potted transformers

[djQUAN]

we kept bees about a few years ago and from what I remember, even just sunlight melts beeswax.

 

[VT67]

Hi resident

The pots you have are they plastic or metal (alu, copper, steel)?

In the past I used PUR (polyurethane), this is a two component pouring mixture. Put the transformer and the pot in an oven for 1/2 our at 40° Celsius. Mix the two components together and pour it in, make sure you have no airbubbles. It's as simple as that.

Cheers

 

[resident]

They're metal.I think it's steel.
Where will I find PUR?

 

[rcavictim]

They're metal.I think it's steel.
Where will I find PUR?

I think GeWa is speaking of one of the two part, water clear epoxy finishes available at better building supply and hardware stores. I use Behr "Build-50" which is so named because it is the equivalent of 50 coats of varnish in one application (without the yellowing). I have used it to stabilize the windings in homebrew power xfmers after winding without potting. I originally bought it to coat the fine magnet wire resonators i was winding for small Yesl coils. It looks beautiful. A similar product is "Pour On", available at Home Depot. This stuff is really trick but expensive. Costs about $50.00 for three liters/quarts.

If potting an xfmer in a case though, especially advice to the fellow that has no layers of insulation in his transformer, best to place the unit in a vacuum chamber after pouring in the potting compound. This will outgass the epoxy and at the same time allow itto completely penetrate and wet all internal surfaces and fill the tiny voids between windings. It also assures no mechanical transformer noises. It will cure on it's own n about 12 hours as a thin layer on furniture but much faster from the exothermic reaction obtained from a concentrated mass. After vacuum pump treatment one could place it in an oven at 150 degrees for an hour or so.


One alternative would be polyester fiberglassing resin with separate catalist from autobody repair supply shops.. That is cheaper than the clear furniture finishes,

 

[kevinkr]

Hey shifty,
I like those cans, look good and I would have never guessed they were cans.. I have been thinking of potting caps inside campbells soup cans.. Are those can tea cans? I have always thought the twinings ones would make good ones..

Kevin