# Heat press upper platen temperature difference



## cbs1963 (May 31, 2007)

I have a Geo Knight DK20 heat press I purchased about six months ago. The platen temperature digital readout is off by 13 to 21 degrees depending on what side and which end I measure. Should the upper platen have different temps on each side and front and back. The left is the hottest and the front is hotter than the back of the press. I'm only using a digital kitchen type thermometer, which might not be completely accurate either. Shouldn't the platen temp be pretty much the same all over? Is this normal for a new press? Should I contact the company?


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## jberte (Mar 25, 2007)

have you had issues with it not pressing evenly? if that's the case, yes call aaron at geo knight - and i suspect he'll need a reading from something perhaps a little more accurate than your kitchen thermometer


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## rrc62 (Jun 2, 2007)

My DK20S is almost exactly the same. It runs a little cool. I set it at 410 to insure an average 400 which has always worked fine. The platen will always be a little hotter directly under the heating element.


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## cbs1963 (May 31, 2007)

jberte said:


> have you had issues with it not pressing evenly? if that's the case, yes call aaron at geo knight - and i suspect he'll need a reading from something perhaps a little more accurate than your kitchen thermometer [/quote
> 
> I sure did. Some parts of transfers would transfer well while other parts did not. That's what led to the thermometer.


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## jberte (Mar 25, 2007)

then i'd fer shure give aaron a call - but prob not til wednesday


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## rrc62 (Jun 2, 2007)

> I sure did. Some parts of transfers would transfer well while other parts did not. That's what led to the thermometer.


More pressure will fix the problem. That's probably what Aaron will tell you. Either that or use a nomex pad on top of the lower platen. The other thing about Knight presses is the upper platens are not flat. They all seem to have some amount of concave. Mine is bout 1/16". What it means is that if you are using light pressure, you will get an uneven press. I'd bet that the concave thing is causing you problems more than the temp.

Lay a straight edge across the platen and measure the distance between the straight edge and the platen in the middle. That's the amount of concave you have. I've see reports of anything a few thousands to 1/16" or more. Aaron will tell you that the concave in the upper platen is a design feature.

That concave made it very difficult to press ImageClip because the first stage requires light pressure, and light pressure with 1/16" of concave in the upper platen is not possible. I had to devise my own procedure.


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## cbs1963 (May 31, 2007)

rrc62 said:


> More pressure will fix the problem. That's probably what Aaron will tell you. Either that or use a nomex pad on top of the lower platen. The other thing about Knight presses is the upper platens are not flat. They all seem to have some amount of concave. Mine is bout 1/16". What it means is that if you are using light pressure, you will get an uneven press. I'd bet that the concave thing is causing you problems more than the temp.
> 
> Lay a straight edge across the platen and measure the distance between the straight edge and the platen in the middle. That's the amount of concave you have. I've see reports of anything a few thousands to 1/16" or more. Aaron will tell you that the concave in the upper platen is a design feature.
> 
> That concave made it very difficult to press ImageClip because the first stage requires light pressure, and light pressure with 1/16" of concave in the upper platen is not possible. I had to devise my own procedure.


Thanks for all the help. Hey Ross you were right about the upper platen not being flat. I did have problems with image clip. At first it seemed fine, but then it failed badly. Ironall has not been a problem, but he heat sensitive papers like Image clip and Duracotton HT don't always turn out well. I do try to crank up the pressure on most things. How does a nomex pad help?


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## rrc62 (Jun 2, 2007)

The nomex pad is a lot softer and thicker than the rubber pad on the lower platen. It helps to even out the pressure when using light pressure. It's also used for sublimating things like tile. The downside is that if you use it for a thick object, an impression of the object is left in the nomex which makes it useless for paper with light pressure again. 

You have to dedicate a pad just for pressing ImageClip. It worked great with ImageClip until I made the mistake of pressing a tile. The pad could not be used again for pressing paper.

I don't have a problem with anything other than the ImageClip first stage, but I also use very heavy pressure on everything.


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## countennis (Dec 24, 2007)

I used Knight machines for quite a few years and had the same problem with the temp and sometimes worse. Aaron always defended the equipment saying that all machines on the market had the same temperature various as well as the uneven surface. This is not true! I have been using a Metalnox pneumatic machine for four years and have never experienced anything as good and I have been doing this since 1977. The main problem with any of the machines is the quality of the parts they use to build the machine. As with Knight and others they tend to use the cheapest parts they can find to keep the profit line up. You can never be sure until you buy the machine and see how long the parts last.


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## cbs1963 (May 31, 2007)

rrc62 said:


> The nomex pad is a lot softer and thicker than the rubber pad on the lower platen. It helps to even out the pressure when using light pressure. It's also used for sublimating things like tile. The downside is that if you use it for a thick object, an impression of the object is left in the nomex which makes it useless for paper with light pressure again.
> 
> You have to dedicate a pad just for pressing ImageClip. It worked great with ImageClip until I made the mistake of pressing a tile. The pad could not be used again for pressing paper.
> 
> I don't have a problem with anything other than the ImageClip first stage, but I also use very heavy pressure on everything.


I really appreciate the input here. Thanks for the info and suggestions.


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