Tungsten Putty Weight?

Randy Clark Mar 16, 2019

  1. Randy Clark

    Randy Clark TrainBoard Member

    Has anyone had success over the long haul using tungsten to replace the lead/steel wights in compound locomotives? I just ordered some weights to bring a dozen freight cars up to NMRA weight standards and while I was at it ordered some tungsten putty to try and increase traction in a couple challengers and v=cab forwards.
  2. John Moore

    John Moore TrainBoard Supporter

    I have used Tungsten Putty for years now in steamers and locos in addition to the factory weights not as replacement weights. I simply tuck some putty into the void spaces being careful to try and maintain balance. The improvements have been an increase by at least 10 more cars in a consist and more, and a marked improvement climbing grades. My Class A Climaxes have quite a bit of Tungsten putty in them and they are good for 8 cars up grades of 7% and more on lower grades. Double headed they have pulled 16 to 18 cars up that steep of a grade.
  3. Randy Clark

    Randy Clark TrainBoard Member

    WOW! I am only looking to get 2 or 3 more Kato or Micro Trains Heavyweights behind a Challenger. I extended the grade by rasping and power sanding the foam roadbed. I can get 5 Kato streamliners up the grade with the Athrearn Challenger. Tomorrow I should get by extra weights. I have my Cab Forward pulling 18 Micro Trains 37' reefers and I am happy with that. Wish I had the room for the mileage of track and no heavy grades but most of us are a victim of space.

    JIM SIDDY New Member

    Hi from the UK. I have had a very little experience with tungsten putty myself, but some modellers have found that the putty can ooze out of position, even at normal operating temperatures. Some brands also seem to have an oily base which in theory could attack plastics and rubber components in the long term ? I know a few people have cast or formed weights from Tungsten powder bonded with epoxy resin - which would seem a better solution as it would remain stable once cured , though i have not tried yet.
  5. DCESharkman

    DCESharkman TrainBoard Member

    As one spoiled with the space for the layout, it is still needed to sometimes add weight to some locomotives. I haven't used tungsten, I opted for very small lead shot that I cast into a weight that will fill a void. I have had to do this with my Minitrix Pacifics, and once I get my Kato Mikado's back from sound decoder installation I will be adding more weight to them. Even with a slow 1.5% to 2.5%, a Mikado should pull more than 10 cars.

    When no one is looking, I love to watch a set of 4 Kato SD90MACs pull 120+ cars up the same incline......
  6. Tony Burzio

    Tony Burzio TrainBoard Supporter

    There is a difference between tungsten and tungsten putty. Tungsten putty is mostly putty, so it depends on the maker how it behaves. Solid tungsten is a LOT heavier, and you have to tell them why you want it (KABOOM!). . I got tungsten scraps.
  7. gary60s

    gary60s TrainBoard Member

    I've used tungsten powder (99% pure) mixed with elmers glue with great success weighting locos. You want to be sure you dont add too much weight, as you can ruin an engine. Mixed to a thin enough consistency you can even paint it on. I used to get it from Golfsmith but you can now get it on ebay.
  8. r_i_straw

    r_i_straw Staff Member

    Solid tungsten shapes in various small sizes can be obtained at some of the Pinewood Derby web sites. I go as far as grinding and cutting them with diamond rotary bits in my Dremel tool to make them fit. My tiny 4-2-0 has its cab full of it and can pull about 10 MT Civil War cars.
  9. Randy Clark

    Randy Clark TrainBoard Member

    I received a 2 oz. can of putty this morning. Kind of s=disappointed. I was able to get a minor amount of traction but I am leaning towards solid tungsten to get larder increase. There are only 4 spots in a challenger that i have found where added weight can be added. All are in the domes in the boiler and under a board in front of the cab. I really need to compare what was removed vs what was added.
  10. gatrhumpy

    gatrhumpy TrainBoard Member

    I have used the tungsten putty for years. I can cram that into tiny spaces (i.e. the space under the boiler on the Bachmann 2-8-4).
  11. Maletrain

    Maletrain TrainBoard Member

    I am thinking that it might be a better use of free volume to cast lead into the shape of the available spaces. I could make a casting of the volume, then a mold from the casting, and then pour lead into that. Does anybody know the actual density of the tungsten putty? If it is much less than solid lead (or, really, solid wheel weights) then it might be worth the effort to make lead castings.
  12. Inkaneer

    Inkaneer TrainBoard Member

    Rather than casting the weights in lead I think it would be better to cast them using tungsten powder and casting resin such as Envirotex. That stuff will flow into the tiniest of holes or spaces thus ensuring that the tungsten powder was fully encapsulated. The result would be something much heavier than lead or tungsten putty. You will need to watch the weight lest you exceed the models ability to absorb the increased forces.
  13. Maletrain

    Maletrain TrainBoard Member

    It is not clear to me how the tungsten powder or putty compares to solid lead alloy by weight.

    Pure tungsten has a density that is about 1.7 times the density of pure lead. So, the tungsten in putty or epoxy would need to make up about 59% of the mixture to give the same net weight as lead. If the Tungsten "powder" is made up of tiny spheres, and they become "randomly packed" they will take up only about 64% of the volume. Perfectly packed, they would take up as much as 74% of the volume. If the powder particles are not spheres, then they might pack better or not as well, depending on shape. The putty probably has more light weight stuff in it than a space that has been packed with the powder and then infused with penetrating epoxy. So, it looks like using packed powder and epoxy might give a density that is 9% to 25% heavier than solid lead. Not so sure that 9% is worth the cost, but 25% probably is. Since the putty is not likely to have as much tungsten as the packed powder of the same volume, I am not at all confident that the putty is better than cast lead. That is why I am asking for somebody to tell me the actual density of the putty.
  14. Mike Madonna

    Mike Madonna TrainBoard Member

    Good info Russell, thanks!
  15. Flak

    Flak TrainBoard Member

    Back in the old days I just used the crushing weight of my disappointment at how engines ran out of the box. Down side is you'll occasionally lose an engine to suicide, but standards are standards.
  16. NDave

    NDave TrainBoard Member

    According to a seller of Pinewood Derby supplies, the MINIMUM density of tungsten putty they sell is 10g/cm3. The density of lead is 11.3 g/cm3.

    A supplier of tungsten powder quotes a density of 11.5 g/cm3, and says it can be packed to densities above 15 g/cm3.
    MK likes this.
  17. Maletrain

    Maletrain TrainBoard Member

    OK, I found some info on tungsten putty: https://www.maximum-velocity.com/product/tungsten-putty-1-ounce/ . It says the minimum density is 10 g/cm3, which is only 88% the weight of solid lead. It also says that their "nominal 1 oz weight" ranges from 0.9 to 1.0 oz. So, a little math results in their putty ranging from 88% to 98% the density of solid lead. So, to me, using the putty is a trade-off between convenience and cost. But, there is also the factor of hardness. Their putty stays soft, while cast lead is hard enough for making surface detail and can be painted.

    I also found some info on tungsten powder: https://www.tungstenheavypowder.com/tungsten-powders/ . It says their powder has a density of only 11.5 g/cm3, which is almost the same as pure lead at 11.34 g/cm3. But, they say their powder can be compacted to densities above 15 g/cm3, which would be maybe 33% better than pure lead. However, it isn't clear how well penetrating epoxy would penetrate the heavily compacted tungsten powder in order to stabilize it.

    So, to me, casting lead is looking pretty competitive to using soft materials that are weighted by tungsten content. Considering how hard tungsten metal is, and how high its melting point is, I don't see any way for the normal hobbyists to make shapes with pure tungsten metal.
  18. Randy Clark

    Randy Clark TrainBoard Member

    I received a batch of lead stick on weights yesterday. I may hammer some of them into shape and see if they provide better traction than the tungsten putty.
  19. catfan

    catfan TrainBoard Member

    I hope what you did receive was actually Lead. I'm not sure what the wheel weights we use in our automotive are made of now. But it isn't lead.
  20. Maletrain

    Maletrain TrainBoard Member

    Also, the wheel weights don't have the same density as lead, because they contain some tin and antimony. But, I do have some pure lead that I can use for weights. For anybody thinking about using solder as "lead", remember that it has a very high tin content, and, depending on the version of the solder, maybe no lead.

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