good mineral oil removal?

Perhaps mineral spirits - sometimes called Varsol if I am not mistaken -

will do the job.

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 :-#)#

On 10/15/19 12:32 PM, John Robertson wrote:

Interesting question. True about paraffin and oil relationship. Didn't think of that. Well, it was my project. The high voltage transformer was submerged in about 64 oz of mineral oil. It was in a pvc junction box and stayed in there for years. Connections into the box were single hole and single wire, then sealed by RTV or epoxy. Interestingly, it wasn't my seals that leaked. 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. I never trust oil filled electronic devices. I used to work on dental x-ray units, which are (were) all metal housings and even vacuum sealed. 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. 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. 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. 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. It might be too much, but I'm not sure.

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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 :-#)#

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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.

Mineral spirits, Naptha, alcohol ?

Greg

the amount of oil paraffin wax can hold is small.

In Britain, I believe "parrafin" refers to Kerosene

Kerosene in British English kerosene. ? a type of fuel oil that is made from petroleum and that is used in the engines of planes and for heat and light. In British English it is usually called paraffin when it is used for heat and light.

That being said, "paraffin oil" in the United States is not Kerosene, but a version of mineral oil commonly used as fuel in oil lamps and tiki torches.

My wife uses parrafin baths for her client's hands. The parrafin is mixed with mineral oil in the bath to alter the viscosity and to leave a slight coating on the skin when the parrafin hardens so that it comes off easily. The mineral oil also makes the parrafin more pliable at body temperature when cool so that it can be peeled off rather than broken off. When at room temp the parrifin is still pretty hard. I think you don't need to worry at all about removing the mineral oil, just pour in the hot parrafin and the oil will dissolve into the parrifin. Eric

on

).

You may find an oily coating stops the wax sticking & sealing.

NT

Finding wax.

When I worked in a cardboard (corrugated) box plant, we used huge amounts o f wax to coat cardboard that was used for seafood and chicken. It came in stacks of 10 pound (I think) slabs.

There was always a huge pile of discarded wax. If you're near a plant, mig ht get some discarded for free. If it gets dirt or oil on a block you can' t use it on paper. But you could scrape that off easily.

It comes in various grades. Curtain coat was a shiny white and brittle, th en there was a yellowish one that was tougher.

I tried using some of it as bullets, standing an empty cartridge in a pan o f liquid wax then letting it harden to fill the neck with a projectile. th en use a primer for propellant. The books says it works but it didn't for me. The wax didn't hold together, it just shattered.

Just to follow up here, I found that the following did an excellent job not only removing almost all of the oil, but not damaging any surface it

contacted or leaving any residue:

CRC 5103 Quick Dry Electronic Cleaner

It took 3 cans for the amount of oil I had to remove, but it did a great

job. You can find it online, auto stores, or Walmart. I got mine at Walmart as it was cheapest.

I've been well past oil removal for several days and actually on my second wax potting attempt. By the way, the cleaner cleaned well enough

that when I peeled away any remaining wax from my first try, some of it all of it was well in place with no oil residue anywhere. I could easily reuse the paraffin, but I am now going to try a beeswax/ rosin mix as I found that the paraffin shrank too much and had microcracks when cooled. The beeswax/ rosin will not be cheap, however. I had read

a thread where someone added low temperature hot glue sticks to standard

melted paraffin to increase its strength, but unfortunately I couldn't find any specifics on it, such as mix ratios, etc, and determining whether or not the hot glue is EVA seems a big task since the market packaging doesn't indicate it.

A simpler cheaper solution is to pour the paraffin wax in layers. That gets rid of the majority of the contraction issue. If you're concerned what hap pens at the layer interface you cAn always point a hairddryer at it before pouring.

NT