Author Topic: broke my MH exposure unit glass - what do attributes do i tell the glass co?  (Read 2200 times)

Offline Stinkhorn Press

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replaced the blanket, vac was at 5-6 and now needs bled to stay at 17.
new to needing to put the rope across the edge to allow the center to suck in, accidentally left it under the corner of a screen and bang! glass everywhere.

what do i need/not need in terms of new glass for a unit?


Offline jvanick

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lead free, low-iron, non-uv blocking plate glass.

I believe the trade name is 'starfire'


Offline Stinkhorn Press

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basic run of the mill plate glass is no good?

Offline Shanarchy

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When I replaced mine I went to the local glass place, give them the size and told them I have to have optically clear glass with no UV block in it. I believe the glass that they typical use comes with a UV block, which is great for your home. Not so great for our exposure units.

Offline Orion

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  • Ain't no shortcuts in screen printing.
Dale Hoyal

Offline Stinkhorn Press

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got local glass 1/4 normal just to keep going. old glass was normal glass.

we will order a sheet of 3/8" low-iron to swap in. we'll see if there is any change in expo times (5K MH unit, new bulb, full diazo added dual cure Ulano Pro-Claim takes 29-35 seconds to full cure with non low-lead glass) and try to remember to report back...

Offline jvanick

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if you're that fast, I can't see a good reason to swap the glass.... slower exposures lead to more latitude, which is a good thing as long as you're not up in the multiple minutes per screen range.

Offline Stinkhorn Press

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if you're that fast, I can't see a good reason to swap the glass.... slower exposures lead to more latitude, which is a good thing as long as you're not up in the multiple minutes per screen range.

well that's a way of viewing it that might save me some money.

Offline mk162

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we run a 7500w light with dts and still shoot through the glass to slow it down.  I couldn't imagine how fast it would go without it.

Offline mimosatexas

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I have the cheapo 1/4" clear glass (no UV coating) on my DIY unit and it works fine.

Slight tangent, but I am using an Olec 5k with SP1400 (with diazo) and from 28" away it takes me 100 ltu's/seconds for a hard 7 on 225S mesh (1/1 coat, low OEM though I can't give you an exact percentage).  I would push the light closer (according to the math discussed in a previous thread I should be able to have it as close as 18") but that wouldn't allow my glass/frame to flip up for exposure.  Seems like this may be abnormally long.  Wondering if there is anything I should do to speed things up.  100 seconds honestly works out pretty well for my exposure cycle, but speeding it up about 30 seconds a screen would let me get behind a bit vs having any down time.

Offline ebscreen

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I have the cheapo 1/4" clear glass (no UV coating) on my DIY unit and it works fine.

Slight tangent, but I am using an Olec 5k with SP1400 (with diazo) and from 28" away it takes me 100 ltu's/seconds for a hard 7 on 225S mesh (1/1 coat, low OEM though I can't give you an exact percentage).  I would push the light closer (according to the math discussed in a previous thread I should be able to have it as close as 18") but that wouldn't allow my glass/frame to flip up for exposure.  Seems like this may be abnormally long.  Wondering if there is anything I should do to speed things up.  100 seconds honestly works out pretty well for my exposure cycle, but speeding it up about 30 seconds a screen would let me get behind a bit vs having any down time.

Diazo is slow, no way around it. But you've obviously found the benefits of it otherwise you'd be shooting photopolymer.
A tradeoff like just about everything.

Would increasing the distance and shooting 2-4 up help? We're about to experiment with that and an 8K Olec.
Fingers crossed.