1st attempt at casting

[Carl]

Hi just bought my 1st mold and attempted to do a casting. I think I need to really up the temperature a bit as the glass still looks like bits stuck together. The glass I used comes from broken wine bottles. Has anybody any experience they would like to share please.


P1010007 by carl.grigg, on Flickr

even though it is not what I was aiming at it is quite interesting. It is supposed to be a box with lid

[Glyn Burton]

Hi I just found your question so I hope that its not too late to give you information. Using old bottles can seem like a good idea, cheap readily available etc but the glass is designed to be stiff when molten, its easier to make bottles if the glass is not too fluid. Other problems are:
Compatability. If you are using glass from more than one bottle they may be made in different batches or even different factories so they could have radically different COE's
De-vitrification. In order to get a full melt of the glass you must maintain a high temperature for a longish period bottle glass is not designed for this so you will see de-vit  developing across the surface, it looks like a greyish scum. It is possible to polish this off but its hard work.
Its much better to use glass formulated for casting, it saves time energy and effort. Try some Bullseye, firing cycles can be downloaded from the website or Gaffer Glass which is a beautiful glass for casting.
Remember to anneal your work properly which may take some time some casts we have been making have taken 4 days to anneal and cool. Hope this is helpful.
Glyn

[Carl]

Thanks for the advice. I have since tried just a simple disk out of the same glass increasing temp and time and the fuse is not there but better but as you said De-vit became a problem. Shame I like making things from scrap. As I don't like to give up on an idea (creating storage boxes from used bottles) My next plan is to build a bottle cutter and just cast the lid out of glass better suited for casting.

[Glyn Burton]

Good luck with it, let me know how you get on with it.
Glyn

[♥♥Tan♥♥]

I really like the way you are going with this Carl and despite the devit and the fact it hasn't fully fusedit certainly has something.