Emulsion for Paper and texile printing

[KrzysLower]

I'm a small operation with limited funds. That being said, my exposure unit will be a 500w lamp (http://www.amazon.com/Cooper-Lightin...9138191&sr=1-1), will this work?

Now on to emulsion--like I said, I plan doing some paper and textile projects. First, will I need two separate emulsions? Or is there a good general purpose emulsion for both. I've been looking at the Ulano CDF emulsion because of its ease and affordability (no need for scoop coater, etc.), but it says not to use water-based inks. The Ulano CDF will definitely work for my t-shirt projects, but how will it hold up when I do a paper run with some Speedball, water based, poster ink? Will it be that big of a deal? Can I at least get by for a short run? Also, how does the CDF work on high mesh count screens, like ~230?

Best supplier? I'm looking at One Stop Inc at the moment because they have a warehouse close by...

edit: With CDFs, do you need a special screen reclaiming solution??

[paul204]

I use Chromaline DC 521. Great for waterbased, plastisol and solvent-based. Need a different emulsion for waterbased discharge, though.

[Andymac]

I'm too lazy to go look up the Ulano, but if it is a capillary film - cut from roll, adhere to wet screen, peel backing when dry, expose, washout - if it says it won't work for waterbased ink, it might last a few pulls, but will fall apart/pinhole on you.

the cost of a coater will be covered by the difference between a qt of good direct emulsion and some cap film, that shit is expensive, or used to be.

You can get lots of direct emulsions that are 'dual cure' and designed for both solvent based/plastisol and waterbased ink systems.

Reclaiming of both systems is the same. stencil remover/pressure washer.

Supplier? support your local screen supply shop.

[KrzysLower]

Alright, I'll go with some dual cure emulsion. Will I be good for exposing with the light I linked in the OP?

[paul204]

Light is light, if you've got a vac it will be fine, might take 30+ mins though. More of the proper UV rays in better light systems, but any light can work.

[weaponsofmassdesign]

I'm a small operation with limited funds. That being said, my exposure unit will be a 500w lamp (http://www.amazon.com/Cooper-Lightin...9138191&sr=1-1), will this work?

A heads up on those shop lights, most of them have uv shielding glass covers. Remove the glass.

[StuJohnston]

Light is light, if you've got a vac it will be fine, might take 30+ mins though. More of the proper UV rays in better light systems, but any light can work.

I know this is sort of a point of contention among screen printers on this board, but not all light is equal. I can't recall the exact time that people claim with 2 500w halogens, but iirc, it's several times longer than it takes with a 1000w metal halide. Sure the MH Will cost more initially, but depending on the emulsion, I can get as low as 30 seconds! One minor hangup is that it takes around five minutes to warm up, but I often expose multiple screens, so its pretty nice for that.

There is some truth to the statement that light is light. I started with a 150 watt frosted incandescent. Haha, in my defense, I hadn't discovered GP yet. It was taking me something like and hour and a half to expose! It wasn't a big deal because I was usually only exposing one screen at a time. I went to a 150w clear, to a 200w clear (I think it took less than 30min I only did a few screens with it) to a 175w mercury vapor (7 minutes). I saw a 300w incandescent recently and I imagine that would get you into the sub twenty minute range. Notice that the lower wattage MV lamp got me much faster exposure times. All sources of light emit a different spectrum of light. MH and to a lesser extent MV lamps emit a pretty high amount of UV.

[Andymac]

It's UV rays in the 330nm to 440 nm range that makes emulsion expose/harden. The more light in that range, and the power of the lamp, and the distance from the source determine both the length of the exposure time, and the quality/hardness of the exposure. Regular lamps have very little UV.

[{LG}]

If yer really fixated on "saving money" and using those damn halogen bulbs better get some pure photopolymer. It shoots much faster than an emulsion with diazo in it and will keep you from going nuts waiting for those limp, 330-440nm uv-devoid (andymac), bulbs to saturate the stencil with enough light to cross-link it. Many photopolymers are water and even discharge resistant right out of the bucket. Regardless, watch out for heat. Emulsion at a certain temp, I feel like it's over 115deg F or somewhere there abouts, will just start cross-linking all over the place, uv or no.

Better still, just use the sun or go dumpster a low-bay, metal halide bulb and ballast. If you find a "multi-tap" one you can, carefully following the little guide on the ballast, wire it up to a regular 'ol household 110v three pronger. I'll bet you a nickel that a 400w halide will shoot screens faster and sharper than two of those halogen work lights will and produce a lot less heat.

As far as paper v. textiles, I don't think the substrate's all that big of a deal in the emulsion choice. You can use proper mesh selection and coat accordingly to get what you need. It's more about how long the emulsion can stand up to whatever yer pulling around on it and also about the resolution you need to some degree. I'd reckon just about any decent emulsion is capable of holding resolution beyond what most can get out of their inkjet films anyways. Some say that you can hold finer detail with a diazo emulsion but really it just has more latitude or wiggle room in how much of that good uv it needs to cross-link.

Cap film is neato but I think there's only one type (Ulano makes it? I think it's purple...) that's water resistant. The problem (and also one of the benefits in many ways) with the cap film is it just hangs on the bottom of the screen, there's really not much there on the squeegee side. Because you applied it wet and let the capillary action draw the sheet of emulsion up into the mesh, most of the emulsion is on the print side of your screen. Makes for a great stencil technically speaking but not so much in terms of squeegee chatter and drag and durability and resistance. You can offset this by applying the film with liquid emulsion and a squeegee but every time I've contemplated trying it I'm like "eff this, I'll just coat the damn screen". Cap film can be insanely expensive but Ulano makes one, called EZ-Film that does pretty well and is actually not much more per sheet than liquid emulsion costs. Good choice for solvent/plastisol inks and/or if you can't get the dust in your screen making area under control.

[oldbox]

That being said, my exposure unit will be a 500w lamp (http://www.amazon.com/Cooper-Lightin...9138191&sr=1-1), will this work?

I have no vacuum, but I got better results with 2 of those 500w lamps.
also I swiched from ulano to
foteco or
Autotype PLUS 8000 Emulsions <- this just works everytime for me!