Heat Press

[Frog]

Boy, I wish that you had mentioned the Teflon sheet a month ago when we started talking about this! LOL!

Now, you're gonna love that stuff.

[Gilligan]

I'd like to get some solid info on what adding a Teflon sheet does... We use one a LOT for various reasons and maybe we need to make some adjustments.

[Frog]

Plain and simple, it insulates a bit. Depending on how thick it is, and how close to the lowest acceptable temp for a particular material, you are pressing, will determine if it will adversely affect your results.

I am figuring that screenxpress' machine is off calibration a bit, and running lower than it indicates. Combined with the additional insulation, this paper was not getting hot enough to completely adhere the plastic membrane to the fabric, so some remained on the paper when peeled.

30 seconds at 375 (25 at 390) is indicated and critical, and a lot more heat than the 5-15 seconds at 300-330 that the various vinyl and polypropylene films we use require.

[Gilligan]

I guess an idea of how much of a temp drop was what I was looking for, I understand what is happening but just cranking up the heat X degrees isn't a solution if you don't know what X might be.

[Frog]

I guess an idea of how much of a temp drop was what I was looking for, I understand what is happening but just cranking up the heat X degrees isn't a solution if you don't know what X might be.

Perhaps a cheap thermometer like this, or a plain end cable type probe for your Atkins (if you have one) could give you an idea.
Royster referenced a transfer supplier who warned of drops as much as 25 degrees.

Begs the question: why use one? They are generally used to add a "screen printed" look to vinyl. If your heat platen is dirty, a piece of kraft paper is a lot less problematic.

And, If I had to use teflon, and I had no way of checking my machine, I would merely apply a transfer without, to establish correct temperature, and then, with the sheet,  crank it up in increments of ten or so degrees, until I had consistent results.

Wayne's problems stem from no experience with this material. Not the best situation to fudge critical conditions.
Of course, when I say critical, it really still has some leeway, it's just that he was obviously too close to minimum temp to start with.

[Binkspot]

Get a bead probe like Frog said or a set of tempeture crayons, mark a test shirt and press to see which one turns.

[Gilligan]

I just need to find my k type probe now.

We do a lot of multi color stuff or mixed media, 3G and vinyl or screen print and vinyl or screen print and 3G.

[screenxpress]

Is there any issue pressing on a front ink jet crest print when you have a finished ink jet back print?

[Frog]

Not if you use a teflon pillow inside.

[screenxpress]

I've only got a handful of these.  Nobody local sells a teflon pillow.  What do you think of using a folded towel inside?

[royster13]

Sometimes you can find ironing board covers that can be sewn into a pad....

[Frog]

There have been times I've used towels instead of the rubber pad, and cardboard and masonite inside instead of a pillow.
You'll probably be fine.
The pillows are especially useful to minimize seam pressure marks.

Sometimes, especially for small prints, you can just slip the shirt over the lower platen like on a shirt board, and not have to worry about the existing back print.

[screenxpress]

I only have have to put a crest print down so I'm going to try the towel method.

Thanks all.  I figured I'd put this in the post so others might benefit from my learning experience.