Metal strands in graphite packing

[Tony Rowe 1Participant @tonyrowe1]

I am currently in the process of rebuilding a 3 1/2 Tich.  To re-assemble the cylinders I purchased some new 5mm square graphite packing.  I attempted to cut some lengths following LBSC’s “words and music” to find that there are several fine wire strands in the packing weave.

My question is, will the strands damage the gunmetal cylinder bores? and if not how do people cut it cleany at a chamfer (a knife doesn’t get through the wire)

 

[howardbParticipant @howardb]

Wire inserted gland packing is usually used where there are toxic chemicals involved to form a solid strong gland seal.

I’ve only come across it once on the ammonia gas drain off valve on a big old industrial refrigeration compressor using ammonia as the refrigerant gas.

[Dave HalfordParticipant @davehalford22513]

I would assume the wire is intended to hold the packing within it’s groove so why would the wire touch anything to cause damage.

You can get wire cutters for £3 that can barely cut copper wire, those are made from mild steel. Spend double and get a decent pair.

[noel shelleyParticipant @noelshelley55608]

If the wire is a problem then get gland packing without wire reinforcing. It is the wrong type. Noel.

[duncan webster 1Participant @duncanwebster1]

If there is any possibility of the wire being on the surface I wouldn’t use it. Several people have had success with ptfe rings in gunmetal cylinders

[Bo’sunParticipant @bosun58570]

Could it be simply that the wrong type of packing has been supplied?  Just a thought.

[Tony Rowe 1Participant @tonyrowe1]

Thanks for the replies.

I suspected it was the wrong type, so I ordered some from another supplier & it was the same.  I’ve ordered a third lot, this time from a Model Engineering Supplier, so significantly more expensive, but hopefully the right type (still cheaper than potentially reboring cylinders in the near future).

[noel shelleyParticipant @noelshelley55608]

As Duncan has said, I would consider PTFE or O ring cord as packing. The more so in a gunmetal bore. Noel.

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