A simple guide to heat curing

Curing your screen printed garment

When you have printed the garment you need to cure the ink otherwise when the garment goes through the wash you will notice that it fades, cracks and in some circumstances disappears altogether. There are some inks that are air dry but popular inks such as plastisol and waterbased inks need to be cured.

Curing is the actual chemical process by which the ink dries and bonds to the shirt fabric.

We are often asked ‘what is the best equipment to cure screen printing textile ink?’ The simple answer is a tunnel dryer however they can be expensive especially when starting off, so what are the options?

Important: Not all textile ink cure at the same time or temperature. Have a look at ‘The Cure’ which looks into ink curing in some detail.

Always check the documentation that comes with your ink and remember that the best test is always a wash test.

What equipment can be used?

Hair dryer

Hair Dryers – they are not hot enough, they will dry a waterbased ink but not cure it – NOT RECOMMENDED

 

 

IronIron – Don’t give an even heat and most are not hot enough to cure the ink fully. If you are printing T Shirts for your own use and are not worried about the ink gradually disappearing then an iron is an option – NOT RECOMMENDED

Heat GunHeat Guns – With a lot of patience and skill you could cure the ink but you are likely to scorch the garment so be careful. You can use a heat gun to touch dry the ink (the same job as a flash dryer) prior to printing the next colour – NOT RECOMMENDED (limited use)

 

Flash dryersFlash Dryers – normally used for touch drying the ink between prints when printing multi colour, it is possible to use a flash dryer to cure the ink but can be time consuming and requires management to ensure the garment does not burn. Works better for plastisol ink than waterbased ink (which requires longer cure).   LIMITED USE FOR LOW PRODUCTION.

 

 

 

Hand CurerHand Curer – can be used for both touch drying the ink between prints when printing multi colour and comes with a timer making use easier. Can also be used for ink curing as the hand curer uses quartz elements which heat immediately and cool immediately making the equipment safer and more energy efficient than a traditional flash dryer. We use hand curers for exhibitions and training sessions. RECOMMENDED FOR LOW PRODUCTION.

Heat PressHeat Presses – are fine for curing low numbers of garments, most modern presses have timers making it easier to manage. Heat Presses are used for lots of different applications such as vinyl transfer so commonly found in most T Shirt printing shops.

When using a heat press to cure screen printing inks you will need to put some grease proof paper or transfer release paper on the ink first before curing. You will need only a very light pressure and you will need to set the timer according to the ink you are using. Can be used for curing screen printing textile inks

 

Tunnel DryerTunnel Dryers – the best solution to cure large numbers of garments in a short space of time but the most expensive. They can cure potentially hundreds of garments per hour. We make them to all shapes and sizes based on the level of production and the size of garments being used.   If you are printing with waterbased inks choose the longest dryer you can afford to avoid having to put the garment through twice. HIGHLY RECOMMENDED

Exposing yourself!

Making Your Artwork Positive.

Making Your Artwork Positive.

Having problems getting the right exposure times?

Stencil not washing out?

Stencil too easily losing definition?

Experiencing stencil breakdown whilst printing?

There can be lots of reasons for these problems so we have compiled a simple troubleshooting guide which might help you. It won’t solve every problem but hopefully will point you in the right direction.

Problem Possible reason and remedy
Image will not washout Are you using the right level of water pressure? You can use a power hose using light to medium pressure. Normal tap pressure is not enough. If using a pressure washer, is set it to its lowest setting?

How opaque is the film positive? Hold it up to the light. If it is letting light pass through then the emulsion will start to harden making washout difficult. Make sure your film positive printer is set to the darkest settings, you can print out 2 copies of the film positive and stick them together.   You can also use a density spray if printing Film Positives on a laser printer.

Has the emulsion gone past its shelf life? Write the date on the label when sensitising – it may save a lot of time and frustration.

Screen maybe over exposed. Check your exposure timings – you can use an exposure calculator to determine the right timings / settings for your exposure unit

Make sure when drying the screen after coating that you don’t overheat it. Temperature needs to be kept below 40c.

Not all of the image washes out or washes out easily Screen likely to be under exposed other tell-tale signs include:

If the water runoff is heavily emulsion coloured when washing out and if the emulsion feels slippery and soft.

·         Check your exposure timings – you can use an exposure calculator to determine the right timings / settings for your exposure unit

Check for uneven contact between the positive film and screen when exposing. Check the vacuum is working correctly / or glass & weights are in place.

Could be uneven coating of emulsion on the screen. Check the tension of the screen – if it is loose you will not get an even coating of emulsion. Maybe time to get the screen re-stretched.

Only use light to medium water pressure – too much pressure can remove the artwork inadvertently, resist the temptation to give the artwork a blast with the power washer on anything but light setting. After initially wetting the screen on both sides, washout from the print side only with just a final rinse on the squeegee side.

Make sure that the emulsion has been sensitised correctly, the sensitizer powder must be completely dissolved – maybe consider a pre-sensitized emulsion such as Ulano Proclaim EC.

Always degrease the screen before coating with emulsion it helps the emulsion adhere to the mesh as well reducing the chance of pinholes and fish eyes

Stencil washed out but ink won’t go through part of it when printing Check your exposure timings as the screen is likely to be underexposed – you can use an exposure calculator to determine the right timings / settings for your exposure unit

Make sure that the emulsion is thoroughly washed out as the emulsion can run into the stencil on the squeegee side blocking the artwork. Sometimes you can clean it out with a damp cloth (luck is involved – so best to get the exposure timing and washout right)

Stencil not dried properly after washing out – you can’t beat a drying cabinet (either manufacturer or homemade). Always inspect the stencil in the light to make sure no moisture remains.

Before exposing make sure that the screen is completely dry, the emulsion should be the same ambient temperature of the drying room. If the emulsion is cooler it still has some water content.

 

Fish Eyes Normally caused by contamination so make sure you have degreased your screen thoroughly and that your workspace is clean. Also check that the exposure unit glass is clean and that there is no contamination on the film positive.

Check that the coating trough is clean, dust free and that the edge is completely clean (make sure there is no evidence of the old emulsion on the coating trough).

When coating the screen, move the trough steadily and with purpose. If you coat too fast the emulsion won’t adhere to the screen correctly. Conversely if you coat too slow and the coating may be too thick.

Fish Eyes can also occur during printing if there is an issue with the emulsion e.g. over its shelf life

Pinholes Similar to Fish Eyes – watch out for contamination on the mesh so make sure you degrease screens.

Dirty glass on the exposure unit is often a culprit, or contaminated film positives.

Make sure that there are no air bubbles in the emulsion when coating – when sensitizing emulsion leave it at least for a couple of hours (ideally leave overnight) before using it to allow the air to escape.

Don’t coat too fast – allow the emulsion to adhere and fill the mesh aperture

 

 

Top Tip – Useful tools

Chromaline Exposure Calculator

Image result for Chromaline Exposure Calculator

Chromalie exposure calculator eliminates miscalculated exposure time with three kinds of quality checks. An easy, user friendly tool for the novice and the advanced screen maker.

Designed to help determine correct exposure time, print quality check and halftone tests.

http://www.wickedprintingstuff.com/exposing_equipment_and_digital_screen_makers/accessories_inc_bulbs_foam_and_exposure_calculator_LC241/chromaline_exposure_calculator_P2548.html

 

Maybe the best investment you make!

 

 

How to use glitter inks?

glitterGlitter designs add umph to your designs. Just a couple of things to look out for.

As glitter inks require a coarse mesh so the design should not be too detailed. They are best used for a large, block image rather than small wording. This example is perfect for glitter but a small intricate design would not work as well.

When creating your screen use solvent resistant dual-cure emulsions. You want 15-25T (8-10T metric) monofilament for direct printing and for transfer printing use 25-33T (10-12T metric) monofilament. Your squeegee should be solvent resistant and hard we recommend Wooden Squeegee with D Cut ( V Cut) Blade.  Ideal for textile printing with plastisol ink. D cut blades lay down a heavier deposit of ink.

Plastisol inks will not air dry. They must be heat cured. When fully cured the ink will withstand repeat washings.

CMYK screen printing explained

What is CMYK?

How do you do this in screen printing?

Is it the same as 4 colour printing?

Think back to school when you were painting and used blue and yellow to get green, that is the theory of the whole process. It is used all over the place and you will see the little symbol on things you use every day!

I don’t want you to rely on pictures too much because your screen or printer will subtly alter these colours. But have a look at this picture from Wiki to get an idea, yes basically it is just like school blue, red and yellow.

Now these colours can be combined to get all the rest of the spectrum

Now as you no doubt remember from school, combining them does give a murky black which is no good for our purposes which is why we have to have black. Saves ink as well.

So that is the inks but how does it work. Well you put the 4 colours onto the substrate (thing you are printing on) in dots and when the dots are on top of each other you get the various colours and your picture.

Now remember the way screen printing works, the ink is pushed through the mesh in dots! The finer the mesh the closer together the dots are so you can’t see the background colour.

Basically your brain has the illusion into thinking you see a solid colour when in fact what you see is lots of dots. All screen printing works on that principle.

The ink is normally applied in that colour order Cyan, Magenta, Yellow, Black although that can vary with some printers.

There is actually a principle behind the process called “subtractive”. Because you are printing on white, you are subtracting, with the inks, the amount of white(brightness) your eye sees. Now if you don’t fill in all the dots you get to see more white and that gives you paler colours, which can also be mixed and matched to get the full range. This bit is called “half tones”.

Honestly the principle is as simple as that, any water colour artist would see it immediately although they may not know what it is called.

So that is the theory, 4 inks printed in dots, here is an early example from 1902

Now how do you do this?

You have to separate your final image artwork into its CMYK elements.

If you check Photoshop all the colours show what percentage of these colours comprise the colour you see.

Photoshop automatically separates the CMYK colors into channels. Just open the channels palette and select “split channels” from the palettes flyout panel options. You will get four grayscale files, one for each channel. So you need 4 screens that have the required separate colours which when combined will give your final picture.
Be aware, however, that this is NOT how you separate artwork for screen printing. If you are printing the job as a 4 color process on white shirts, all you want are printouts of the separate channels, just print the file as “separations” with a course line screen (35 to 55 lpi) and the following angles – C: 55 degrees, M: 22 degrees, Y: 5 degrees, K: 80 degrees. Not doing this right gives you the Moire effect (it looks blurred). Other angles can be used for example.

There are literally nearly 80,000 videos on the internet describing exactly how to do this and I suggest you watch a few, several times until you feel completely confident you understand the process.

In order for all this to work you need a very high mesh count so you get lots of dots which give your brain the illusion correctly. We have kits with all you need to try this, have a look at http://www.wickedprintingstuff.com/inks_and_additives/plastisol_ink_and_additives/union_inks/trutone_range/wps_uniontrutone_process_printing_pack_P1145.html

The Trutone Process Printing Pack Contents are ;-

  • 4 x Aluminium Screens 16 x 20inches 120T
  • 4 x Wooden Squeegees with a Hard Square Cut Blade
  • 1 x PRPL-2080 Process Yellow 250ml
  • 1 x PRPL-3082 Process Magenta 250ml
  • 1 x PRPL-5080 Process Cyan 250ml
  • 1 x PRPL-8080 Process Black 250ml

This pack contains all of the essentials you need to try out the fantastic Trutone process inks at an affordable price. As ever we are completely happy to give you the benefit of our 30 years of experience so please contact us with any questions.

Here is an example of a finished product, the screens were produced using the Riso QS200.

20140909_112710

Screen Printing Kits

About to start screen printing?
Want a complete screen printing basic kit?
Thinking about upgrading in the future?

From simple start-ups to new business we have it all in one package and you can tailor it to you needs.

Here at Wicked Printing Stuff we have years of providing businesses and know exactly what is wanted when setting up your own screen printing business. We have put it all together in a complete package. From simple starter kits to more complex business start-ups we have it covered. Talk to us if you want advice on the perfect kit for you.

We are pleased to sell a wide range of screen printing kits at fantastic prices, catering for the beginner who wants to get started right through to our high end Pro range which provides all of the equipment and consumables to start a large printing business.

Our range of kits are the:

Essential – for printers on a limited budget, beginners and people wanting to produce simple designs
Mid – for printers with limited space, a small business, medium throughput but produce multi colour designs
Pro– for printers starting or running a large business, wanting high throughput and printing complex designs
Specialist – for printers using specialist inks and printing onto non textile substrates
Club – for printers who want the basic consumables but have access to equipment at a school, club or college

Within each range the kits have been categorised into Foundation, Advanced and Ultra. This is designed to make selecting the right kit for you as easy as possible. Check our website

We also sell 2 kits that are ideal for use with children. They are listed here:

The Foundation So Easy Kit –

The Wicked Printing Stuff Foundation So Easy Screen Printing Kit is ideal for the beginner looking to produce simple designs without the need to expose screens or use lots of chemicals. The kit includes the screen printing basics, perfect for those one off designs.

No chemicals required, so ideal for home use and with children friendly inks it is a perfect way to have some creative fun with the little ones. To make sure the print doesn’t wash away you can use an iron to cure the ink. There are full instructions provided.

The Foundation UU Kit –

The Wicked Printing Stuff Foundation UU Kit is ideal for people wanting to produce simple designs without the need to expose screens or use lots of chemicals. The kit provides more stability when printing as it comes with a UU clamp which can be used with any standard table. Ideal for screen printing workshops. The kit includes the screen printing basics, perfect for those one off designs.

No chemicals required, so ideal for home or school use and with children friendly inks it is a perfect way to have some creative fun with children. To make sure the print doesn’t wash away you can use an iron to cure the ink. Again there are full instructions provided.

So have fun next school holiday with screen printing for kids.

Contact us today

Here is an example of the contents of one of our kits, the Advanced 4 Colour Upgradeable