BOXHILL by Martin Evans

[Jim]

Looking good Julian

Jim

[Roger]

Very snug, what a nice fit!

[jma1009]

a bit more progress...

ive made up a fresh batch of sulphuric acid pickle and the boiler is looking nice and clean and pink. didnt half make the boiler warm up in the process! i deliberately made it strong to ensure that front foundation ring corner i'd missed got cleaned thoroughly. i always then scrub in hot soapy water as it is surprising how much dirt still comes off compared to just a cold water rinse with the garden hose after pickling. for inaccessible inside areas old tooth brushes are very useful.

i spent some time this evening fitting half of the L-H firebox side stays with tight fitting rings of silverflo 55 fitted around them inside the water space hard up against the inner wrapper. L-H side of the foundation ring fitted and blowdown bushes and checkvalve bushes made out of hard drawn phos bronze. when ive fitted the remaining L-H side stays i can silver solder them in plus L-H foundation ring and blowdown valve (and that corner of the front foundation ring i missed in the front L-H corner) all at the same time. hopefully tomorrow afternoon. will try and take a few pics 'before and after' tomorrow.

cheers,
julian

[Deleted]

Don't forget to open out the bush holes on the top of the backhead flange !!........The old pickle makes a good weed-killer on the driveway !!

[jma1009]

a successful 10-15mins heating up and silver soldering of the L-H firebox side stays, L-H foundation ring, and blowdown bush, plus touching up the corner of the front L-H front foundation ring i'd missed last weekend.

ive added quite a few pics coz the method of doing firebox stays with propane hasnt been very well covered in ME, and to show it is quite easy to do with propane. you do have to leave off the inner firebox doorplate though. in fact as STEPNEY's firebox is quite small i think it would be quite difficult to do with oxy-acetylene with the inner firebox doorplate in position.

anyway the pics...

note the chamfer on the outside of the firebox wrapper around the stay holes on the outside and the tapered ends of the 1/8" dia copper rivets used as stays.

note the rings of silver solder hard up against the inner wrapper side in the water space. they are tight fitting so preventing the stays moving plus preventing the rings moving. just a bit of crimping with a pair of pliers to get the tight fit.

flux everywhere inside and out and in the water space.

heated up initially inside the firebox with the tubes covered with thermalite to protect them and the throatplate stays.

after 10 mins each stay in turn moving deeper into the box has a flash of silver solder appear around the stay heads.

then a change to outside and play the torch on the foundation ring side plus that corner i'd missed, adding silverflo 55.

then to the outside of the wrapper running a long length of silver solder rod along each row of stays in turn.

there is a pic of the inside of the water space showing how it all penetrates

cheers,
julian

[Deleted]

Looks great Julian.....thanks for the description, I'm making notes.....btw what method do you use to place the stay SS rings in the water space? ... Looks tricky...?

Pete

[jma1009]

hi pete,
many thanks for your kind comments.
i made up a special tool/gadget for getting the rings into position but it wont fit STEPNEY's smaller water space. so basically i pushed them into position till they were over each hole then pushed the rivet through the ring, then the end of the gadget gets used to push the ring hard up against the water space - just a long length of 1/8" brass strip with a notch cut in the end 1/8" wide to fit around the stay dia and push the ring hard up against the inner wrapper. yes, fiddly but not difficult, and the only way to do it IMHO as virtually impossible to apply silver solder inside the firebox when the torch is roaring away inside (i had to do it for the rivet i'd turned up from copper rod to secure the rear end of the foundation ring to stop the joint opening out and prevent that end of the foundation ring slipping down). not a new idea - i copied the late W.A.(Bill) Carter's method for fitting rings inside the water space for the stay heads inside the firebox.
cheers,
julian

[Deleted]

Thanks for the info Julian... that all makes sense to me which bodes well for when I get to my boiler.

Cheers

Pete

[Roger]

That looks superb, and I too and taking notes. I was wondering why you didn't fit silver solder rings on the inside for the outer wrapper too but I suppose it's easy to add that from the outside by hand. Of course it would be fiddly but might be an idea. Would it get hot enough to do inside and out in one operation?

[shooter]

Lovely job Julian, as always.
I have decided to have a go at the boiler for Doris, when the time comes, but may need to ask for some help re. the drawings.
I am told that they need to be altered to make construction easier and stronger.
For now though, I am happy to see how it should be done.

Cheers for now
Steve

[Deleted]

A "Master Class" in full swing !!------------ Slither-hither o ye of little knowledge and heed the word of the sage...For yea, verily do I say unto you..........Oh shut-up, ALAN !!! JULIAN, lovely job me heartie, surpassing the standards of the mighty Cayenne Pepper himself..... Mine are only good for making the tea with by comparison ..LoL !!---------- as a Madam once said her girls}-- "It's no good flaunting your equipment if you don't know how to use it !! "...........

[runner42]

Hi Julian,

great job well done. Since you are experienced boiler maker you get it right first time. But what if one of the joints between the fire box and wrapper wasn't quite right, particularly if it was nearest the firetubes. how would you attempt to rework it?

Brian

[Jim]

I agree with the others, a very clear and instructive set of photos showing how it is done rather than just telling how it should be done.
One thing that you don't mention Julian and which would be very useful to see is the size of the propane torch you are using.
Thanks again

Jim

[jma1009]

thank you all for your kind comments.

i will try and deal with brian's query. silver solder flows by capillary action, gravity, and by heat direction. you do need to get the fit of the parts correct in the first place - an over generous gap cant be filled with silver solder and is likely to cause problems later on. i tend to make my flange depth quite generous (flange depth is all quite a bit more on STEPNEY's boiler than the BOXHILL boiler). i also apply far more silver solder than is strictly necessary. do the joints first on each assembly where there is a greater mass of metal to be heated up, and when doing nearby joints later on flux up the previously done joints in case things get a bit hot. in this respect the smokebox tubeplate is probably more difficult - you have quite a large mass of copper very close to the tubes closest to the smokebox tubeplate flange and barrel plus the ends of the relatively thin tubes all of which must be done at the same time. check everything scrupulously as you go along after each heat up, and scratch at the joints and poke about with something like a sharp dental probe. for hard flux deposits immerse the boiler in a strong solution of very hot water and sodium hydroxide (drain cleaner) for 35 minutes after pickling and scrubbing first with hot soapy water.

of 'defective' boilers ive examined and cut up for scrap the culprits appear to be poor joint design, bad fit of parts, dirty joints, and being too stingy with the silver solder.

cheers,
julian

[Shawki Shlemon]

Indeed the soldering looks sound , and doing it by steps as you mentioned is the way to go , a free good fit is an important key in soldering . Well done job , congratulation .

[Deleted]

JULIAN------- I think that last comment of yours Re}---"Stingy" with the Silver Solder ( and by inference..the COST ) is probably the tendency most beginners will have at the back of their minds when actually engaged on their very first boiler-build.......That "Dawn of realisation" starts with an appreciation in real-time of just how much heat their "Copper Kettle" is soaking up before it gets anywhere near the melting point of the Solder..............And the more bigger it gets the more re-heat ( Exponentially) is going to be required............My advice is always to over estimate on the gas, solder, flux etc. required....You can always ease-off with the heat application if needed, but running out of gas or skimping on solder rods at a crucial moment of construction will only result in a second-grade product that might fail its' initial tests....OR WORSE !!!!--

[jma1009]

a bit out of sequence, but when the side stays to both sides of the firebox are silver soldered with propane the inner firebox doorplate (left off to silver solder the side stays) then needs fitting and silver soldering in position. the inner firebox doorplate to backhead stays and firehole ring can be silver soldered to the inner firebox doorplate at the sametime, but i prefer to fit them beforehand with high melting point stuff...

so here's a pic of the inner firebox doorplate with the stays and firehole 'ring' trial fitted. i silver soldered them in position with silverflo 24 a short while ago and it is still soaking in sodium hydroxide solution at the moment after pickling and scrubbing.

the stays (i decided to fit 15, far more than the meagre 8 on BOXHILL) are turned from 3/16" dia hard drawn phos bronze, turned down each end to automatically provide a spacer for the backhead when fitted in due course, and taped 5/32" x 40 tpi for the inner firebox doorplate, and centred and turned down 5/32" dia the other end. the top 3 stays are tapped 8BA for fitting the scale tray above the firehole that i propose to fit, and to which the firehole door assembly will also be fixed.

cheers,
julian

[Deleted]

Who is that "young chap" in the new Avatar photo then ??-----------

[jma1009]

me!
(driving my 5"g GWR Armstrong Standard Goods loco)

[Deleted]

Thought I'd follow suite and change my image as well.........But all I could find was a photo of some 65-year old scroaty bloke..........So fell back onto something timeless and reliable.......