I need to make a mold from a sterling silver master ring. I’ll be using Castaldo VLT rubber, which requires a vulcanization temperature of 70–80°C.
How can I attach the sprue to the master ring without soldering it? Is there a temporary solution that can withstand the vulcanization process (70–80°C) and then be easily removed afterward?
I’m considering epoxy, but I’m concerned it might harden too much during the process, making it difficult to remove later.
My favorite way in this situation is to put the metal sprue and the model unsoldered but next to each other when I pack the mold. It’s usually pretty easy to find the two parts when cutting the mold apart and then to cut a link between sprue and model with my scalpel blade. I’ve done this countless times over the years.
This is an age old problem, so I’m sure others have great ideas as well.
I have used a dab of J-B Weld 8265S Cold Weld Steel Reinforced Epoxy in Castaldo VLT rubber molds to join both resin printed or brass sprues to resin printed or metal models. No damage to the mold and no problem removing the model with the sprue still attached.