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Cleaning Injectors

How to get the steam cones out!

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Nigel K06/05/2022 20:11:22
18 forum posts

I have two injectors whose steam cones stubbornly refuse to come out. I have searched in vain on the Internet for guidance on this subject but cannot find any help. Any ideas? I assume that the cones on small model injectors are supposed to come out for maintenance or are some of them fixed in place?

My injectors look sort of like this only with the cones still in!  (Photo credit: Paul Lousick)

Parts of a Model Steam Injector

Edited By Nigel K on 06/05/2022 20:11:52

Edited By Nigel K on 06/05/2022 20:12:57

Edited By Nigel K on 06/05/2022 20:13:27

Clive Brown 106/05/2022 21:08:31
826 forum posts
41 photos

The steam and combining cones should normally come out I'd have thought. Have you soaked in a citric acid solution to remove any scale?

There could be a light interference fit.

D A G Brown in his book suggests a cone removal tool thus.

cone extractor.jpg

Edited By Clive Brown 1 on 06/05/2022 21:10:54

bernard towers06/05/2022 23:32:50
618 forum posts
109 photos

Yes the cone extractor is the tool to use

Nigel K07/05/2022 22:12:14
18 forum posts

Many thanks - I will give it a go!

norm norton08/05/2022 11:31:48
186 forum posts
9 photos

I am surprised that no other small loco enthusiasts have offered a view so I will try and add a small bit of help Nigel.

The two cones that you see in the picture will come out on some makes of injector and if they do so easily then fine. But if they are stiff then leave well alone. On some of the good injectors they are pressed in. You also have another, third, cone pressed into the body and you must not attempt to remove this as its depth position is critical.

Undo the top nut and take the ball out.

If the cones come out, do not try to clean them with any type of abrasive or metal object; delicate wiping with a tiny wooden or plastic blade to remove any film is the most you should attempt. Do not poke in wires. Inspect the tip of the steam cone, which is the most delicate, to see it is still a good order and not corroded or mis-shaped.

You need magnification. Look along the bore of the injector toward a bright surface and check that you can see a clean, round hole. Similarly check any removed cones, and again when they are fitted back in.

A used injector that has been fitted for a year or more will need a dilute citric acid (5%-10%) soak to remove limescale deposits. A couple of hours in warm/hot citric acid is good and an ultrasonic bath very helpful. Otherwise use a plastic syringe and tubing to flush it through during the soak. Be very careful not to damage a cone if they are detached or liable to fall out. I put a piece of silicone rubber tubing over the steam cone body to protect the tip.

If the injector has been contaminated by dirty water, especially well-fermented rainwater (!), the citric acid will not shift the muck and a strong alkali detergent cleaner will be needed, again hot and for 30 minutes or an hour. Do not use any strong acid that will attack the brass.

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