Safer counterweight material

[ekostjuk]

Why not use solid square steel/copper/tungsten flat stock (same or more densite than lead, 100% packed/efficient vs 63-74% of sphere) + top-up with steel/copper balls for balance? Or go for local TIG electrodes.

Could probably half your counterweight container volume.

[jfuchs]

I also had this concern. My current plan is to use fender washers like these because they're easy to adjust and pack densely. I'll have to design a new enclosure for the counterweight, which will need to be thicker, but not as long.

edit: it looks like it'll take about 60 of these to be in balance for the DIYson express.

[ekostjuk]

I have kids running around the house, so anything lead is a no-no.

Managed to reduce counterweight dimensions (-50mm length, -4mm heght) by priting it from bronzefill. Single 100mm 16x16 stainless square stock+few square flat inserts did it for me for a single Ulanzi light. Would be difficult to go for dual lights or larger one without swapping that stainless thing for tungsten. Do like the new dimensions more though.

[stevenbennett]

@ekostjuk @jfuchs I am with you on wanting to replace the lead shot with a better/safer alternative. As with other components on the lamp, the answer to the question "Why not use X?" here comes down to access and reproducibility. A practical alternative needs to be common enough that folks can easily buy it off-the-shelf, adjustable enough to account for weight variances across builds without redesigns, and ideally shouldn't require additional tools to prepare it for use.

@jfuchs washer suggestion is great because it's ultra accessible, just about anyone can buy some sort of washer similar to the one you shared. And as @ekostjuk points out for the most efficient geometry we would use rectangular pieces which fit precisely within the counterweight. Seems like an ideal solution would be a set of small and dense rectangular weights that could be stacked inside of the counterweight housing. If anyone has found something like this please share a link 🙂

[jfuchs]

I have kids running around the house, so anything lead is a no-no.

Yeah, similar concerns for me.

The nice thing about fender washers specifically is that their bore hole diameter is a small percentage of their outside diameter, so if you have them stacked, you're pretty close to packing the space as much as possible — at least if you're okay with the counterweight enclosure shape being dictated by the washer. I'm considering something like this:

But on the other hand, I recognize that this breaks with the rest of the design language. Suggestions welcome.

edit:

Here's an alternative design that to me feels more connected to the DIYson express lamp holder

[legopc]

Maybe we should take a page from monitor stands a take a look at springs as counterweight?

[jfuchs]

Maybe we should take a page from monitor stands a take a look at springs as counterweight?

As I understand it, a spring's force is going to vary with its displacement — but in this case i think you'd want it to be constant across different displacements. Maybe there are kinds of springs I don't know about though!

[ekostjuk]

Long enough pre-loaded spring/elastic might be stable enough vs minimal friction across limited range of movement. Though, not stable enough with time?
I'll keep looking for tungsten stock, as front plate is also done from polished bronzefill, which adds.

[JeSuisAnanas]

How about filling the 3d printed part with sand or a sand epoxy mixture before printing the top layers?