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[Mad_Mike]

For those of you who havent been following my thread on plasticard steam engines;

http://www.modelboatmayhem.co.uk/forum/index.php?topic=37920.msg378995#msg378995

ive finally managed to get hold of a boiler so now i can build proper ones  . Ive won a boiler off ebay for £17.50. Its homemade which could be risky but for 17.50 i cant complain and im actually quite chuffed with how well its made. However when i receved it, it was only part assembled so I need help filling in the blanks 

Firstly here it is, the boiler is about 3 inches by 6 inches long, not including the box and the chimney of course:


meths burner:


some pipes, a valve and a pile of screws:


I asked the seller how the boiler has been soldered he tells me it is silver soldered, he didnt make the boiler though and upon inspection i wasnt sure:



It has the odd ding in the boiler but nothing terrrible, anyway to check to see if it was silver soldered i thought the best way was with my gas soldering iron, if it melts then its not silver soldered, seems plausible. I heated it up for a good 10 minutes, now usually when i put the flame to solder it melts instantly but this stuff the soldering iron didnt touch it.

Just to make sure my iron could even solder copper i tried it on a bit of pipe and sure enough it got hot enough to melt soft solder.


I also tried a fitting on another pipe and the solder melted too:


I can assume then that the boiler is brazed, thus safer, but i thought brazed boilers had tiddier seams? what do you guys think?

[Mad_Mike]

I had an attempt at rebuilding the boiler, it has a super heated steam line. Judging by experience can anyone tell if the steam line goes between the pipes and the boiler;


 
Or under the pipes;



Also a peice which seems to fit the pipe to boiler this 90 deg bit:



Its the only part which joins the 2 but it has a small hole in it, looks like something has been cut off with a hax saw. Anyone know what this could have been?

One seriously major problem im having with all these steam parts is theyre all imperial nut a bolt measurements and i dont have a clue. I know what a m6 nut is but i wouldnt know a 1/4 BSW if you threw it at me.

The nut for the site glass needs resoldering back on too:



I havent got the gear to do this so if anyone is up for it ill be happy to pay someone to do it for me

Another problem is that it seems some parts a missing. I know the glass is missing because the seller told me it was broken, But from what i can guess there is probaly 2 nuts thatr go round the glass on to these 90 deg bits and then 2 screws or something which blocks up the holes on the side



One of the holes is bigger than the other. I have no idea what size nuts and bolts to buy, anyone got a clue?

Can anyone tell me what this hole here is for on the other side of the boiler?



there is also this peice of pipe dunno what does either 



As you can see I havent a clue what im doing so anyhelp will be much appreciated.

[Circlip]

The small diameter pipe at the top Left hand side in the photo 3rd down connects to the small bore on the right angled boiler connector.You've reassembled the right angled connector the wrong way round from what you see in the first photo on the first posting. It's for a pressure gauge which you also haven't got. Forget Metrics and BSW or BSF, all the threads are probably going to be ME or Model Engineer threads, 32 or 40 TPI. Zig zag Steam drier pipe goes between boiler shell and water tubes as in first photo of second posting and yes, you are deferably going to need contact with someone who can fix it.

  Regards Ian.

[Mad_Mike]

i looked at those two parts and fitted them togeather, they both have solder on too:


I suppose it will need silver soldering too seeing as its so close to the boiler.

thanks for your help 

can anyone else tell from the pictures if this boiler is silver soldered or not?

[pettyofficernick]

It looks a bit dull and grey to be silver soldered The joints shown in the attached photo should help you make a comparison, silver solder is a silvery yellowish colour with a nice sheen to it. 

[Mad_Mike]

hmm pants i got 2 different answers see i asked the same question on the mamod website and some people on there think it is silver soldered. The guy who sold me it said it was but ive seen brazing and it is yellow isnt it. Thats why i doubted when i received it. It really needs someone with more experience to look at it. Ive emailed a local bloke but he hasnt replied yet. Maybe a bit of polish might show its true colours eh, if it is soft soldered then ill be limited to low pressures wont I?

[pettyofficernick]

It looks very similar to one of Tubal Cain's designs form the little book I sent you. Try scratching the solder a bit, silver solder is much harder than lead solder, if it is easy to mark it, it is probably soft soldered
Regards,
Nick

[Mad_Mike]

ive not scratched silver solder before. I just scratcched the solder on this boiler with a wod chisel, its harder to scratch the solder than the copper boiler. Suppose it would be copper is soft 

Ive polished it up a bit too and the solder is shiny like electrical solder is, its not looking good this

[pettyofficernick]

Solders of all kinds also have a higher melting point once the joint has been soldered, so more heat is needed  if you have to take it apart again...

[Mad_Mike]

My soldering iron didnt melt the solder even directly under the flame and thats rated at 1300 oC when used as a blow torch. Im a bit cheesed off actually if it is soft soldered i wanted a silver one so i could run a half decent usable pressure. 

[pettyofficernick]

You should be ok with about 25 psi, My TVR runs quite happily at that pressure. I had a soft soldered brass boiler made by Krick which was good for 30psi, so it's enough to get you going. You will, at some point need to do a pressure test to establish the integrity of your boiler. Have a look round for a local modelengineering society, where you will find a wealth of knowledge to help you along. . The main thing is to enjoy your engines.
Regards,
Nick.

[derekwarner]

Mike...you must understand that even though a pencil type gas torch may have a flame temperature of  1300 degrees C....by the time it is applied to a mass of ambient copper [the boiler or fittings] they will absorb all of the heat

You may need to consider an alternate preheat method.......Derek

PS....both of these have a 1300 degrees C flame.....but the unit on the left has approx 1000 x the heat output than the baby on the right  

[Mad_Mike]

I thought it would made the solder at least a  little wet  i noticed that the heat disapates away very quickly on the copper boiler. i melted a peice of electrcial solder on to it and used the iron to see if i could heat it up a bit more so that the solder would stick to the copper, i found that the copper boiler was cooling the older faster than i ws heating it.

Someone told me that if i bathed the joints in citric acid soft solder turns black. Well im doing it now and the boilers getting clean but the solders still silver, well at least for the moment anyway.

[frazer heslop]

Citric acid turns soft solder black I am the quilty some one

[steamboatmodel]

Citric acid turns soft solder black I am the guilty some one

I have never seen any acid turn any solder black soft or not! Could you post photos?
I have checked online and can find no mention of this, unfortunately my soldering equipment is all packed away so I can't test this.
Regards,
Gerald.

[Mad_Mike]

i tried electrical solder wire in some citric acid and there was a black residue on it. seams to have some kind of truth but weather its good to test for silver or soft solder i dont know its not reliable.

[Circlip]

Soft soldered joints will blacken with exposure to an acid, your joints on the end caps and watertubes are more than likely to be Silver Soldered. Damn stuff runs all over if you're not careful when constructing. Nicks photo shows a "Professional" job that may have been masked when they made it. At the pressure you'll be working at, it won't matter if it is soft soldered as long as you don't let it run out of water before burner fuel runs out.

    Regards  Ian

[Mad_Mike]

Ive been emailing a mate of mine and he said a god way to test it is use a file, if its hard like steel then its silver soldered. So i tried that and i can say its like filing brass, its has a shiny surface though. After i heated it up in a 200 degc oven and then used to my iron to see if i could melt the solder, still did nothing but now theres a tarnish on my boiler i can only describe as brownpinkyellow. Funnily enough though the area where i filed the solder and only that area has gone to yellow colour that silver solder usually goes.

Circlip if you think it is silver solder why isnt it yellow like what you usually see?

I want to run the boiler between 30 and 40 psi at most. But i also have the intention of putting it in a boat and if i am careless enough to let it run dry then its got a better chance of not blowing up being silver soldered than soft soldered.

[Circlip]

Gently scrape the surface of the "Solder" with a modelling knife, you will easily scratch soft solder, hard solder (Silver) won't. Try it on a piece you've soft soldered.The "Yellow" colour of Silver solder is not as dark as Brass yellow, there are many grades of Silver solder but the appearance of your boiler ends look like Silver soldered construction. It spreads when heated if you don't use a "Stopper". Excess soft solder tends to form a thicker blob or tear drop.

  Regards  Ian

[frazer heslop]

Hi Gerald,sorry to say I don't have any pics of the soft solder turning black but you could always try it for you're self .The original answer was on a simple steam forum and was given as a simple test but obviously there appears to be some doubt.
Hi Circlip at least two of us have come across the phenomena cheers.
As to the boiler I would be more concerned about its integrity
1 what was the designed pressure
2 what gauge copper has been used in its construction
3 The water tubes are they brass?
I don't post  about my builds but I have designed several boilers of my own and built many from simple pot to multi tube loco and marine and would not suggest some thing I did not know was true. The best and only answer I can give you is take the boiler to some one who knows model boilers for example a boiler tester at a model engineer club
kind regards
Frazer

[Mad_Mike]

The boiler was buitl by someone sold to someone on ebay and i bought it lol. The boiler is copper and the water tubes are brass. The operating pressure i havent a clue, also the safety valve needs setting. I cant tell the guage of the boiler either.

Im trying to get in contact with a local engineering club but i seem to be drawing a blank at the minute.


Ive offered on here and on the other forum monies for someone to do it for me but noone has come forward yet. Basically i need someone to resolder the parts on the boiler and then hyrdaulic test it for me. Ill send the item by post exchange money by paypal and then they send it back

[davidjt]

hi mike

why dont you try tony greens place, if you are in lincon, his son is now runnig the business,  i would think they would advise you what to do
they are at thorpe on the hill hope this helps

davidjt

[frazer heslop]

Hi Mike, good luck finding some one to do the repairs but you may have problems due to the brass water tubes.
What size is this boiler

[Mad_Mike]

the boiler is 6inches by 2.5 inches. Why would the brass tubes be a problem?