I haven’t seen this topic anywhere yet, but has anyone ever paused a print before the top layers in order to fill the print with something (like epoxy resin) to make the finished print more robust and heavier?
I’m making a bunch of different beer tap handles and they feel way too light, and filling them with something to weigh them down would make them feel more “real”, if that makes sense.
There is a pause function either on the printer or it can be inserted in the g-code, but you can’t just remove the unfinished print, fill it and and place it back expecting everything to line up perfectly. You would always get some layer shift as the sheet can be placed in a slightly different position.
But if you use gyroid infill, you should be able to drill a small hole (or rather two) and fill the model with epoxy after printing if it’s just one body… in theory. Let us know how it goes 
How about printing it in two parts – with a hollow section in the main body for filling and a cap to seal everything up?
To be clear, I wouldn’t be removing the prints from the bed… just using a small container to pour in weighted substance X (which now that I think about it could be something like BBs).
The 2-part print idea is intriguing. Thanks for the ideas!
PS - The correct process would be to “prototype” the part and make a silicone mold from it, then use resin to crate the part. But the 4-color AMS just makes things so much prettier than a 1-color pour.
Something like this would make more sense since it wouldn’t potentially destroy your bed/printer if you accidentally drop a few.
Pouring epoxy in to a print on the bed seems like a particularly bad idea.
If the print leaks, or you spill any, you’ll be epoxying the print to the print bed. And “leveling” the epoxy so it doesn’t interfere with the subsequent printing might be tricky, unless you just “underfill” the part so there’s space above the liquid level.
Also, waiting for the epoxy to cure might be problematic. The print is going to change size slightly as it cools, and when you resume printing there’d likely be a visible layer line/discontinuity.
If your objective is weight alone, filling with BBs is a better idea. But that won’t improve strength. Have you considered 100% infill?
A few years ago I designed and 3D printed a dummy radial engine for a RC airplane. The model needed nose weight to balance, so I printed the cylinder heads hollowed out. I filled them with a “slurry” of epoxy and some stuff the model railroad hobbyists use to add ballast to their rail cars (basically, steel or lead shot, but available in various gauges from stuff the size of BBs down to stuff that’s almost like sand).
Search for “model railroad ballast” and you’ll get tons of hits.
This sounds like the move. Thank you!
I’m doing this for a while, just not with epoxy. Dunno if there is some epoxy that is thick enough to “stay and cure and do not spill out” but I tried few times and I had issues of epoxy leaving part through walls (leakage) and also I had issues where epoxy would heat up during curing process and destroy the part… there is another thing that I do for almost a decade … I print using octagon pattern, I pause before the solid layers, I fill all holes with scrap metal, scrap lead & iron bits and pieces and then I fill that with low temp glue gun (one from 3M with those yellow low-melt sticks that Adam shows here: Adam Savage's Favorite Tools: Best Hot Glue Gun! - YouTube ) and then I hit resume and close the part up… these 3M low-melt sticks do not mess up the PLA and do not leak through PLA nor ABS nor PETG walls. Another two options I use is to leave “bigger” hole inside the part to embed a piece of steel (a bolt, a rod, piece of tubing, nut …) pause, embed the steel piece that fits snugly so no need to glue to stop rattling inside, resume and finally sand/gravel, for e.g. I was printing some “self rising dolls” that needed to have heavy base and I did a sparse 10% hexagonal infill, paused, filled with sand, resumed, worked great…
So basically your idea is good only the issue with resin is that it tends to heat up during curing and tends to find a way to leak through otherwise watertight part so mixing some filler (lead, iron, steel, sand) and low melt glue gun is more less same idea only works ok
Yeah. I’d thought about epoxy heating up as it cures, and that might also be a problem for the plastic even if the epoxy doesn’t leak. It wasn’t a problem when I did the epoxy/ballast slurry to fill my dummy radial engine cylinders. But. I diluted the epoxy with about 30% IPA so it was more liquid. That made it a lot easier to pour. It weakens the epoxy, but I wasn’t going for maximum bond strength anyway. But I’m thinking this IPA dilution may have reduced the temperature the epoxy reached while curing.
Yes, possibly IPA can help, I’m not that experience with epoxy to know, there’s maybe also some epoxy that is slower to cure but do not heat as much, also not sure what plastic OP is using, ABS or PA might not be problematic. I tried resin with PLA and it was terrible idea 
Anyhow filler + these low-temp hotglue’s are solution that works great for me. 3M is 130-140C but cools pretty quickly and while temp is much higher than PLA’s Tg it never deformed PLA while I was filling it with it. Issue I have with 3M sticks is that they are rather hard to get in Europe and are very expensive so I use more UHU 110C version that works even better and is much cheaper to get than 3M ( https://www.amazon.de/-/en/gp/product/B000GPI7RW/ref=ewc_pr_img_3?smid=A6P2RX1M0AXS4&th=1 below 10$ for 200g). Even with resin I think it would be much better to fill the part with filler first and only then add resin, there are professional resin fillers like crushed granite, other different crushed stones, metal shavings and of course simple sand 
… your diluted resin will mix even better with sand …
I’m only not sure how long this will take to cure, will diluted resin leak through walls, note that you need to have your bed heated all these time so you do not get your print unstuck, printer working non stop top not lose position… I doubt you can continue print immediately after pour? The mess & damage this will make if it leaks… This is why I love those low-melt hotglue sticks, they cool off and solidify in minutes, no mess, no risk, and you do not need a lot of glue, basically just to “fix” the filler so it does not rattle.
I wouldn’t use epoxy as a filler.
It heats up a lot while curing (enough to soften PLA) and it shrinks a lot.
If you’re a fan of disaster movies you can give it shot though. 