Hey guys, its been a good day. I was calling around for a flash dryer to flash between colors and for final curing until I can afford a conveyor. I accidently (a good accident) called a screen printer, instead of a supplier and he happened to have "one collecting dust." I get there and find two that he doesn't use, both Blackbody BF1's with a stand. I bought both for $70!!! I saved myself $530. I also bought a IR thermometer to ensure the shirt was getting hot enough to cure at 325 F (international coatings 700 series ink). I tried curing 2 shirts today, and the first time I messed up and burnt the shirt. The second one came out good and read at 350 F. Now the question is, is it ok if the ink reaches above the cure temperature? And does it matter how many seconds it needs to be at cure temperature? (I will be washing the cured shirts to see the quality of the print). Thanks guys.
Yes it matters,if your using plastisol ink you can get a sublimation effect were the dye from the shirt will start coming thru into your ink,you can also crack your ink.
Waterbased inks need to be cured longer because of the water in the ink,it takes more time for the water to be burnt of before curing can begin as aposed to plastisol where plastisol is solvent based ink.
I would contact your supplyer for drying times;
-about 170c for 2-3 mins is what i do with plastisol.
-about 180-190c 2-3 mins for waterbased.
But this with a conveyor. so i would watch for scortching in your case.
What Rudi said......plus, watch out for cool spots in the corners of flash dryers. They're notorius for having one of the corners cool and the rest will scorch your shirt, leaving you with a burnt cracking mess that has part of it washing out.............hope not.
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Low and slow is best. Low temperature for longer - so the heat can penetrate the ink film and heat up the shirt under the ink where the ink bonds to the shirt. It does no good to cure the surface of the ink, but be in a hurry to move on and the contact point where the ink touches the shirt is not heated enough. Imagine cooking hamburgers or pancakes only on one side.
Another lesson is to pre-heat your home oven to 320°F and put a shirt in it for 10 minutes. No damage. The shirt can handle it. But if you take the shirt to 360 - 370 you saw the damage to the shirt when you scorched it.
The danger with flash panel units is that they are actually between 900 and 1200°F like any infra-red panel. Too long under the panel and the shirt goes to 400+°F and you start to see smoke.
Mark Twain wrote, "If all you have is a hammer, then everything looks like a nail." If all you have is an IR panel, you can do excellent work, it's just more time consuming and and more nerve racking.
It takes the same amount of time to cure your ink, you just don't have the ability to automate and let the speed of the belt control the exact time you want the shirt to be heated while you are doing something else. You have to nurse the curing of each shirt. Get some sort of count down timer that you can set to 30 seconds or 34 seconds or 68 seconds. Your time will vary. You have to test with our own thermometer.
Remember, your IR thermometer reads different colors differently. When you put a shirt in your home oven, use a white shirt and a black shirt and measure them both when you whip open the oven door. You know they are the same temperature, but I bet they will read differently.
The ink doesn't know if the heat is coming from an IR panel in a $30K oven or a $10 hand iron. If you have two panels, you can print and flash your underbase as the flash unit is supposed to, and cure your shirt at a lower temperature with a cookie sheet under the shirt - for a longer time, with your second unit.
If you bake cookies, how is it that you can burn the bottoms and the tops are not cooked - the cookie sheet, heats up and cooks the bottom while the burner cooks the top.
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Last edited by RichardGreaves; April 18th, 2007 at 05:08 AM.
Thanks guys. I guess I need to buy a heat control, ah thats $200!?! I guess theres no choice since these flash dryers don't come with it. The reason it was at 350-360 or so was because I couldnt control the heat. How far away do you guys put the dryer at? Mine was at 1 inch, but I guess I should put it at 2 inches. Any suggestions?
I have my flash dryer at 2 inchs above the platten. I just use mine as a flash not a dryer.
I will be using one as a flash, and the other as a final dryer. I am going to print shirts today and cut them into sample squares, than test stretch and test wash. I will be testing different heights and times. I guess its all about experimenting and creating a chart for future use (same thing with exposure times). I would like a $200 heat controller, but so many other more experienced printers in the area are telling me its a waste of money since you'd still have to experiement with it too. I am thinking I can reduce the temperature output of the dryer to the shirt but putting it furthur apart.
Last edited by TeddyRocky; April 18th, 2007 at 10:18 AM.
I have a temp controller for my flash dryer. I don't use it. it is easyer to just work with out it. It is made bt Black Body. It actually slows me down when i use it.
Two dryers! 
