as much easier to make them now if more are required in the future. i am looking forward to making all the boiler fittings as this is something i really enjoy. they will comply with the current regs being all captive valves and as scale as i can get them within reason.

cheers,
julian

[jma1009]

as might be expected i rather rushed a preliminary hydraulic test on the boiler today! there is a ring of silver solder around the dome flange that prevents the temporary screws having a decent seat - these were dripping. i need to spotface the seats for the stainless bolts i will need to make up. otherwise no leaks so far from any of the silver soldered joints. i also used some old 1/4" x 40 tpi caps for some of the bushes which also dripped a bit - i need to make up a set of blanking plugs of this size.

the pic shows 150 psi which was the most i could get with the above leaks from the inner dome flange. boiler on the kitchen sink this evening!

the copper pipe sticking up in the pic is the handle on my boiler test rig pump

cheers,
julian

[Roger]

Excellent! At least you can be pretty confident that all's well. What a cracking job!

[runner42]

Hi Julian,

you should be well pleased, not lost the master's touch. How long does the pressure need to be maintained to qualify for a pass?

I like your costings so how much for a Doris boiler to be delivered to Adelaide South Australia? LOL.

Brian

[jma1009]

hi brian,

the above wasnt by any means a proper hydraulic test. the current UK regs state

"10.12 The test pressure shall be held for as long as necessary to allow
the boiler to be thoroughly examined throughout for signs of
distortion, damage or leakage and evidence of joint failure. The
boiler shall be subject to a minimum test period of TEN minutes at
full test pressure."

i always carry out my own exhaustive test on a new boiler before submitting same for the official club test. it can take awhile to get all the blanking plates and plugs ok, and nothing annoys a club boiler inspector more than a boiler submitted for a test badly prepared with leaky plugs and water squirting out of same! so by way of example i skimmed the face of the inner dome flange this evening removing the excess silver solder so the bolt heads would seat properly, and instead of the temporary screws i used yesterday made a batch of stainless fitted bolts - all of which i should have done before. i must admit that making bolts out of stainless is one of my least favourite jobs, but they are made now and the inner dome re-fitted. ive also turned up some proper 1/4" x 40 tpi blanking plugs instead of the dodgy caps found in my 'ODDY' box which i used yesterday.

cheers,
julian

[smallbrother]

Jun 16, 2014 23:36:32 GMT jma1009 said:

hi brian,

the above wasnt by any means a proper hydraulic test. the current UK regs state

"10.12 The test pressure shall be held for as long as necessary to allow
the boiler to be thoroughly examined throughout for signs of
distortion, damage or leakage and evidence of joint failure. The
boiler shall be subject to a minimum test period of TEN minutes at
full test pressure."

i always carry out my own exhaustive test on a new boiler before submitting same for the official club test. it can take awhile to get all the blanking plates and plugs ok, and nothing annoys a club boiler inspector more than a boiler submitted for a test badly prepared with leaky plugs and water squirting out of same! so by way of example i skimmed the face of the inner dome flange this evening removing the excess silver solder so the bolt heads would seat properly, and instead of the temporary screws i used yesterday made a batch of stainless fitted bolts - all of which i should have done before. i must admit that making bolts out of stainless is one of my least favourite jobs, but they are made now and the inner dome re-fitted. ive also turned up some proper 1/4" x 40 tpi blanking plugs instead of the dodgy caps found in my 'ODDY' box which i used yesterday.

cheers,
julian
[/quote




Hi Julian,

Just picking up on your comment regarding boiler inspectors. If I found one annoyed with my crude attempts I would get a tad annoyed myself and ask what the hell is a beginner supposed to do.

However, in your case, you would certainly deserve a severe telling off!

Magnificent work and photos from you.

Pete.

[ejparrott]

I've been lucky and only had good quality new boilers, well except the one that came from Lynx, but for me it's treated with the respect appropriate to the builder. If a build with Julian's experience brought me a boiler that was leaking all over the place I'd tell them to go away and sort it out, if a newby brought me the same, I'd walk them through it, sort it out and get a pass on it, assuming there wasn't a major fault with it of course

[Deleted]

Hello all----------as per anything that you are preparing for "official" testing it's common sense to have it tested yourself first and make good any repairs, such that the actual test itself will be a mere formality ( The much-quoted similarity of your cars' MoT is a good example here..)..................Also remember that all test results are at the discretion of the Boiler Examiner anyway. eg}--- One may allow some small leakage under slight pumping whilst another might not.............. As has been mentioned elsewhere you can always discuss with your examiner just what the parameters expected are beforehand ( You can do this with your MoT as well, but how many actually do ??)..Hmm, what's that unusual aroma ? >>>>>>>>>>>>>>>>>

[jma1009]

sunny evening here so another test on the boiler with the new stainless fitted bolts and proper blanking plugs...
hopefully all ready for the club official test!
cheers,
julian

[Deleted]

200 smakeroonies, on the nose !!............Way to go, Batman !!