After you have printed your shirts, and the ink has dried, you need to heat set it. You need to follow the directions for the brand of ink you are using. I have been using Speedball water based fabric inks. Requirements for other water based fabric inks may vary.
Heat setting bonds the ink to the fabric by raising the heat of the ink above 250 degrees. Once the ink is properly heat set, it will not wash out during repeated washings. According to Speedball “If the optimum heat-setting is achieved, the graphics will endure as long as the fabric.”
Iron Method:
This can be a very time consuming method if you are printing many shirts.
Place a piece of paper over the dried ink, and iron at a medium setting for 3-5 minutes. Turn shirt inside out, placing paper between inked image, and other side of shirt (to prevent possibility of hot ink being transferred to non-printed part of shirt). Iron for 3-5 minutes.
Oven Method:
This method is from a Speedball FAQ page, and is the one I use nowadays.
Place the t-shirts on cookie sheets, making sure inked images are not touching anything including cookie sheet, other shirts, or same shirt. Set the oven at 400° F, and whenever that temperature is reached, turn off the oven. Quickly, insert the cookie sheets with the shirts, into the oven for ten minutes or until the oven cools.
I’ve been using a heat gun like is used for peeling paint, do you know if putting plastisol ink in an oven would let off dangerous amounts of toxic fumes, it sure would make the job easier
Comment by Greg — October 3, 2006 @ 10:59 am
I don’t know. Probably no more than heating it with a heat gun. You can try contacting the manufacturer of the ink, and ask them. They will probably have 800 number that you can call.
Comment by Rob — October 3, 2006 @ 4:29 pm
Thanks for the information. I am trying my first home-screenprint for the first time this weekend and this was a step I was really worried about.
Comment by Kaalo — November 17, 2009 @ 4:36 pm
It’s easy stuff Kaalo. I heat set a couple shirts just this morning.
Comment by Rob — November 17, 2009 @ 10:58 pm
Just an added note–you can pick up a laser pointer-style temperature gun from most industrial supply shops for under $10. Since most inks have a setting temperature, you can use a space heater or broiler (or a flash dryer if you have the spare cash for one) and use the temp gun to prevent leaving the shirt in the heat for too long…
Comment by todd — November 28, 2009 @ 5:12 pm