Using an air compressor

[ikeaddy]

Hi everyone,

I wonder if it would be possible to get some advice. I have bought a Mamod engine for my son - who is an avid steam enthusiast. We shall steam it up of course, though as he is only 9, I would also like to set him up with mini air compressor. I have bought a basic 12V 10A AC car tyre compressor - but would lkke to convert this to mains so we can use it in our house (240 V as we live in the UK). The only converters I can find can handle 5 amp appliances (120 watts), which isn't enough. Any ideas?

Any help would be hugely appreciated.

Mike

 

[Blogwitch]

I'm very sorry to be a bringer of bad news, but.............

ON NO ACCOUNT FEED PRESSURE TO A MAMOD OR ANY OF THE SOFT SOLDERED TOY STEAM BOILERS.

They are very suspect as they are, and don't need any further pressure throwing at them. In doing so, you could end up with catastrophic results.

You are OK feeding the engine, as long as it isn't through the boiler.


John

 

[ikeaddy]

dear john

many thanks for your advice. You may have gathered i am rather a novice. So you would advise never using air with a mamod?

Mike

 

[Blogwitch]

Mike,

I have been to a few shows where people are running engines direct off air, that is perfectly OK, but also you get people feeding air to the boiler (usually through the safety valve or filler port), that is where the problem lies.

The boilers are not designed to be used like that, in fact 10 psi should be about their max pressure, but these 'toy engine' experts think nothing of running the boilers with gas firing or feeding air up to about 30 psi and cranking down the safety valve so the boiler is under too much pressure. That is the normal sort of running pressures of a fully silver soldered copper boiler, but NOT a soft soldered brass one.

If you want to show the engine running on air, then I would suggest you use a small hacksaw and cut through the feed pipe from the boiler to the engine, and connect the compressor to the engine that way. To then run the engine from the boiler using say sterno tablets, just use a bit of silicone thick walled tubing to repair your hacksaw cut.

It is better to be safe than sorry, especially with a youngster about.

There used to be a vid of a 'toy' boiler blowing up in a classroom full of students, where they had screwed down the safety and over fired it, maybe another member can remember where it is at.

BTW, a small mains powered silent fish tank compressor might be a little more in keeping with what you want to do. If the engine is free enough, then one of those should have no trouble running it.


John

 

[ikeaddy]

Hi John

Well i think i'll leave well alone. Maybe a bicycle pump will be good enough! Thanks again for your concern. My son is very keen on steam engines so one day i hope he'll be knowledgeable enough himself.

Mike

 

[spuddevans]

If an aquarium type air pump wont do, I got a air-brush compressor that has it's own small storage tank for running my little "steam" engines with, works quite well too.


Tim

 

[ikeaddy]

Hi Tim,

Yes I spotted this-but didn't really know what they are. Where could I find an 'airbrush' compressor?

Mike

 

[mklotz]

(240 V as we live in the UK). The only converters I can find can handle 5 amp appliances (120 watts), which isn't enough...

Assuming a power factor of unity,

240 v * 5 amp = 1200 watts

What am I missing here?

 

[ikeaddy]

Hi Marv

I'm afraid i'm not sure what you mean. Not even remotely an expert!

Best

mike

 

[JorgensenSteam]

Assuming a power factor of unity,

240 v * 5 amp = 1200 watts

What am I missing here?

A zero. ;D ;D ;D

 

[steamer]

I get 1200 also

 

[dalem9]

You can get a small compresser at Harbor Fright ,Also Eastwood has them but at a higher price.Dale

 

[Troutsqueezer]

It sounds like the compressor you bought runs at 12V with a current draw of 10 amps. That calculates to 120 watts. Sounds like your converter should work to me, unless I'm missing something as well. However, if your converter can indeed only deliver 5 amps at 12V then that is only 60 watts.

 

[Ken I]

Mike, Exactly what Bogs said - those Mamods are soft soldered - the mistake people make is feeding the compressed air in via the safety valve hole (its the only hole available to you) thereby removing its protection. My nephew blew his up by doing this.

If you can find someone to turn you up a "T" piece fitting - basically a male / female extension piece which goes between the safety valve and its port - with a side entrance for the air line fitting - this should have a 1mm drilled hole so that no matter what you can't feed in more air than the relief valve can blow off.

Ken

 

[spuddevans]

Where could I find an 'airbrush' compressor?

I got mine from here :- http://www.rdgtools.co.uk/acatalog/COMPRESSORS.html

The ones at the top of the page do not have a storage tank, so the compressor has to run all the time, further down the page there are ones with a little storage tank attached so that the compressor will charge the tank up and then cut out (not that they are noisy though). I got the one that comes as a kit with 2 airbrushes.


Tim

 

[Herbiev]

A car battery charger should give you 12volts at 10 amps providing it is a heavy duty one. Some of the cheapies only give 6amps

 

[Jeremy_BP]

Assuming a power factor of unity,

240 v * 5 amp = 1200 watts

What am I missing here?

Assuming he is using a converter to 12V:
12v * 5a = 60w

I am also confused.

 

[lee9966]

Don't forget that those little emergency 12V tire inflators can put out a surprisingly high pressure. I have seen 80psi when mine was new. It broke mechanically soon after that

Lee