[theelous3]

Sure, if you want to shield a wall or container or something you will just slap lead on it, but this could be used for complex shielding of sensitive components in nuclear machinery and devices. Machining hard materials is extremely expensive and difficult (exotic material cutters or edm, with slow high precision grinding).

[userbinator]

Lead shielding is usually applied in sheets; and due to its low melting point, it can also be cast as a layer on other machined parts on applications where sheets are more difficult to use.

[theelous3]

so machine a die, machine your part, build random fixtures, cast lead on to your part...

or just print it?

It's a bit of a no brainer.

Even if you just want a shielding layer, the convenience of this will win out on low volume parts.

[kragen]

lead isn't a hard material, and if you need a hard material, this filament isn't what you're looking for either; it will be almost as fragile as pure petg

[theelous3]

I didn't say it was hard. I said machining tungsten is hard. Machining lead is also difficult and weird and the end result can be barely usable for anything, especially in hot environments or with any load. It's just not good.

If you need complex parts, this could be an excellent choice.

Idk what the confusion here is. Maybe you are unfamiliar with machining?

[proto_lambda]

The first sentence of your comment was structured like this: [reason to use lead], but [reason to use tungsten]. At least I expected the second sentence to expand on the pros of tungsten, when in fact it was about the pros of lead; interpreting it as the former would mean lead is a hard material.

[theelous3]

The article explains the beneficial properties of tungsten with rad shielding. Tungsten sheilds better than lead. Lead is easier to form to simple shapes (flats, straight forward wraps). It is essentially impossible to form it in to complex shapes. Tungsten has a high temperature resistance, and low deformation under load. Broadly speaking it can be relied upon to stay in the shape it's machined to. But getting in to that shape is very expensive and difficult - an understatement.

I can't explain everything in every comment. You can research the materials if you want to understand the discussion in more context.

Tbh I have no idea how you came away thinking I said lead is hard. "also difficult". "this" is the material that is the center point of the discussion. Context, yo.

[proto_lambda]

> Tbh I have no idea how you came away thinking I said lead is hard.

I did not, in fact, come away thinking lead is hard. I did, however, explain and spell out for you how @kragen probably did so; I'm not sure how I can make it any more clear.

[kragen]

i appreciate you being willing to clarify the things that were hard to understand or that we were wrong about

(i actually had the impression that working lead on a lathe was very easy indeed due to its softness, but i've never tried doing it myself, and my bachelor's degree from youtube is worth what i paid for it)

i think you may have misunderstood something in the comment you were replying to yourself

[theelous3]

Lead is a nightmare to machine. It's gummy. You'd think aluminum was easy because it's softer than steels, but that comes with it's own challenges. Lead is worse so. You're right that this isn't so bad on a lathe as opposed to a mill or (lol) a grinder, but you're not going to see a need for a lot of solid round shielding.

A little bit of lead in steel will increase machinability, but only a teeny amount. Similar to adding a small bit of phosphorus.

It's also hard to hit dimensions in lead, and if you do hit them, the second the temperature changes you'll lose them. Additionally, whatever you make can't see any stress, or the part is donezo.

Idk if you've ever handled lead - but considering you can bend thick sheets of it by hand and melt it on your stove, I'm sure you can imagine the kind of issues you might have integrating expensively machined chunks of it in to hot high pressure environments with moving parts.

Even though lead is cheap and this filament is expensive, actually getting the lead to shape by machining or working it is also a costly process. 3d printing has a sort of cost ceiling. Once a part is designed, all of the real work is done. For fabrication and machining - once the part is designed the work has only begun.

What might look like a small and simple combination of geometric shapes can cost thousands to machine.

I'd rather spend 500 on filament and a day's engineering labor on a part than the same day's engineering, 100$ of lead, and 1k or more on manufacturing. Not to mention the lead times on machined parts can be wild.

[kragen]

well i'm certainly no master machinist, heh

you seemed to be saying that this filament might be a better alternative to lead sometimes, but i couldn't tell when that might be. pure tungsten is clearly a better choice sometimes, for example because it shields better than lead, is harder, is denser, and is more refractory, but none of those seems to be true of this filament

from your other comment at https://news.ycombinator.com/item?id=35206874 it looks like you're saying that, although this composite is inferior to lead in those ways, it's easier to print

[Prcmaker]

We have issues working with lead at work, mostly due to toxicity. Putting a hole in a sheet isn't as simple as getting out the drill, not mechanically, but due to all the swarf that needs to be cleaned up. 3D printing a bolt-on cover would be lower risk than drilling lead, a quicker turnaround than getting a die made and lead cast, and give a prototype that doesn't need to be handled with gloves.

For the right application, there are some good wins here.

[kragen]

i appreciate the useful feedback

what do you think about copper-filled or baryta-filled filaments as cheaper alternatives

maybe this is wrong but i feel like both tungsten and copper are in the 'if you have it embedded in your body you are going to need surgery to get it out before you get gangrene' while lead and baryta are not