mineral oil removal/ DIY wax embedding?

Oops, now this is causing concern. The until will be in virtually non-climate controlled storage with varying temperatures.

Where might I obtain rosin? I may remelt everything and try this in the Spring. Can I continue using the candle paraffin and mix with rosin?

Any thought on glue sticks also welcomed. I just came across some threads where folks mixed glue sticks and wax to make a tougher potting result.

When the parafin is molten you should, hopefully, find the oil and the parafin to be soluble with each other. Again hopefully, the room temperature consistancy would be a solid, though a softer one.

Hul

Jim Hort> Hi. I have an old project that had high voltage components under

Paraffin has a high coefficient of thermal expansion (up to 600 ppm/degree C) which accounts for its pronounced shrinkage. Beeswax has significantly lower shrinkage and better adhesion. You can order rosin and beeswax on Amazon or eBay, as well as most craft supply stores. Rosin is available in small chunks and powdered forms. For example:

I'd recommend using filtered and refined cosmetic-grade white or yellow beeswax (also available via Amazon or eBay). Beeswax melts at about 65 C while rosin melts at 100 - 150C, so you may need to experiment to find a low melting temperature rosin that will melt in a double-boiler.

Melted low-temperature ethylene-vinyl acetate (EVA) copolymer glue sticks might work even better than beeswax-rosin. Low-temperature EVA (with 25 - 28% vinyl acetate) has a relatively low melting temperature (~65 - 70 C), about the same as beeswax. It has a high dielectric strength (~20 kV/mm), and a relative dielectric constant of about 2.9. It should work well if blended with beeswax.

Some experimenting on small samples should hopefully result in an inexpensive blend that will easily melt and meet your HV embedding needs. I've successfully melted and encapsulated small-bodied HV diodes (that were made to be operated under oil) in EVA instead in order to operate them in air.

Thanks, at this moment, I'm trying to melt the junction box containing the 6.5 lbs of paraffin. I have it in the stove and the temp set at 200

F. This is going to take a LONG time unless there's a quicker way I don't know about. I also *did* notice even more shrinkage when I removed the cover from the junction box to check the wax. Not good. Even the "well" I spoke about before was slightly deeper.

I'm looking into the beeswax/ rosin alternatives you kindly shared, Bert, but first thing I have to do is put the transformers into a smaller container. Otherwise, it's going to be far too expensive. I could use a smaller junction box within the larger, or just pick up a plastic container locally. There's no need for the larger size I don't think. The melting and working with the wax will be far easier too.

Hmmm, I'm having a hard time finding these. Most of the manufacturers don't indicate what type of sticks they use, let alone the lowest melting temperatures. Just hoping maybe one of the brands Walmart carries might do the trick, if I can find out more info.

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Why do you need to fill the enclosure? Can't you just paint the wax on? I n the old days they would dip candles and build up a thickness to whatever they needed. In this case you could just paint it on making sure to get in to all the nooks and crannies (which shouldn't be there along the critical paths really). Be sure to use a brush that won't leave hairs behind. A ni ce coarse brush will let you see loose bristles before the wax hardens.

When it comes to info Walmart is not your friend. You will probably need t o consult the manufacturers. Find a manufacturer and he can tell you where they can be bought.

ards.

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I do have a cheap, single stage pump, but when I checked it out a week ago, it was leaking... probably about half of the oil leaked out into its storage container. Had only used it half a dozen times over two years and even then for no more than a min or two each time. I drained out the remaining oil and cleaned up the pump's outside and the storage container. I'm going to try using silicone on the oil chamber gasket and see if that fixes it. I have some leftover Permatex high temperature red, but I don't think that resists oil. So, for the moment, it's out of commission unless I wanted to add oil for this purpose and then drain out again.

I wouldn't trust doing it that way. When the HEI coils were under oil, working out of phase, they were able to produce up to 5" sparks. It would be really easy for sparking to occur in unwanted places unless fully insulated. Because the rewaxing job using the beeswax/ rosin is going to be too expensive for the size container, if it ever melts, I'm going to rehouse the transformers in a much smaller container and then go with either my original paraffin wax/ hot glue method, beeswax/ hot glue method, or beeswax/ rosin method, depending on cost and what information I can find out about low temperature hot glue. So far, not having much luck with hot glue info.

I contacted Adtech directly, since that is what Walmart seems to carry. Waiting to hear back on the melting temperature and whether or not it's EVA. Then, it's trying to figure out the mixing ratio needed.

A "half-assed" vacuum can be made by using a bicycle pump backwards. Vacuum level depends on how good the flap valve is, and then the construction. One of those rotary roller fish-tank air pumps are excellent - no extra seals to mess with. "Limited budget" my ass.

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The 'well' does deepen overnight as it cools fully. SOP is to add more wax

- when really depends on the size.

Be slightly wary of things described as 100% beeswax or made with 100% bees wax - often they're just paraffin wax with 5% beeswax or 0% & a hint of bee swax-like perfume.

In the old days they would dip candles and build up a thickness to whateve r they needed. In this case you could just paint it on making sure to get into all the nooks and crannies (which shouldn't be there along the critica l paths really). Be sure to use a brush that won't leave hairs behind. A nice coarse brush will let you see loose bristles before the wax hardens.

that has little chance of working. But not filling the whole thing would be a positive move. If you can't re-case it you could fill some of the voids with something.

You can up the oven temp to 212. I'd melt the wax in a /metal/ double boile r on the stove top then pour it in to the oven heated circuit. That's by fa r the quickest way to melt wax.

NT

? In the old days they would dip candles and build up a thickness to whate ver they needed. In this case you could just paint it on making sure to ge t into all the nooks and crannies (which shouldn't be there along the criti cal paths really). Be sure to use a brush that won't leave hairs behind. A nice coarse brush will let you see loose bristles before the wax hardens.

ed to consult the manufacturers. Find a manufacturer and he can tell you w here they can be bought.

Quicker to use rosin I'd think. To get some, stick (untreated) coniferous w ood into the oven. Resin oozes out. Drive off the volatiles & you have rosi n.

NT

I'm going to try and stick with online beeswax purchase if I go that route, but I still wish I knew if the paraffin/ hot glue idea would work. I just finished freeing the transformers from the paraffin. The oven heated it up enough to make it slightly pliable, so a little hand work was all that was needed. So now I have 6.5 lbs of paraffin once again, a new container for the transformers that will only need 2.5 lbs of wax, and me trying to get more info on the low temp hot glue/ paraffin method before I invest in anything else.

That's almost exactly how I did it yesterday. Should be easier with only 1/3 as much once I figure out the route I'm going to take (that being either beeswax/ rosin, beeswax/ low temp hot glue, or paraffin/ low temp hot glue).

If it's anything like the stuff sold as household lubrication oil, it's soluble in organic solvents like acetone, white sprite (but not methylated spirit). Even dish-washing liquid and water reduces it to a thin suspension.

The problem is that it soaks into porous surfaces such as concrete, unsealed tiles, and such, and it needs to be persuaded to unsoak.

I'm dealing with that at the moment. I seem to be having *some* success mixing acetone with sodium bicarbonate to make a thick paste, applying it to the surface to be cleaned, covering it with plastic wrap, putting something on top to weight it down, and leaving it for 12 hours. But it's slow going.

Sylvia.

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 and 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.

To remove oil from concrete mix wood ash and laundry detergent with water to make a paste, apply a thick layer to the marked surface and keep it damp. replace every week until done.

it should de done in a month or so.