Before You Went LED, What Were You Using?

[alan802]

I'm up to 100 seconds now, still got slime.  I coated a few screens with Saati PHU and a few with HVP.  I'll get them into production this afternoon or tomorrow morning and report back. 

[GraphicDisorder]

I'm up to 100 seconds now, still got slime.  I coated a few screens with Saati PHU and a few with HVP.  I'll get them into production this afternoon or tomorrow morning and report back.

At that kind of time what would be the point of LED. What were your times on your MH unit before it bit the dust?

[IntegrityShirts]

Yeah seriously, my home-made unit was around 40 seconds to get 100% slime free lol

[alan802]

I'm up to 100 seconds now, still got slime.  I coated a few screens with Saati PHU and a few with HVP.  I'll get them into production this afternoon or tomorrow morning and report back.

At that kind of time what would be the point of LED. What were your times on your MH unit before it bit the dust?

With an 18 month old bulb we were around 50 seconds for the thickest stencils and about 15 seconds for 305's.

I wasn't patient enough to wait on the PHU and HVP and shot them when they were a tad bit moist.  I did the PHU for 60 seconds and it failed, but it was a lot better than previous test screens, the HVP for 90 seconds and it passed, but was a bit soft feeling.  Both 150/48's with 20 micron EOM.  I then put them in the dip tank for 5 minutes and the emulsion came right off.  So with different emulsion I'm going back in the right direction.  By tomorrow I'll start backing down on the times till I get a failure. 

[GraphicDisorder]

I'm up to 100 seconds now, still got slime.  I coated a few screens with Saati PHU and a few with HVP.  I'll get them into production this afternoon or tomorrow morning and report back.

At that kind of time what would be the point of LED. What were your times on your MH unit before it bit the dust?

With an 18 month old bulb we were around 50 seconds for the thickest stencils and about 15 seconds for 305's.

I wasn't patient enough to wait on the PHU and HVP and shot them when they were a tad bit moist.  I did the PHU for 60 seconds and it failed, but it was a lot better than previous test screens, the HVP for 90 seconds and it passed, but was a bit soft feeling.  Both 150/48's with 20 micron EOM.  I then put them in the dip tank for 5 minutes and the emulsion came right off.  So with different emulsion I'm going back in the right direction.  By tomorrow I'll start backing down on the times till I get a failure.

So your thinking emulsion is your issue.

[ZooCity]

At that kind of time what would be the point of LED

Good question.

150/48, 2/1 round edge coat,  Xenon Nova with diazo added

Starlight 3140 shooting 1up:  230s
5k Olec with super wide reflector shooting 1 or 2up:  135ltu ≈ 135s 

Give or take on the LTU : Seconds, of course, will vary with bulb strength.   Above was taken on a medium aged, Olec OEM L-1250 and we do have our setup set to 1ltu=1s as far as calibration goes.

LED is not "fast".  Yes, it is fast at shooting PP emulsions.  All units are fast at shooting PP emulsions.  PP emulsion is a secondary priority in our testing but our halide is just about perfectly equal in speed shooting a PP as the Starlight and is 2x as fast considering 2up shooting.

5k halide will produce roughly 2-3x more fully cross linked, diazo emulsion screens in a shift than LED, depending on your setup.  Electricity, bulb, photocell and reflector costs are the trade off, or the point if you like.

If the Starlight were built to shoot 2up, the gap would narrow significantly but halide would still be faster.  Keep in mind that our halide unit is setup for 2up shooting, if we had it optimized for 1up it would blow LED out of the water on times.  Years ago we did shoot 1up and I recall shooting HVP screens at around 7s.

A little food for thought.  It looks like the Starlight is in fact going to replace our halide setup, should be final on that next month, so please don't misinterpret this as a "flame" or whatever you call it on LED or one brand or another, just some facts for your consideration.  Still going to make good on posting more complete test results comping halide to LED.

[mimosatexas]

So I'm getting an olec next month?

[ZooCity]

So I'm getting an olec next month?

Haha, you have been sooo patient!  Probably yes.  We have a heat issue with the LED but I think it can be engineered away pretty easily.

[mimosatexas]

I told you I wasn't in a rush   If the damn things ever came up used in this part of the world I would have gotten one, but I search daily and there has been nothing...

[z.rashid]

H

[GraphicDisorder]

At that kind of time what would be the point of LED

Good question.

150/48, 2/1 round edge coat,  Xenon Nova with diazo added

Starlight 3140 shooting 1up:  230s
5k Olec with super wide reflector shooting 1 or 2up:  135ltu ≈ 135s 

Give or take on the LTU : Seconds, of course, will vary with bulb strength.   Above was taken on a medium aged, Olec OEM L-1250 and we do have our setup set to 1ltu=1s as far as calibration goes.

LED is not "fast".  Yes, it is fast at shooting PP emulsions.  All units are fast at shooting PP emulsions.  PP emulsion is a secondary priority in our testing but our halide is just about perfectly equal in speed shooting a PP as the Starlight and is 2x as fast considering 2up shooting.

5k halide will produce roughly 2-3x more fully cross linked, diazo emulsion screens in a shift than LED, depending on your setup.  Electricity, bulb, photocell and reflector costs are the trade off, or the point if you like.

If the Starlight were built to shoot 2up, the gap would narrow significantly but halide would still be faster.  Keep in mind that our halide unit is setup for 2up shooting, if we had it optimized for 1up it would blow LED out of the water on times.  Years ago we did shoot 1up and I recall shooting HVP screens at around 7s.

A little food for thought.  It looks like the Starlight is in fact going to replace our halide setup, should be final on that next month, so please don't misinterpret this as a "flame" or whatever you call it on LED or one brand or another, just some facts for your consideration.  Still going to make good on posting more complete test results comping halide to LED.

For what its worth, we are shooting Chromaline Diazo on 158's at 43 seconds on our Starlight. 1 up of course.  No Vacuum.

[alan802]

Back to my saga.  I have been experimenting with different emulsions this week, and it looks like HVP is again the winner in our shop.  I shot a few screens this morning with the Orange, HVP and a new prototype blue (film won't stick to this emulsion at all) and put them to the white-shirt-swipe-on-the-squeegee-side (slime test) to test for full exposure.  I got up to 2 minutes on the Orange and Blue emulsions and couldn't get the small details like the registration marks to spray out but there was still a lot of emulsion coming off on the white shirt.  Right now I'm down to 40 seconds on the HVP without slime and I'm inching my way down in exposure time until I get some slime with the HVP. 

I think the Blue emulsion might be a winner for a good metal halide shop, fresh film and screens that had been coated for an hour in very humid conditions didn't cause the film to stick so that's good news.  It dries very quickly, and the big open areas fell out of the screen with very little effort, I just had problems with the small stuff.  It reclaims very fast as well.  I'd like to see how it runs on an MH unit though.  I will be dropping the Orange emulsion from production, and I have about 3-4 gallons left if someone wants to try it out.  I'd put some in a quart and ship it to you on your UPS account if you want some. 

[mimosatexas]

Is that kevin's orange stuff?  How well does it hold halftones?  I The SP1400 hasn't given me a single issue, but it does take a long time to expose, and really isn't necessary on lots of my short run stuff.

[alan802]

Is that kevin's orange stuff?  How well does it hold halftones?  I The SP1400 hasn't given me a single issue, but it does take a long time to expose, and really isn't necessary on lots of my short run stuff.

Yes, that's the one.  I'd say it's good with halftones, it's not something that jumps out at you either way, good or bad, definitely not a weak spot.  Something tells me that it would run great with an MH unit, along with the new Blue. 

[Homer]

our starlight and HVP, back when we used it was something like 15 seconds...give or take. currently,  our longest exposure with a diazo emulsion is 60 seconds.....the number of LED's is the factor here, the Vastex unit appears to have about half the amount our starlight has....

I'd send it back.