After quite a hiatus, we’re up raring to try out our silicon mould and casting techniques again on 3d prints! This time though, we will try to make things a little easier by slight tweaking the initial mould box and getting that also 3d printed out, instead of forming it out of acrylic like we did before in this earlier post.
So this is what it looks like when the STL model file is opened. For this case, its important that the model comes with a flat back surface.
From there, it was a simple matter of modelling a mould box around it. In order to save on the silicon mould material, we opted to make quite a tight box but allowed the side walls to go about 3 times the height of the model. This comes in really handy as we’ll see later on.
All modelled up and then we spun it through the handy Makerbot slicer to get it ready for print. Ain’t going to go deep into that as that’s the easy bit. Here’s the physical 3d print on the right. The model on that left is already a reversed negative model box which was also found on thingiverse but in the end didn’t turn out well (so we’ll ignore that…)
As per the steps, pour the A-B 50-50 volume mix of silicon into the mould box, carefully and slowly to avoid trapping air bubbles in it. As you can see. hand protection is handy (heh, see what we did there?) here more to so avoid messy goop getting on you.
Then it’s time for some patience as the silicon mould sets. Best to leave for a full day for it to fully cure before demoulding.
Next day, simply pop it out and tada, a perfect negative silicon rubber mould of the original object!
And here’s the really nifty part – because the silicon rubber mould was cured in the box enclosure, you can simply flip it around and fit it back in to get a rigid structure to hold your mould for the resin pour.
Stage 2 just sees us mixing up the 50-50 vol resin material for pouring and…
A quick and careful pour gets the material into the moulds. This is almost an after-picture as white generall means it’s near the end of curing. They start of as a kind of translucent pale colour and you see the white bits slowly bloom as parts of the material cure.
Pop the rubber mould out, then pop the recast piece out and voila – great replica of the original piece in much less time than it would take to have printed a new piece! Also, the fidelity of the recast is so good that the 3d print layer lines can still be seen.
Well, that’s it for now – a simple trick to make recasting piece much easier. Maybe more complex 3d prints and moulds will come soon in the future! 😉