Glass Polyester Thermosetting Varnish

[Wgn9953]

I would be grateful if some information on the shelf life of the ULT 372 Glass Polyester Thermosetting Varnish can be provided (old product line from sterling-tech.com ). We had purchased a large quantum of same over 5 years ago and are experiencing rapid hardening rate before use. This usually cause great difficulty for the motor rewinders.

 

[UKpete]

Is it a solvented varnish? If so, you can check the specific gravity and add extra solvent if necessary. I did once work in a shop where repaired motors were dipped and baked, the varnish in the dipping tank had not been drained for many years - they just added solvent once in a while. I dread to think what it was like at the bottom.

 

[mc5w]

Urethane varnish is chemically related to Crazy Glue, so you should run a chemical test of your varnish to determine if it is partially set up in the can.

Somebody could also be adding too much catalyst because they want to work faster or be misreading the directions. If you have 2 different concentrations of catalyst vials confusion can happen.

 

[Wgn9953]

sorry all, i neglected to mention that the hardening took place while the varnish was in storage at temps around 39 deg C.

 

[stardelta]

We use Sterling-Tech resin to impregnate rewound stators and armatures. As part of our QA procedures we regularly send a sample back to them, they anylise it and report on its condition and performance. This may be an option open to you. I can give you the name Steve Mayall who offers Tech Support but that is here in the UK.