Newbie problems with Glass Cast 10/50

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Newbie problems with Glass Cast 10/50

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Steve Broad	Steve Broad posted 5 Years Ago HOT Topic Details
Group: Forum Members Posts: 408, Visits: 4.1K	This is my first attempt at casting and I obviously have a lot to learn. I was disappointed that the resin didn't do what is was supposed to do, that is, expel all bubbles. It looked good when in the mould but there are thousands of tiny bubbles. This was cast in two layers. The first layer was left to cure for 12 hours, as suggested by Warren. The broken T was then pressed into the resin and the second layer poured. What was surprising was that, although the resin was very stiff by this time, the T kept trying to float to the surface and had to be continuously pushed back down using a thin needle. Eventually the resin cured enough to secure the T but it was still closer to the surface than I wanted. What have I done wrong or not done so as to have so many bubbles? I mixed the resin carefully with a slow stir. I ran a heat gun over both layers. Difficult to see in the photo but there are thousands of micro bubbles in the resin. The face adjacent to the plaque is polished but the others are sanded to a matt finish. Edited 5 Years Ago by Steve Broad
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Warren (Staff)	Warren (Staff) posted 5 Years Ago HOT Post Details
Group: Administrators Posts: 2.5K, Visits: 8.2K	What temperature was the resin when you mixed it and the room when it cured? The GlassCast range of resins are quite sensitive to temperature changes both in terms of cure time and also viscosity. Even a few degrees below 20C and the viscosity will be noticably higher which means you will trap more air in mixing and it will be harder to self degas. Assuming you solve that issue, then if you still suffer with small bubbles, what can help is to run the heat gun over it in thinner layers, eg pour a few mm, run the heat gun then a few more and repeat until you get to the desired pour depth for that pour. You will get some mixing of the layers but it should on balance have more air removed. Then you can walk away and come back in 20min or so and give it another heat gunning if needs be. Just be careful to keep the gun moving and not leave it on for too long. You can try putting the Tee on a little earlier maybe? It is always a little difficult if the part is less dense than the resin as ideally you are relying on the tack of the first resin to hold it in place. Warren Penalver Easy Composites / Carbon Mods - Technical Support Assistant
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Steve Broad	Steve Broad posted 5 Years Ago HOT Post Details
Group: Forum Members Posts: 408, Visits: 4.1K	+x Warren (Staff) - 12/4/2019 9:56:02 AM What temperature was the resin when you mixed it and the room when it cured? The GlassCast range of resins are quite sensitive to temperature changes both in terms of cure time and also viscosity. Even a few degrees below 20C and the viscosity will be noticably higher which means you will trap more air in mixing and it will be harder to self degas. Assuming you solve that issue, then if you still suffer with small bubbles, what can help is to run the heat gun over it in thinner layers, eg pour a few mm, run the heat gun then a few more and repeat until you get to the desired pour depth for that pour. You will get some mixing of the layers but it should on balance have more air removed. Then you can walk away and come back in 20min or so and give it another heat gunning if needs be. Just be careful to keep the gun moving and not leave it on for too long. You can try putting the Tee on a little earlier maybe? It is always a little difficult if the part is less dense than the resin as ideally you are relying on the tack of the first resin to hold it in place. Hi Warren. Ah, not quite as good as the label suggests, then? :-) This was done on the kitchen table so temperature was around 22c. No mention of pouring in such thin layers but I will know for next time. I think the T needed to be put in later. The resin was pretty stiff after 12 hours but even after a few more hours it was still slowly rising. Just a typical learning curve I guess but I have to say that I am a little disappointed with the result based on the description of the material: Glass Cast 10 is extremely easy-to-use. It is low odour, easy to mix and measure and does not require vacuum degassing; in fact this amazing resin will drive tiny air bubbles out of the resin during the cure resulting in a perfectly clear, glass-like casting.
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