Q & A's

Posted by Addition Collaborator on

Q & A's
This is a collection of short articles answering frequently asked questions.

Q.1 I have broken my boiler sight glass - how do I repair it?
A. 
Fitting the water gauge glass is mostly art and very little science!
It is impossible to make the fittings and the boiler that will align without some adjustment.The following assumes you have accessed a suitable piece of 5mm OD glass tube, have cleaned out the broken glass pieces and salvaged the "O" rings - or have replacements if they were damaged, have removed the nut on the top  fitting so that you can pass a rod through where the glass tube was.
Then:.
1. You need to make a 5 mm steel rod longer than the length of the replacement glass.
2. Place the steel rod in place of the glass and bend the top fitting using the steel rod so that the steel rod is aligned with the bottom fitting.
3. Place the steel rod in the bottom fitting moving it so that the steel rod is next to the top fitting. Bend bottom fitting to align to the top fitting.
4. Work the steel rod, in place of the glass, and repeat the above until a smooth fitting is achieved. The rod should spin freely.
5. Place the glass into the fittings with the "O" rings and securing nuts in the right positions on the tube and make sure that the tube is 100 % FREE to move.
6. Tighten up the nuts using fingers only. If the glass is not free you will break it. If not free, repeat the above again. You must be within one degree of alignment to avoid current and future failures. If you look at the glass in the fittings and you see more space one side than the other repeat the above again.
It can take up to 30 minutes to fit a replacement gauge glass to a boiler - there is only one outcome - the glass must not fracture and the secret to that is making sure it spins freely - is 100 % FREE to move -before nipping up the nuts on the "O" rings!
I trust that this helps.

Q.2 What do I do, to paint my engine? 
A. If you plan to paint the components of the engine, please be alert to the fact that commonly available paints do not consistently adhere to bronze surfaces. Please use an “etch primer” as available in your locality to prepare the engine surfaces to obtain a durable finish for your engine with the paint of your choice.

Q.3 Do you recommend using distilled water in the boiler?
A. Yes, if you can purchase it or make it yourself (Check the internet for ideas!). Water quality can vary between towns and countries. If a boiler is regularly filled with water that has a high mineral content (often spoken of as "hard water"), in the process of making steam these minerals will be deposited as "scale" on the internal surfaces of the boiler and cause a loss of heating power and eventual failure of the boiler. There are descaling chemicals available to clean out the scale but it is better to avoid the collection of scale in the first place. Some locations have "soft" tap water which can be safely used but "distilled" water, however made, is very much preferred.

Q.4 Why don't you offer whistles for your 2" Boilers?
A. Effective operation of a whistle needs a good steam pressure and volume to make a satisfactory sound. The smaller boilers can deliver this in short bursts but the engine loses a lot of power while the boiler replaces the steam ejected. The 3" & 4" boilers have a bigger reserve of steam and a faster recovery rate, but even then, apart from annoying the neighbours, the engine performance can be affected. 

Q.5 Can I fit a boiler water feed pump?
A. Yes - our 3" & 4" boilers have a 1/4" 40 tpi port fitted for this or other needs. The boiler is supplied with a blanking nut fitted. 

Q.6 Do you recommend fitting a boiler feed pump?
A. It depends on how you are going to work your boat. If you are planning to have fast turnaround on refueling stops it can be very effective in that you can commence filling the boiler as soon a the boat stops. You don't have to wait for the boiler to reach zero pressure. If you want to go this way, consider having an open top refill tank feeding the pump that you can pour hot water into for the refilling and minimise the recovery time to establish working pressure in the boiler.

Q.7 How do I fill the boiler and how much water should I use?
A. 
There a variety of answers depending on the boiler you have. Our 3" & 4" boilers have separate refilling ports where a nut is removed to obtain access to the inside of the boiler.The 2" boilers are refilled by removing the safety valve. In both cases  the water can be poured in using a funnel or a syringe. The use of a syringe is preferred in that it is possible to overfill the boiler and have to remove some water. We consider that a boiler is properly filled when about 75% of its internal volume is filled, indicated by seeing the water level just in view at the top of the glass. The other 25% of space is required to act as buffer between the development of steam and its use by the engine. As a general rule if you can't see a water level in the glass either you have overfilled it or need to add water! Given the normal safety considerations, hot water can be used on a refill, but remember that the syringe and its fittings,and a funnel are usually plastic and may fail if the water is too hot. The only safe way to introduce boiling water into a boiler is with a boiler feed pump. 

Q.8 Why do you not have superheaters in your boilers? 
A: The correct answer to this question requires a little background - please bear with us: 

The claim that a boiler provides superheated steam it not the same as saying the boiler has a super-heater.
In general terms steam can exist in three states::
The first is "wet steam". This is what is been generated by water vaporising (boiling) in an unrestricted space at - normally 100 Degrees C.
The second is "dry steam". This is steam that has continued to absorb heat energy, generally by increasing the pressure in the restricted space. In simple terms is still at its temperature of vaporisation but has absorbed "latent heat" to where it cannot absorb any more heat without receiving more heat energy.
The third is "superheated steam". this is "dry steam" that has absorbed even more heat that can only be released in special engine designs. Electric power generating steam turbines are the most common. The example closest to our modeling world is the "tripple expansion" steam engine.
There may be exceptions, but in my view the "superheaters" fitted to model steam boilers are more "secondary heaters" that add heat to wet steam from the boiler by passing it through tubes fitted in the exhaust stack, or a similar space, to extract further heat from the boiler flue gases. Their chances of generating genuine "superheated" steam are slight.
We pride ourselves that, with a properly setup burner/boiler, you can pass your hand over the top of the stack reasonably slowly without getting burned. This is only possible if there has been a very efficient transfer of heat to the steam in the boiler/burner design that makes a "superheater" unnecessary. Of course it also requires very efficient burner and boiler designs to generate the high quantity of heat needed. We believe the design and construction of MSM Boilers does not need a secondary heater.

2 comments


  • Dear Sir,
    I have recently assembled a TVR1 which I plan to use in a 36" tug I am currently building. To this end I am very interested in one of your boiler/gas heater combinations. As the Australian Standards Model Boiler Code permits a boiler capacity of 1litre max, would it be possible, and at what cost, to increase your 3" boiler to a max length of 200mm? This 200mm length, applying the 75% capacity rule and detracting the centre flu volume, would give an approximate 700ml capacity which would give me a much longer run time
    Secondly as the funnel I will be using will be around 150mm high, could the brass extension you show in the photographs be omitted so I can fit my own extension?
    Lastly, I take it that the short angled copper tube shown on the 4" boiler funnel is for waste steam from the safety valve and/or oily water separator if fitted.
    The TVR1 is recommended to run on a max of 30psi so I take it that your safety valves can easily be reset for the lower pressure which also conforms to the Australian Standard for small model boilers
    B G Wats

    Bernard Watts on

  • Hello gentlemen,
    I’d be interested by a kit 4072, but with a Clyde engine.
    Is it possible?

    Raphael on

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