# Harvesting copper from transformers



## Rag and Bone (Jun 17, 2008)

I cashed in two transformers today for $0.17/lb

The total weight was 786 pounds. I figure there was at least a few hundred pounds of bare copper in them.

How would someone get the copper out with basic tools?

Damn, my back hurts. Time to go fishin!


----------



## Anonymous (Jun 17, 2008)

What type of transformer? The steel cans can be pretty thick and the iron cores are most of the weight, also the oil in them. 

I think you would get a little better money but it would be tons of labor to get the copper. If it is old it my contain PCBs or if it was burnt, ie shorted out you might need a mask to handle the fumes.

Jim


----------



## Rag and Bone (Jun 17, 2008)

I'm not sure what type it is. The steel pieces are very thick. The copper seemed to be flat coils. There was lots of sticky adhesive junk holding the coils together.


----------



## Strangebrew (Jun 18, 2008)

I use a sawzall with an 18 tooth metal-cutting blade to slice the copper off one face of the transformer, then pry the rest of the copper out of the other side. I still only get #2 coated price for it as it's coated with varnish or resin.

In my area at today's price that equals 1.00 per lb. for copper, and 7.5 cents per lb. for iron.


----------



## Gotrek (Jun 18, 2008)

You can roast the resin off easily(wear a respirator) or incinerate the lot when you are done to get clean copper. The yard may give you a better price.


----------



## Strangebrew (Jun 18, 2008)

Gotrek,

I've gently torched some copper similar to transformer windings such as yokes from CRTs. Whatever they use to hold some of these windings together is rough stuff under combustion. Without a fume hood in my neighborhood, I gotta settle for less.  At least with ordinary #1 wire I can strip it.


----------



## Gotrek (Jun 18, 2008)

I think they are polyester based resin's. Not sure of it's toxicity when cured or liquid but I'm sure you on't want to be breathing it.

Porbably similar msds to this

http://www.istusa.com/skyMSDS_701.pdf

It's a varnish so as toxic as most varnishes


----------



## silversaddle1 (Jun 19, 2008)

As a vet of scrapping just about every sized transformer made, I can shed some light on this topic.

For small transformers, like the ones you would see in small power supplys and microwaves, get a sharp wood chisel and hammer. Place the transformer in a vice or on a concrete floor and hammer the chisel right thru the windings on one side. Be sure to cut all the windings all the way down to the core. Once you get all the windings cut, turn her over and use a big screwdriver to pry out the windings. You will dull your chisel a few times before you get the feel for it, so make sure you can resharpen it. And use a cheap chisel.

Another method is a sawsall, as mentioned above, this works good too!

For big transformers, like to ones in the topic, I use a concrete cutting saw to slice thru the windings.I use the type with the abrasive type blades, not the steel blades. Works like a champ. Once the windings are cut, I throw a bunch of old pallets in the big barrel, put the trans on top and light it off.Now I know most of you don't live out in the country like I do and can't open burn. So you can also use a prybar to break the windings loose and start pulling them out.

It will always pay more to strip the trans then to sell it whole.

I just cleaned a transformer that weighed 980 pounds whole. If I would have sold it as a whole unit, I may had gotten .20-30 cents a pound tops. So on the high end I would have made around $300.00 on it just hauling it in.

But by cleaning it, I got almost 300 pounds of clean #1 copper and made just short of $1000.00 on the copper alone. The steel will pay another $50.00 or so. 

Feel free to ask questions and I may post some pics.


----------



## flankdrive04 (Jun 30, 2008)

Are these big transformers easy to come by??

Have you ever scraped big AC Invertors?

I am picking up a load of 20 X 55kw units. They weigh about 70kg each. Hoping to get some good copper out!

Have noticed that they each have a "huge' alluminium heat sink inside. About 18" x 30" and about 14" thick including fins WHOO-HOO!!

Do you have any transformer pics for us??


Cheers!


----------



## Rag and Bone (Jun 30, 2008)

I do have some photos, I'll try to find one. 

Let us know what you find in the AC units. I left a huge stack of them behind because I didn't want to mess with freon.


----------



## flankdrive04 (Jul 1, 2008)

Sorry, may have given you the wrong idea...

They were AC Invertors, ie; Converts AC to DC for industrial motor drives and controls.

Cheers!


----------



## Rag and Bone (Jul 1, 2008)

Oh...AC


----------



## jimmy759 (Jul 16, 2008)

I have taken apart a few transformers in my day. 

the last ones i had weighed about 500-600 lbs each. got around 150lbs of copper each.

I used a normal angle grinder and cutting wheels to strip a layer of copper off and then it was in nice bendable pieces to be boxed. I kept rolling the transformer and cutting till it was just a chunk of steel plates left. did well and it took me about 2-3 hours per transformer. i didn't take the shellac off of the copper windings so i only got number 2 clean for price but it was only $.20 difference from number one.

Was worth my time and effort wish i could get some more.


----------



## Rag and Bone (Jul 16, 2008)

Jimmy,

They gave you the 2 clean price even with shellac?

What's the deal with PCBs in transformers, how'dya know?


----------



## Anonymous (Jul 16, 2008)

There are field kits available for testing the oil for pcb's . Generally the older the transformer the greater the possibility for pcb oil. 

You can not rely of the manufacture date of said transformer:

Retrofilling of a transformer means emptying the equipment of its dielectric fluid, and replacing. this with a new non-PCB oil.

PCB Field Testing Kits
http://www.dexsil.com/products/detail.php?product_id=2


----------



## Anonymous (Jul 16, 2008)

Rag and Bone said:


> Jimmy,
> 
> They gave you the 2 clean price even with shellac?
> 
> What's the deal with PCBs in transformers, how'dya know?



My yard gives me #2 also for motor windings, I do not burn them. I think you would loose more than the difference to oxidation when you burn them, exspecially smaller like 14 gauge wire.


----------



## Anonymous (Jul 16, 2008)

Rag And Bone

When you encounter pcb's, It will be oily and smell sweeting. Pcb's have not been used for many years, in fact I entered the electrical field in the late 70's and pcb's were talked about by the oldtimers then, but as a caution because we could still find them from time to time.


----------



## skippy (Jul 16, 2008)

FWIW, my usual scrap yard give me number two Cu price for laquered windings as well.


----------



## Rag and Bone (Aug 6, 2008)

Located 2 more big transformers (600-700 pounds apiece). I plan on stripping these down to get maximum value. I'll post some photos if the deal goes down.


----------



## goldsilverpro (Aug 6, 2008)

We used to stack pallet wood, upright, 6 or 8 layers thick, around the opened transformer. The fuel was 50/50, diesel/gasoline.


----------



## Rag and Bone (Aug 6, 2008)

That sounds like soooo much fun.  

I'm stuck tackling them with a sawzall


----------



## goldsilverpro (Aug 6, 2008)

Actually, it was a lot of fun, especially since the end point was 100s of pounds of nice copper bars.


----------



## Rag and Bone (Aug 18, 2008)

I found two more transformers, bigger than the last two. I'm trying to harvest these ones rather than cash them in as is. I'm trying to cut through the 1/4" thick coils with an angle grinder. The trouble is the blades keep wearing out. It's costing me $2 worth of blades to get $3 worth of copper.  

I've been using the metal cut-off blades. I'll try a masonry blade for kicks. 

Any advice would be greatly appreciated.


----------



## Anonymous (Aug 18, 2008)

use a saz all at low speed.


----------



## Rag and Bone (Aug 18, 2008)

I tried the concrete blade. It wasn't any better. If I need to buy a sawzall for this I will. It would be nice to do it with what I already own.


----------



## Anonymous (Aug 18, 2008)

did you try cutting the bolts holding the iron laminates together? Transformers I get are no were near that size but they have a weld holding the lamianted iron, I simply grind out the weld and knock it with a hammer, fast, easy and to the point.


----------



## Anonymous (Aug 18, 2008)

How thick are the laminates? I may be interested in a few for knive making - laminate with carbon steel to make damascus steel.

Jim


----------



## Rag and Bone (Aug 18, 2008)

James,

The laminates are 5x3" and 17" tall. I'll keep you in mind if I need to cut them. Maybe fill a Flat Rate Box and give a mail carrier a hernia. :shock:


----------



## Anonymous (Aug 18, 2008)

I would hate/like to see the sign them things were running :lol:


----------



## Rag and Bone (Aug 18, 2008)

These were harvested from uninterruptible power supplies (UPS).

They were in steel cabinets. There was lots of good metal inside besides the transformers. (Al heatsinks, brass hardware, #1 and #2 copper wire, steel, circuit boards). No garbage except for a few pounds of plastic. Also some large capacitors I don't know what to do with.


----------



## SapunovDmitry (Aug 18, 2008)

There can be as low as 20% per weightt of copper in transformer. You will get at least 15% or 75 pounds from a 500 lb piece.


----------



## skippy (Aug 18, 2008)

Rag and Bone, I found a transformer just like that in a dumpster last year, I managed to lift the damn thing right up and over the side of the dumpster. I don't know how I did it, because I couldn't hardly lift the thing off the ground when I was moving it around later to chop it up. It was like kind of like the stories you hear about the woman who lifts the car off her child. I cut the windings with a sledge hammer (held one handed near the head) and a big cold chisel.


----------



## Gotrek (Aug 19, 2008)

How about a steel/diamond toothed angle grinder blade? Those abrasive disc's are good for nothing on dense material.


----------



## Harold_V (Aug 19, 2008)

If you're asking about using a diamond blade, they are not for use on steel. Carbon (diamond) is readily dissolved by steel when it's hot-destroying the diamond. 

If you use abrasive blades, silicon carbide is a bad choice for steel, but great for non-ferrous. Aluminum oxide is the abrasive of choice for steel, in spite of being softer than silicon carbide. Silicon, like carbon, is readily dissolved in steel (iron), so it performs poorly. 

Harold


----------



## Gotrek (Aug 19, 2008)

Harold_V said:


> If you're asking about using a diamond blade, they are not for use on steel. Carbon (diamond) is readily dissolved by steel when it's hot-destroying the diamond.
> 
> If you use abrasive blades, silicon carbide is a bad choice for steel, but great for non-ferrous. Aluminum oxide is the abrasive of choice for steel, in spite of being softer than silicon carbide. Silicon, like carbon, is readily dissolved in steel (iron), so it performs poorly.
> 
> Harold



I thought he was cutting copper sorry.


----------



## Harold_V (Aug 19, 2008)

I think he IS cutting copper------but it's hard to avoid touching steel (iron in the case of laminated elements in transformers). 

Assuming that's the case, a silicon carbide blade would be the best choice, assuming he could minimize contact with the iron. Silicon carbide blades are the ones that are recommended for cutting brick or stone. If a blade (or wheel) is recommended for steel, it is almost always aluminum oxide, which would perform poorly in copper. 

Considering the cost of diamond blades, I don't think they'd be a good choice in any case for removing copper. It's not hard, just tough----so it would tend to damage the diamond blade by pulling diamonds out of the matrix. Diamond is outstanding for cutting hard objects, not so good for soft. 

Harold


----------



## Gotrek (Aug 19, 2008)

Harold_V said:


> I think he IS cutting copper------but it's hard to avoid touching steel (iron in the case of laminated elements in transformers).
> 
> Assuming that's the case, a silicon carbide blade would be the best choice, assuming he could minimize contact with the iron. Silicon carbide blades are the ones that are recommended for cutting brick or stone. If a blade (or wheel) is recommended for steel, it is almost always aluminum oxide, which would perform poorly in copper.
> 
> ...



Gotcha.


----------



## Rag and Bone (Aug 19, 2008)

These transformers are kicking my ass. 

I picked up some 6" 24tpi Milwaukee blades. It's the best thing so far but still very, very slow. The angle grinder works fast but it destroys the blades in minutes. The next problem is how to get the remaining copper between the steel laminates. It's stuck in there solid as a rock.


----------



## Anonymous (Aug 19, 2008)

Did you try removing the bolts and seperating the laminate parts?
or, it would most likely be better to cut the steel sections and knock the copper out as a coil. Steel does not grab the grit as much as copper does so it will were the blades less, and it looks to me, like there would be less thickness of steel to cut.


----------



## Rag and Bone (Aug 19, 2008)

james122964 said:


> Did you try removing the bolts and seperating the laminate parts?
> or, it would most likely be better to cut the steel sections and knock the copper out as a coil. Steel does not grab the grit as much as copper does so it will were the blades less, and it looks to me, like there would be less thickness of steel to cut.



They are welded together. Even if the steel was cut off, a giant mass of coils isn't going to just pop out. The steel is quite thick.


----------



## NuggetHuntingFool (Aug 19, 2008)

Would a cutting torch suffice or would that damage the copper and knock the value down?

Just wondering, it would seem very fast. Is there flammable stuff inside the transformer?


----------



## Rag and Bone (Aug 19, 2008)

A torch would be a disaster for the coils. The paper and resin would burn like a Chechen village and disturb the neighborhood. It might work on the steel laminates although they are 5x3". I'm going to the rental shop tomorrow for a masonry saw. No more messin' around. If that doesn't work I'll be requesting the recipe for silver nitrate.


----------



## Anonymous (Aug 19, 2008)

how deep are the welds? the transformers I get are welded but only 1/4 inch deep, grind out the weld and the E shape laminate falls away, I place the coils between 2 blocks and drive the I shape lamination out with a big hammer.

but my transformers are only from appearances about 1/4 the size of those.


----------



## silversaddle1 (Aug 20, 2008)

I can go into some detail on how to harvest these coils. What I use is a rail saw, used to cut railroad rail. It's basic just a abrasive saw like the ones they use to cut concrete. They are hand-held and weigh around 30-40 pounds. You can rent these saws at most rental stores. The one I have takes a 14' blade. I use regular Norton steel cutting blades. So on with the process. I take the saw and just make a ut right down the side of the coil. Start at the top and go towards the bottom. Keep making passes thru the coil untill you start cutting into the steel frame. You know you're to the core when the sparks start flying. Most the large transformers that I have done have three coils, so be sure to cut all three coils before you start pulling copper. After you have ut your coils, you can go to the other side of the transformer and use a long pry-bar to start working the copper loose. Dont try to do a bunch all at once, a little at a time at first to get started. Once you get the first few wraps loose, you will find that it gets easier as you go. I always do the middle winding first, as it makes the whole thing go faster with the two outside coils coming off easy. Once I get all the windings out, I burn them clean in a 55 gal barrel. I don't know what kind of winding your transformers have, but I'm sure they are nice and thick, so the burn won't hurt them. Any other questions, PM me.


----------



## Rag and Bone (Aug 20, 2008)

Success!!!

Got the job done with a 2-stroke masonry saw with a 14" abrasive masonry saw blade (required 2 blades). Cut down each side of the windings on both sides of the transformers. Removed the copper in big, heavy chunks. Knocked out the remaining copper between the laminates with a sledge and chunks of wood with the transformer sitting on top of...4 more transformers :wink: . Looks like about 200 hundred pounds total.

I have a new appreciation for the tenacity of copper. Sure, it's soft but it is TOUGH and really holds up against abrasion. I've never broken so many tools and blades. Copper, salud. 

This was a learning experience. I thought I was onto easy money but after all the tools, blades, time and running around it got kinda pricey. On the other hand, I made several good contacts around town. Lined up more big transformers. The next round will be the easy money!

I locked in for $2.53/lb at the scrapyard. We will weigh the stripped laminates and I will report back the copper/steel ratio. The laminates have a beautiful grain. They would be excellent for knife blades. 

Many, many thanks to all the people on the Forum that shared their hard won knowledge. Nobody else I talked to had a clue how to get this done right and I talked to alot of people. Cheers!


----------



## Harold_V (Aug 20, 2008)

Rag and Bone said:


> The laminates have a beautiful grain. They would be excellent for knife blades.


Wrong! They won't work worth a damn.

Laminations in transformers and motors are NOT steel. They're iron. There's a small, but VERY significant difference. 

Steel is iron that has a percentage of carbon dissolved in its makeup. A minimum of .04% is required for minimal heat treating, with 1% being a significant percentage, permitting extremely hard results. In shop talk, something like 62 Rc. 

It's the carbon that allows the iron to be heat treated. It also is what permits iron to retain magnetism, when the material has been heat treated. Laminations are made from carbon free iron, so they won't retain magnetism, and they can't be heat treated. Thus, they'd make a poor knife blade. 

Harold


----------



## Rag and Bone (Aug 21, 2008)

O.K. Not good knife blades. Excellent steel lesson though.. :wink: 
Half the people around here would call this "tin". :lol: 

Somone mentioned Damasacus Steel, thats the first I've heard of it. If someone (that has something to say) wants to start a post about Damascus Steel or knife making it would be cool. The Wiki on D. Steel is quite interesting. 

Whatever the case, the grain is beautiful. If I had a camera like Noxx's I'd show you.


----------



## Harold_V (Aug 21, 2008)

It won't be me. Damascus steel is way beyond my knowledge. 

I do seem to recall that it was the method of making firearms at one time, but with not great results. If memory serves, the material is hammer welded together, thus is not very strong. 

I stand to be corrected. 

Harold


----------



## Rag and Bone (Aug 21, 2008)

Please keep this post limited to

"TRANSFORMERS: MORE THAN MEETS THE EYE"

sung in a robotic voice 

to the 'toon of "The Transformers: Theme Song"


----------



## Anonymous (Aug 21, 2008)

I think your getting ripped at $2.53 lb, I just took in 900lbs #1 August 8th at $3.20 a pound.

Todays Kitco Base Metals on copper $3.4747

You have to use some social engineering techniques, make yourself known to the powers higher up and always telephone first for a price fix. This way he thinks your shopping and will quote his best.

Chances are that scrap yard needs your copper to fill quota.


----------



## Rag and Bone (Aug 21, 2008)

gustavus,

Point taken. I'll do some more calling before I cash in. Keep in mind I'm in no mans land. Big cities and processing are far away. Scrapyards charge a premium for proximity around here. 

"Do I drive to the shredder in Green Bay or cash in locally and save gas/time".

Also, I'd be in a better position if I had 900lbs. vs. a couple hundred, no?

Thanks for the heads-up.


----------



## Anonymous (Aug 21, 2008)

Never mind the drive, send it UPS.


----------



## Rag and Bone (Aug 21, 2008)

I cashed in at $2.53/lb. There was 210 lb.s total from the 2 transformers. I wasn't able to weigh the laminates yet. Another yard offered $2.59/lb. but it was quite far away.


----------



## Anonymous (Aug 23, 2008)

I would still be interested in some of the laminates. I do know how to make them into blades. The ones I get are small and I have to weld several together just to get started. It would be nice to have some that I could just start folding.

Thanks,

Jim


----------



## Oz (Aug 23, 2008)

James, 

I do not have experience with the iron in large transformers, but if Harold is correct about their carbon content (he is after all a machinist as well) then you would be wasting your time folding and forge welding these together. Not only would you not get a serviceable blade but the etching due to different carbon contents in the iron will not give you the pattern you would want even for a piece that is just for show. I do have a fair background in blacksmithing if you would like to know more. I would suggest however that ironwork be taken to PM messages unless some others here want to hear about it as well.


----------



## Rag and Bone (Aug 23, 2008)

See the post "Ironworking Knife Blades Tools" for metal-working talk.

What's the biggest transformer you ever harvested :?: 

Any good transformer harvesting tricks :?:


----------



## Oz (Aug 23, 2008)

I don’t in general deal with base metal recoveries as a primary source but do recover them as a byproduct. So to answer your question I have never messed with an oil filled transformer just small ones. 

I have not seen posts on ironworking here other than this one. I am not currently doing much blacksmithing or wrought iron production lately but only wished to save you wasted time if you wished to fold low carbon steel for decorative or functional damask.


----------



## Rag and Bone (Aug 23, 2008)

What exactly are you doing these days Oz? Got any irons in the fire or just speculating?


----------



## Harold_V (Aug 23, 2008)

james122964 said:


> I would still be interested in some of the laminates. I do know how to make them into blades. The ones I get are small and I have to weld several together just to get started. It would be nice to have some that I could just start folding.
> 
> Thanks,
> 
> Jim


Fact is, the laminates could be fashioned into knife blades, assuming they're thick enough-----then they could be pack hardened, and drawn. Carbon steel blades, in other words. 

Iron has a great affinity for carbon and will absorb it readily. Pack hardening is an old and well proven method for increasing carbon content in low carbon steels, and has the added benefit of yielding a soft center, which helps in preventing the blade from breaking easily. it will generally provide for roughly .010" penetration per hour, so a knife blade could be hardened through, assuming that was the goal. Depth of penetration tends to trail off after about .090", but that's generally more than the thickness of a knife blade. The real negative is that carbon steel has low resistance to staining and rusting. 

Harold


----------



## Oz (Aug 23, 2008)

Well I guess there is a little interest in iron after all. 

So… if I am reading what Harold wrote correctly what he is calling “pack hardening” I call surface hardening. In the days of old when getting high carbon steel from a bloomery was an accident rather than by intent they would make an iron box and fill it with horse hoof trimmings placing the low carbon iron they wished to make into steel within with it. They would then place the box in a forge or furnace and take it to a dull to cherry red temperature. This provided a reducing atmosphere that would turn the organic horse hooves to carbon but not burn off the carbon due to a lack of oxygen. At a cherry heat the iron molecules are susceptible to the migration of carbon within their matrix. The longer the iron is kept at this temperature the deeper the carbon can penetrate the iron.

Harold alluded to a distinct advantage of this method, if done carefully you have a hard wear resistant exterior of steel that will not dull rapidly with a soft core backing it of iron that is not prone to shattering due to the soft core. 

In a more complicated example I could explain why this is important in true damask. To be clear the above is not damask.

Harold please correct me if I missed the boat somewhere as I respect a (should have said it right the first time) toolmakers opinion.

Harold is also very correct in stating the rusting problems with high carbon steel. Then again well made damask has outer laminations of low carbon iron on the face of the blade.

As to your question on what I am doing these days… I have no clue, can’t you tell? 

Irons are in the fire too seldom. I have a forge set up at the family farm, my house, as well as my girlfriend’s house but usually only fire them up to teach a youngster that has interest, so knowledge is not lost. It is a not for profit endeavor these days. 

And yes, I am always speculating.


----------



## Anonymous (Aug 23, 2008)

Oz said:


> James,
> 
> I do not have experience with the iron in large transformers, but if Harold is correct about their carbon content (he is after all a machinist as well) then you would be wasting your time folding and forge welding these together. Not only would you not get a serviceable blade but the etching due to different carbon contents in the iron will not give you the pattern you would want even for a piece that is just for show. I do have a fair background in blacksmithing if you would like to know more. I would suggest however that ironwork be taken to PM messages unless some others here want to hear about it as well.



Make a sandwich, iron (laminate), steel (old sawblade), forge weld, fold, weld fold, weld fold, repeat for 20 - 30 time or if making a samuri sword a couple hundred. Forge the blade with careful hammer blows to develope the pattern. Sharpend, treat with acid to see the beautiful pattern in the steel (damascu) get offered good money for it, but keep in your handmade collection.


----------



## silversaddle1 (Aug 24, 2008)

I just scrapped two 900 pound transformers. How big of lamanates are you wanting?


----------



## Anonymous (Aug 24, 2008)

I would only need 10 - 15 lb. I really could cout the I sections or I could make do with E sections, if the they are built the same as my little 2000va microwave trans formers.

thanks

Jim


----------



## jimmy759 (Aug 25, 2008)

haven't been around for a bit nice job with the transformers though.

I'm in a larger city and we have a large scrapyard here. that pay top prices. for the most part. 500lbs of more total not just one metal results in higher prices across the board. 

But i was getting grinding wheels for free from work and i picked up a wack load from a garage sale for .50 cents a piece last year. the ones from work are higher quality. have to check name again i never pay attention.


But i'm glad you found a way to do it safely.

I was wondering if anyone would object to using a plasma cutter to cut through a transformer?


----------



## Rag and Bone (Sep 6, 2008)

Got the big transformers down fine with a rail-saw and sledge hammer. The smaller, 20-60lb. were tougher to crack. Next time we dismantle or cut steel on the smaller ones. Newfound respect for copper


----------



## butcher (Sep 27, 2008)

Besides using transformer plates for making knives, I use the iron cut small pieces in my ferrous sulfate recipee. (Ps made great damascus knife using old file and old chainsaw blade, ball bearings and several other metals) .


----------



## lanes (Oct 13, 2008)

Hi here is how I do them . I get a wood fire going and burn them and while there hot from the fire I us a hammer and flat screw driver . They just slide a part pretty good. I forgot you have to take brackets off first . 
Thanks Rosita


----------



## qst42know (Oct 14, 2008)

Plasma cutters have a limited depth of cut. They are well suited for sheet or plate metals and even some limited gouging tasks. 

In my opinion one would make quite a mess of a transformer.


----------

