Stainless frits seized to the end fittings... Help!

[dkreller]

Hi,

I have been running some mobile phases that many of you would probably consider a bit nasty, including a pH 9.0 mobile phase that contains 1.7 mM Ca2+ ions. I don't know what exactly is to blame, but I have half a dozen stainless steel end pieces within which the frits are absolutely stuck. I have tried sonicating them in 10% HNO3, and that didn't get them out. I am not interested in saving these frits, I just want to get the frits out so I can re-use the end pieces.

Anybody have any suggestions, short of using explosives?

Thanks for your consideration!

David

[Bruce Hamilton]

Some end fittings have frits pressed into them, so if you manage remove them, you will have a slightly longer distance to ferrule and may not have a smooth fitting surface. May be OK for new ferrules on tubing. If your fittings aren't one of those ( you know the frits are separate ), you can try the following.

1. Forget the acid. Just dry the sinter, then fully wet it with one non-volatile, immiscible solvent. Then pump the other immiscible solvent, and use your HPLC pump at high flowrate to blow the sinter off. Can be quite impressive - so don't point it at anything fragile.

2. Just drill the sinter out, preferably in a lathe or drill press. This would be my preferred option if I kew the frit was separate, as the act of drilling will often grab the frit and remove it before hitting the fitting.

Please keep having fun,

Bruce Hamilton

[JGK]

Some end fittings have frits pressed into them, so if you manage remove them, you will have a slightly longer distance to ferrule and may not have a smooth fitting surface. May be OK for new ferrules on tubing. If your fittings aren't one of those ( you know the frits are separate ), you can try the following.

1. Forget the acid. Just dry the sinter, then fully wet it with one non-volatile, immiscible solvent. Then pump the other immiscible solvent, and use your HPLC pump at high flowrate to blow the sinter off. Can be quite impressive - so don't point it at anything fragile.

2. Just drill the sinter out, preferably in a lathe or drill press. This would be my preferred option if I kew the frit was separate, as the act of drilling will often grab the frit and remove it before hitting the fitting.

Please keep having fun,

Bruce Hamilton

Never tried option 1 but used to get our biomedical engineering shop to help on option 2 which can be a delicate operation to aviod damage to the end fitting.

[dkreller]

Colleagues,

Thanks for your input. I am getting in touch with our machine shop on campus and I'll see if they will help me w/ drilling the frits out. I'll try to remember to post a reply in regards to how that goes.

Sincerely,

David