In the past I used ball bearings and steel disks for weight. However, this time I wanted to try out sand since this particular model had lots of nooks and crannies. So I had the second print pause at 4 layers before it was about to close off the top and with a funnel and cup, I poured sand into the cavity.
I do not recommend anyone do this at home. I was not able to vacuum or blow all of the sand out of the lead screws and I can hear the grinding. Hopefully, I won’t have to replace them. But lesson learned.
Well I’ll have to thank you for sharing your experience. I would never have thought about the sand blowing everywhere! I genuinely got a good laugh at your expense there.
Other than the obvious problem you have experienced, there is another one you may not have considered.
Thermal mass. Many things you may wish to throw inside the model as it prints to add weight or just for fun will add a change to the total thermal mass of the print. Sometimes a little, sometimes a lot.
Imagine (please do NOT do this at home kids) pouring water inside your model during the print. As a good conductor, the water will absorb the heat from the print and cause significant problems whilst printing.
Sand holds its temperature very well (people are now using it in long-term thermal energy storage solutions), and the sand would affect long and warm prints with unknown outcomes.
You are better off adding things in that are not good conductors.
If you wish to sand or even water, make your design capable of having those poured in after the print has been completed and then screw a cap into the hole you used.
Oh man, I’m sorry for you. As you talk fish, a better weight may be lead fishing weights, or wheel balancing weights. You can buy them at reasonnable bulk price although for sure fish tank gravel is cheaper but also lighter. They can be bought at a very small price on aliexpress but I will be wary of purchasing them there, both are not supposed to be real lead (toxic) but on aliexpress who knows…
I’m sure any tire repair shop will have plenty used ones they need to recycle at a cost (unless they actually sell them to the metal recycler…), they may be just willing to part with them for free if you ask them. I will try that myself because your story gave me some ideas
Been there, done that…
Wasn’t as dumb to use sand though, no, I did it properly and used runny plaster mix ROFL
Let’s just say that prints are not always as watertight as we think…
Anyway…
I no longer do too fancy things but in case the need arises again I have some leftovers.
In particular a good quantity of Field’s Metal.
There is better fusible alloys out there, not containing heavy metals, but I got it rather cheap and for my purposes it won’t matter.
How does it work?
You CAN do it like with the sand…
But I prefer to just leave a small hole in the bottom.
I have some tea pot in mini size, barely good enough to make a single, small cup of tea…
In goes the metal and then the pot into a big one filled with water on the stove.
Let is slowly simmer away…
Then just take the pot, dry it off and fill the metal into the print…
Not as heavy as lead but close enough…
Avoid alloys containing Gallium if you want to use this to make casting or if you don’t want to risk giving all in contact a grey stain…
I’m intrigued, where does one source steel blasting media? Do you have a link?
I’ve refrained from using lead only because it costs too much to transport by weight for some reason from Amazon sellers. My local sport shops only carry fishing weights which don’t allow for dense packing due to their unusual shape.
As example of the lead weights I tried were these on Amazon.
Thank you. This material looks very promising. On a cost per pound basis it is very appealing and its small size should nicely pack densely inside any cavity.
I do use sand as a regular weight-increase infill, and I love it. But I adapted the design to fill it after printing, e.g., a small hole in the bottom, using a funnel to fill and a respective plug, thread or not, or whatever fits best to close and seal it.
Depending on the sand origin, moisture is one issue you may or may not have noticed. Sand can absorb moisture, and I made a stupid error in sealing it inside a print. I also like to fill the void volume and avoid the maracas sound.
I learned from sunshade bases, which require heavyweight to be stable. Manufacturers recommendation is always sand.
To your point, I ran two experiments with the sand I have, though I haven’t used it in a print yet. I didn’t account for the fine silica dust from sand abrasion inside the bag, which surprised me. Even after cleaning up the loose sand inside the printer, there was a coating of fine dust on the camera and everywhere else. As a result, I applied a trick I learned for cleaning dust from activated charcoal: I washed the sand under running water through a mesh cloth to remove all the silica dust. This also filtered out finer particles, leaving behind the heavier grains I wanted. I then baked it on parchment paper in the oven at 200°F for three hours to remove the moisture. I now have that desiccated sand in a container ready for the next phase of my experiment.
BTW: This I’m told is another way of making a poor-mans desiccant bag out of readily available material although I have not tested that theory.
For the next phase of my experiment, I’m borrowing a trick from the furniture repair industry. I plan to pour the sand into a 3D-printed open cylinder and apply cyanoacrylate glue (Crazy Glue) on top. This method, seen in YouTube videos for repairing chipped flakeboard, supposedly creates a strong shell, effectively trapping the sand. The videos were impressive; the sand and Crazy Glue mixture not only cured quickly but was workable like wood. Once I stabilize the top layer of sand into a hardened shell, I can seal it with the remaining 3D print without worrying about the sand being blown around by the nozzle fans. Or so I hope.
Careful with that superglue. By the sound of it you are going to pour a fair amount of superglue in your print to seal the sand but the curing will emit vapour that combined with humidity depending of the RH level in your room/printer (or your sand) will leave white residue (remember those CSI episodes using superglue to reveal fingerprints?) that could stick to your model but also on the surroundings (and just a bit could prevent your next layer to stick)
Oh C’mon Philch!!! Chill… That’s nonsense and you know it my friend.
As you know, cyanoacrylate cures instantly, which is one of its main selling points. I’m only talking about doping the surface with a few drops anyway, not impregnating the entire volume of sand, so vapor risk is low and no more so than if I just glued two items together. The CSI episode you’re referring to BTW. uses a fuming method with heat to create superglue vapor in a chamber with a lot of glue. My use won’t apply any heat after the the few drops of the product has set and cured.
Here’s just one example video of how little one needs to create a hard shell and how it behaves and how quickly too. Just a few drops and you get a nice instant hard candy shell.
This technique featured in the video is what I intend to experiment with. It’s a brilliant and uncommon application of a product. My original idea was to print a 1mm cap over the sand before resuming the final sealing print. Then I thought of using superglue to affix that cap when I remembered YouTube videos showing how superglue hardens sand, serving the same purpose as my printed cap would have. Again, its an experiment so I haven’t proved it will work at this point.
Here are scores of other videos showing the same principles in use, from fixing cracked ABS to making odd-shaped sanding tools. Some use sand, some baking soda even concrete. I mean, who knew just how versatile Superglue can be? Not me, for sure, if it weren’t for YouTube.
1st in Beach Contest given… Back to the drawing board I guess
