我发现玻璃胶已经干了，但我担心它还会释放甲醛。据了解，玻璃胶在固化过程中会放出刺激性气体，而且即使干了，它也可能继续释放甲醛，因为这些有害物质需要一段较长的时间才能完全散发出去。

关于玻璃胶的凝固时间，中性类型通常在2小时内表面干燥，而酸性类型则是30分钟左右。但是，这只是表面的干燥时间，而完整地干透则需要更长的时间，比如中性型需48小时，酸性型需24小时。

在进行修补时，我们必须注意到不同类型的硅酮胶具有不同的固化和粘附特点。如果要对表面进行修补，那么必须在玻璃胶表面变硬之前完成操作，这个时间取决于胶水的种类，一般来说是5-10分钟或30分钟内。如果使用分色纸覆盖某些区域，则必须在外皮形成前移除。

Glass adhesive's curing time is directly related to the thickness of the applied layer. For example, a 12mm thick acid-based glass adhesive may take 3-4 days to fully cure, but within 24 hours, the outermost 3mm layer will have hardened. When bonding glass, metal or most wood materials at room temperature, a minimum of 72 hours is required for an adhesion strength of 20 pounds per inch.

If you use glass adhesive in a sealed environment where no air can escape and there are no gaps or openings for moisture or air to enter from outside during curing process then it could remain in its liquid form indefinitely.

When working with metal and metal surfaces ensure that any debris is removed before applying the glue. The surface should be free from dust and oil residue before application. Ensure all surfaces are clean and dry before application.

The above information provides insights into how long different types of glass adhesives take to dry and harden as well as their bonding properties while ensuring safety by minimizing exposure to harmful substances such as VOCs (Volatile Organic Compounds).