Grand List of Emulsions, exposure times and opinions/details!

[Gilligan]

Right which is why light units will vary even with same brand/model.

What I'm looking for though is some basic numbers of starting with.  I've been using a 400W MH bulb and this is 1200Watt and it's old.  So really no time reference will work.

I find it odd, I easily got advice on what time I should start trying with (which was perfect to fine tune my times) when I was using a home built system with an arbitrary distance vs right now when I'm trying to find out a starting reference point to one of the most popular exposure units around.

*sigh*

[Denis Kolar]

Try step wedge with 5 LU increments. Start with 50 and go down. 50, 45, 40 ,35, 30, 25, 20 ,15, 10, 5
Find which area washes out the best and then try it again around that number with smaller increments. If everything washes out, start with a higher number.

Is that too hard to figure out or you do not want to waste one coated screen?

You will need to waste a few coated screens anyhow

[Frog]

While I agree that it would be great to have a close idea of howto set things, you have plenty enough to make a stab at a test that by its nature includes a wide leeway on both ends.
You have your times and distance from your old unit.

You can figure that your new times will be half or less (figuring in distance as well)

Determine your light unit to time ratio, and pick a screen to sacrifice its life for a good cause.
Repeat if necessary.

[Gilligan]

Sure, if I didn't have 10's of people on here with a 3140 that could ball park me, I'd agree... it's just what you have to do.

Problem with it is that this bulb is 2 years old (at least, from what I was told).

So... do I do what Dennis suggested, or would my exposure times be 3x that.  I understand that I'm going to have to waste some emulsion and some screens... I'm just looking to not completely waste a screen or two with numbers that just aren't even close.

If I knew that 30-60 would be a ball park and I'd get a usable number out of that then at least I could be narrowing it down from there.  But if I do 30-60 and nothing washes out... well that was WAY too long.  If I do 30-60 and EVERYTHING washes out then I wasn't even close and now I have to pick another essentially arbitrary practically random number to try.  I could easily waste two complete screens just flat out guessing and getting ZERO usable results.

Maybe I'm spoiled because Andy gave me some good times to start with last time and I was able to get my exposure time on the first wedge test I ever did.

[Denis Kolar]

Sure, if I didn't have 10's of people on here with a 3140 that could ball park me, I'd agree... it's just what you have to do.

Problem with it is that this bulb is 2 years old (at least, from what I was told).

So... do I do what Dennis suggested, or would my exposure times be 3x that.  I understand that I'm going to have to waste some emulsion and some screens... I'm just looking to not completely waste a screen or two with numbers that just aren't even close.

If I knew that 30-60 would be a ball park and I'd get a usable number out of that then at least I could be narrowing it down from there.  But if I do 30-60 and nothing washes out... well that was WAY too long.  If I do 30-60 and EVERYTHING washes out then I wasn't even close and now I have to pick another essentially arbitrary practically random number to try.  I could easily waste two complete screens just flat out guessing and getting ZERO usable results.

Maybe I'm spoiled because Andy gave me some good times to start with last time and I was able to get my exposure time on the first wedge test I ever did.

You are contradicting yourself again. (Or just asking too many questions)
Per your posts, we have determined that every unit is calibrated differently. If someones unit is calibrated to have LU for (lets say) 8 seconds and yours is 5 seconds, the numbers that person gives you will not help you. Bimmrider said that he calibrated his unit as 1LU=1Second, so not every 3140 will be the same.

Trial and error my buddy

[Gilligan]

Not really... in my first response to you on this subject I said:

Not true.

Light Units can be calibrated in some systems and on my older 3140 you can tilt the sensor up and down so it will read more or less light as a way of "calibrating" your light units.

Alan's unit for example uses only like 10 light units or something ridiculously small like that to expose a screen.  I'm sure it has something to do with the much larger bulb but I'd also venture to say that maybe that setup was designed for things that typically need longer exposure times (more units).

So even from a 40-1k to a 3140... or even an older 3140 to a newer 3140 they will be different.  How much?  I don't know.  That is why I specified that I had an older 3140.  I'd LIKE info from a user of an older unit.  But any 3140 info would be at least A starting point.

Basically, that they would be different.

BUT, not everyone calibrates theirs... example the older units as I mentioned can't really be calibrated but only the sensor angled.  Well, it's not likely someone pointed the sensor the other way completely.  Again this is just a way to give me a smaller target to start off with.

You are a WHOLE lot better at playing pin the tail on the donkey if you can take a peak with one eye after they spin you... even if you are blind folded.  In my pin the tail on the donkey metaphor, I'd like to be within 1 foot of the target vs 5 feet from the target on my first "stab".

So maybe instead of me "contradicting myself again", you are just being a stubborn ass, again.

[Frog]

But seriously Kevin, besides the fact that you struggle with coating a screen, now that you see no one is jumping in to rescue you from this chore, what's the big deal?
Don't look at it as a wasted screen(or two) but a tool used in a really important process. The "bad" exposure examples often give a really useful look at the process.

Get a coated screen and use a little less than the time with your old unit as a low end start and go up from there. (You've already determined the relationship between light units and seconds now, right?)
With the right calculator, you of course can do twenty steps or so in one shot. If needed, you can even block off whole sections of your screen and do four or even ten times as many variable all on the one screen.

Without a proper calculator, you know the drill as well.

Just do it! (apologies to Nike)

Man, this part of this thread almost needs to be on it's own as it's raising an issue of its own rather than your "Grand List". The list is a great idea, but in this instance would also short change you of a really valuable learning opportunity.

[Gilligan]

I agree it deserved it's own topic.

But it was an opportunity to bump it up again and get it in people's face a bit as well as it served as an example where the list could have solved this issue for someone.

Even if Pierre would have put light units vs seconds (I'd love to have both for those without integrators but similar wattage), then I could have used that as a spring board to start with.  If someone would have a 3140 and used Chromablue then for SURE I'd have had a starting point to cast my net.

This list could be so valuable in many ways, this just being one... one that I honestly hadn't even thought of when I started the list!

Also, I'm still plumbing up my washout booth so I'm not ready to expose just yet.  Might as well see if anyone chimes in.  (I was actually on here to sneak one last look at Mooseman's solids tank before I drilled my last hole).

[Denis Kolar]

Not really... in my first response to you on this subject I said:

Not true.

Light Units can be calibrated in some systems and on my older 3140 you can tilt the sensor up and down so it will read more or less light as a way of "calibrating" your light units.

Alan's unit for example uses only like 10 light units or something ridiculously small like that to expose a screen.  I'm sure it has something to do with the much larger bulb but I'd also venture to say that maybe that setup was designed for things that typically need longer exposure times (more units).

So even from a 40-1k to a 3140... or even an older 3140 to a newer 3140 they will be different.  How much?  I don't know.  That is why I specified that I had an older 3140.  I'd LIKE info from a user of an older unit.  But any 3140 info would be at least A starting point.

Basically, that they would be different.

BUT, not everyone calibrates theirs... example the older units as I mentioned can't really be calibrated but only the sensor angled.  Well, it's not likely someone pointed the sensor the other way completely.  Again this is just a way to give me a smaller target to start off with.

You are a WHOLE lot better at playing pin the tail on the donkey if you can take a peak with one eye after they spin you... even if you are blind folded.  In my pin the tail on the donkey metaphor, I'd like to be within 1 foot of the target vs 5 feet from the target on my first "stab".

So maybe instead of me "contradicting myself again", you are just being a stubborn ass, again.

Not being a stubborn ass again.

I just thought that you have been on this board long enough to learn something. This is a same thing as when someone ask what are the settings on their conveyor for white on black shirts (I believe you asked that before, I'm sorry if you did not).
NO ONE CAN TELL YOU THAT!!! Everyones ambient temperature is different, everybody prints differently, uses different ink, different shirts, different moisture in the air and shirts, different EOM on the screens, different squeegee........... and so on....

Same thing with exposure unit. (Only different things change)

But I'm guess I am the only "stubborn ass" that is telling you that and everyone else is being politically correct.

Move your ass and do a proper wedge test and you'll be OK!
You wasted enough yours end everybody else's time on this subject, you could have it already dialed in by now.

From now on I'm done being a "stubborn ass". You can struggle and wait for "settings" as much as you want

[Gilligan]

Dennis, as I stated, I'm still plumbing up my washout booth.... so I can't expose anything anyway.  Currently waiting on some gorilla glue to cure, so I'm not wasting any of my time here.

Funny you mention the dryer.  My dryer (old Chaparral) has suggested starting settings in the manual.  They suggest hight of panels, speed of belt and temp.  I've seen this in several places since my time of asking (fyi, at the time, I didn't have the manual on my unit).  Because though (and it's stated) this won't work for everyone, it's a good starting point.  From there you can adjust things like speed, height and temp to get where you need to be.  My dryer goes from stop to probably 30' per second, height is a HUGE adjustment (over a foot to almost right down on the garment) and the temp is a big ole swing as well (multi hundred degrees).

So do I start 12" off my garment at 500 degrees and 30' and work my way back from there?  When experimenting you should only change one variable at a time... this would mean LOTS of changes and lots of trials and errors.

OR, given the settings of 4" 800 degrees and 8' per second do I come to the conclusion that I need 900 degrees and 7-8' per second at 4" in a MUCH shorter time!

I'm certain that these starting points saved me a few scorched garments and probably hours of frustration (I had enough of that repairing panels under a time crunch).

[Frog]

 If someone would have a 3140 and used Chromablue then for SURE I'd have had a starting point to cast my net.

Though not from personal experience with the two, I gave you a very reasonable starting point. Cast away!
I will reiterate. Even when you have a number that is almost certainly accurate, it is good to see the results on each side of that number as well. It will provide, through visual references, important information that you will use in the future.
This goes directly to the same point that I tried to make in the thread about crap coming off of some auto presses. Good equipment or not, some folks don't seem to have a handle of just what is happening and why, so that when things get screwy, they are stymied.
It will eventually happen in this part of the process as well.

Get that sink plumbed, and have at it. You may even enjoy the lesson. 

[Gilligan]

I'm with you Andy.  I'm not looking for "exactly 35 units"... I'm gonna do a wedge test and it certainly won't be my last.

I've got to learn out to coat consistently before I can even really begin to log what mesh counts mean what to me.  Right now no matter what mesh count I use 1 min seems about right.  Yellow mesh pushing that to 1:20 and that wasn't long enough, slime on the back... I did that on the fly given the 30% number as a guess... I had to get the job done... it worked, but I knew I needed to increase it next time... then of course I forgot.

[alan802]

I finally put in some info on it.  Not much but it's a start.

[Homer]

FOR THE LOVE OF GOD GILLIGAN, TAKE A FKING SCREEN AND EXPOSE IT. we all had to start at zero to figure out our times, pay your dues and figure it out! I'm not handing over my info that I spent YEARS to figure out. . . exposure calculators are FREE.

ok, now back to my chips-n-salsa.

[Gilligan]

FOR THE LOVE OF GOD GILLIGAN, TAKE A FKING SCREEN AND EXPOSE IT. we all had to start at zero to figure out our times, pay your dues and figure it out! I'm not handing over my info that I spent YEARS to figure out. . . exposure calculators are FREE.

ok, now back to my chips-n-salsa.

Man Jay, for someone that likes to frequent a forum that was built for sharing screen printing knowledge you seem to think everyone should "pay their dues" and you don't like to hand out information for "free".

Just as a follow up, I completely wasted a screen as I got nothing underexposes... from 20 light units to 64 light units, nothing underexposed and I probably could have washed out everything if I would have realized how much pressure I could hit it with.

Also, I googled around and found some people mentioning 35-45 light units for their 3140's and pure photo polymer.  I found mine to be good at 35 as well.

AGAIN, half of the point of me proposing the question was (I had time to kill as I plumbed up my booth) and it demonstrated how valuable this "database" could be for helping people start out when they have nothing to go by.

Now I see why you haven't participated in said database.  Sad.