# Any info on this TRW Cap



## pokermandown (Sep 13, 2018)

I am trying to figure out what I have. This cap came from a 1969 or 1970 HP Analysis plug in. I have searched the web for info and they told me everything I already new by cutting one in half. It is a metalized axial capacitor. How do I tell if it is tantalum? 




As always, thank you for the assistance.


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## jimdoc (Sep 13, 2018)

If it was tantalum you should be able to tell by the weight of it. 
It is most likely aluminum.


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## pokermandown (Sep 13, 2018)

Thanks for the reply Jimdoc. it didn't look like aluminum to me. But now that you mention it, there is an easy test, I will melt it. if it melts with propane, it is not tantalum.


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## FrugalRefiner (Sep 13, 2018)

Look for posts by Göran (g_axelsson). He's described how to identify tantalum caps many times. Search his post for tantalum and other similar key words. Being a Viking, I believe he usually recommends chopping one open. :lol: If I remember correctly, tantalum should be very hard to cut through. If I'm mistaken, I'll count on him to correct me.  

Dave


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## g_axelsson (Sep 13, 2018)

Dave is correct, I'm a viking and very hard... what was it we were talking about?

Tantalum is heavy, Al foil is light. Every tantalum capacitor is a metal slug, not foil. At least the ones I've seen.
Aluminium is easily to dissolve in HCl or NaOH, tantalum is inert.

That should be enough for you to test it.

Göran


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## cosmetal (Sep 13, 2018)

g_axelsson said:


> Dave is correct, I'm a viking and very hard... what was it we were talking about?
> 
> Tantalum is heavy, Al foil is light. Every tantalum capacitor is a metal slug, not foil. At least the ones I've seen.
> Aluminium is easily to dissolve in HCl or NaOH, tantalum is inert.
> ...



Not an everyday Viking - he's a Viking berzerker.

Here he is testing the hardness of his PPE shield before attacking a PM drop. :shock: 

James


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## etack (Sep 13, 2018)

Tantalum foil will burn up in a flame. 

the caps are somewhat heavy with a Cu(CuAg plated),Al or Ag cases never plastic.

Eric

here are some common IDs on TA foil caps 
CL20,22,30,32,51,52,53,54,70,72 
CLR25,27,35,37,71,73
Military 3965 or 
39006/1,2,3,4


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## g_axelsson (Sep 14, 2018)

Thanks for teaching me about tantalum foil caps. I guess the only times I've run into them is when I repaired a couple of boards belonging to working equipment, so I couldn't cut them open and study the construction. 

Göran


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## pokermandown (Sep 14, 2018)

Big thank you to everyone that answered ( including James because your post made me laugh!) When I cut the cap in half, it was hard to cut with my best diagonal cutters, but I was unsure because the layers of foil don't cut well. I spent 2 weeks searching for info and got next to nothing useful. 24 hours after I posted the question, I have all the info I need and thanks to Göran and Eric useful info I will use in the future. Thank you all!


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## g_axelsson (Sep 15, 2018)

cosmetal said:


> g_axelsson said:
> 
> 
> > Dave is correct, I'm a viking and very hard... what was it we were talking about?
> ...


Hey! Where did you get that picture of me? I don't like how my buckteeth shows. :mrgreen: 

I do my melts without a torch, just breathing on the melting dish. Take a look at my avatar if you don't believe me. :wink: 

Göran


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## cosmetal (Sep 15, 2018)

Despite your buckteeth, you're still a treasure to GRF and Scotland.

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

Peace,
James


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## g_axelsson (Sep 15, 2018)

Very interesting, I'm probably going to Trondheim next month so I'll be keeping my eyes open to see if I can find another chess piece.

Göran


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