mineral oil removal/ DIY wax embedding?

Detergent and water does a good job on oils. If your oil is recalcitrant, dissolve it in a more friendly oil, even cheap cooking oil.

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 Thanks, 
    - Win

What about the oil on the transformer? It is an HEI ignition type that had been in the mineral oil. I probably should have mentioned it before. It is the oil I need to remove from this mainly before I pot in the wax.

3M's Citrus Base Cleaner removes oil. You can then use IPA as a rinse afterward.

Thank you, 73,

--
Don Kuenz, KB7RPU 
There was a young lady named Bright Whose speed was far faster than light; 
She set out one day In a relative way And returned on the previous night.

Kerosene is probably the most likely solvent that isn't too aggressive and will remove oil from the thing without dissolving much else and then evaporate leaving it mostly oil free.

Candle makers add stearin to classic soft paraffin wax to increase its melting point to 80C which makes it more rigid and gives a slower burning flame.

Even so be careful you don't get it ignited by accident. More of a risk when cleaning things with a flammable solvent.

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Regards, 
Martin Brown

Winfield Hill wrote in news: snipped-for-privacy@drn.newsguy.com:

Sop up absolutely as much as possible. Heat the device, enclosure and all, and allow it to drain to a corner of the enclosure to pour out, then heat again and tip and rest on another corner angle and let drain again. Then, you can flush the container and device. The thing is to choose the right solvent. Obviously not aqua based unless you plan on baking it for a while and even vacuum bake ideally.

Seems like a vacuum would be needed to fully impregnate the wax as well.

n

Mineral spirits is suggested over kerosene for cleaning...

John :-#)#

On the floor, yes. On the transformer, NO! It could damage the insulation. So, just use something absorbent, like paper towels, and replace periodically until it is dry enough for your purposes.

Jon

"floor" ??? Do you care explain what you mean?

3M's Citrus Base Cleaner is formulated to remove thermal grease from processors, among other things. It's more-or-less the first treatment of the Arctic Silver thermal material remover.

Thank you, 73,

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Don Kuenz, KB7RPU 
There was a young lady named Bright Whose speed was far faster than light; 
She set out one day In a relative way And returned on the previous night.

Thanks for all the advice, but I ended up going with QC Electronic Parts Cleaner. It can be found both at the auto store as well as Walmart, with Walmart's being half the cost. It took 3 cans to get the inside of the enclosure and transformer mineral oil free, at least from what I could tell. I didn't see or smell any residue so pressed on.

The next part was finding wax, which I had a hard time doing. Hard to believe a 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.

It helps greatly to do that in a vacuum...

That stuff will attack polystyrene, and possibly also other plastics used in electronics.

--
  When I tried casting out nines I made a hash of it.

After letting cool all night in the oven, I pulled out the potted transformer this morning. I was surprised that some of the wax settled in the center of the junction box, about 1.5" depression in an area roughly 1.5" or so wide. It wasn't enough to expose anything, but a surprise. I was tempted to melt and add more wax to this area today, but since nothing was exposed, just covered it over with the junction box cover and was done. Although I could still feel a bit of warmth coming from the box, I did a quick test after hooking up the driving circuitry. Sparking is what it should be, just as before with the mineral oil.

I know others have mentioned doing something like this under vacuum, but for a budget limited hobbyist like myself, it's pretty much out of the question. I'm also not sure how I would go about it with hot wax. I do have a small chamber and single stage pump handy, but those are for insect drying and nothing the size of this transformer box.

Jim Horton wrote in news:qo6tg6$62a$ snipped-for-privacy@dont-email.me:

You do not need a full vacuum, so you can fashion your own chamber and used vac pumps are cheap.

You just need a lower pressure to allow the air to expand and bubble out, and the was to migrate in.

One problem is that if you are having an arcing condition, they typically cause carbon tracks to form, and even subsequent potting without treating those established pathways may result in a failure mode even with fully vacuum potted jobs.

We had power supplies where if the builder breathed 'coffee breath' on the multiplier section before potting, it would cause subsequent detachment, and detached potting is like no potting in the HV realm, and failure is certain.

I just saw some on ebay doing a search on "vacuum pumps" and they have one new for like $49. So the used ones are probably dirt cheap.

Fun stuff, thanks for sharing your experiences. I was going to suggest melting the whole thing in a water bath (double boiler), which I remember from making candles as a kid on the stove top. But you did that on your own.

George H.

Thanks. I do have one of the Ebay $49 pumps (actually Amazon). I used it to pump out a Mason jar with caterpillars inside (after the caterpillars were frozen). By evacuating the air, the caterpillars freeze dried within 2 weeks.

However, after a couple of years in storage, I brought out the pump recently to find a small puddle of oil underneath. Luckily, with anything that has oil inside, I always store in a container large enough so that if it leaks, nothing gets on the floor or shelves.

This was a pump I hardly ever used. That will be my next project, to see if I can find and repair the leaks. For now, all the remaining oil was drained and I have it in a new containment bin until I can get around to it.

This project uses two HEI ignition coils with outputs opposite phased. It is driven by a quadrac circuit to produce up to 5" sparks between electrodes. So the insulation really is for around the transformers as the HEI coils themselves are already potted of course and now in the wax too. For years, the PVC junction box housing with mineral oil worked fine until I saw seepage into yet another storage bin that surrounded the assembly while in storage. I'm still not sure how the oil seeped out. I had connections into and out of the box, but carefully sealed the single wires with silicone (I made sure not to use stranded wire anywhere), so it didn't appear to be my seals that leaked. Anyway, I now have it all back together and 5" sparking. Of course, I don't have to have the electrodes that far apart and for safety and transformer sake's, I probably won't.

This was a demonstration unit I built some years back. I have it looking somewhat like a spark coil would look with two adjustable electrodes on top. Everything is inside PVC junction boxes. It is never meant to run more than 30 seconds at a time and I have never exceeded that. I also have quadrac settings for low, medium, and high output.

That's what I ended up doing as it was going to take forever melting the wax bars in the stove. I didn't have any large coffee cans handy so picked up Walmart's cheapest coffee only to find that it is cardboard and not tin. I still used it and amazingly neither the wax ruptured out or water in, but I don't trust it to use again and will seek a proper tin can the next time. So the "can" was lowered into a pot of boiling water. I had to do several meltings, but the oven did keep the poured wax molten for several hours afterwards and between pourings. I do regret the depression I found this morning, right in the center of the wax, but it's small and nothing was uncovered so I put the junction box cover on, tested it, and all good.

The good news is that the junction box, wiring and even some poly ropes I use to carry the device around all faired well in the stove at 200 F. The bad news is how I will ever melt the resulting 6.5 lb wax potted transformers if I needed to do repairs. Maybe leaving in the stove for

24 hours at 200 F would do the trick, but not sure. I didn't have the patience to find out if the entire block would melt in the stove or not this time around.

By the way, I'd like to highly recommend QC cleaner:

Whether from Amazon or Walmart, nearly the same price per can. I'd say it cleaned 99.5% of the mineral oil out of the container and off of the components and did not leave a residue or smell. It did take 3 cans for a complete job.

You could put the whole thing in a water bath in the oven. The water helps the thermal conductivity into the gizmo.

George H.

Sounds like it worked!

Paraffin (if that's what you used) tends to shrink considerably as it hardens. This is likely why you got the depression in the wax. However, it also continues to shrink if you get it cold and also becomes brittle. If shrinkage or later cold-cracking causes any air gaps in high E-field areas, the air in the gaps will ionize, potentially lead to ozone/UV damage and carbon tracking of insulation.

Old-timers used to mix 1:1 beeswax and rosin when they impregnated mica capacitors or HV transformer windings. The material shrinks less, remains relatively soft and tacky, and tends not to pull away from the embedded objects. The rosin also increases the melting temperature (beeswax alone melts at just 147 F).

Good luck and play safely!