T-Shirt Forums banner
1 - 13 of 13 Posts

·
Registered
Joined
·
33 Posts
Discussion Starter · #1 ·
Just wanted to show you guys my homebuilt exposure unit.
ITS NOT PRETTY BUT IT GETS THE JOB DONE!:)

I bought a 400watt metal halide bulb and ballast through craigslist for around $45 and spent probably $25 on the wood and another $20 for a sheet of glass and $5 on a kitchen timer.

It takes around 8 min to expose ulano Proclaim. I use a sliding piece of particle board as a shutter. Hinges, latches and chair making foam make up my screen to film to glass pressure.
When i bought the metal halide ballast the guy gave me 3 extra bulbs, I'm sure if i bought a bulb that was designed to put out the right kind of uv frequency for emulsion the exposing times would go down significantly.

In action (notice the rectangular slot and the piece of wood leaning on the unit - This is my shutter, nothing fancy)


Timer and Hinge shot (also that receptacle/switch thing was laying around my house, works out perfectly though)


Lid open (you can see the foam and the shutter closed)


This is the inside with the shutter open


Here is a close up on the shutter rails
 

·
Registered
Joined
·
1,949 Posts
looks good..well built...how thick is the glass? is it tempered?I built a exposure unit and use 6 20 watt black lights.....about 10 minutes to expose cci dual cure (the pink stuff) ...exposes really nice halftones.

btw, what is the shutter for...is it so the light bulb can warm up?

nice job

Inked
 

·
Registered
Joined
·
33 Posts
Discussion Starter · #4 ·
yeah it could use some paint inside, i would think black though, to prevent the light from bouncing around. (just my thinking) I have thought about this but I think i need to upgrade from laser vellum to a pigment or ink printer and transparencies before worrying too much about that.

at Inked: Your exactly right, metal halides need time to warm up and it is better for the bulbs life to just leave it on if you think you will be burning more than one screen. oh and the glass is only 3/32" thick, I have broken 2 panes of glass by being careless and knocking something into it, but luckily the shutter has been closed and its been relatively easy clean-up.
One day i will have exactly what i need, one day...
 

·
Registered
Joined
·
1,949 Posts
oh ok...so you leave the light on and use the shutter to line the screen up . I use a 1/4 inch piece of tempered glass...and a little weight to hold the film tight to the screen...I had a piece of 1/8th inch glass but it broke under the weight..so I upgraded to 1/4 tempered ..seems to be working just right.
How does your setup burn halftones?

Inked
 

·
Registered
Joined
·
33 Posts
Discussion Starter · #6 ·
the shutter in under the glass, i just use it to block the light while the bulb warms up. its only open when burning a screen.
im able to burn 1pt. lines on a a step-wedge positive i have.
I'm sure it could burn halftones perfect if I only had an epson printer. but right now im using vellum and a laser printer, so the lines can get "choked up" pretty easily.
I'm printing a run for my band, it has some pretty fine lines..
i will upload in a little while.
 

·
Registered
Joined
·
1,204 Posts
the shutter in under the glass, i just use it to block the light while the bulb warms up. its only open when burning a screen.
im able to burn 1pt. lines on a a step-wedge positive i have.
I'm sure it could burn halftones perfect if I only had an epson printer. but right now im using vellum and a laser printer, so the lines can get "choked up" pretty easily.
I'm printing a run for my band, it has some pretty fine lines..
i will upload in a little while.
i have the same set up but nowhere near as nice and clean as yours..yours is a work of art..but yeah paint the inside white and get a piece of sheet metal curve it and place it under the bulb...i burn a screen in 60 seconds my emulsion is textil PV.
 

·
Registered
Joined
·
6,326 Posts
I made a home unit just to see if I can make one. I used six shop lamps I bought from cheaplights.com based in NC. Some of the covers came broken, but I didn't need them anyways. I need to buy a piece of glass still. I watched the videos on youtees.com and he suggested buying old 80's stero cabinet door glass which is tempered and has to UV protection in it. I didn't think of a kitch timer, thanks, I'll look for one.

I also have an exposure unit from Ryonet I think. It's one of those stands with a 500 watt shop lites on PVC schedule 40. It came with glass, and a dvd to show how to use it, but I saw one on YouTube that's pretty good too.

We just signed a lease for six months for our first shop. We were in our home, and we can't move an inch cause we have too much stuff (okay junk). I felt like one of those people on those new reality TV shows, so I said okay, that's it we're getting a shop and moving all our equipment to the shop.

Right now rent is cheap probably due to the economy so I'm going to take advantage of that. Hopefully we can get some of the other industrial tenants to buy from us too. I can make them a real good deal if you know what I mean.
 

·
Registered
Joined
·
9,534 Posts
The vellum may be contributing to higher exposure times.
Or maybe the absence of shade or reflector. I am not familiar with your emulsion but 8 minutes seems much too long for a 400w halide even if it is an industrial type halide lamp.

I plan to use a 400w halide soon. Nut I currently use a mercury lamp that stands on a shade or reflector. Exposure is about 2-2:3-m without warmup and subsequent exposures is about 1-1:20m or so. When I tried to reposition the bulb in a lying position and use a shade/reflector fashioned from aluminum baking sheets exposure time more doubled + a few seconds more.
 
1 - 13 of 13 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top