steam setting acid dye on silk
  • Can anyone tell me if silk painted on with acid dye can be steam set using an autoclave. (Temp will be around 250F and 20 psi pressure like in a pressure cooker, I believe.) .
  • If my understanding of what an autoclave is is correct, it should work well for setting acid dyes on silk. An autoclave is essentially a steam pressure cooker, right? As long as your fabric is rolled in paper and is not in danger of getting wet (no dripping from condensation or exposure to liquid water), you should be in business. Let us kno how it goes and if you have any other questions!
  • It seems to have worked. I did a a 15 min cycle at 15 psi and the temp setting was 250F, no dry time. ( A liquid cycle). The machine is set that way, I cannot change the conditions much. A bit of the color, I assume the excess color, got washed off in the cold water rinse. The colors were light to begin with but ended up not too bad.

    My bigger problem is dissolving the acid dyes properly and trying to attain darker shades. I found that the citric acid has a less acidic pH (around 6.6) compared to vinegar . I have only tried the citric acid in the dyes so far. Any suggestions on how to improve colors will be appreciated. I will try spraying the fabric with vinegar before direct application of the dye. I have also read that some dyes work better at pH 2. I am not sure what pH some of my Jacuard and dharma dyes work best at.
  • Vinegar pH is around 2, on my tests with PH paper.
  • You will almost always have excess dye that washes out in the rinse after steam setting. This is to be expected. But making sure your dyes aren't overly concentrated will help reduce the amount of excess dye in your fabric.

    When you mix your dye powder into water, you'll want to make sure not to use more dye powder than you need. In general, you won't want to exceed 3-4 grams of dye powder per liter of water. Any load higher than this and you will have a hard time getting the dye to dissolve. Also, you'll want to use HOT water. Acid dyes like to be around 185F. Use hot water to help dissolve your powders, and heat it on the stovetop if you continue to have issues with dyes not dissolving. Each color has different solubility properties, so some colors may be more challenging than others.

    You acid dye solution should be around pH 4. You can certainly treat the silk with the acid before painting. However, if you are steam setting properly, it is not necessary to use an acid. It certainly won't hurt, but steam will suffice for good fixation. That said, most silk painters like to acidify their acid dyes before application. A little vinegar or citric will work great (but pH2 is probably on the low side...)

    Good luck!