Comsol repair to Boxhill boiler...?

[kurplunked]

Hello All,

Some years ago, before I purchased my Boxhill loco, Somone has carried out a comsol repair to the firebox stays and, I think,!the foundation ring. I am now in a position where by the boiler is needing its first hydraulic with my own club. I feel that the state of this repair is messy and needs re-doing to a tidier standard. My plan, is to remove the boiler from the frames and cladding and get it professionally cleaned by a friend to remove all dirt etc heat it up and wipe away the over run and huge globs left behind by the previous attacker and run in some more if required.

My question is, any issues with what I plan to do? My club tester is happy that comsol where it is, is acceptable due to the difficulty of silver soldering in the box. Has anyone carried out repairs to a copper boiler before? Any help appreciated as I have never touched boiler work untill now and would benefit from your experience.




Regards
K

[Tony K]

Mmm! I have been here.

Presumably you have been happy with life with this boiler so far and your boiler tester has not failed it?

I set off down the path of repair and once I got started there was no end to it, except to have a new boiler.

My advice is to leave well alone with an old boiler - it does not look pretty, but it works at the moment?

Perhaps you are cleverer than me (not difficult!) and it will turn out OK - the approach seems viable. As they say on the railways - proceed with caution.

IMHO of course.

[jma1009]

i am afraid i am somewhat more pessimistic.

comsol stays must be threaded and nutted in side the firebox as comsol has no inherent strength and is only a caulking medium. your boiler has stays that dont even appear to be copper rivets with rivet heads silver soldered, and some look like they have been peened over on the inside but other have not been so treated. i cant see any nuts or threads.

i am always extremely suspicious of main structural flanged joints or foundation ring joints liberally covered over with soft solder.

if the boiler has no club pedigree of a history of certificates then most club boiler inspectors would want the boiler out and stripped of cleading and fittings.

it is extremely bad practice and potentially dangerous to cure leaks in major structural joints by covering them with comsol. the odd run or blob of comsol is to be expected as it does have a habit of flowing where not wanted, but in your pic the whole of the inner firebox tubeplate joint has had comsol flowed all over it hiding the 'standard' of the silver soldered joint.

one should also bear in mind that the original BOXHILL design has only a 1/16" inner wrapper for a working pressure of 100psi so the side says have very little area in contact through the inner wrapper.

a lot will depend what view your club boiler inspector takes and whether you have any previous certificates that came with the boiler. if the throatplate to barrel butt joint is also covered with comsol then i think that is pretty fatal and indicates a very badly made and potentially dangerous boiler.

cheers,
julian

[kurplunked]

I have a boiler history dating back to when the previous owner bought it in 2007 and it received a shell test by the last club. It has had these repairs during its ownership at a previous club and had hydraulic tests since.

My main worry is the club boiler tester will look at this and "not like it" and refuse to even try hydraulic testing it.. I'm not sure how I stand with that.

[uuu]

You need to show it to your inspector first. Then proceed from there. Like TonyTrans, the Pump House crew have attempted repairs on Comsol-afflicted boilers with poor results. You'll fix one leak only to have another open up, and waste time and money on a lost cause. Cross your fingers that the inspector will grant you a test, then again that it passes as it is.

Wilf

[Tony K]

Apr 19, 2014 10:02:14 GMT kurplunked said:

My main worry is the club boiler tester will look at this and "not like it" and refuse to even try hydraulic testing it. I'm not sure how I stand with that.

That is when you fix it.
There is no harm in trying a test and going on from there. My experience is boiler testers do not refuse to test without a very good reason and it is not related to aesthetics. I assume you have pumped it up yourself and it is OK. If it aint broke .....

[jma1009]

i think you are missing the point - comsol stays should be threaded and nutted inside the firebox.

none of the stays in the pic are so treated.

if plain stays were run over with comsol only that is seriously deficient and dangerous. even more so if the working pressure is 100 psi and only a 1/16" inner wrapper as per the original BOXHILL design.

if you cant see the integrity of the main structural joints because they have been run over with comsol that in itself raises alarm bells. why would good sound silver soldered structural joints need running over with comsol if they were ok in the first place? and how can you see if the structural silver soldered joints are ok if run over with comsol in any event? why has comsol been run over the foundation ring joints? this could only mean that the silver soldered joints are defective, and comsol wont rectify this.

personally i wouldnt accept comsol on any boiler with a working pressure above 80 psi as the temperature of the inner firebox could easily approach the temperature when the comsol starts to become brittle and deteriorate.

the original BOXHILL designed boiler pushed the boundaries quite a bit so far as boiler design was concerned in 1963/4. martin evans then back tracked a bit to more orthodox methods. the original design is one of the few that IMHO needs to be scrupulously made to be sound. the pic confirms the boiler was neither made to the drawings or acceptable standards then or now.

being 3/4 way through my own terrier boiler (with considerable improvements i have incorporated on the original BOXHILL design) i am keenly aware of these problems plus the short comings of the original design. unless you can show the stays were silver soldered originally and properly and soundly the boiler doesnt comply with the spec in 1964 or today's standards.

the only reason for running comsol over a main structural joint such as the inner wrapper to tubeplate joint in the pic is that the silver soldered joint has failed, and these days a comsol 'repair' would not be acceptable. it will not prevent the joint from suddenly blowing open.

cheers,
julian

[steam4ian]

K.

Nothing is lost by cleaning up the boiler particularly the firebox to get a good look at what is there.

I used brake fluid to cut into the soot inside my firebox and finished up getting it clean. I have a cheap Karcher which also helped blast stuff away.

You can get a bucket for AUD 1.00 and some citric acid from the home brewing suppliers for about AUD 5.00 to make up a pickle solution.

If you like do a pressure test first by making a connection so the garden hose pipe can be connected to pressurise the boiler, you will typically be able to get 50-100 psi.

I read Julian as saying chuck it out. I am saying it will cost very little give it a preliminary test and clean it up. Check around the stays to see if they have been silver soldered and with soft solder only used to control any weeps; that is the joint is doing its job structurally but has some pinhole porosity. Cracks in joints are another matter.

For about AUD 50 Jaycar have boroscopes which plug by USB into you computer with a head small enough to go through the dry pipe bush or regulator bush or dome. That way you can get a good look at what is on the other side of the tube plate and at the girder stays on the firebox roof.

I was talking with a boiler inspector at my club who bought a 2nd hand loco, He is busy repairing some boiler leaks with 965 soft solder which is allowed under the AMSBC Code. Our other club boiler inspector will do the testing.

Good luck

AUD 1.0 = 55 pence

[Shawki Shlemon]

I would show the boiler to the boiler inspector and discuss the steps required , in my opinion clean , do NOT remove any soft solder at all , test , if pass the test , leave it alone . If you remove some solder and then it leaks , this will cause a lot of trouble , repair one and cause other leak/s , Soft solder (here 965 ) is allowed in NON structural joints such as minor leaks from stays for caulking purposes . It may look much worst than it is .

[runner42]

I endorse the comments that say clean, but don't attempt to rework any soft solder areas. One can assume that the leak that required a repair was around a stay and that the blobs of soft solder in other areas is due to an overuse only. This point can be discussed with the BI if he is concerned over the amount of soft solder used and if your aware of the provenance of the boiler this can help in convincing the BI that it's a cosmetic issue and not structural. Even the AMBSC Code Part 1 doesn't concern itself with cosmetic or workmanship issues.

I might add that Comsol or similar is something to avoid at all costs, because once used there is no subsequent structural repair that can be carried out on the boiler in the same or close by areas.

Brian

PS Oh dear another Senior's moment. How did I manage click on this thread and think that it was current, just noticed it was raised in April 2014.

[robmort]

"Comsol or similar is something to avoid at all costs, because once used there is no subsequent structural repair that can be carried out on the boiler in the same or close by areas."

I don't see this argument; do you know of anyone doing a successful structural repair on any boiler (even if not Comsoled), as such a repair is likely to create many problems and leaks on other silver-soldered joints in a never-ending process.
So Comsol is as good as anything.

Rob

[runner42]

Feb 7, 2015 17:28:18 GMT robmort said:

"Comsol or similar is something to avoid at all costs, because once used there is no subsequent structural repair that can be carried out on the boiler in the same or close by areas."

I don't see this argument; do you know of anyone doing a successful structural repair on any boiler (even if not Comsoled), as such a repair is likely to create many problems and leaks on other silver-soldered joints in a never-ending process.
So Comsol is as good as anything.

Rob

Hi Rob,

I see you are in Havant Hants, my last residence in the UK was Havant.

No I don't know of anybody who has done a repair on a boiler my exposure to boiler making is very limited. I assume that a structural boiler repair would require silver soldering and see it as just a bit more of the same as in boiler construction where one has to create new silver solder joints without affecting adjacent ones. If this can't be done then boiler making itself is a hit and miss task. I am painfully aware of what soft solder does to copper when heated to silver soldering temperatures it burns a hole in the copper.

I know that Comsol has its place in boiler making and know of a very experienced SASMEE colleague who have used it. I should have prefaced my comment with IMHO.

Brian

[alanstepney]

I have seen, and even repaired, boilers that had leaks, when, and only when, they had been silver soldered.
Comsol as a "caulk" has its place, but ANY soft solder, including Comsol, does preclude sibsequent repairs with silver solder.

Way back, I used to make boilers commercially, and have now made some 50 or so. IMHO, Comsol should be used VERY sparingly, and just as a caulk, or not at all.


As for Havant, I used to live nearby when I worked for an electronics company in New Lane. (Plessey for those with long memories.)

[robmort]

It's a small world! I worked at Plessey West Leigh and South Leigh 25years ago on military radio etc., but New Lane was separate I think so doubt if we met.

I've had bad experience on my two boilers of making any repairs on silver-soldered joints when the boiler is complete, let alone structural ones, and I know several here who had the same experience, and I believe it's common though not widely documented. Reheating a boiler to fix leaks just results in breaking previously sound joints.
I think the only way to do such repairs with silver solder is with specialised equipment e.g oxy-acetylene, unless you know better.

I don't recommend Comsol, if there are better methods, and there are many other good leak sealants.

[alanstepney]

I will admit that I used to use Oxy-acetylene when I made, and repaired boilers. And, yes, it does make a difference.



As for Plessey, I spent a little time at West Leigh (some work on the Clansman, I think it was) , and even the then-new coil winding division at Waterlooville, as I was involved with test gear, which was used everywhere.
But my time with them pre-dated the time you mention so it is unlikely we ever met.

[runner42]

Feb 8, 2015 8:35:00 GMT alanstepney said:

As for Havant, I used to live nearby when I worked for an electronics company in New Lane. (Plessey for those with long memories.)

I lived opposite the Rover Pub on the Petersfield Road, which is nearby to Plessey New lane and was offered a job in the Test Department there but didn't take it up as I was off to Australia . This was in 1975 so maybe before your time.

Brian

PS Just looked on Google Earth and it's now called the Heron.