# Wet tantalum?



## Kaiser613 (Feb 27, 2020)

Came across these metal bodied axial capacitors, with polarity markings, ripped one open but instead of the anticipated tantalum pellet, they're wet electrolytic, with wrapped film, I doubt they are, but could these be wet electrolytic tantalum? 

If not, what am I looking for to seperate these from tantalum (without ripping them open) also metal bodies are non-ferrous and very soft, ripped with nail nippers, could they be silver metal? 

These came out of a 1960's Texas instruments magnetic tape program recorder, the boards contain a lot of components I don't immediately recognize, I'll have to go over them very carefully, I suspect silver mica caps too


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## Thipdar (Feb 28, 2020)

Kaiser613 said:


> Came across these metal bodied axial capacitors, with polarity markings, ripped one open but instead of the anticipated tantalum pellet, they're wet electrolytic, with wrapped film, I doubt they are, but could these be wet electrolytic tantalum?
> 
> If not, what am I looking for to seperate these from tantalum (without ripping them open) also metal bodies are non-ferrous and very soft, ripped with nail nippers, could they be silver metal?
> 
> These came out of a 1960's Texas instruments magnetic tape program recorder, the boards contain a lot of components I don't immediately recognize, I'll have to go over them very carefully, I suspect silver mica caps too



I think what you've got are "aluminum electrolytic capacitors" that contain no Tantalum.

https://en.wikipedia.org/wiki/Aluminum_electrolytic_capacitor

If you want to know for sure, have some analyzed: https://www.azom.com/article.aspx?ArticleID=8451

-- Thipdar


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## anachronism (Feb 28, 2020)

Try a piece of the metal wrapper in HCl


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## snoman701 (Feb 28, 2020)

Looks like aluminum canister tantalum foil.

But the picture sucks, the crimp is right for silver canister, so check it with acid. 


Sent from my iPhone using Tapatalk


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## Kaiser613 (Feb 29, 2020)

http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=142281082566&category=4662&pm=1&ds=0&t=1583016912160


Anyone have more info on "tantalum foil e-caps" 
I have a 50 microfarad thats the same diameter and very visually similar, with a similar capacitance density (3in long 200microF, .75in long 50microF) if aluminum vs, tantalum, there should be a gap in volumetric capacitance density, yes?

Will test bodies with hcl sometime this week (have to obtain more acid,) what acid would attack Al / Al oxide to test foil?

Sorry about photos, they're resized, look at this picture, notice one end I'd crimped around some kinda rbber plug, the other end is "cupped" with a flat face and square shoulders, with the other lead crimped in nipple, and how thats different from eBay item pictured

Trying to nail down externally visible details about construction so they can be roughly ID'ed without acid testing


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## jimdoc (Feb 29, 2020)

Did you look through this thread?

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=59&t=15909


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## Kaiser613 (Feb 29, 2020)

They look a LOT like the pictures of WET tantalum. On page 7 of that thread, also the silver case pictures,plus mention of foil caps, I found this data page from vishay for ALUMINUM e caps

https://www.google.com/url?sa=t&source=web&rct=j&url=http://static6.arrow.com/aropdfconversion/c0fc1eca544286791784e54470b74cfd2522afa0/28328.pdf&ved=2ahUKEwjUyuO9kfjnAhXyV98KHbywDHgQFjABegQIAhAB&usg=AOvVaw1FnjjmKvh49yrJ01hka0oh&cshid=1583026818051

But it doesn't line up 100% the sizes don't match the included chart and there's only half the markings mentioned in datasheet (no date code, temp code, no manufacturer name, ect.) Vishay is old enough to have provided components to this device, I guess we'll find out tomorrow, after acid test


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## etack (Mar 2, 2020)

Any and I mean any wet Ta cap that is a foil style will be crimped in both ends with a Ta wire that will be square. Also wire will be coming out of both ends and will be plugged on both ends like a wet TaAg cap. 


I have and have seen many Ta foil style caps they will also have a feel and smell of sulfuric acid. 

Any questions send a PM or ask. 

Eric


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