Measuring shirt temp?

[yorkie]

Get onto your knees and watch for the smoke. The smoke is a signal which indicated when the ink is hot enough to smoke, which "coincidentally" is the same temperature needed to cure.

I have a 4 foot dryer, the first 3 feet have heating elements and the 4th is blank. Looking into my dryer, the shirt needs to be smoking during the 3rd heating chamber. If there is smoke on the first, the dryer is too hot. Considerable smoking at the second is still hotter than needed. If its smoking before the forth, it is too late.

On my dryer, the shirt is already cooling in the 4th foot, so it is all but finished smoking when it comes out of the dryer. The dryer exhaust contains the vast majority of the smoke. For dryers without a cooldown section, i'd have the shirts come out smoking.

heat can be controlled either by dryer temperature or speed. If the smoke is hitting too early, you can either turn up the speed to increase production or turn down the dryer temperature to save energy costs.

My dryer is a brown, which come with (pc style) cooling fans on the exit path of the dryer. We use a pole fan following  the flash dryer.

The issue might just be you have sensitive hands. They make cooking gloves which allow working at oven temperatures. There is no shame in using the protective equipment. The shirts coming out of the dryer will be hot.

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[tonypep]

OK heres my take.....yes donut probes are the most accurate but yes really intended for longer dryers 10 to 12 ft. They will "tell the story" as to what is really happening in the dryer and can identify cool spots if they are present. Some gas dryers have IR "bump" panels in the front and (less frequently) in the rear exit section. Often on older dryers this is one of the first elements to go.....the donut probe will identify this problem. Also for discharge and density printing the are quite helpful. Density gels for example can melt and
"fall" if overheated.
Can't find a picture but in SC I had a bunch of dryers with short outfeeds and had the "blistering" problem.
Had my maintenance man hang two box fans from the ceiling; securing the base of the fans to the top of the dryer with the fans angling away from the exit chamber. Worked perfect and disperses discharge and poly fumes as a bonus. They still use them today I believe.

[GraphicDisorder]

I have a Boomerang, it does have a short exit chamber. 

[ebscreen]

Andy's correct in that the same donut can be used with any thermometer with the correct
(K-type I think) thermocouple input. Unfortunately the donuts are unique to screen printing
and priced as such.

Also, though I'm relatively new to the gas dryer world, I agree with the person that thinks
that a long gas dryer "saturates" the garments with heat. That's been my impression as well.

[sportsshoppe]

I too do the pull test but I do it the next day... Have pulled them especially white after they cool and not tears but the next morning and it may pull apart. Have you ever tested some of the Wal Mart shirts? I wonder sometimes if we do not go overboard but I see shirts I have printed 5 years ago still walking around town and looking good. I use test strips on my dryer and it is a monster ( electric 220 3-phase ) I guess it is 12' of heating and about 5' wide ( Pheonix Turbo ). I have re-wired some of the elements and turned off the temp adj. it stays on. I adjust the speed of the belt for the prints that need less heat. I check it every morning....Fuses do go out

[Evo]

crazy logic question: Does a long chambered gas dryer "saturate" the whole shirt with heat, vs. a short electric dryer just hits the top?

Yes.

The Boomerang is nailing the entire shirt with super-heated air, and the tunnel is 10', and the heat is convective top to bottom, where as an IR panel dryer is radiating infra-red energy onto the top of the shirt only.

You won't really know exactly where in that 10' chamber that the ink is hitting the correct temp for a proper cure without a donut probe. You can measure at the exit but that only tells you what the temp is at the exit. A gas dryer can bring the temp to where it needs to be and hold it there, while not scorching the shirt. It's a gentler, more even heat than running it under IR panels.

So it's totally possible you are hitting the correct temp within the ink film by the first 5' of the dryer and the rest of the trip through is just baking the shirt until it's too hot to handle.

Just tell Brandt to shove is arm wayyyyy in there with the temp gun...
 


We used to run into this at the shop I worked at running wb and plastisol prints at the same time. The wb prints needed the dwell time, so all of the shirts came out the end of the dryer at max temp.  (15' tunnel gas dryer) The catchers wouldn't "catch" as much as let the shirts pile up in bins and stagger the stacking as they cooled a bit.

[tonypep]

Forced air gas dryers use a burner chamber, blower motor, and a series of baffles to circulate the hot air at an accelerated rate. Some of the better models even re-circulate exhaust air. And many have an optional IR bump panel in the front to speed up the process allowing the belt to run a bit faster. Important when running multiple autos or manuals and only one dryer. Forced air electric tries to replicate this but is never quite as efficient. Downside is gas dryers are typically much larger and more expensive but if you have the room a used one is an excellent consideration.
tp