Model Engine Maker

Supporting => Boilers => Topic started by: Gas_mantle on January 09, 2018, 01:05:40 PM

Title: Cleaning boiler tubes.
Post by: Gas_mantle on January 09, 2018, 01:05:40 PM
I guess this is going to be a daft question but if you don't know then you don't know.

Is there any sort of cleaning agent that I can use to dissolve away the soot deposits in the tubes of my vertical boiler ?

I am currently cleaning them out after every 2nd firing using a flue brush mounted in my hand drill, it works fine but with 51 tubes to do plus the removal of fittings (or removal from base) to get at them means it's a pain in the ar** type of job :-(

My hope was there was something I could use to flush out the deposits then just use the flue brush periodically ?

Cheers  :)
Title: Re: Cleaning boiler tubes.
Post by: pgp001 on January 09, 2018, 01:12:06 PM
Hang on a minute

who was it not so long ago that was going on and on about how good it is having a proper old smelly noisy dirty coal fired boiler  :LittleDevil:
Looks like you are discovering why most people resort to gas firing  ;D

Phil
Title: Re: Cleaning boiler tubes.
Post by: Jasonb on January 09, 2018, 01:22:04 PM
Does the top cover not come off your boiler so you can poke the brush downwards rather than having to do it from the bottom. They are often only held on with a few screws
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 09, 2018, 01:23:12 PM
Hang on a minute

who was it not so long ago that was going on and on about how good it is having a proper old smelly noisy dirty coal fired boiler  :LittleDevil:
Looks like you are discovering why most people resort to gas firing  ;D

Phil

Aye up, I'm trying to clean it so we can put some of my homemade smelly old coal produced Yorkshire steam through your Croft mill engine  :stir:

Gas firing is for cissies  ;)
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 09, 2018, 01:28:29 PM
Hi Jason,

Yea, I'm taking of the top cover but it involves removing the steam outlet, safety valve, steam blower inlet. It's only a 5 min job to do that but a bit of a nuisance every 2nd firing.

Coming in from the top is easier (or will be when it is base mounted) but has the added problem of some tubes are partly obscured by super heater plumbing, so it's just a general pain of a job.
Title: Re: Cleaning boiler tubes.
Post by: michaelr on January 09, 2018, 02:09:52 PM
Have a look at this product it may help http://www.flueclear.co.uk/usage_instructions_5.html (http://www.flueclear.co.uk/usage_instructions_5.html) there are other similar products available.

Mike.
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 09, 2018, 02:24:54 PM
Hi Mike, thanks for that, I hadn't really thought about trying to stop the deposit build up in the first place but it looks to be worth a try  :)

Its actually suprising how much difference in performance there is once the flues start to get constricted. I have been starting the fire using wood because initially I didn't have an electric steam raising blower so that may contribute to the soot build up.

Using wood as I have been, I get 2 sessions of perhaps 1hr each before performance starts to drop, by the 3rd firing it will generate steam but struggles, if I try a 4th session it simply wont fire at all.

Hopefully with a new electric blower I can get things started more efficiently  :)

It's not difficult to see why the railways wanted rid of steam locos as fast as possible  :(
Title: Re: Cleaning boiler tubes.
Post by: Dan Rowe on January 09, 2018, 02:56:51 PM
Charcoal soaked in rubbing alcohol is what the G1 folks use to start a coal fire, might be better than wood.

Cheers Dan
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 09, 2018, 03:37:23 PM
Thanks Dan, I did try some barbeque charcoal soaked in white spirit but wasn't impressed at the time (without an electric blower) so I used wood which will allow the boiler to naturally draught, now with a blower I'll give the charcoal another try  :)
Title: Re: Cleaning boiler tubes.
Post by: Jo on January 09, 2018, 04:52:58 PM
White Spirit is no good  :ShakeHead: Methylated Spirits is what you need.

And do not use Briquettes :hellno: Lump wood charcoal.

Jo
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 09, 2018, 05:02:52 PM
Thanks Jo, I couldn't get any lump wood charcoal so I bought those barbeque briquette things that look like pony poo and they aren't ideal.

I was told white spirit or paraffin was ok though and I had some spirit on hand.
Title: Re: Cleaning boiler tubes.
Post by: Jasonb on January 09, 2018, 05:17:15 PM
I would go with paraffin over meths. Soak some charcoal in it to get the fire going and then add dry charcoal. You can also soak some split bits of wood in it and use that to get the coal fire going. If you are going to but wood then use hardwood as softwoods like pine will leave a sticky residue in the tubes.
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 09, 2018, 05:40:51 PM
Cheers Jason,

I kinda need to experiment a bit, running a coal boiler is new to me so I'm sort of feeling around in the dark as to what works best.

I was using just household firewood sticks to get it going without an electric blower, that works reasonably well and will allow it to naturally draught but isn't ideal an it eats wood at a phenomenal rate. Once on coal it's a tad easier  :)

Title: Re: Cleaning boiler tubes.
Post by: Jo on January 09, 2018, 05:42:18 PM
JB have you tried to buy paraffin in a normal hardware store? Meths is always available, BBQ lighter fuel is also ok.

Pony poo is what barbeque briquette burn like :facepalm: After the LUMPWOOD Charcoal a few well dried twigs from around the garden do well before some real lumps of coal  :) You have to burn an amazing amount of wet pine for it to cause creosote.

Jo
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 09, 2018, 05:54:04 PM
Does it sound about right that the fire tubes get fully blocked after perhaps 3 hrs of use ?

There are 51 tubes but they are only 5/16ths dia so it doesn't take a lot to start constricting air flow. I think (but not sure) that using poor quality wood without an electric blower generates a lot of soot and is far from ideal but hopefully an electric blower an charcoal will cut down on the soot etc ?
Title: Re: Cleaning boiler tubes.
Post by: Jo on January 09, 2018, 06:03:08 PM
Sounds like poor coal..... What type are you using best Welsh steam coal or something of a lesser quality  :(

Blowers are only for starting a fire, once they are going then the chimney should produce enough draw.

Jo
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 09, 2018, 06:14:53 PM
Sounds like poor coal..... has someone been relieving themselves on it?

Blowers are only for starting a fire, once they are going then the chimney should produce enough draw.

Jo

I did wonder about the coal quality but the stuff I have is proper Welsh steam coal from a recognised UK model supplier.

The boiler does have enough draught without the blower once I have steam, I have modified it so the engine exhaust vents up the chimney.
Title: Re: Cleaning boiler tubes.
Post by: Jo on January 09, 2018, 06:17:10 PM
How small have you broken your coal up into? Smaller bits = greater surface area = easier (quicker) burning.

You would be surprised how smaller a lump you will need to be using on a boiler that size.

Jo
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 09, 2018, 06:25:42 PM
How small have you broken your coal up into? Smaller bits = greater surface area = easier (quicker) burning.

You would be surprised how smaller a lump you will need to be using on a boiler that size.

Jo

It's proper steam coal that is sold for smaller model steam locos, the lumps are the size of sugar cubes,

Excessive soot I think is because in the past I have been using pony poo and cheap wood to get it started before I had an electric blower.

With 5/16ths dia fire tubes I guess it is always going to need a regular clean out.
Title: Re: Cleaning boiler tubes.
Post by: Jasonb on January 09, 2018, 06:37:29 PM
JB have you tried to buy paraffin in a normal hardware store? Meths is always available, BBQ lighter fuel is also ok.

I don't usually get that far as I can buy it from several local petrol stations and also garden centers. However B & Q and Homebase also sell it and they have replaced many of the old traditional hardware stores, look in the gardening deparments as it is used for greenhouse heaters
Title: Re: Cleaning boiler tubes.
Post by: Jo on January 09, 2018, 06:49:39 PM
Down here I spent ages trying to buy paraffin and if they had it no one knew about it. Was told at the local club not to waste my time and stick to the easy to come by stuff: Meths is the preferred stuff as it burns much hotter than BBQ lighting fluid.

Don't use wood :ShakeHead: it burns cooler than charcoal go straight to coal  :)

Jo
Title: Re: Cleaning boiler tubes.
Post by: Zephyrin on January 09, 2018, 08:48:21 PM
maybe the fire is not hot enough, too much incomplete combustion, try with the blower on permanently...

if the grate is large, (relatively as compared with a G1 loco!) you must check that the fire is distributed all over the grate and not limited in a part.
I personally use first meth soaked charcoal, then coal, never wood and the electric blower.
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 10, 2018, 03:00:14 AM
Thanks Zephyrin,

What sort of boiler are you using ?

I think when using one for the first time like I am there is a bit of a learning curve and a bit of experimenting is needed. Admittedly it's not rocket science but I do find that getting a steady decent pressure from a small coal fired boiler does require a bit of technique.

I'm about to start on a making a base in the next few days and part of that will be to raise the boiler slightly so that I can get air entering from the full 360o rather than just the front portion as it is now.

(https://i.imgur.com/HGw23aml.jpg)

(https://i.imgur.com/L3zHt5wl.jpg)

Title: Re: Cleaning boiler tubes.
Post by: nonort on January 10, 2018, 10:44:50 AM
Have you tried fireing the boiler for an extended period using lumpwood charcoal. I ran simular boiler by using BBQ lighting fluid then changing over to dry lumpwood charcoal.By leaving the fire to burn out there seemed to be no ash to speak of and a few moments with an old vacuum was all that was needed for the clean up. Please take care with the carbom monoxide problems that could occur in confined spaces.
Title: Re: Cleaning boiler tubes.
Post by: Zephyrin on January 10, 2018, 06:34:16 PM
Beautiful boiler, very nice piece of model engineering. for the tubes, I have got what you say...as regard the soot, you may try different type of coal, size etc, but yes you have to remove a lot of ashes and soot in the smokebox, and every 2 sessions is not that bad...

I had made a coal fired gauge 1 loco, copied from M. Evans' drawings "Southern Belle", a 221 (or 442) Atlantic, 1/32 scale, the time spent in maintaining her was huge, after each running session (mainly on a test bench), she had only 7 fire tubes and a larger tube for the superheater. I had to make at last 3 grids before the last one in solid stainless steel, the temperature of the fire was frightening for me in those days (A sissy as you said !!). I sold her as I really prefer building engine than running locos. 

Now I see at my club other modellers struggling with coal fired loco, from Aster or other, and all I can say is that the difficulty to maintain a stable fire comes from the inhomogeneity of the fire, usually glowing bright red in front of the door and darker deeper, in spite of mixing the coal regularly. This depends on the size and the form of the furnace, the grate etc, and would lead to a fire that vanishes at the first lack of attention.
With a loco boiler, starting the fire with an electric blower is mandatory, up to 2 bar, where the internal blower replaces the external one; at this point the pressure should continue to rise in spite of the blower steam jet, up to the running pressure 3-4 bar, when the exhaust from the running loco being sufficient for the draught. it takes about half a hour from starting the fire up to the loco running.

Now I have only meths internally fired locos, 5 min from lighting the fire to pulling trains...   

Title: Re: Cleaning boiler tubes.
Post by: Stuart on January 10, 2018, 06:42:22 PM
As to coal

I used to run my 3 1/2 locos on Anthracite Grains
The 5 inch on Anthracite Beans

Itís smokeless and can be got at any good coal merchant

Ok it does leave a deposit in the tube but much less than steam coal ( you cannot get the real good stuff now a days itís to soft

Stuart
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 10, 2018, 08:05:13 PM
Thanks guys,

I haven't tried it on lumpwood for extended periods, the problem I'm having is not that it doesn't steam well (on the contrary it steams well) but that I only get about 2 sessions before it needs a good clean out. I thought that doesn't seem long but it appears from what others say that it is the norm.

I'm hoping weather permitting I can try it tomorrow using an electric blower for the first time, that ought to mean I don't need to run it on wood till I get a decent head of steam and hopefully will reduce the soot build up.

It may be that when I have used up my present coal supply I'll try other grades to see what works best but the stuff I have now is meant for small steam locos upto 5" gauge.

I don't intend to raise pressure aggressively but here is a one off test I did to assess the steam blower efficiency - it goes from 20 - 90 psi in about 30 sec  :)

ojCZBDSP-eI
Title: Re: Cleaning boiler tubes.
Post by: tinkerer on January 16, 2018, 06:22:05 PM
Well just sing the Mary Poppins chimney sweep song, & go to it LOL Chim chminy chim chim ceroo LOL Seems to me those are pretty small flue tubes? Maybe larger tubes would allow better flue gas flow & not accumulate so much ash & soot? Would the heat transfer area be that negatively effected?
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 16, 2018, 11:42:28 PM
The tubes do seem small but the boiler is to a recognised Tubal Cain design dating back to I think 1950s ? So it's fair to say they are appropriate to the style and size of the boiler.

I haven't worked out properly what the surface heating area is but it appears to be quite high with 51 tubes and a larger centre flue. Without measuring accurately it appears it can use water at about 1.25 gallon p/h when steaming hard.
Title: Re: Cleaning boiler tubes.
Post by: Jasonb on January 17, 2018, 07:22:29 AM
What did TC originally design the boiler to run on? If designed to run off gas you usually use more smaller tubes as you don't need to worry as much about keeping them clean and having a good draft through the fire.

One other thing you mentioned the other day was that you are going to raise the bottom of the whole boiler, how will you control the much increased amount of air getting in as that will make a coal fire burn even faster?
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 17, 2018, 08:50:10 AM
It was originally designed as a coal fired boiler - I have got some notes and plans I can email if you were interested.

I have bought some materials to mount the boiler to a base, my intention is to fabricate a 'box' about 1.5" high for it to attach to and to make an opening with a door at the front. The door will regulate airflow and allow access to the firegrate for cleaning etc.

I didn't want to create a full blown build log here but I did think of taking a few photos to show how the idea develops including adding a water tank etc.
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 19, 2018, 09:43:58 PM
One other thing you mentioned the other day was that you are going to raise the bottom of the whole boiler, how will you control the much increased amount of air getting in as that will make a coal fire burn even faster?

Now that I have the materials to make a base I've been thinking a bit more about this.

My boiler dia is 5" so the surface area of my fire grate is 20sq" approx (assuming the fire hole door is closed all the air needed for combustion passes through this 20sq"). At the moment using my boiler as I have been using it without a base the only air intake (apart from the fire hole) is a cut away slot on the botton of the boiler front - I estimate this to be about 3sq".  (Looking at my earlier photo may help)

The idea is to blank off the front cut away slot and have all the air needed to enter a 'box' that the boiler will sit on with a 5" dia hole under the grate -  in other words instead of having a 3sq" of air intake going to a 20sq" grate I can substantially increase that but control it via a 'air door'

I'm really not sure how much air a boiler of this size and design needs so I'm kind of guessing here but I dont think it would be difficult to get nearly 20sq" of air holes in the 'box'.

I guess what I'm kind of getting at is does it sound right to have the same amount of air intake surface area in the base as the fire grate area of 20sq" ?

In practice the area of the grate exposed to air is probably closer to 15sq" than 20sq" allowing for fire bars but you see what I'm getting at.

Anyone got any thoughts before I start cutting and soldering ?

Thanks
Peter.
Title: Re: Cleaning boiler tubes.
Post by: Jasonb on January 20, 2018, 07:18:46 AM
You don't need anywhere near the area of the grate as an air supply, will post a bit more later as off out.
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 20, 2018, 01:51:19 PM
Part of the reason for wanting to raise the boiler and have it sitting on a box is to enable me remove the grate while leaving the boiler fixed, at the moment the air intake isn't large enough but it isn't practical to widen to the size needed.

(https://i.imgur.com/JjBDCYQl.jpg)

I thought by soldering a copper ring onto some brass sheet with a 5" dia hole cut out and making a door at the front I could get increased air flow and allow removal of the grate.

(https://i.imgur.com/Hg7cumBl.jpg)

To be honest my method of allowing access to the grate isn't ideal, I can see it being fiddly to slide in then up into the fire box but I can't really think of another solution that is fairly easy to make.

Title: Re: Cleaning boiler tubes.
Post by: Stuart on January 20, 2018, 03:10:02 PM
One point I forgot to mention is make sure you sieve / riddle your fuel you do not want to stoke with dust it will get up the tubes abut there


Stuart
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 20, 2018, 03:50:57 PM
One point I forgot to mention is make sure you sieve / riddle your fuel you do not want to stoke with dust it will get up the tubes abut there


Stuart

Thanks Stuart, I'll bear that in mind :-)

My gut feeling is that the existing air intake slot is a tad small (but that's just a guess), even if it isn't too small I think it will be better to have the air entering from a full 360o rather than just at the front as it is now. 

I now have an electric blower meaning I'm not relying on burning a lot of wood to get it started so I'm hoping that with better airflow as well I can reduce soot and generally get better combustion :-)
Title: Re: Cleaning boiler tubes.
Post by: Jasonb on January 20, 2018, 05:08:48 PM
Right just a couple of examples of grate to damper (air inlet) size to show that you really don't need much more if any.

2" Fowler has a 5" boiler, grate area of 16sq in and the damper when fully open will give about 3 sq in. This is an engine design that can do real work and will happily pull two adults about on coal.

2" Superba has a 6" dia boiler, grate area of 25sq in and the damper when open would give about 5sq in area. Again an powerful engine capable of real work.


Also you should not be opening the fire door to get more air into the boiler as that has little effect on the fire, the air needs to come from below to feed the fuel with oxygen, not just waft over the top of the coals and then up the chimney.

Your best bet to regulate the air would be to add a second slot at the rear of the boiler and then make two slots in that ring you have but allow the ring to rotate which will allow you to control how much of the two boiler slots are open to air.
Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 20, 2018, 05:19:44 PM
Thanks Jason, it sounds like my grate and air intake are comparable to the 2" Fowler.

I was planning on having the copper ring soldered to the brass plate as a firm support for the boiler to sit in, I had considered drilling a few holes around the circumference to allow air to enter more evenly. I do have a ceramic burner that is a good fit so although I intend to use it on coal I want to make a hole in the ring so that a gas feed can pass through.

I'll try and make a start tomorrow and hopefully do a bit more to the Muncaster  :)

Title: Re: Cleaning boiler tubes.
Post by: Gas_mantle on January 22, 2018, 02:03:10 PM
I guess this thread has now drifted off the original topic and I maybe should start a mini build log.

Anyway, I've made a start on the base ring, it was about 6mm over size so to get a close fit I've needed to saw out a piece and solder it back together. I really struggled with a small Mapp gas torch getting enough heat in and now have my doubts as to wether I'll be able to solder it to 3mm thick brass plate  :(

It did eventually work and although the solder didn't fully run at the top it was about as good as could I expect.

(https://i.imgur.com/m2Se2MKl.jpg)

It is a reasonably good fit on the boiler but neither the ring nor the boiler itself are 100% circular so it does fit better in certain orientations.

(https://i.imgur.com/Q3rLnJel.jpg)

Next thrilling instalment - soldering the ring to the plate and cutting a 5" dia hole  :pinkelephant: