T-Shirt Forums banner

1 - 20 of 79 Posts

·
Registered
Joined
·
199 Posts
Discussion Starter · #1 ·
I have gathered that the best way to make an exposure unit for under a few hundred dollars is to get a 1000 watt metal halide light with a ballast. This is still a couple hundred though. I have read that people use halogen lights and they work as well. Would something like this work if I were to put my screens on the floor with a piece of glass over the transparency to hold it flat and one of these two lights 21" - 24" above?

Northern Industrial 1000 Watt Twin Head Halogen Tripod Light | Free-Standing Work Lights | Northern Tool + Equipment
Northern Industrial 500 Watt Portable Halogen Worklight | Free-Standing Work Lights | Northern Tool + Equipment

I only need to expose my designs once and then will reuse the same ones over and over. I only suggest those because I could simply plug them in and use them. Does anyone know what king of fixture I would need to use a light bulb such as this:

Single End Halogen
 

·
Registered
Joined
·
33 Posts
If time is not important the halogin lights will work fine. I made exposure units using the halogen lamp and another one using flourecent lights.

The halogen takes between 18 and 20 minutes to expose, depending on the emulsion and screen mesh, but it produces good detail. The flourecent takes about 4 1/2 minutes. One of these days I'm going to break-down and make a unit using the metal halide. But right now the time factor isn't such a big factor.

John
 

·
Registered
Joined
·
1,624 Posts
I hang a 500W halogen work lamp I got from Lowes about 18 inches above a piece of foam that I put the screen on and then a piece of glass on top of my film. I expose for 5 minutes and wash out the screens immediately. So far...so good.
 

·
Registered
Joined
·
199 Posts
Discussion Starter · #5 ·
Very nice. So would it be better/quicker to use two 500 watt halogens or would it produce a better image if I just used one? I am starting a line of shirts so I only need to expose these once. As long as it works, it doesnt matter if it takes an hour for each.
 

·
Registered
Joined
·
1,810 Posts
Very nice. So would it be better/quicker to use two 500 watt halogens or would it produce a better image if I just used one?
Only where the light overlaps. Where they don't overlap you would only get single exposure.

Two lights from, two different directions, will undercut your positive and choke the final line.


Remember to remove the safety glass that filters UV energy to protect your curtains, upholstery and eyes!
 
  • Like
Reactions: workshopnitomas

·
Registered
Joined
·
1,502 Posts
The most important thing in exposing a screen is UV Light, if you sit it in the sun it works just as well. Google the UV rating of different lights, we have found that black light clear florescent are the best. Hope it helps, John :)
 

·
Registered
Joined
·
389 Posts
There is a mathematical formula to placing a light source the ideal distance. I think 21" is like an all purpose general distance for a t-shirt screen.

Two lights may expose faster, but I do think that would be recommended. There is a reason why the high dollar exposure units are designed the way they are.

You want one light source in the middle. The more light sources you have the more light is going to get at the image area and weaken any fine lines.


Very nice. So would it be better/quicker to use two 500 watt halogens or would it produce a better image if I just used one? I am starting a line of shirts so I only need to expose these once. As long as it works, it doesnt matter if it takes an hour for each.
 

·
Registered
Joined
·
389 Posts
A guy I know says he uses the boxes that his frames come in as a stand. He cuts a hole in the top. Puts the frame inside the box with piece of glass and sits a worklight on top of the hole.

He claims it works fine.
 

·
Registered
Joined
·
44 Posts
I am so confused!!

I've been researching this for what seems like ages and i've come to the conclusion that

- 1 light source is better than 2
- but not as good as a box with a whole bunch of fluorescents (however expensive and harder to build)

I am however confused as i have read so many different viewpoints/opinions/discoveries

The thing that worries me the most is that one guy selling a exposure unit using 2 500w halogen lights on ebay mentioned "Halogen lamps also give off a lot of heat, this means that extremely prolonged exposures (of over 10 minutes) may result in heat build up which in extreme cases may
damage the acetate sheet or possibly even the screen.Feedback from customers has indicated that exposure times are usually around 3 minutes or less on average for most common emulsions. Therefore overheating is not an issue for most users of normal emulsions."

However another guy selling something similar on ebay (but with just 1 1000w halogen light) says that screens take 20 minutes to expose. Surely that would be a bit risky fire wise?

So i don't really know what to do.

I need:

- Exposure unit that can take upto A1 frames (though will likely be using A3 size more frequently)
- Something that is low cost
- Or easy to make with basic tools that isn't really difficult/time consuming to source parts (I am in the UK)
- Won't burn my house down (very important)
- Preferably something that can be disassembled easily as i have limited storage space

What do you think? Is their a solution out there for me do you think?

I really hope you can help!

Many Thanks, Megan
 

·
Registered
Joined
·
557 Posts
How about a second hand bank of fluro tubes (maybe you could source the holder from a demolition yard, the commercial fluro units, well over here at least have 4 or more tubes, would they be big enough for you?)

Then you may be able to speak nicely to a sparky who (assuming it is safe to do so) could add a standard leed to it for you
 

·
Registered
Joined
·
372 Posts
500 watt halogen = $10
pvc + joints = $10
time to assemble/setup: = 30 minutes

now you have your exposure unit set and ready.
 

·
Administrator
Joined
·
14,640 Posts
I am so confused!!


I am however confused as i have read so many different viewpoints/opinions/discoveries

The thing that worries me the most is that one guy selling a exposure unit using 2 500w halogen lights on ebay mentioned "Halogen lamps also give off a lot of heat, this means that extremely prolonged exposures (of over 10 minutes) may result in heat build up which in extreme cases may
damage the acetate sheet or possibly even the screen.

However another guy selling something similar on ebay (but with just 1 1000w halogen light) says that screens take 20 minutes to expose. Surely that would be a bit risky fire wise?
You can't compare 2500w lights to 1000w lights. 1000w does not get as hot as fast as 2500w.

if you are looking for the least expensive, most compact solution, then look at the picture I posted in the post above.

If you are looking for the quickest solution, then fluorescent will expose quicker and also be cooler than halogen.
 

·
Registered
Joined
·
44 Posts
You can't compare 2500w lights to 1000w lights. 1000w does not get as hot as fast as 2500w.

if you are looking for the least expensive, most compact solution, then look at the picture I posted in the post above.

If you are looking for the quickest solution, then fluorescent will expose quicker and also be cooler than halogen.
That does sound like the best option for me.

Do you add extra bits of pipe to increase the height? I'd be doing a1 screens sometimes.

How does the lamp attach to the pipes?

Do you use 500w or 1000w?

Thanks for your help!
 

·
Registered
Joined
·
372 Posts
500 watt halogen lamp exposes in 12 minutes with my emulsion.
the height from bulb down to the surface of my screen is 20 inches (i can always add or reduce the height by cutting or adding the pvc legs. but 20 inches is working perfect to me.)

check SPLATHEAD's photo at the top. it's the same setup i have.
 

·
Administrator
Joined
·
14,640 Posts
That does sound like the best option for me.

Do you add extra bits of pipe to increase the height? I'd be doing a1 screens sometimes.

How does the lamp attach to the pipes?

Do you use 500w or 1000w?

Thanks for your help!
I use 500w. With my emulsion, it takes 13 minutes.

The lamp attaches to the pipe with 'c' clamps.

I am not familiar with the size of A1. There are formulas on how high the light should be based on the screen size. I don't have those numbers, however.

If you use the pvc stand, and you need several heights, then you could just substitute the 2 upright pipes when needed.
 

·
Registered
Joined
·
5,478 Posts
Lowes also carries an 800 watt halogen single light. Now talking about heat. How hot a temperature are we talking about. If I created an array of say four 500 watters would that be enough heat to cure plastisol inks?
 

·
Registered
Joined
·
44 Posts
Thanks guys that is great, a trip to the diy store soon I hope.

Is there a best type of foam to use under the frame to support it from thexweight of the glass?

What thickness of glass is best? I'd hate it to shatter with the heat or just be too light to do it's job.

Thanks again!





Oh yes, and do I take the glass off the front of the lamp or just leave it?
I'm quite excited now I feel a bit less overwhelmed!
 

·
Administrator
Joined
·
14,640 Posts
The foam is not there to support the glass. The glass is not that heavy. I don't use foam at all for mine. I just set up the unit on a black surface to prevent light reflection. My guess is the foam is used fill in the screen on the ink side to prevent reflections, but I don't know for sure. If you use some, make sure it's black.

Glass should be 1/8 inch. Like the kind you find in picture frames. I tape the edges to prevent cuts.

Yes, remove the glass cover off the lamp.
 
1 - 20 of 79 Posts
Top