Dissolving a stem that cannot be removed from the crown

[onzenuub 361]

And another useful tutorial from Francisco

 

First, I would like to thank all the forum members that helped me to discover this technique.

 

Some times the stem may break itself in the way that following picture shows:

 

 

As seen, there is no enough room to take the stem and to unscrew it from the crown. Therefore, it seems impossible to remove the stem. Hence, a new stem should be bought, what could be sometimes very expensive.

 

In other cases, it is possible to unscrew the stem, but the rest of the stem is too short and the stem is expensive or spares are not available. In such cases, if the broken part is the threaded part, a stem extensor can be used. Next picture shows a stem extensor.

 

 

The broken stem would be screwed in the small tube. However, in our case, a stem extensor is not useful, as we cannot remove the broken stem form the crown.

 

What we are going to do is to dissolve the stem. This is possible because crown is made of a material much more resistant to corrosion than the stem.

 

To dissolve the stem we will use alum powder. If you cannot find it in a local store, it can be easily found at Ebay. Follows one example:

 

 

I bought this one:

 

 

We put quite alum powder in a small glass.

 

 

Really, I did put twice quantity than the picture shows. The alum powder is dissolved in water.

 

 

The crown is submerged in the water. Moreover, I added an old stem to see the effect of the alum powder on it.

 

 

This is a very slow process. The time needed depends, of course, of the amount of stem to be dissolved. I recommend shaking the glass every couple of days.

 

In this case, as I wanted to see the effect on the old stem, I wait quite a long time. Last picture was taken after 9 days. It is possible to see small pieces of the stem on the bottom of the glass.

 

Alter two weeks, the crown is free of the piece of the stem. In addition, the old stem shows this horrific aspect. Please check that one part of the stem is open.

 

 

Now it is time to check whether the hole of the crown is truly free of small pieces from the stem, and if a new stem can be screwed. It seems so:

 

 

As next picture shows, there is no any problem to screw a new stem. Therefore, the crown has been repaired.

 

 

Thanks for reading,

 

Francisco

[jameo210369 0]

Great addition Onze

[omni 38]

I can add that my jeweler sped that dissolve waiting time down to 2 days by heating the alum solution up.

[sconehead 5]

I can add that my jeweler sped that dissolve waiting time down to 2 days by heating the alum solution up.

Good tip Omni...

[KeNnY 61]

Amazing ! GOing to try it out asap !

[gran 247]

WOW!!!!!!

[Dr Yan 14]

If Johng was doing this he would use nitro-hydrochloric acid

[narikaa 129]

Salts of Alum

 

 

Little used and seldom found

 

 

Has a myriad of uses

 

 

 

 

 

 

.

[DR3M3L 6]

I broke mine today :s does anyone know where to get a stem?

[Member X 91]

RWG shop

 

Or Ofrei in the US, or CousinUK in the UK.

[DR3M3L 6]

RWG shop

 

Or Ofrei in the US, or CousinUK in the UK.

 

Thanks mate!

[Nikosaldente 641]

Great tutorial!

[chrish8 0]

couldn't one just use this

 

[flyr 4]

couldn't one just use this

 

Not much good when the stem is snapped off inside crown and there is nothing to get a grip on.

[flyfishng2 0]

excellent tip. another technique for my toolbox

[GenTLe 1,539]

I used vinegar and got same results in around 10 days