Assuming the carb body is aluminium, dissolve a heaped spoon of alum in a glass of warm water, leave the part in it for a few days, every day poking the remains of the tap with a needle until it falls out.

Neil

What material is carb?

Posted by Fowlers Fury on 18/12/2018 23:03:51:

Don't use alum if the carb is aluminum, if it's brass (or a bronze) then try it.
You may find it of interest to read this article if the carb is aluminium: "How to dissolve steel without affecting aluminium alloy" :-
**LINK**

I've used alum in aluminium alloy bike bits for broken taps in the past with no problem. I can't see where in your link it says don't, in fact alum is recommended by a couple of posters.

Edited By Mick Berrisford on 19/12/2018 00:09:35

1. Yes it works on HSS
2. Keep it warm (think coffee cup heater)
3. Replenish with water each day to make up for evaporation
4. Have the opening at the top
5. At 8BA you will need to initially encourage circulation in the hole (syringe?)
6. Clear debris from hole daily
7. Use a glass jar so you can see the bubble stream.

You should get a fine stream of bubbles rising from the hole (might be very fine or intermittant at 8BA). When that slows clear the debris. If clearing the debris does not result in a stream of bubbles after a couple of hours then replace the solution. If replacing the solution does not result in a stream of bubbles then it is probably done.

Or perhaps caught out by the name 'Alum' being used for at least six different chemicals, only one of which is suitable. You want Potassium Aluminium Sulphate, also called Potash Alum or Potassium Alum.

Of the true Alums, Sodium Alum might work as a substitute tap remover, but maybe not Chrome Alum or Ammonium Alum.

Some chemicals called 'Alum' aren't Alum at all: Aluminium Hydroxide and Aluminium Sulphate. These are useless for removing taps.

The confusing nomenclature is historical. Once a common name has caught on in a trade it's difficult to change it.

Dave

If anyone knows of a source for the right stuff, I'd be much obliged.

Just looked at my eBay history, Minerals-water Ltd 800g £12 inc postage.

Hope this helps Paul

Thank you very much Paul.

You can buy alum rock chrystal from lots of outlets. I have used it on my pits for years now after developing an allergy to deodrants. I expect someone will tell me its the wrong sort of alum though.

Rik