Mesh, Temperature, and Tension, a TSB Mythbuster adventure

[Frog]

A few days back, the subject of heat, and its effect on not only emulsion but the mesh itself came up.

I set forth the proposition, that screen tension may very well rise in the heat, as I have seen old timers set old funky flat stock screens on top of dryers claiming that they "tighten up" Some say, no way, as things expand when hot. I pointed out that Polyester jerseys can shrink in our dryers and heat presses.

Can someone, with a screen, and a Newton meter and a non contact thermometer please take a few minutes out to do this for me(us)?

Please take a tension and temperature reading of a normal screen (even a run of the mill static, or heck, a small variety) at a normal ac office temp or shop temp if you don't work in an oven, and then take it out in the sun to get a little hotter, and get those readings?

I would appreciate this, and the results could be interesting to others as well.

[3Deep]

Frog I can tell you right now that heat will tighten up a screen..I don't know if it was the wood frames or screen mesh or both, but I had a guy out back reclaiming some old wood frames with 137 mesh on them the tension my have been around 13n maybe 15n on them.  Well he laid them up against the fence so they could dry in the sun and I touch one and was a hold lot tighter ( could have been the wood frames drying in the sun), but later that day I check them and five of those 20 something screens had ripped mesh.  Don't really think this is proving much for what you are asking, but hey thats what happen.

Darryl

[Frog]

Well, though your story is considered anecdotal, and not considered a scientific study, it is exactly what I am getting at!

btw, like a tuned drum, my screens that had just dried in the sun fifteen minutes ago also had a "higher" note when thumped. Though not nearly as scientific as a coin dropped trampoline style and the rebound recorded, any experienced screen person can tell that something is going on.

Now, I'd like it quantified by someone with the correct instrument.

It may also help explain some of the mystery self-destructing screens we hear about here.
The shrinking can strain an already weak spot that does not do anything at the lower tension
The same with glue ready to give up the ghost.

[prozyan]

Have a screen outside in the sun right now.  Will have pictures in an hour or so.

[ScreenFoo]

But is the heat making the mesh tighter, or the frame bigger?    (or does it matter? )

[prozyan]

TSB Mythbusters say:  CONFIRMED!

[Frog]

TSB Mythbusters say:  CONFIRMED!

Good job!
You are now an honorary member of the crew!

My old eyes ain't what they used to be. What are the readings? And do you have the actual temps as well?

[Frog]

But is the heat making the mesh tighter, or the frame bigger?    (or does it matter? )

Roller frames, and their grandfathers, the cord and groove wooden frames, as well as the five piece panel frames all essentially make the frame larger, or at least increase the distance between the mesh anchor points on each side.

[prozyan]

Inside reading was about 13.5N with the thermostat set at 75 degrees.  Outside, the ambient temperature is 91 degrees and the tension meter read just under 15N.

[alan802]

I'm testing this right now with a 110/71 murakami S thread.  From 35% humidity, 70 degrees to 102 degrees.  I'm just waiting a few more minutes before I put the tension meter on it.

[Parker 1]

Very well done!

What about a higher tention screen say @ 35 to 40N?

[Gilligan]

I'm waiting Alan's results as he has higher tension as well as roller frames.

I'd think wood would definitely have room for expansion.  But I'll thoroughly admit I was wrong after we get back some from a newman... granted, it could still be a the metal as it wouldn't take much.  But I'm still gonna give it up at that point.

[prozyan]

The way my luck runs, if I put one of my newmans outside it would pop   

[Gilligan]

Mine did... but it was after I brought it back inside.  *shrug*

[alan802]

Drumroll please...
70 degrees=28 newtons
104 degrees=29 newtons
Shurloc EZ frame with 110/71 Murakami S thread

I'll gladly do this a few more times with different frame types and mesh manufacturers, just not today.  I'm beat, we knocked out 3K impressions today and boy are my arms tired.  Good news though, with our new dryer, temps in the shop are around 10-12 degrees cooler than last year, and our electricity bill is fluctuating between $550-700 less than this time last year.  It actually paid to buy a new dryer.  I guess I'll start a new thread on that.