Heat Press

[Gilligan]

Little off topic, but when dealing with vinyl, is there any problem with more heat, time and pressure than on the instructions?

[royster13]

Little off topic, but when dealing with vinyl, is there any problem with more heat, time and pressure than on the instructions?

IMO, yes......Vinyl is a petroleum product and too much oF anything dries it out and causes it to crack sooner sooner rather than later.....

[Gilligan]

That's a good point.

My guys answer to when he is having problems is to cook it longer, hotter, harder... So now I have a reason to tell them not to try that.

[mimosatexas]

I have actually found the opposite with many things.  Shorter, lighter, or cooler often solves issues with adhesion.  Typically it is changing one or two of those variables in a seemingly counterintuitive way that make the difference.  For most of my tag transfers I find that very little pressure and a short time, but high heat works better than standard heat longer time or more pressure.

[Frog]

I don't really think it's from cold spots. 

I had an 11 inch wide sofstretch image that I tried pressing more than once and I could not peel any of it off without it ripping in shreds.  I was watching them press with the Hix clamshell and he put some umph on it.  Mine is a swingaway and I thought I had a lot of pressure but I'll try to max it tomorrow and see.

My experience, with inkjet transfers like Jet Pro Soft Stretch, has been that peeling problems are usually due to cooling off. It has to still be hot!
I have sometimes had to cover with a sheet and repress it to be able to peel the paper that stuck.
I wonder if perhaps you are not hot enough in the first place.


Also on the question of increasing time, heat or pressure. Follow the general rule of troubleshooting and change only one variable at a time.
Too much of any one of these factors can actually melt vinyl or at least reduce opacity as well.

With cad-cut vinyl, a second pressing with a cover sheet is always good insurance

[1964GN]

Temping your heat press is always a good idea. Checking for cold spots, 10-20-30 degrees off of the set temp, etc is important info as well as staying away from the edge.

[Frog]

I have actually found the opposite with many things.  Shorter, lighter, or cooler often solves issues with adhesion.  Typically it is changing one or two of those variables in a seemingly counterintuitive way that make the difference.  For most of my tag transfers I find that very little pressure and a short time, but high heat works better than standard heat longer time or more pressure.

What transfer material for this specific issue of adhesion problem?

Stahls has always taught that increasing any one of the holy transfer trinity and reducing another is the way to fine tune.

[royster13]

The adhesive used on heat transfer vinyl melt at a certain time, temperature and pressure....At the optimum point the glue is melted and pressed into the garment.....Under do it and the glue does not melt....Over do it and the glue goes in too deep or sets up too quick....There is a margin both ways but best to hit in the centre of the zone for best result....

If you need to use less or more heat, it may be a calibration issue....

[screenxpress]

I have done hundreds of Vinyl transfers and they peel off like butter.  The problems I have been experiencing leading to this thread are with the Jet Pro Sofstretch (Andy knows this but the others posting or reading may not).

[royster13]

Is your press cooling off too much between presses resulting in too low of temperature when you complete your cycle?..

[screenxpress]

Wish you could be here to watch. 

I don't see how I can have any cooling spot(s), that damn paper is so hot when I start to pull, I have to keep grabbing in short bursts in various places, lol.  I mean it is HOT!

I'm not in a serious hurry as I don't have any orders to fill right now, but I am going to try and use a blank shirt and heat gun this afternoon to just try and check any serious temperature anomalies. 

I know this should not make a difference, but going to ask.  Because the previous owner had evidently gotten ink on the underside and I've been unable to clean it off short of sandblasing, I was using a teflon sheet over on top of the transfer paper (between the top plate and the transfer).  Surely that could not diminish the heat enough to be a problem....right?

[royster13]

Wish you could be here to watch. 

I don't see how I can have any cooling spot(s), that damn paper is so hot when I start to pull, I have to keep grabbing in short bursts in various places, lol.  I mean it is HOT!

I'm not in a serious hurry as I don't have any orders to fill right now, but I am going to try and use a blank shirt and heat gun this afternoon to just try and check any serious temperature anomalies. 

I know this should not make a difference, but going to ask.  Because the previous owner had evidently gotten ink on the underside and I've been unable to clean it off short of sandblasing, I was using a teflon sheet over on top of the transfer paper (between the top plate and the transfer).  Surely that could not diminish the heat enough to be a problem....right?

Some heat transfer suppliers say teflon can reduce the temperature up to 25 degrees.....I think it is more like 10 or 15 degrees.....Certainly some reduction...
http://www.seaygraphics.com/Plastisol_Transfer_Price_List.html

[Frog]

With the inkjet transfer, if I use a cover sheet at all, it's only the thin brown craft paper. Wayne, if I were you, I'd try one of your transfers without any cover sheet. See what happens on a scrap. Can't hurt.


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[bulldog]

I have a Hix Ht400P. Works as it should. Before that I bought a used Geo Knight and had problems with transfers not peeling right, leaving some of the design on the paper, etc. There were two problems...first, the lady I bought it from must have had it in a very humid area because under the rubber the plate had started to rust BADLY. I peeled that rubber up and there were rust chunks 1/8" or better. Also the arms were kind of worn out and wallowed at the holes leaving some slop.

Both of these problems caused uneven pressure. One guy told me to line dollar bills around the perimeter, half on the rubber, half sticking over and clamp it down to where the dollar bill in the front won't move. If you can move any other bill you have uneven pressure. You can also try it with tightening down until a dollar bill in a different spot doesn't move and double check the rest just to make sure the front one wasn't the "high spot."

[screenxpress]

Okay, here's the update.

I checked the temp as best I could with a temp gun.  The gun did seem to show some differences, but I would not go so far as to say cold spots. 

I took one of the mini transfers (a 6 inch version of the 11 inch one) and cranked up the pressure some and increased the temperature to about 400.   After 20 seconds of pressing, the backing peeled right off.  This was without the teflon sheet. 

So, feeling brave, I pulled out the 4 dri-fit shirts the customer supplied (was a side part of a larger non-dri-fit order) and the last 4 11 inch transfers I had printed a week back. 

Even though I burned my fingers pulling off the backing (that stuff is hot), I think it peeled off like it's supposed to.  Extremely little ink was left on the paper and the backing peeled off pretty even.  I did have two that ripped where half came off but I was able to grab the other half and it pulled off in one piece.  Prints really look great.

I think the teflon sheet may have been the culprit.  The reason I had been using the teflon in the first place was on the first print attempt a week or two back, a little bit of plastic residue from some bags I had done a month ago got on the shirt and messed it up a little.  I cleaned the plastic residue and entire bottom of the element and thought I was playing it safe using the teflon. 

Looks like I might have created my own problem with the sheet.  I'm not even sure I had to run at 400.  I'll experiment some more, but I think I'm on the right track now and feel a lot more comfortable using the sofstretch transfers.

Thanks for all the comments and suggestions.