On 10/15/19 1:03 PM, John Robertson wrote:
On 2019/10/15 9:45 a.m., Jim Horton wrote:
On 10/15/19 12:32 PM, John Robertson wrote:
Perhaps mineral spirits - sometimes called Varsol if I am not
mistaken - will do the job.
https://www.wisegeek.com/what-are-mineral-spirits.htm
Is there a problem with coating the parts in wax even if they are
still coated in some residual oil? I expect the reason for the
paraffin was to waterproof the parts and as paraffin is just another
form of oil would it now work just fine all be it somewhat
discoloured if the oil residue dissolves into it? It just won't look
as nice...
John :-#)#
Interesting question.Â* True about paraffin and oil relationship.
Didn't think of that.Â* Well, it was my project.Â* The high voltage
transformer was submerged in about 64 oz of mineral oil.Â* It was in a
pvc junction box and stayed in there for years.Â* Connections into the
box were single hole and single wire, then sealed by RTV or epoxy.
Interestingly, it wasn't my seals that leaked.Â* Somehow, the oil
seeped into screw holes on the bottom of the PVC box and leaked down
into another storage bin I've had the entire thing in just for that
purpose in case it ever leaked.Â* I never trust oil filled electronic
devices.Â* I used to work on dental x-ray units, which are (were) all
metal housings and even vacuum sealed.Â* However, more often that not,
even perfect ones in storage would end up with an ounce of oil under
them after being stored for years.Â* However, that was a tried and true
business, never had to remove oil from anything and if the transformer
was bad, it was just junked. Here, with my own project, is obviously a
different story if I am going to pot the coil in the paraffin.Â* I
think I'm going to pick up a couple of cans of electronic component
spray cleaner, which doesn't leave a residue, and spray out the
transformer and PVC junction box insides as much as I can, let dry,
and then refill with the molten paraffin.Â* I'd like to leave the
assembly in the oven for a while to make sure as much air works out as
possible, but my oven has a minimal of 170 F.Â* It might be too much,
but I'm not sure.
A way to lower your oven temp - if it is a 220 one - is to run it at 120
instead. That was how I lowered the minimum temp on an old 70s style
household oven we use in the shop when we need temps around 120 to 150F
for curing Smooth-On molds.
John :-#)#
Well, it seems to be done. I had trouble finding wax locally. Hard to
believe place like Walmart doesn't carry it except by special order. I
had to travel a bit, but found some at Hobby Lobby. Not cheap, but I
did need 6.5 lbs.
Since I am a newbie at this, I first placed the now clean transformer
and container in the oven with a wax brick, and set the temp at the
lowest setting of 170 F. However, I could see this was going to take
forever to melt, so I placed a coffee can within a larger pot and put
some water in the pot to reach boiling. It took several melts of the
wax, but each time it melted well and I opened the oven and poured it
into the transformer box. I have moisture concerns, but it *seems* like
any water in the molten wax was at the bottom. I hope that's correct.
I spilled some while pulling out the transformer container to fill it.
It was caught by a foil pan I got at the dollar store, but I'm probably
going to have a breakaway around the bottom job once solid.
I am letting it cool down slowly. I turned the oven off, but I am
keeping the door closed. I don't worry too much since this is an
already sealed transformer, but then again I didn't want to cool things
too quickly either.
Now to just hope I did it right and the wax does its job as replacement
insulator for the mineral oil.