Found Silver & Tantalum

Silver and Tantalum capacitors is what I found. Been studying and scratching my head in a "dazed and confused" mode. Determined to put all my resources to work in finding the different types of tantalum capacitors. Mostly rereading every post on this subject here at SMF, dealing with Tantalum capacitor things. Started by looking at all the PCB'S that I had previously sorted to low grade or had depopulated. I concentrated on the boards that I had depopulated first. Why those? simply because less to look at and less components to scrutinize on those boards. I chose to further focus on two types, the metal axial-leaded and the epoxy/ceramic "gum drop" dipped tantalum capacitors.

The Tools: I used my eyes aided by magnifying glasses (5 x's magnification) looking for the plus sign markings on both the board and the capacitor. Then once finding these capacitors I used a scrapers best friend, a magnet! Finding all tantalum capacitors have magnetic properties. The many previous post on SMF, both descriptions and pictures (big help) for identifying conformation. Dremel rotary tool with a cut-off wheel to remove capacitors from board. Also used manufacturers data sheets for final conformation. Utilized both digital scale and micrometer for documenting weights and dimensions.

Conclusions: When I started on this today I had zero Tantalum Capacitors with a value of zero. I now have a little over 100. They weigh as little as .2 to 9 grams each and I have over three ounces. The SMD and "gum drops" weigh almost nothing, the wet Ag/Ta's weigh a little bit more (7 to 9 grams) each. With most all scrap prices down right now and Tantalum capacitor scrap paying from $20 to $80 per pound. I just want to find more alternative ways to earn money for what I already have. With the silver/tantalum paying $5 per ounce, that's better than $.50 per pound for aluminum. I got a long way to go, but I got started on the elusive tantalum thing!

Congrats - I'm still confused with what they look like/where to find them.

Keep us posted on your progress.

Originally Posted by logansryche

Congrats - I'm still confused with what they look like/where to find them.

Ditto

It's good to try it out for awhile. Breaking down the PCB's for their components is a learning experience that gives you a better understanding of E-waste.

For me: It didn't seem to be worth doing for the following reasons.

1: Time .... When i weighed everything up after a day's work there seemed to be fairly little return for the time invested. It occurred to me that it might be better to find something else to do that was more profitable.

2: The job hazards ....There are different methods for breaking down a PCB and they all have their risks. The least harmful option was to shave the board with a sharp chisel but even that released a micro fine dust into the air. Short term it might be okay but over the long term you would probably be risking some kind of poisoning. Came to the conclusion that it would be better to do this kind of thing in a closed environment of some kind. That way all of the dusts & whatnot would be safely contained.

3: The left over was devalued / depopulated boards that need to be properly disposed of. I ended up shipping them at a loss to a refiner. They might have had a value of .30 /lb but it cost .60 - .80 / lb to ship them.

4: It might have been worthwhile doing 20 years ago because the boards that one would run into back then were richer in recoverable value items. The boards that you commonly run across today are much scarcer. Axial tanty caps are rare and the SMD's are tiny compared to what was used in the past.

5: The economy of scale. There's a difference between dismantling and refining. Once you start breaking the boards down it's getting into the realm of refining. Refining is a specialty. If there's a guy out there that can do the job 100 times faster and achieve a higher recovery rate of PM's i'll gladly hand that job off to him. He's a better choice for that kind of work.

Just my two cents .... it might be a different story for somebody else in a different situation.

You have to figure out what methods work best for you.

Originally Posted by logansryche

Congrats - I'm still confused with what they look like/where to find them.

There is a thread with pics.

A little update: As I said I'm only taking tantalum capacitors off boards that I have previously removed components. These were boards with easily removable (not soldered) IC chips for the most part. All boards were green/green, with the older ones being dark green on component side and a lighter green on soldered side. Theses green boards were medical, computer and communication boards all pre 1990. I have found some tantalum capacitors on green/brown or tan boards that were heavy with switches, transformers and relays. These were all on what I would call control boards, in that they "controlled" temperature, air flow or machine movement. All of the boards had the positive "plus" sign with the anode side of capacitors attached.

I'll give you one example of the tantalum capacitors that I'm finding. These were made by the Sprague Company and have date codes from the 1980's. Looking at them with the anode on the right and cathode on the left. They are marked as such and I'll call "lines": (line 1) 109D+, (line 2) 220UFXO, (line 3) 30DC, (line 4) 2 "in side a circle" +, (line 5) 8828+. These are the only marking on the case, the case is metal, nonmagnetic and "SILVER" in color. These are in a Axial package, round cylinder shaped with through hole leads at each end. On the anode side of case there is a "deep crimp", much deeper than you would find on a "normal" aluminum capacitor. The case has a clear plastic protection sleeve. The anode lead is magnetic and that side of case has a "epoxy" like green seal. The cathode side is silver sealed with a tinned copper lead, that is nonmagnetic. These capacitors weigh 3.9 to 4.0 grams.

Looking at the Sprague data sheet for the 109D tantalum capacitor, these should be the Silver/Tantalum "wet" capacitor!

Any and all added responses and/or questions are welcomed and appreciated. Thanks everyone.

I have taken some pictures, but there not very good. I will try to post them tonight. The only camera I have is my cell phone, but I'll give it a try little later when I can.

First let me clarify the silver/tantalum capacitors did not come off any brown or tan boards. They have all come off of medical, computer and communication boards. I have found the axial leaded "hermetically sealed tantalum" capacitors. Made by a company called KEMET series T110 these are the smallest of axial type I have found so far. They did come off of a green/tan board, from a "indusriall machine" used to process chemicals. I don't have my notes in front of me right now, but these t110 caps have a tantalum case. I'm going on memory so will check notes in the morning on those ones.[IMG][/IMG]

The above picture is from a scintillation camera. If you look at the above picture, in the 5 o'clock position is two capacitors, these are the 109D silver/tantalum capacitors made by Sprague. The board on top is called a "Pizza Board" by G.E. Medical Systems. These boards have lots of gold IC chips. It was your post from a couple of months ago, that put a "bug in my a$$" that said go look at those camera things again, so thank you! I'm trying to figure this photobucket thing again so I'll post some more pictures in a few, going to go set by the fireplace and eat some cherry pie! back in a few.

[IMG][/IMG]

These are the same two capacitors that are on the Pizza Board posted earlier. Sorry about he poor picture, it has to be the space between my ears!

ScrappinRed it is thanks to you! Your post and much better ability to take decent, in focused close-up pictures. I do read, reread the SMF post, as well as enjoy the very exciting, dynamic and "Edge of Seat" manufacturers data specification sheets. Thanks again for your post.

Reading some tantalum capacitors spec sheets this morning about "wet" tantalum capacitors. Seems like the case body is utilized as part of the cathode. Thus increasing the cathodes "plate" area. So using a Fluke 77 multimeter and a handful of confirmed wet tantalum capacitors I tested this out. After scratching and penetrating the protective plastic sleeve verifying indeed the case is connected to the cathode lead. I went on to test a bunch of standard aluminum electrolytic capacitors, verifying the cathode leads of these capacitors or not connected. Next up I tested some axial leaded capacitors that have the "+" markings on both the boards and the their cases. These did have the cathode leads connected to the case body? The unconfirmed axial leaded caps have no magnetic properties. The confirmed tantalum caps (all verified by mfg. data sheets & case body markings) all have magnetic properties. To add confusion there are a lot of capacitors that are not tantalum that have magnetic leads.

I'm trying to come up with more ways to quickly and positively find/confirm tantalum capacitors. My hypothesis on this so far, I got a long way to go before I become a tantalum expert. Any and all help or comments greatly appreciated and welcomed. Thanks everyone.

Can tantalum capacitors be found on low grade boards? Yes, but usually not, I have in front of me three small circuit boards that have two tantalum capacitors on them. These are from Honeywell thermostats that were made in 1991. These are the small epoxy tantalum capacitors, that come in many different colors, I call these "Gum Drops". Certainly not going to fill ones wallet quickly looking for them on low grade boards, but they do utilize them on some tan/green boards. I also have found a new color for these "gum drop" caps, black. These come from a power supply used on medical monitors, green/green boards.

Hope to post some pictures tonight.

[QUOTE=bigburtchino;229173]

looking for the plus sign markings on both the board and the capacitor.

Don't get too hung up looking for the plus sign on boards. At least 50% of the ones I find have no marking on the board.

I find that usually the circuit board is marked with the + sign, but you are correct a lot of them are not. You can't really go by the + sign on the capacitor either, as the + sign is on a lot of electrolytic capacitors also. If you take the time to educate yourself about tantalum capacitors, how they are made, the material that is used and where they are used. You can get fairly efficient at locating the type of board and then finding the tantalum capacitors on the board. I do have a background in electronics, electronics engineering degree, FCC license with a radar endorsement and twenty + years trouble shooting, identifying, isolating and fixing complex mechanical and electronic equipment. This was in my last "lifetime" and the old saying "Use it or loose it" is all so true! I like getting back into it, finding E-waste allows me to at least think about, what I used to do.