A small boiler

[Florian]

Hi Rich

I would mount the alignment jig again, if you are going to solder the next time, otherwise id didn't help anything.

Florian

 

[firebird]

Hi Florian

Yes I intend to use the jig when I do the rest of the soldering. If I didn't they are bound to move.

Cheers

Rich

 

[firebird]

Hi

Cut both the lawns, built a new garden seat, the wifes gone shopping so I went and soldered my boiler. It took me quite a while to get the end plates set up in the boiler barrel with the jig fitted and the stays in and get everything lined up. Got the whole thing fluxed up and set up in the brazing hearth and set to with the propane torch. Within seconds of the propane torch playing on the boiler it must have expanded a little enough for the end plate to drop inside. Disaster. A few choice words. Dismantle it all again. I gently tapped at the end plate flanges until they were a tighter fit in the barrel then cleaned everything up, re fluxed and set up again. This time more success.

Turn the boiler over and solder the other end plate and stays

Then back in the pickle for a scrub. Meanwhile I made up some silver solder wire rings by wrapping it round a piece of bar.

Then fluxed and fitted all the studs in.

Then fitted all the silver solder rings over the studs.

Then soldered them all in.

Another scrub up and pickle and then soldered in the dome and the bush for the safety valve.

#

In the pickle again over night. It looks good. I'm quite pleased with that.

Cheers

Rich

 

[Mcgyver]

Looking good Rich

 

[Bernd]

Nice job Rich. Hope you don't have any leaks when you do the static pressure test. I'm keeping my fingers crossed for you.

Bernd

 

[Divided He ad]

Fair do's That looks pretty damn smart

I hope it all goes well too, I want to see this (millipede-esque) boiler powering a little (or big!) steamer ;D



Ralph.

 

[BobWarfield]

Kewl!

Are you planning to hydro test it? Please document if so!

Cheers,

BW

 

[Bogstandard]

Lovely work Rich,

For a first boiler, you have shown everyone that it is possible if you take everything in logical step by step stages, boilers can be made to very good standards.

The one you are making here should give you many years of trouble free service.

It also looks like you have got the silver soldering nailed, another very good string to add to your bow. I shouldn't think you will have any trouble pressure testing by looking at the quality of your joints.

Maybe now would be the time to get a full set of blanks made and pressure test it, before you go any further.

If you need some help to make your testing rig, I am sure I have drawings somewhere of the bits you will need to make.

Very well done.

John

 

[mklotz]

Allow me to add a request.

Given the number of novitiates among our membership and the extreme importance of pressure testing any pressure vessel, let me implore you to make a photo record of your efforts and present that here so everyone can see how it's done by someone who obviously knows what he is doing.

 

[chuck foster]

great idea marv, if i ever get to working on my traction engine i will need to know how to test it and test it properly!!

chuck

 

[firebird]

Hi

I must say that without the encouragement and help of everyone on this forum I couldn't have built this little boiler. Theres a long way to go yet so keep the help and advice coming, I really do need it. Thankyou all.

John, are you psychic? Iv'e just come in from the shop having made a full set of bungs. 1 @ 3/16, 5 @ 1/4, and 2 @ 5/16.

Now then, on to pressure testing.

I have a small pressure guage that I know to be fairly accurate, Iv'e checked it against 2 others that are known to be correct.

My idea is to connect the guage to the boiler and firstly try it on air pressure of say 10 or 15 psi and hold it under water, easy to see air bubbles. If alls well I can then hydraulic test it. I mentioned way back early on in the project that I have a bit of kit at work (motor trade) that is used to pump up the hydrolastic suspension as fitted to Rover cars. I believe the first mini's were the first to use this type of suspension followed by the Austin 1100 and 1300 and 1800 then metros, even the latest MGF sports cars have it. Anyway I plan to fill the boiler with the hydrolastic fluid then pump it up to twice the working pressure. I think a working pressure of 30psi will be plenty so a test pressure of 60psi and see if it will hold that pressure for 15 or 20 minutes while checking to see if there are any unwanted lumps or bulges. Then finally a steam test to check that the safety valve blows off at 30psi.

Thats the plan anyway. What do you think?

Cheers

Rich

 

[Bogstandard]

Rich,

One thing you should never do, even if it is a very low pressure, is to put air into a boiler to test it. The toy brigade (Mamod, Willesco etc) have a very bad habit of using an adapter to blow air into the boiler and so run their little engines. A very dangerous practice.

If it 'blows' the air is expanding as it escapes. If hydraulically tested, just a couple of drops of water will lose all pressure, so no safety problems.

You can use a very clean piston pump grease gun to apply pressure. That was the way we would charge up liquid spring shock absorbers on aircraft. Using a grease pump, you can get up to 4000 PSI with no problems.

John

 

[firebird]

Hi

Thanks John. I'll scrap the air idea and just hydraulic test it. I need to make up an adapter to connnect the pump to the boiler first.

Cheers

Rich

 

[Divided He ad]

Now come on Rich.... MGF 'sports car'? ..... You got to be kiddin!! :big:
It's a metro with the engine in the boot!! :big:

A Schrader valve is surely all that is needed to connect a hydrospastic pump up? that green fluid will sure make a pretty fountain if it for some odd reason it leaks!! ( I am assuming that you have 'O' rings on those new bungs? )

Personally a tyre valve with the rubber trimmed and wirewheeled off and then silver soldered into one of your new bungs (with a hole in it!!) would be my line of connection.

But that's me! ;D

I am sure someone will tell me if I am wrong!?


I'm getting very interested in this subject. Keep us posted



Ralph.

 

[SandyC]

Hi Rich,

Great job on the boiler.

ON NO account put hydrostatic fluid anywhere near your boiler...... you must only use CLEAN WATER.

If you cant ensure the pump system you are proposing to use is totally cleaned of all oil.... then don't use it...... find a suitable piston type hand pump instead..... such as those used in model steam locomotive tenders for boiler feed.
You will also need to fit a non-return valve between the pump and the boiler.

I believe John said he had some details of a suitable boiler test set..... if not, then I may be able to find some info for a suitable unit..... I will look tomorrow.

Best regards.

Sandy.

 

[Divided He ad]

Plot, lost? No I don't think so I've got it here... Well I, erm ... Well I must have, Erm, hold on a mo' it's ... Well I had it a moment ago.... It must have fallen on the floor? I'll P.M. you when I find it! :big:



Thank you Sandy.... New lesson stored for future build use... 'only clean water' Got it.

Hopefully Rich see's that before he tries the green nasty stuff!?!



Ralph.

 

[doubleboost]

Minis metros 1300s 1800s ambasadors the allegro the austin maxi the princess happy days
The MGF just look at the front sub frame half way to 4 wheel drive
Nice boiler by the way
John

 

[Bernd]

John correct me if I'm wrong, but isn't a hydrostatic test of a pressure vessel done in a tank of fluid that messures the displacement of the liquid when said pressure vessel is under pressure. Which I believe checks to see if there are any bulges of the pressure vessel. Also there has been discussion that I've read that when this is done you are actually stressing the pressure vessel every time the test is done.

So basically the test performed on a tank as we would do it is to see if there are leaks, bad solder joints and to see if the pop valves work correctly and not to see if the pressure vessel expands.

Mmmmm! this has got me thinking I need to read up on this subject again.

Bernd

 

[chuck foster]

correct me if i'm wronge but i think if you were to get oil in the boiler it would cause the water to foam ???

chuck

 

[rake60]

OK
Air will compress. Fluids do NOT compress.

If you take 10 cubit feet of air and force it into a space of 1 cubic foot, it WILL go there!
Allow it an escape route and it becomes 10 cubic feet again.
Uncontrolled that can become a force you don't want to be near.

If you take 10 cubic feet of say water, and compress it, the pressure grows, but the volume
does not decrease. A failure of the containment will result in a spray that a I guy of my age
would be proud of!
:big:

Look at it this way,
Have you ever hooked up a dry garden hose to the water faucet then squeezed the
nozzle wide open?
When the compressed air in the hose mixed with water meets the nozzle you'd best be
hanging on tightly. Once that air has been purged the pressure is much more controlable.

There's no difference here.

Rick