Tungsten - Weight vs Cost

[Chris333]

Here is the info on the weights I had made for two 44T's:
https://picasaweb.google.com/ErieChris333/NScale#5353981070035805282

[mmagliaro]

Ok, I rechecked my math. The bar of tungsten alloy I described weights approx. 1.821 ounces for $25, or about $13.70 an ounce. I looked at the sight you referenced, and they advertise pure tungsten shapes for the price you note, but they are not useful in N scale and cannot be machined by methods available to most of us. In terms of the items not labeled pure tungsten, I did the math on the 3/8 cubes and if it takes 15 of them to weigh an ounce, it is a very low ratio alloy and not very useful in N scale.

Chris, do you know what you paid for the tungsten you procured?

All in all, tungsten alloy is not cheap but provides the benefit of greater density of lead and it can be machined.

I don't get the same results.

The 3/16" cubes and the tiny disks are very close to pure tungsten. 
(I assume you meant 3/16, and not 3/8, because I don't see any 3/8" on their site, and they sell
the 3/16 in packages of 15).

Tungsten  19.25g /cm^3
3/16" = .476 cm
So one cube = .1078 cm^3, which should be 2.076g
15 of them should therefore weigh 31.14g, if it were pure 100% tungsten.
They say this package of 15 weighs 1 oz, or about 28g.
So these cubes are 90% of the density of pure tungsten.

How is that not useful for N Scale?   

[johnh35]

Here is the info on the weights I had made for two 44T's:
https://picasaweb.google.com/ErieChris333/NScale#5353981070035805282

Yeah, i remember that post. I received a quote from tungsten.com for the same piece in my original post for $75 each. The company I am looking at using is 1/3 the price. It is 97% tungsten (97%W 2.1%Ni 0.9%Fe). Do you remember how much the piece you purchased weighed?

[johnh35]

I don't get the same results.

The 3/16" cubes and the tiny disks are very close to pure tungsten. 
(I assume you meant 3/16, and not 3/8, because I don't see any 3/8" on their site, and they sell
the 3/16 in packages of 15).

Tungsten  19.25g /cm^3
3/16" = .476 cm
So one cube = .1078 cm^3, which should be 2.076g
15 of them should therefore weigh 31.14g, if it were pure 100% tungsten.
They say this package of 15 weighs 1 oz, or about 28g.
So these cubes are 90% of the density of pure tungsten.

How is that not useful for N Scale?

For some reason my mind went to 3/8 (.375) and I calculated from there. I believe you have a good point. I will have to revisit that one. Thanks for pointing that out.

Update: Yes, I redid my numbers and you are correct. I will have to remeasure my mechanisms again to see if those cubes will fit in my plans. I figured I could get away with .125 width, but not sure about .1875. I it works, it will be cheaper per ounce.

[mmagliaro]

Oh good.   I never actually checked their density figures before.  I always just
trusted that they were pure tungsten because they say they are.

I would have hated to discover I've been wasting my time all these years
with the tungsten, if I could have gotten the same results with lead!

[johnh35]

Oh good.   I never actually checked their density figures before.  I always just
trusted that they were pure tungsten because they say they are.

I would have hated to discover I've been wasting my time all these years
with the tungsten, if I could have gotten the same results with lead!

Well, at least ya now know that the 3/16 blocks aren't pure....LOL! Now I am curious as to why everybody else is so much higher priced. Though what I priced is a 97% alloy, I cannot understand twice the price.

[Chris333]

Those cubes always looked like alloy to me with their rounded edges. I still use them when ever I can.


John, I'd have to search for the weights over at Atlas to find my post, but I did record their exact size and weight. It was 90% though. 90% is 17.12g/cm3​, 7% nickel, and 3% iron. Pure would have been 19.25g/cm3


 1/3 the cost!  I'm interested.

[SkipGear]

They are higher priced because of the market they are selling in. Desperate parents who know nothing about mechanics or physics will spend insane amounts of money to attempt to garuntee Jr. a win at the local pinewood derby.

As far as the cubes being useful. Every IM Tunnel motor I own has two of the small cubes tucked in the fuel tank. There is dead space that they fit perfectly in. I use the discs stacked inside steam domes, as caps on steam cylinders, and many other places. I will try both lead and tungsten to see which is heavier. Lead can be fitted to every nook and cranny but sometimes a regular shaped chunk of tungsten is still heavier. I have even fit lead around the tungsten to fill in the dead space. I have an assortment of at least one package of each of the smaller sizes available.

Some more usefull, but expensive options are available from Revell also in their Pinecar line. They offer cylinders that fit well in many steam loco boilers that come in 3-4 different lengths as well as some flat stock.

http://www3.towerhobbies.com/cgi-bin/wti0095p?FVPROFIL=&FVSEARCH=%3Cb%3Etungsten%3C%2Fb%3E+weights