Author Topic: 3 inch boiler build  (Read 23158 times)

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #240 on: January 01, 2019, 10:59:38 PM »
Continued with the meths burner housing today.

Drilling the fixing holes for the base:



I'm liking my new transfer punches:



The various components - the housing, the burner plinth and the Trangia alcohol burner. The ductile cast iron water pipe end which forms the main body is lined with a tough plastic material. I like the blue colour, which I think goes nicely with the brass base and aluminium plinth, so I decided to keep it. There's a fair chance it will start to melt or scorch from the heat and need some attention, but I'll cross that bridge if and when I come to it. The exterior was painted with black stove paint :



Almost complete now - I just need to fix the various components together:



Here it is with the boiler in situ. I tested the setup a few evenings ago with a jury-rigged version which was almost identical in principle, so I see no reason why it shouldn't work. However, if the height of the burner needs to be changed, the plinth can be adjusted, and if it needs more air, holes can be drilled in the housing. Hope to have it all fixed together and tested sometime over next weekend:



gary

Offline Gas_mantle

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Re: 3 inch boiler build
« Reply #241 on: January 01, 2019, 11:43:14 PM »
Taking shape nicely  :)

Are you intending to add wood cladding once it is up and running ?

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #242 on: January 02, 2019, 06:28:39 AM »
Thanks Peter.

At this point I have no plans to do so, but I wouldn't rule it out in the future. I'll consider it if and when I get to to the point that I'm trying to squeeze more efficiency out of the system.

I also quite fancy the idea of some kind of insulating fabric covered in polished aluminium sheet, but I suspect it could be a nightmare getting all the holes for the bushings line up properly in the aluminium...

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #243 on: January 02, 2019, 06:29:44 AM »
BTW thanks to MJM460 for the idea of using the Trangia burner.

 :ThumbsUp:

Offline MJM460

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Re: 3 inch boiler build
« Reply #244 on: January 02, 2019, 10:04:06 AM »
You are welcome Gary, they seem made for vertical boilers, and you can see some similarities in my rectangular ones for horizontal burners.  Still room for experiment I think.  Need to improve my tin smithing skills!

I am looking forward to seeing some success with the trangia.

MJM460
The more I learn, the more I find that I still have to learn!

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #245 on: January 02, 2019, 12:28:12 PM »
Cheers MJM460   :)

I just took another look at your pictures and see what you mean about the similarity to the Trangia.

I also find sheet metal very tricky but I suspect your burners would outperform the Mamod type with just mesh on top...

BTW this is interesting on the subject of alcohol burners:

https://www.youtube.com/user/tetkoba

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #246 on: January 02, 2019, 10:17:49 PM »
I was unhappy with the number of flutes in the column of the burner plinth I made yesterday, so I made a new one with 12 divisions instead of 8:


Online crueby

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Re: 3 inch boiler build
« Reply #247 on: January 02, 2019, 10:39:59 PM »
Very good looking!!

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #248 on: January 02, 2019, 10:44:25 PM »
Thank you   :)

That said, while I think the overall look is nice in terms of proportions and so on, there are a couple of aspects of that plinth I'm still not overjoyed with, including the standard of milling of the flutes, which I know I can make a better job of.

I might redo this part yet again, but I'm going to test it for optimum burner height before I do.

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #249 on: January 05, 2019, 12:28:19 AM »
Well... I tested the above arrangement today, only to find that the setup would raise but a meagre amount of steam. Not enough though!

Trying the Trangia at different heights relative to the bottom of the boiler did make a bit of a difference, as did the steam blower, and the beginnings of steam made themselves apparent, but the pressure gauge held resolutely to  zero.

Was it because the Trangia was too shut in and not getting enough oxygen? The next experiment should help to clarify that (Trangia, with boiler supported by an open framework).

Noteworthy though that again today my primitive four wick meths burner did raise decent steam ( as per video above), albeit perhaps against all odds. Maybe a way forward...?

And a forum friend has encouraged me to consider gas as an alternative. Well, no harm in keeping one's options open, I guess...

This is all more tricky than I expected but I'm not out of ideas yet...

Will keep tinkering, and post the results...



Offline Gas_mantle

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Re: 3 inch boiler build
« Reply #250 on: January 05, 2019, 12:59:57 AM »
Gary, what does the Trangia burn like in the open air? That ought to give you a bit of an idea if it is an airflow problem.

Does it burn better off the metal plinth? I understand those burners need to get hot to vapourise the meths and 'force' it through the jets. I very much doubt the plinth will be conducting the heat away but it's something that costs nothing to try.

Does the level of the meths make any difference?

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #251 on: January 05, 2019, 01:26:20 AM »
Peter -

on how it burns in the open air - that's why I plan to test it with the boiler on an 'open framework'.

I suspect the plinth is a red herring. It's aluminium, and doesn't pull away much heat.

Level of meths - seems like a pretty constant heat until it nears empty.

I suspect airflow is the issue, unless the Trangia just doesn't put out enough heat for this particular job..

Will get on to it.

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #252 on: January 07, 2019, 11:28:08 PM »
Following my unsuccessful attempt (details above) to raise steam with the Trangia in a partially enclosed housing, I made a new trial setup which is wide open in structure and tested it this evening. I decided to simply fire it and wait and see if it would get the safety valve to blow off.  This evening, the Trangia slowly but surely raised steam. It took 50 minutes from cold and just over one fill of the burner with alcohol to blow off the valve without using the steam blower. The suppliers of the valve told me it was rated at 45 psi, but the gauge showed closer to 70 by the time it blew. How accurate the gauge is I do not know. I then played around with the steam blower for a bit and enjoyed the definite way in which it pulled at the flame. The Trangia throws out less heat than my crude four-wick burner but it burns in a much cleaner and more controlled way.

This was hardly a controlled experiment as I carried out this evening's test inside my workshop whereas the previous attempt took place outside. I am therefore left wondering whether tonight's firing was much better because of the burner not being shut inside a housing or because being indoors the flame wasn't being blown around (although there wasn't much wind the other day). It will be easy enough to check this tomorrow evening by firing it under the same conditions as this evening but with the burner inside the housing rather than open.

A little bit of a feeling of progress this evening. Picture below:


Offline steamboatmodel

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Re: 3 inch boiler build
« Reply #253 on: January 08, 2019, 05:11:59 PM »
Hi Gary,
I haven't used a Trianga as a burner in a boiler, but when using them for camping you normally want them 1 to 1-1/4 " below the pot. I have also made and used pop can burners which require the same space.

Gerald.
Be wary of strong drink. It can make you shoot at tax collectors--and miss. Lazarus Long

Offline gary.a.ayres

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Re: 3 inch boiler build
« Reply #254 on: January 08, 2019, 10:39:06 PM »
Thanks Gerald. Will check my heights and continue to experiment. I think I was probably within that range though.