Hi,
I got all excited by the recent Warm Glass sale and bought a couple of casting moulds for making beads. The instructions say that you get a better finish with Boron Nitride Spray, so I used some that I had previously bought (but never used) from Reading Stained Glass (EKamold TG).
Using the Nano bead mould, I read and followed all the instructions, sprayed 3 thin coats of Boron Nitride on the mould before filling it with the recommended weight of frit and firing using the schedule printed on the Colour de Verre sheet for the mould.
Every single bead stuck where the mould comes up in the centre of the bead, so now I have a ruined mould and a pile of beads with ceramic stuck in the middle :(
Can anyone give me any further advice on using Boron Nitride spray before I use (and possibly ruin) the second (Round Bead) mould that I bought?
I thought Boron Nitride was for steel moulds?
Edited to add:
Just seen that it says can be used on ceramic moulds.
However, it does say on the instructions that it is best used at lower temperatures (704 deg C) as it is more likely to burn off at higher temperatures.
I know when I did a frit casting into a small plaster mould, I went up to full fuse, or at least a tack fuse, which would be around 760 on Bullseye
What temperature did you go to?
Warm Glass recommend Primo for the colour de verre moulds:
http://www.warm-glass.co.uk/primo-primer-p-2808.html
That is such a shame, I bought a few different ones too, but haven't used them yet. The video show them using a spray and I have read about other people in the US using the spray successfully, so I would be interested in the advice too. Maybe it would be worth emailing warm glass for advice.
Hi Zeldazog,
My firing went up to 770C as per the leaflet here: http://www.colourdeverre.com/docs/65.pdf which also says that if you use MR-97 (the Boron Nitride spray that Colour de Verre recommend) rather than Primo for this mould, there will be less need for coldworking since the beads will have smooth surfaces and fewer or no "spurs".
The can has the warning about higher temperatures, which directly contradicts the CdeV advice.
I don't have much room or any equipment for coldworking, so I bought the spray specifically so that I could avoid as much coldworking as possible.
The Boron Nitride spray that Warm Glass sells doesn't say or show that it is MR-97, and is quite specific on temperature, so I am guessing that there's something different in the formula somehow (in the same way that batt wash, shelf primer, whatever you want to call it, is different I guess?).
Was the spray that you got from Reading Stained Glass MR-97 or another brand?
As for cold-working, for small items and removing spurs, you could consider diamond hand pads, they are only the size of a dish sponge; no need for expensive and room taking equipment then?
Just reading this Elaine, you must be gutted that your first firing ended like this :( I find that a carborundrum.....I'm sure that spelling is wrong......stone is great for getting rid of larger spurs and the diamond hand pads that you can pick up dirt cheap on ebay are fantastic for finishing off
Hi Dawn,
It was EKamold TG, which is the same one that Warm Glass sell. You're right, it has probably got different properties from MR-97. The MR-97 blurb says "contains 3 times more boron nitride than other brands". OTOH, I've not (yet) seen MR-97 on sale in the UK.
Tan: Yes, I was somewhat... disappointed... It's a good thing that no-one was within earshot!
I have some diamond files and a carborundum stone - not bought any diamond pads yet but they are "on my list". I would imagine that it is cleaning the inside of the bead which would be tricky.
Perhaps I'll just try the other mould with Primo. After all, you can use Boron Nitride after using Primo on a mould, but not the other way around.
I'd wondered about trying boron nitride spray in a cabochon mould - I watched the video and liked the idea of no cold finishing too! But I was put off by the price of it, and from the sound of it I was lucky.
I've just been searching online for info on MR-97, and found this interesting discussion on Linked-in:
http://www.linkedin.com/groups/I-am-having-problems-boron-713837.S.165674026
Someone mentions a supplier of MR-97 in Reading; and there is some explanation of why it copes with higher temperatures.
I like the sound of the Primo, too, I hadn't come across it before. Still learning!
Primo is great stuff I have never ever had any problems with it
Hi Moira, thank you for the pointer to that discussion - it was very interesting. The "supplier in Reading" is the place where I bought my current BN spray and they didn't have MR-97 in stock when I last popped in there so maybe they decided not to order a competing product. When I'm next down that way I will go in and ask.