Scotch Type Marine Boiler

[zeeprogrammer]

Awesome Pete. I'm very much looking forward to more pics.

 

[doubletop]

Pete, On my last centre flue boiler I tested the flue by blanking the end with demijohn rubber plugs .Drilled a hole down them one had a plain nut and bolt through the other had a nut and bolt with a centre drilled hole tapped to take a pressure gauge .The plugs are pushed in the flue then tighten the bolts up they act a bit like anchor bolts and held up to about 40psi enough to prove he flue was sound. The plugs are the ones they use for the air lock when brewing wine hope this makes sense
Frazer

Frazer

Your approach occurred to me overnight and it's appealing. Making equipment that can be re-used and not affect the integrity of what you are building has to be a good idea. Trouble is my homebrew days are long past and anyway this is NZ and we make some good stuff here. I'll have to see if I can track down some stoppers from somewhere.

Zee

Just about to get into it; another cup of tea and I'll be out to the shop (I am a Pom so tea is a mandatory part of the process)

Pete

 

[doubletop]

I eventuality made it out to the shop got myself organized. Its the down season here in NZ so my hearth makes use of the barbecue. As John said, "make sure you have enough heat available". This big kahuna burner does 6.7kg of gas per hour and was the cause of the melted bushes on the last boiler..

I re-did one or two of the joints on the burner tube cross pipes as you can't have enough solder on those joints and nobody is going to see them ever again.

I then prepped the first plate in the boiler body. As before; the rivets aren't riveted they are just pushed into the holes. They serve to hold the plate in place and add a bit of bling to the finished boiler. The silver solder will hold them in.

Even with the big burner and gas flames squirting out of every orifice it didn't seem to have enough heat. I got half of the plate soldered pretty well but by that time the flux seemed to go off. So I let it cool and gave it a few hours in the pickle to get it nice and clean and start again. However this is what the tube looked like after each go

All black an sooty. I came to the conclusion my gas was coming to the end and I wasn't getting enough pressure so the flame wasn't burning efficiently (This burner needs 4bar). So that was it for the day. I've refiled both my bottles ready for another go. In the meantime both parts have been in the pickle ready for round 3.

Looking from the inside the tell tale solder ring is just about there but not enough in one or two areas as far as I am concerned .

That's it for now

Pete

 

[doubletop]

With the gas bottle refilled and up to pressure I did a bit more to finish the intermediate plate and was happier with the joint. Time to do the burner and flue tubes, this went so well that I was done after 10 mins and after it had cooled down it went into the pickle. I'm now getting joints closer to what I am expecting. As Marv said on Zee's, thread beginners tend to use too much solder. I'm still doing that but getting a bit better.

Time to do the flue/burner end. Prior to applying the flux

Again it only took 10 mins as I only did the burner and flue tubes at this point. I had the boiler horizontal to minimise the chance of the cross tubes falling out with the torch throwing heat straight down the burner tube. I'll do the flange with the boiler vertical, like this, and the heat applied to the outside. That way it should keep the heat away from the burner tube to some degree.

Straight after completion and still in warm state. I'm still not sure about the blackening and still think its to do the burner not working efficiently despite the full bottle of gas. (I got it from BP but I don't think its appropriate to make any smart comments at the expense of you poor guys on the Gulf Coast. I spent some time working at Fort Walton Beach once and can't imagine the mess it must look right now)

The weekend should see the flanges done and if that goes well I can get the bushes in. It really depends on the number of solder/pickle cycles that are needed as the whole thing is now taking a day to get really clean in the citric acid pickle. Maybe time for another $5 outlay for a refresh.

Pete

 

[bearcar1]

Your boiler is shaping up a treat there Pete, as for the sootiness on the shell in that last photo, I was always told that condition was the result of too much gas and/or not enough oxygen in the flame. A carburizing flame I believe they call that condition. Either that or crud in the lamp tip orifices. If you just got a new bottle of gas, perhaps the pressure is a tad on the high side causing the flame to burn 'rich'. At least that is my unsolicited thoughts on the matter. Keep up the good work, TallyHO!

BC1
Jim

 

[doubletop]

Jim

I'd thought that was the problem but I'm not sure what is causing it sometimes it comes out covered in black and other times its pretty clean. I've got the Sivert regulator on the bottle, max pressure for the big burner and minimum for the smaller ones.

Anyway I've the reason for no posts for a while is I've been chasing leaks.

Water tube extended bushes

I got the end plates on and the bushes fitted and started the pressure testing, Three of the rivets leaked, in fact the first one shot across the workshop as it wasn't soldered in at all, one bush leaked, then another, then one of the flue return tubes. Each time clean the job, flux the joint, fix, back into the pickle ready for the next test and another leak to be found. It got a bit disheartening and all the time I'm hoping I am not destroying the joints in the burner cross tubes. They can't be fixed.

I realise now that I should have put the boiler end plates in the other way around as they can't be seen when the boiler is finished, then the positioning rivets wouldn't be under pressure, in fact I could have riveted them. I'll change the plates on the next version of the drawings.

Anyway today tested at 150psi and it held it for half an hour that's 3 times the pressure I plan to use this boiler so now time to move on.

Again I'm using the mountain bike shock pump for pressure testing. And yes the boiler and pump are full of water not air.

That's it for now. I've installed the super-heater, made some of the pipe fittings and soldered one of the outer end plates. It's in the pickle right now so I show you that later.

Pete

 

[tel]

Ahhh, the joys of boilermaking! The end results are usually worth it tho', and yours is certainly going to be.

 

[Blogwitch]

Pete,

If things never went wrong, wouldn't life be boring?

If it can be fixed, there was never a problem in the first place, it is just another part of the build.

Now the crucial bit is done, it should be downhill all the way now.

Great build.

John

 

[doubletop]

Thanks guys; it certainly felt down somewhere in the past week or so.

It had got to the point that yesterday, I thought I'd console myself by doing something else and have another go at safety valves now that I have the Kozo Hiraoka article on the same. Also followed Johns mantra of always make more than one. Made D bits to drawings, went through the step by step instructions in the article, seated the ball did the vacuum test. Nothing.. reground the D bit, re-cut the seat, re-seated the ball, did the vacuum test. Nothing.... So still no working safety valves. It's a damned good article though.

Anyway; I'm certainly over the hump as far as this boiler is concerned and today was a great day in comparison to others recently.

regards

Pete

 

[Diversion900]

Lookin' good so far Pete, don't let it get ya down mate.

this hobby of ours can really test our patience at times, I have had plenty of days like this. : My experience showed that it all works out in the end.

I'm just hoping that you find all the bugs before I do. ;D

Mine is temporarily on the back burner while I finnish my latest engine (verticle twin rotory valve).


Cheers, Neil

 

[fcheslop]

Hi Pete, looking good I'm really getting boiler envy :big:
regards Frazer

 

[Maryak]

Pete,

That's looking really nice. :bow: I've yet to see a new boiler of any size come up to pressure 1st time and hold it without some minor leaks somewhere. All part of lifes rich tapestry.

Best Regards
Bob

 

[doubletop]

I went out tonight to do the second outer end plate after successfully fitting the the first outer plate yesterday, start to finish 10 mins max. I went thorough exactly the same procedure out of the pickle, rinse, dry, flux the joints, assemble, flux the rivets and insert. Heat, allow flux to glaze and flow, apply solder and all I got was solder globs, reheat re-flux no go. So its cool down and into the pickle until tomorrows installment.

What is going on???

So I write this with Desperate Housewives running in the background. Forget Desperate bloody housewives..........

Pete

 

[tel]

Sounds to me like not quite enough heat - when you get a blob keep pouring the heat in and it should flash and follow the torch around smooth as silk.

 

[Blogwitch]

As Tel says Pete, more heat required.

Don't worry about previously made joints, if you don't go absolutely stupid with the heat, they will be perfectly OK.


John

 

[doubletop]

And of course gents, you are right again.

I hadn't read your posts when I got in tonight, but eager to get this sorted I went out before dinner. Got it out of the pickle, rinsed, dried, fluxed and had the burner on full loud and still had the same problem. "Sod this" I upped the gas regulator half a notch and just about straight away the blobs disappeared down the joints like scared rabbits. I was back in the house drinking tea within 15 mins of starting the job, and smiling.

There is a trend here, around gas pressure, and it may be as simple as ambient temperature in this case. Over the weekend we were at about 13degC. Last night a cold front came in and we were down to 10degC or maybe even 9degC. The last time I was having trouble I was running out of gas and as soon as the bottle was filled the problem went away.

I still have the ogre of the melted bushes from the last boiler but then they were brass bushes on a small end plate, I had hopeless flux and was using my humongous burner out of frustration. Other than that as you say Bogs the possibility of melting the other joints is slim with all this copper in the boiler the heat has to be directly on the joint to get the solder to flow.

Anyway its in the pickle now, club night tomorrow so pics probably Thursday

Happier chappy

Pete

 

[tel]

Glad you got it sorted Pete.

 

[doubletop]

As promised heres some pics after the outer end plates were (finally) fitted

Door end with the coil of 1/4" tube for the super-heater in place but the ends not finished

Flue/burner end with water gauge bushes

I bolted on a few bits so I could take it to the club and show it off last night

Flue/burner end with the burner in place

Door end with door in place. As I've said before this door isn't functional and may even be a problem as it needs to be sealed properly so the return flues work properly. I'm looking for a way to seal it, fibreglass or asbestos (or similar) cord

Hopefully that's the hard bit over and I can now work on the details. I've decided I'm going to conform and paint this one black or maybe maroon as Bogs suggested.

Pete

 

[tel]

As I've said before this door isn't functional and may even be a problem as it needs to be sealed properly so the return flues work properly. I'm looking for a way to seal it, fibreglass or asbestos (or similar) cord

Or a smear of Boss White, or even fireproof cement, around the door before you latch 'er up.

 

[doubletop]

Or a smear of Boss White, or even fireproof cement, around the door before you latch 'er up.

That may just do it thanks

Pete