# Drying emulsion



## ino (Jan 23, 2007)

Hi,

A few days ago on U tube I saw a guy drying his emulsion with a hair drier or heat gun? is this possible or advisable to do.


----------



## ezilla (Feb 27, 2007)

You could. I think it would kill the hair dryer very quickly though and take a lot of time. I block out any light in my bathroom, take some paint sticks and lay them down in my shower, then place my emulsioned screen on the paint sticks to get air under it. I can then stack the screens, with sticks between them, and aim a small fan in their direction to speed up the air flow and drying time. Takes a few hours but they dry. I also have a drying cabinet. The shower method is used during daylight hours or when my cabinet is full. I can send you a PDF of some plans for a drying cabinet if you like, just PM me with an e-mail address.


----------



## rwshirts (Dec 5, 2007)

My son built a screen drying rack out of basic plywood and some frame work. He added a hinged door, an extraction fan on the bottom, and a ceramic heater on top. It holds 9 screens. 

Of course, on nice days, he just lines them up in the back of the shop near the open doors, and runs an air mover across them.


RW


----------



## ino (Jan 23, 2007)

Thanks guys for the input. I was just curious why the guy was doing that.

I,m an ex joiner so making a cabinet is no problem for me.


----------



## Epic Graphics (Jan 13, 2008)

i just use shelves in my dark room with spacers between each screen and they come out just fine. The air flow speeds up dry time, I still like to give at least 12 hours if not 24 to let the emulsion set up properly.

It may seem dry on the outside, but the integrity may not be so setup if you are just doing a feel test on the surface of the screen.


----------



## RichardGreaves (Nov 7, 2006)

Is this possible, or advisable to do?

In 15 minutes you will know if it is possible. Try it.

*Science*
Heat is bad for stencils. Exposing the stencil to heat above 105°F *can *have the same effect as exposure to UV energy. Heat will also relax the polyester threads and you will loose tension.

The best way to promote drying is to make the AIR dry, and the dry air will pull the moisture out of the stencil. Mother Nature likes equilibrium. 

This is done better with a dehumidifier, rather than heat. In the summer when the relative humidity is 70%, there is no reason for the water to come out of the stencil. When you get bored with the hobby methods, you will buy a dehumidifier.

Yes - Raising room temperature, raises the amount of moisture the air can hold because the gas (air), expands with heat. This is the relative part of relative humidity.

The best screens are coated the day before, but when you need a screen in a hurry - drastic measures must be taken by any means 'possible'.

*References*
http://www.t-shirtforums.com/screen-printing/t14668.html#post93699 Pictures of Mr. Dehumidifier ..... and a relative humidity gauge you should buy so you stop guessing if the screens are dry.


http://www.t-shirtforums.com/screen-printing/t21615.html#post130837


----------



## Epic Graphics (Jan 13, 2008)

hear hear.

Agreed with poster above


----------



## ino (Jan 23, 2007)

Thanks Ricard, Your advise is my comand. I,ll let mother Nature run its course.


----------



## Cdubs (Dec 2, 2008)

Hey guys, i have been using a space heater to dry my emulsion and its usually done in 10 minutes. lately i havent been able to fully get the emulsion off the screens and i think it might have to do with that. Any thoughts or tips?

Thanks much


----------



## Solmu (Aug 15, 2005)

The aim is to dry out (or dehydrate) the emulsion, not to cook it. To that end, you'll get better results with a dehumidifier than with a heater.


----------



## Cdubs (Dec 2, 2008)

it would reach temps of up to around 118 degrees, maybe thats why the emulsion is not coming off.


----------



## midwaste (Apr 8, 2008)

I use a hair dryer to dry every screen I ever coat because I am a low-production small shop. It takes about 10 minutes (bout the same as to dry my hair), and as long as you keep the hair dryer moving, it will not get too hot.


----------



## RichardGreaves (Nov 7, 2006)

How do you know the stencil is dry?

Sensitizers degrade in temperatures above 104°F (40°C). 

If heat works, you have no complaint.


----------



## Cdubs (Dec 2, 2008)

Im using QX-1 i was measuring with a heatgun.

I knew it was dry because it didn't feel sticky or tacky anymore. 

Heat did work but until lately i cant get the emulsion out after im done with the screen. Im fairly new to this but i havent been doing anything diffferent then usual. Any thoughts?


----------



## midwaste (Apr 8, 2008)

I know it is dry because I can see the spots that are still wet internally by holding the frame up to a light. After a little practice, it's pretty easy to spot. In addition, the wet edges from the coater are the thickest and will dry last, so if they are dry, I can be confident the print area is plenty dry.

I did some testing regarding temperature vs distance/speed of moving the hair dryer and I am confident in that as well. 

I know, it would probably be easier to just build a proper drying cabinet.

Edit: Do NOT use a heatgun to try to dry emulsion.


----------



## Boomerbabe (Sep 5, 2009)

When drying screen, do you put the ink side up or down


----------



## InkedApparel (Mar 18, 2009)

when drying newly coated screens....well side up...shirt side down...

Inked


----------



## RichardGreaves (Nov 7, 2006)

Boomerbabe said:


> When drying screen, do you put the ink side up or down


Emulsion is mostly water that surrounds the polymer particles. When the water evaporates the molecules move closer together and when the water is gone, they stick to each other and make/form a film.

As the film shrinks it takes on the rough shape of the mesh and looks like a waffle. Even if you fill the mesh openings completely, it will only have whatever the "percentage of solids" is when it is dry.

For fluffy knit textiles, this rough surface doesn't matter much, but on non absorbent products like glass, metal or plastic you get edges that look like a saw. (Saw Tooth). 

That said, it can't hurt to imagine gravity will pull the drying stencil. I have always dried the first coating with the inside up - but for face coats, bottoms up.


----------



## Boomerbabe (Sep 5, 2009)

So, what you are saying is that you do a 1st coat ( say one coat on the print side and 1 on the ink side), dry it then do another face coat and dry again? 
TIA
PJ


----------



## RichardGreaves (Nov 7, 2006)

Boomerbabe said:


> So, what you are saying is that you do a 1st coat ( say one coat on the print side and 1 on the ink side), dry it then do another face coat and dry again?


I assume "we" are printing textiles at this forum, so keep in mind what I wrote, "For fluffy knit textiles, this rough surface doesn't matter much, but on non absorbent products like glass, metal or plastic you get edges that look like a saw. (Saw Tooth)". I made some earlier posts in this thread that are worth re-reading.

The best articles on face coating are hidden deep in the KIWO web site.
http://www.kiwo.com/Articles/
http://www.kiwo.com/Articles/Screen Coating Techniques.pdf

When you become unhappy with the sharpness of your edges, you will want to learn to face coat your stencils to make a better "gasket" like stencil to control your ink.

Follow the example I have on the coating page of the Ulano web site and make a stepped coating screen.

Experiments like these are like spinning donuts in an empty parking lot after the first snow or sighting in a rifle. You discover, you learn.
Coating FAQ of Screen Making Products

*The Mesh Has Holes In It*
How many coats until the inside is glossy?
Coating FAQ of Screen Making Products









There is no way one coat will fill the holes of your mesh, AND then, all the water evaporates and you only have the ?40% that is solids as the stencil shrinks!

If your stencil is good enough, don't worry. Print.


----------



## printing40years (Dec 27, 2008)

The guy you saw using a hairdryer probably had it on a low heat setting keeping themp below 90 degrees so he didn't cause problems locking in the diazo emulaion. Its a little faster but sitting several coated screens in front of a regular house fan is almost as fast and much safer. Make sure your emulsion is completely dry. It will make reclaiming without harsh chemicals much easier.


----------



## davidpena2228 (Dec 21, 2016)

ezilla said:


> You could. I think it would kill the hair dryer very quickly though and take a lot of time. I block out any light in my bathroom, take some paint sticks and lay them down in my shower, then place my emulsioned screen on the paint sticks to get air under it. I can then stack the screens, with sticks between them, and aim a small fan in their direction to speed up the air flow and drying time. Takes a few hours but they dry. I also have a drying cabinet. The shower method is used during daylight hours or when my cabinet is full. I can send you a PDF of some plans for a drying cabinet if you like, just PM me with an e-mail address.


could you send me those plans for a drying cabinet? thanks [email protected]


----------

