Long Run discharge

[T Shirt Farmer]

I will be printing my largest discharge run next week, 3000 shirts front and back. As of now I have only had runs of a couple hundred shirts max using discharge. What should I be thinking about to be prepared for the long run. Is there a preferred block out tape?  I have hardener and will burn a set of backup screens should I have stencil breakdown / leakage.

any comments are much appreciated.

Robert

[patfinn]

how many colors? what color ink? shirt color etc. I use blue R tape for my blockout tape never have a leak. use hardener and post expose your screens for durability. also if you can depending on the design, try to have your blockout tape be where your edges of your squeegees are. since thats the most likely place you will have break down. but if you give me some more specs i can help you out. last big run i did was 5000. went great.

[ebscreen]

A properly prepared screen should have no issues. We use a 20" wide scoop coater for 16" wide squeegees
and winged floods, standard rubber based adhesive tape for blockout and never a leak. No tape on the print side ever.
If you need reggie marks put em where you can shorten the stroke after registration to not print them, then tape over top.

G'luck.

sean

[jsheridan]

Diazo based emlsion exposed corretly

Hardner if you have it but don't really need it.

Tape everything from the inside and block pinholes with nailpolish, your favorite color.

Add ink and print.

Have a nice day.

[Screened Gear]

john,

Nice to see you posting. I thought we lost you. You are a great asset and a pleasure to have on the forum.

Jon

[Admiral]

Doing over 6k pieces of discharge next week.

Emulsion will be murakami sp-1400, hardened and post exposed(definitely harden and post expose)

will have a couple backup screens just in case

it's 1 pass white discharge print, I'm estimating 7-8 gallons of ink total for the print size

[jsheridan]

(definitely harden and post expose)

This is a myth, don't take the bait.

Properly exposed screens have no use for post expose.

[ZooCity]

No, take the bait.  Post expose and harden as needed.

With the milky type of film most of us use  complete, "proper" exposure is practically a myth unless you want to give up detail.

But this is technically true, just not good real world advice.  The post expo and the hardener make a clear difference and it's cheap insurance against losing one of those's 'properly exposed' screens mid run.

[jsheridan]

With the milky type of film most of us use  complete, "proper" exposure is practically a myth unless you want to give up detail.

Proper exposure isn't a myth, it's a skill that you have yet to master.

[ZooCity]

I didn't say it was. Try and master the skill of reading carefully. 

[RICK STEFANICK]

There is some truth to johns post. with a properly exposed screen using diazo based photopolymer it wont help much.i forget the number but depending on your light source  like 5 minutes post exsposing is the equivelent of like 15 seconds initial exposure time. now a under exposed screen will cause a nightmare with discharge inks so i can understand the safety of post exposure but to get results dont kid yourself it needs to be back on the light for some time. I like hardner though.

[tonypep]

The purpose of post exposure is to ensure that the emulsion blockout is exposed. It's insurance.

[Itsa Little CrOoked]

<snip>No tape on the print side ever<snip>  EB, I misread this at first.

But now that I understand what you meant, I wonder what you would do mid run, should a pinhole open up in an accessible spot.  They are rare for me, but I always just tape over those, unless I can't get to it. I'm all manual, so maybe it doesn't apply, but why no tape "EVER" on the print side?

Thanks!
Stan

[bimmridder]

I always felt post exposure was a waste. I can't (or haven't) prove it, but it seems to me anything you may want to post expose has already been washed down the drain in initial development.

[Itsa Little CrOoked]

I post expose discharge jobs with a significant piece count, but I don't know why. Somebody told me to do it, so I do.

HA!, that is ordinarily NOT a very good reason to do something, or so my recently departed mother told me once.

Charlie Taublieb had some info on it in a workshop I attended, but it wasn't clear to my feeble brain. It is a nuisance and an extra step.  Maybe I should quit.