<p>In my opinion, filling large busts with casting resin is a waste of money. Plaster is a much more viable option, but it doesn't stick well to the walls.</p>
<p>I would try simple construction silicone or caulk. It's readily available and relatively cheap. Silicone sticks to almost everything and can increase the strength of the printed walls. You can mix in fillers like sand or stones if you need to increase the weight of your busts.</p>
<p>I don't know if it's an advantage or disadvantage that construction silicone doesn't flow into holes.</p>
<p>However, you cannot simply fill the bust up to the brim with silicone. The lower areas won't be able to cure and therefore won't improve the integrity at all. You'll have to create a second wall of silicone inside the 3D printed wall to allow curing.</p>
<p>To help in the application of the silicone, prepare a small water bowl with dishwashing soap. Anything that is coated in this water (inclusing tools and your fingers) won't stick to the silicone. But if a section of silicone wall is covered with this water, freshly applied silicone also won't bont to it.</p>

CC BY-SA 4.0
2024-10-07T15:55:02.423Z
2024-10-07T15:55:02.423Z
Elmy
<p>I have a number of large scale 3D printed statues\busts created using an industrial resin printed.</p>
<p>For various reasons prints on this scale are frequently printed as hollow shells several MM thick, with a light support lattice inside.</p>
<p>In order to allow unused resin to drain the prints have multiple drain holes punctured through them in software, and sometimes additional drainage holes drilled after printing.</p>
<p>The prints are very light weight, and have little strength to them. This is an inherent weakness of the printing process.</p>
<p>I plan to use the models as blanks to create silicon molds using two part mold making silicon. I am concerned that the extraction process may cause the prints to crack or collapse in on themselves if put under too much pressure. Making it impossible for me to reuse them. For example if the initial molds failed in some way and I wanted to make more.</p>
<p>What would be an appropriate substance to fill the models with to make them solid. For example, two part casting resin?</p>
<p>The interior of the molds will have been washed with industrial grade IPA, drained, and placed on a warming rack evaporate the remaining IPA, before being washed down with water and detergent. There may still be uncured resin residue inside, as well as IPA.</p>
<p>I would normally use sand or plaster to fill hollows in non 3D printed busts. For example, kiln baked clay busts where a packing medium has been burned away during firing, but have previously had issues with doing this with 3D prints.</p>

CC BY-SA 4.0
2024-11-06T08:52:54.130Z
A very tentative suggestion, that depends on the internal shape (hence why it's a comment): I wonder about filling the majority of the volume with a wooden structure (which could in itself be hollow) and pouring resin to fill the gap between the shell and the wood.  of course in a  traditional bust, getting much wood into the head section would be like building a ship in a bottle.  But bulking out the resin with sawdust would also be an option; the limit is probably the need to keep it runny enough to flow
Chris H
<material-selection>
Filling a hollowed out 3D printed model?
Aaargh Zombies
# Filling a hollowed out 3D printed model?

(Asked by: username_0 on 2024-10-02)

I have a number of large scale 3D printed statues\busts created using an industrial resin printed.

For various reasons prints on this scale are frequently printed as hollow shells several MM thick, with a light support lattice inside.

In order to allow unused resin to drain the prints have multiple drain holes punctured through them in software, and sometimes additional drainage holes drilled after printing.

The prints are very light weight, and have little strength to them. This is an inherent weakness of the printing process.

I plan to use the models as blanks to create silicon molds using two part mold making silicon. I am concerned that the extraction process may cause the prints to crack or collapse in on themselves if put under too much pressure. Making it impossible for me to reuse them. For example if the initial molds failed in some way and I wanted to make more.

What would be an appropriate substance to fill the models with to make them solid. For example, two part casting resin?

The interior of the molds will have been washed with industrial grade IPA, drained, and placed on a warming rack evaporate the remaining IPA, before being washed down with water and detergent. There may still be uncured resin residue inside, as well as IPA.

I would normally use sand or plaster to fill hollows in non 3D printed busts. For example, kiln baked clay busts where a packing medium has been burned away during firing, but have previously had issues with doing this with 3D prints.

**Tags:** material-selection

> **Comments:**
> **username_1**: A very tentative suggestion, that depends on the internal shape (hence why it's a comment): I wonder about filling the majority of the volume with a wooden structure (which could in itself be hollow) and pouring resin to fill the gap between the shell and the wood.  of course in a  traditional bust, getting much wood into the head section would be like building a ship in a bottle.  But bulking out the resin with sawdust would also be an option; the limit is probably the need to keep it runny enough to flow  

---

## 1 answers

### Answer by username_2 on 2024-10-07. Score: 2

In my opinion, filling large busts with casting resin is a waste of money. Plaster is a much more viable option, but it doesn't stick well to the walls.

I would try simple construction silicone or caulk. It's readily available and relatively cheap. Silicone sticks to almost everything and can increase the strength of the printed walls. You can mix in fillers like sand or stones if you need to increase the weight of your busts.

I don't know if it's an advantage or disadvantage that construction silicone doesn't flow into holes.

However, you cannot simply fill the bust up to the brim with silicone. The lower areas won't be able to cure and therefore won't improve the integrity at all. You'll have to create a second wall of silicone inside the 3D printed wall to allow curing.

To help in the application of the silicone, prepare a small water bowl with dishwashing soap. Anything that is coated in this water (inclusing tools and your fingers) won't stick to the silicone. But if a section of silicone wall is covered with this water, freshly applied silicone also won't bont to it.


---

