Textile PV

Catspit Productions is an authorized SaatiChem dealer and we can offer the complete line of their top quality products. If you don’t see it on the website please give us a call for sales assistance. Here you can discuss Saati equipment and supplies. You may direct questions to Saati as they may respond directly here.

http://catspitscreenprintsupply.com/

Moderators: Saati, Catspit Productions

User avatar
upperhandprinting
Senior Screen Printer
Posts: 59
Joined: Sun Sep 02, 2012 3:05 pm
Location: Washington, DC
Contact:

Textile PV

Post by upperhandprinting »

Two questions


Are you able to use this with discharge inks?

The shop I work in uses chromablue, but when I'm doing my own printing there, I use Saati Textil PV. I like it and know my exposure times. They coat screens with the lights on. It's not daylight, just fluorescent lighting in the shop. They then put it in a drying cabinet where it's dark. Then they burn the screen and wash it out under the same normal lights. I've always used UV safe bulbs, but I've got to say, it's much nicer working in full lighting. I've thought about trying one screen like this,but thought I would ask the experts first. Thanks!
Craig
Upper Hand Printing - Custom band merch
http://www.upperhandprinting.com
Trumpet The Harlot - My band
http://www.trumpettheharlot.com
User avatar
ppdlao
Master Screen Printer
Posts: 139
Joined: Fri Jul 20, 2012 9:18 am
Location: Villahermosa, Tabasco, México.

Re: Textile PV

Post by ppdlao »

Hi Craig, you know?, I coat and expose my screens with some lights too, in my living room, with one light from the ceiling fan which already has a translucent screen, and a desk lamp that I turn over to the wall, which reflects a "weak" (not direct) ray of light, (both are "white"fluorescent lights) none daylight, closed courtains, and I reveal my screens outdoors under a little ceiling, but I think it would technically depends and varies from brand to brand, my emulsion works fine, it is more suceptible to the sun ray than to the interior fluorescent lights, as I have to reduce my exposure time when it's very sunny in here (30°C-38°C)
But professionally talking, I think you should keep your coating and revealing method done inside a dark room with a safe light. It is matter of different styles I think. And yeah I think it's nicer working with full lighting too :)
User avatar
Catspit Productions
Site Admin
Posts: 1995
Joined: Wed Mar 21, 2012 10:47 am
Location: Phoenix, Arizona

Re: Textile PV

Post by Catspit Productions »

First I’ll say that you can work in ordinary room light often with most emulsions. The faster the emulsion the less likely you can do that without issues. Most emulsions are not fast enough to be affected by a short exposure to ordinary room lights as they do not have an intense UV output. Many screen print shops work just as you described because most of the work they do is not that critical as far as detail and the screens don’t spend too much time in the room light.

Textil PV is a fast photopolymer emulsion but even still if it is shortly exposed to fluorescent room light it probably won’t be much of a problem. The longer it stays in the room light however, the more difficult it may be to wash out causing you to use more pressure. More pressure will force the stencil to wash out being that it is semi cured emulsion but it will also cause more sawtoothing.

That means the gaps between mesh openings will not be bridged rather the emulsion will follow the mesh grid and make a jagged edge.

So for most spot color printing this may be fine but when you do halftones or fine detail you may want to avoid unnecessary exposures to any UV light source be it weak or strong. The easier the emulsion can wash out the more detail you will be able to get. In order to get the emulsion to wash out easily, we do not want to expose it to UV light in any way. The emulsion should dissolve when being washed out; it shouldn’t be pushed out of the mesh. That’s why a very dense film positive is best too.

The Textil PV technically is only resistant to plastisol inks but if you post expose it when you make the screen it will be fine for water based inks. For discharge inks you may want to use Textil PC which is resistant to water based and discharge inks when post exposed. It is also a photopolymer emulsion.

A post exposure simply means exposing the screen to UV light again after you expose it with the film positive, wash it out and dry it. You expose the emulsion a second time without the film positive or the vacuum in order to fully harden it.

Saati emulsions can be found here and are available at a discount using the Catspit promo code:

http://www.catspitproductionsllc.com/sa ... icals.html

I hope Saati will chime in here too. Let me know if I answered everything here. I was doing a lot of questions today.... ;)
Jonathan Monaco
Catspit Productions, LLC
Learn how to screen print tee shirts!

http://catspitscreenprintsupply.com/
http://www.youtube.com/user/CatspitProductions
User avatar
upperhandprinting
Senior Screen Printer
Posts: 59
Joined: Sun Sep 02, 2012 3:05 pm
Location: Washington, DC
Contact:

Re: Textile PV

Post by upperhandprinting »

Perfect Jonathan. thanks so much! I'll put up my lights and just work the way I'm use to doing it. Quality is my main objective and I'll be just fine doing it the way I have been.

I'll give the PC a shot when I get the money to try out discharge.

thanks again!
Craig
Upper Hand Printing - Custom band merch
http://www.upperhandprinting.com
Trumpet The Harlot - My band
http://www.trumpettheharlot.com
Saati
Instructor
Posts: 82
Joined: Thu Mar 22, 2012 10:02 am

Re: Textile PV

Post by Saati »

There is a difference to what you can do and waht you should do. We recomend safelight conditions for best performance with any emulsion. With that being said......Indoor lighting is much more forgiving than natural lighting. Short exposures to florecent (office lighting) can be tolerated with textile PV. Dual cure and Diazo emulsions will be much more tolerant.

I always recomend a safelight test to be sure.

Take a screen coated with your emulsion. Lay it on a counter or in your work area. Take a peice of cardboard and lay it on the screen covering all the emulsion except for 1-2 inches. Every 5 min move the cardboard another 1-2 inches exposing more of the emulsion. After 1/2 hour you should ahve a screen with 6 steps on it. try to wash the screen out. See if it washes out clean or if you see defined steps. If you see steps then count back to see where there is no fogging of the screen and theat is your safe exposure limit.
User avatar
upperhandprinting
Senior Screen Printer
Posts: 59
Joined: Sun Sep 02, 2012 3:05 pm
Location: Washington, DC
Contact:

Re: Textile PV

Post by upperhandprinting »

That's genius. Thanks so much!!!
Craig
Upper Hand Printing - Custom band merch
http://www.upperhandprinting.com
Trumpet The Harlot - My band
http://www.trumpettheharlot.com
Post Reply