OlivierC
Well-Known Member
Hello everyone,
I have some long overdue updates for you. I'm pretty much done with the silicone mold making and halfway through my first cast.
So first, I molded the forehead part. I hesitated between doing a brushed-on mold with a hard shell or a much simpler pour-in mold. I went with the second option because I don't have much experience in mold making and it looked easier. This was my first mistake : I ended up using A LOT of silicone, a lot more than I wanted, even with an optimized mold shape. Beside the fact that silicone ain't cheap, the mold is also super heavy, which is a problem, considering I want to rotocast this part.
So I decided to not repeat the same mistake for the jaw/chin part, for which I made a brush-on mold. You can see it in progress here:
You can also so the mold for the bucket itself sitting behind, I forgot to take pictures while I was making it, because I was not too sure if I was doing it right, but I think it worked pretty well in the end. I have yet to pull the master out, as I have not made the mother mold on top yet, I was waiting for the jaw silicone to be done, so I could make both mother molds at the same time.
Then I decided to try to cast the forhead.
First I tried rotocasting it with Smooth Cast 65D, and it did not go so well :
I tried twice without any luck:
It's really hard to figure out what is happening inside your mold when you can't see it.
So then I tried to completely fill the mold with resin instead, using Smooth Cast 300 but that did not work either because that's not what I designed the mold for. Even after I cut some vents so air would not get trapped, it would not fill up because of where the pouring spout was located, it's just physics. No matter how I orientated the mold, it would either not fill up or overflow through the pouring hole I had positioned too low. On top of that, such a high volume of resine gets hard very fast, so you don't have much time to work.
So as a last resort, I tried rotocasting again, but with smooth cast 300 instead of 65D. And guess what, it worked:
This is funny because the 65D is clearly advertised for rotocasting, for its high viscosity. But in my case, this viscosity was more of a problem, because it would not allow the resin to flow everywhere inside the mold, while the 300, which is much more fluid, did.
The tip is a bit messy because the mold did not cure very well there, but I can fix it with a bit of sanding and putty. I will eventually remake this mold as a brushed-on like the others when I'm completely done with the first cast.
Next to that, molding and casting the smaller parts was like a breeze, no issue there :
The small cone is rotocast, so it gave me some practice for the big bucket
Now I just have to finish the mother molds for the chin and bucket, and cast them, which should be much easier than the forhead, for which I had to continualy rotate a 20 pounds mold for many minutes, it was exhausting
I have some long overdue updates for you. I'm pretty much done with the silicone mold making and halfway through my first cast.
So first, I molded the forehead part. I hesitated between doing a brushed-on mold with a hard shell or a much simpler pour-in mold. I went with the second option because I don't have much experience in mold making and it looked easier. This was my first mistake : I ended up using A LOT of silicone, a lot more than I wanted, even with an optimized mold shape. Beside the fact that silicone ain't cheap, the mold is also super heavy, which is a problem, considering I want to rotocast this part.
So I decided to not repeat the same mistake for the jaw/chin part, for which I made a brush-on mold. You can see it in progress here:
You can also so the mold for the bucket itself sitting behind, I forgot to take pictures while I was making it, because I was not too sure if I was doing it right, but I think it worked pretty well in the end. I have yet to pull the master out, as I have not made the mother mold on top yet, I was waiting for the jaw silicone to be done, so I could make both mother molds at the same time.
Then I decided to try to cast the forhead.
First I tried rotocasting it with Smooth Cast 65D, and it did not go so well :
I tried twice without any luck:
It's really hard to figure out what is happening inside your mold when you can't see it.
So then I tried to completely fill the mold with resin instead, using Smooth Cast 300 but that did not work either because that's not what I designed the mold for. Even after I cut some vents so air would not get trapped, it would not fill up because of where the pouring spout was located, it's just physics. No matter how I orientated the mold, it would either not fill up or overflow through the pouring hole I had positioned too low. On top of that, such a high volume of resine gets hard very fast, so you don't have much time to work.
So as a last resort, I tried rotocasting again, but with smooth cast 300 instead of 65D. And guess what, it worked:
This is funny because the 65D is clearly advertised for rotocasting, for its high viscosity. But in my case, this viscosity was more of a problem, because it would not allow the resin to flow everywhere inside the mold, while the 300, which is much more fluid, did.
The tip is a bit messy because the mold did not cure very well there, but I can fix it with a bit of sanding and putty. I will eventually remake this mold as a brushed-on like the others when I'm completely done with the first cast.
Next to that, molding and casting the smaller parts was like a breeze, no issue there :
The small cone is rotocast, so it gave me some practice for the big bucket
Now I just have to finish the mother molds for the chin and bucket, and cast them, which should be much easier than the forhead, for which I had to continualy rotate a 20 pounds mold for many minutes, it was exhausting