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Ti Pwun · 17th Feb 2019, 6:26 pm

FAIL ONE:

Well, this initial mould was a definite fail so I'm not going to pretend otherwise. I think my problem was that I didn't use enough mould release spray, or perhaps I didn't allow it to dry for long enough.

Try as I might, I could not find my separation line at all. When a small line eventually started to open up I assumed I had found it so I separate it there.

As you can see, this was way off. The two halves were well and truly bonded together.

So, as far as the Silicone I used and the method of degassing and pressurising in the pressure pot, it worked perfectly - I don't see a single bubble where it matters.

Clearly, I need to start again with this, but I'm confident that when I sort out the release spray thing, it will work out well. Maybe I need to get a better quality release spray. I used one at £6 per can, rather than the higher priced recommendation at £14 per can, so I will look into that.

Watch this space, as they say. No point skipping this failure to show a perfect mould because that isn't what I got, but even though this was a failure, it was a partial success and I now know that the mould is good other than the fact that both halves became bonded together. I'll go away and work on that and I will return when I'm ready to colour some resin and cast a knob.

17th Feb 2019, 6:26 pm	#2
Ti Pwun Heptode Join Date: Aug 2013 Location: Bradford, West Yorkshire, UK. Posts: 888	Re: Casting a set of Vidor knobs FAIL ONE: Well, this initial mould was a definite fail so I'm not going to pretend otherwise. I think my problem was that I didn't use enough mould release spray, or perhaps I didn't allow it to dry for long enough. Try as I might, I could not find my separation line at all. When a small line eventually started to open up I assumed I had found it so I separate it there. As you can see, this was way off. The two halves were well and truly bonded together. So, as far as the Silicone I used and the method of degassing and pressurising in the pressure pot, it worked perfectly - I don't see a single bubble where it matters. Clearly, I need to start again with this, but I'm confident that when I sort out the release spray thing, it will work out well. Maybe I need to get a better quality release spray. I used one at £6 per can, rather than the higher priced recommendation at £14 per can, so I will look into that. Watch this space, as they say. No point skipping this failure to show a perfect mould because that isn't what I got, but even though this was a failure, it was a partial success and I now know that the mould is good other than the fact that both halves became bonded together. I'll go away and work on that and I will return when I'm ready to colour some resin and cast a knob. Attached Thumbnails __________________ Jon.