Meltrpoe III Seized compression ring

[flying500]

Can anyone please suggest a method of undoing a seized brass compression on the Meltrope III.
I cannot free it. I have been very patient with the penetrating oil but still no joy.
I and am a bit hesitant to use a blow touch as I am unsure of the possible effects on the body.
Has anyone experienced this?

[alang]

Put it in the freezer overnight. Or use freeze spray sold at automotive stores for freeing seized screws.

Good luck!
Andreas

[flying500]

Thank you I will try tonight.

[emgcr]

Hopefully freezing might work but please be aware that it may not be successful. A positive outcome can be dependent upon the alloy contents of the Mazac or Pot Metal which can be notoriously difficult.

You may find this thread helpful :

viewtopic.php?f=11&t=33157&hilit=Meltrope&start=30

Please let us know how you get on and good luck !

[old country chemist]

I would say that trying a "freeze" spray called "SHOCK & UNLOCK" sold in this country at motor car accessory shops may help. I have used it and found it helpful. The instructions, easy, should be followed as to how long the spray is aimed at the item.

[Curt A]

DEFINITELY DO NOT USE A BLOW TORCH!!! Pot metal parts melt at a low temperature and you will end up with a melted mess of lead colored slag... trust me on this, I know...

[chunnybh]

Most Meltrope III soundboxes won't have this problem, but the later Meltrope III and especially the Meltrope IIIa are notorious for the poor quality of the pot-metal.

On these, I've never managed to undo the ring without breaking the housing for the rubber. I once even tried to cut off the ring but the two parts had fused together, they would just, not come apart.

My advice is to not remove the ring and use it as is. If the rubber really is petrified then cut and drill it out. Then use a strip of rubber 1mm thick or less and roll it into the housing.
Good luck.

[flying500]

Well, I have tried 'the freeze' but with no success and judging by others experiences its going to be a case of 'use as is'
Its not obviously swollen or cracked as with other pot metal casualties that I have encountered.
Some of The later Decca models do not have a compression ring and from what I can remember they don't sound Bad at all.
Any comments?
Hopefully at some time in the future I will find a Good Body that I can use the excellent diaphragm and triangular needle mount with.

[emgcr]

Some of The later Decca models do not have a compression ring and from what I can remember they don't sound Bad at all.

Some of the Astra soundboxes also had flexible rubber mountings and were designed without a compression ring although the main body was longer to give greater surface area. So long as the rubber is a good airtight fit on the tonearm there should be no problem and performance should be excellent. I would second Chunny's advice to dig out the hardened rubber and replace with as much compliant material as you can tucked in below the compression ring. You might be able to squeeze in a full rubber if very soft. I am not sure which model you have but it is worth remembering there are two sizes of holder and therefore rubbers---deep and shallow. Chunny may have these in stock ? Good luck.

They are also available here : https://www.ebay.co.uk/itm/MELTROPE-III ... Swztde5QQu

https://www.ebay.co.uk/itm/MELTROPE-III ... Sw7ple77Qq

[flying500]

Thank you All for your advice.
As you can see I have taken Chunnys advice and fabricated a working solution from two strips of 3mm rubber sheet.
I have tried it on a Decca 130, Dulcetto Senior and my Gramophone Co Junior Monarch and it sounds really Good on all of them.

Graham, thank you for the Meltrope thread in particular the Wild modification which looks like the method may also be useable on on Orchorsol soundbox?
I will also have to keep a watchout for the elusive Astra Box. A beautiful looking item.