Ultrasonic damage

[MartinTenbones]

Well this is a new one for me.   I've cleaned and repaired countless pens now.

 

I had a Waterman Stalwart with a very stubborn section I needed to remove to change the sac.

 

I was doing what I normally do.  Soak, heat, soak, and also some ultrasonic cleaning to get the section out.

 

I have been trying for days off and on.

 

This morning I put the pen in the ultrasonic and when I took it out it was very hot.   Just the pen not the water.  It blistered the pen on the opposite side from the lever.  This area is above the waterline as I was only just above the nib section with water.

 

I have no explanation as to why.   All the other times I had cycled it it hadn't heated up.

 

Any thoughts?

 

 

[MartinTenbones]

[joss]

This is not good. The ultrasonic waves generate frictional heat and the water will only cool the parts that are submerged. In this case it could be the pressure bar but that should be located on the other side of the barrel, under the lever. It might be the ring that connects the pressure bar to the lever, if these pens have such a ring? Or something else that sits in the barrel.

[MartinTenbones]

I'm also wondering if it's possible there's a piece of contaminant within the plastic itself.

 

This Waterman uses a box lever so there isn't a ring around it that I'm aware of and you are correct The lever is on the other side.

 

I also find it odd the pen never heated up the first 20 times.

  

[Ron Z]

I've had it happen a couple of times over the 20 years or so that I've used mine.  I won't discount the possibility of a flaw in the material.  But when it happens, it seems that it came with insufficient water in the tank to keep things cool.  But I rarely if ever immerse the whole cap, and even less often the barrel in an ultrasonic.  A cleaning solution and a test tube brush are sufficient.  The ultrasonic is reserved for nibs and feeds, breather tubes that can be completely immersed.

 

Two other factors to consider.  A 35-50W ultrasonic is plenty strong enough for pen work.  None of the professional units (i.e. Rapidograph etc) has heaters for the tank.  Fine for metal parts, never for plastic.

[MartinTenbones]

Thanks Ron.

 

I have learned a lesson this morning indeed.

[Carrau]

I wonder if there may have been a surface defect that was enlarged gradually with repeated US treatments, and permitted cavitation bubbles generated to get under the surface of the barrel material, expanding to create the blister?

[Gloucesterman]

Looking for advice about purchasing a new (for me) ultra sonic cleaner.

I understand the 35-50w power Ron mentioned above and time duration ability.

And old one I had offered different "intensity/power" levels. It was nothing fancy or professional.

Any advice is very much appreciated.

Specific names and models would also help.

Thanks to all.