[Naptime]

so, i was out in the shop tonight burning screens, and getting ready for a rather large job tomorrow.

i'm washing out my 5th screen, and my 6th screen is on the exposure table.

that's when i happens, the loudest pop i've heard in a while. i swear it sounded exactly like gun fire.

so what did i do, well, i hit the deck of course!!!

i was scared to get up.. waited maybe 15-20 seconds befroe braving myself to my feet.

checked outside. all seemed good.

came back in to go back to what i was doing.

timer goes off for the screen that's burning... and that's when i notice it...

my 25x21 1/4" thick plate glass on my exposure table had exploaded!!!

maybe 10 larger pieces and a bunch of smaller pieces.

my guess is that it was the heat from burning so any screens in a row with no break to let the glass cool off. my table has 2 500w halogens. and the top is a compression top. i figure the pressure from the top, combined with the building up heat, is what did it.. i've been using this table and glass since last fall.

dang was it loud!!!!

 

[Naptime]

 

[TYGERON]

You sure it wasn't a ricochet from a disgruntled customer? Some people take shirts VERY seriously .

Sounds like maybe heat. Was the glass fit very tightly in the frame? Since it was so loud, the glass might've expanded from the heat and had little room to do so.

If you replace it, leave room around the edges to allow for expansion and you might consider a fan blowing from underneath.

Think about expansion joints in concrete sidewalks.

And glad you're still here to tell the story!

 

[Naptime]

You sure it wasn't a ricochet from a disgruntled customer? Some people take shirts VERY seriously .

Sounds like maybe heat. Was the glass fit very tightly in the frame? Since it was so loud, the glass might've expanded from the heat and had little room to do so.

If you replace it, leave room around the edges to allow for expansion and you might consider a fan blowing from underneath.

Think about expansion joints in concrete sidewalks.

And glad you're still here to tell the story!

there was enough room, that the glass could wiggle. but maybe like 1/16" all the way around for 1/8" total. it wasn't in there tight, but not exactly super loose either.

I might have my compression setup a little too tight also.

my lid is hinged, and I have clasps at either side in the front to lock it down.

my screen frame is the same height as the opening, so my lid does NOT press against the frame itself.

however, what I compress, may be too much..

I have a black pillow case, filled with maybe 30-40 old used black test pellons. and then on top of those, I have 2 medium density diy foam cushions from Wal-Mart.

it’s all neatly stacked in the pillow case, and then its taped shut.

I put my screen down, place the pillowcasecushiondealio and then close the top.

but, I do have to put pressure to close the top, almost leaning all my weight onto it to close the clasps. my daughter has to lay across the lid to close it.

I’ve been doing it like this since fall. but I’m thinking maybe my stack of pellons & cushion is a little too thick.

and, combined with running one screen after another tonight, probably did it in.

I do NOT have a fan on the underside.... but I betcha I will by tomorrow thanks for the tip.

so now I lose some morning tomorrow to go get a new piece of glass and a fan.

ugghhhh

just glad I wasn’t standing too close.


my daughter was in the shop helping me.. and 20 minutes later, she was still shaky from the sound and the initial adrenaline rush. (she hit the floor too when it happened)

 

[TYGERON]

Whew. Glad she's OK.

Sounds like things are a bit tight on the compression thing. Looks like you could hook up a vacuum type compression with a piece of neoprene and a shop vac and nix the hinged lid.

And if you get in a bind tomorrow and it's sunny out, use sunlight.

 

[PhilR]

That'll happen with non-tempered glass if treated to rapid heat/cool cycles. I had a couple of panes go on me like that (and I wasn't even using vacuum pressure) before I built my exposure unit with tempered glass.

 

[Fenrir]

Definitely consider having a piece of tempered glass made to that size, you're lucky your setup prevents shards of glass from flying in all directions because that could have ended badly. Another thing that could have shattered it is contact with a colder item, do you have any screws or hinges that touch the glass when you close the frame? That normally shatters it the moment of contact, though, so it could just be repeat heat stress that did it unless the glass expanded enough to touch a hinge.

The only problem with tempered is that it turns into a billion abrasive pebbles when it breaks! Which is much much safer as far as not having jagged shards flying into your face, but much much more annoying as far as cleanup, especially if there's anything important underneath it that just got filled with 6 grit sandpaper!

 

[lben]

That is very scary. I'm glad you and your daughter weren't injured when it exploded. You were very lucky the top was covered or we could be hearing about you on the news. Tempered glass sounds like a good idea, as does the fan.

 

[ScreenFoo]

I guess I'm lucky being in a cul-de-sac. (Can't drive-by )

Yep, tempered is the way to go if heat is an issue, and probably some fan wouldn't hurt either--stencils can act funny when they get hot.

Not sure if it was part of the issue, but warped screens don't help either--the low corners will be high-pressure points.