# I'm building a exposure unit with a 1000w metal halide bulb



## joseramos (Apr 16, 2008)

Hello t shirt lovers, I just want to inform you that I will begin building an exposure unit made out of wood with a 1000w metal halide bulb as a light source. I've been reading a lot in this great forums that I feel I can built one. I just started a screen printing business, and in order to save money I have built some pieces of equiptment like a screen sink washer, I use to have a 4 color press that I built myself 5 years ago following the instructions from Scott Fresner (his book "How to make t shirt for fun and profit"). Since it was made out of wood it was not very practical but finally I could save some money and I bought one 6 color 2 station from some guy on ebay (not very proffesional but it will do its job). I'll be getting my supplies (ink, squeeges, emulsion, etc.) next week. Meanwhile I'll built my exposure unit.
Today a bought the bulb for 49.95 from a local electric company (they had 32 bulbs in stock and no ballats, darn!!), I'm still in need of a ballast, fortunately there are about 6 electrical companies in my area so I I'll see if they have the ballast I need.
I'm planning on having it ready this weekend. I'll post some pictures if somebody wants to see it.


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## neato (Mar 21, 2006)

Sounds like a good plan.

You might find it easier (and cheaper) to get a 400w MH instead. These are very common fixtures. I found one for free since a lot of schools and factories are retrofitting them to the newer flourescents. I think a 400w bulb is about $20 instead of $49.

It's the only piece of homemade equipment I've held on to this long. I just can't justify replacing it since it burns such beautiful screens.


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## MotoskinGraphix (Apr 28, 2006)

I need to make some sort of exposure system with uv bulbs or something. I guess a trip to Lowes is next for me.


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## joseramos (Apr 16, 2008)

Thanks for the advice Neato.
Could you tell me how long it takes you to exposure a 20x24 screen with your 400w and also if possible can you post a picture of it (or some description of it) so I can have a better idea to build mine?.
Thanks a lot.


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## neato (Mar 21, 2006)

When I use Saati Textil PV, it takes about 1.5 minutes to burn a 160 screen and 2:20 for 230-280 mesh.

If I think about it later, I'll snap a pic. But it's basically a tall box with piece of Aluminum sheet as a shutter. Just make sure the distance between your glass and the bulb is about 24-28" or so.

I also made a vacuum top for it. IMO, that is a must have!


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## MotoskinGraphix (Apr 28, 2006)

Will the 400 watt metal halide grow lites on ebay with reflector be ok for this home built exposure system?


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## EasyTeesK (Nov 28, 2007)

My partner and I built a nice exposure unit based on plans we found on the Internet (I think from a free video and some other printed plans). It works great! We are fairly new to the business, so we still have some timing issues to work out. But, it's an enclosed box about 24" x 30" x 8", with 6 plant UV lights from Wal-Mart . We also tried the unfiltered black lights, but the plant lights are doing the trick. The entire project cost about $100, since we bought both the plant lights and the black lights. I'll post pictures and plans soon. With pink dual-cure emulsion, we get an exposure time of about 5 minutes. We're working on blue emulsion with a possible 1 minute exposure.


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## SurfMobile (Apr 11, 2008)

neato said:


> When I use Saati Textil PV, it takes about 1.5 minutes to burn a 160 screen and 2:20 for 230-280 mesh.
> 
> If I think about it later, I'll snap a pic. But it's basically a tall box with piece of Aluminum sheet as a shutter. Just make sure the distance between your glass and the bulb is about 24-28" or so.
> 
> I also made a vacuum top for it. IMO, that is a must have!


Id like to see that picture, especially the aluminum shutter part. Id be worried about heat build up from boxing-in the super hot MetalHalide bulb. Is it ventilated? and how do you keep light from 'leaking' from these vents......if any?


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## MotoskinGraphix (Apr 28, 2006)

Just got back from Lowes and saw something else that might work. It was those large kitchen fixtures alyhough these were more industrial. that contain 2 shop lite units with 4 bulbs aprox. 24" wide by 40" long. The units have a frosted plasic lens I could chunk and replace with a quality clear glass. They also had som square ones around 24"x24". I I replaced the bulbs with UV bulbs would this set-up work?


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## joseramos (Apr 16, 2008)

This is a follow up.
Now I have the bulb (1000w metal halide $49.95 . I just found out that the store where I bought the ballast has the same bulb for $32, Darn again!!! ) and I have the ballast (Universal brand) which I paid $152 including one socket. So I'll head to Home Depot to buy wood, screws and more.
I'll keep you posted!


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## MotoskinGraphix (Apr 28, 2006)

These bulbs and lites are on E-bay for about half of what you are paying complete with balasts, pre-wired...you just plug them in.


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## joseramos (Apr 16, 2008)

MotoskinGraphix said:


> These bulbs and lites are on E-bay for about half of what you are paying complete with balasts, pre-wired...you just plug them in.


*******
Well, I'm so impatient when it comes to waiting for some stuff in the mail. Also, I rather buy those things locally that way I can complain in the store if what I bougt is not good, contrary to buying it from ebay. But anyways I have what I need now let's start bilding it!


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## macmiller (Jul 23, 2007)

i have those same exact parts. with ulano qx-1 i can burn screens from between 50 sec to 2 min, depending on mesh color and count.

have fun w/ your project!


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## neato (Mar 21, 2006)

MotoskinGraphix said:


> These bulbs and lites are on E-bay for about half of what you are paying complete with balasts, pre-wired...you just plug them in.



Yeah, but $200 isn't much to pay for a darn good unit that will last for years and years.

I'm jealous. Now I want to upgrade to the 1000w. 

And don't waste your time with flourescent tubes. A metal halide will be 100 times better and save you from a lot of exposure headaches.


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## joseramos (Apr 16, 2008)

McMiller, could you tell me how far is your bulb from the glass? It happens that I will also be using the same emulsion, Ulano QX-1.

Thanks.


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## macmiller (Jul 23, 2007)

it's about 34" from the center of the bulb. glass is about 2x3 feet


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## MotoskinGraphix (Apr 28, 2006)

Ultra viollet lite the key isnt it?


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## SurfMobile (Apr 11, 2008)

Anyone else here use the 400Watt Metalhalide bulb? i just saw 400watt metal halide bulbs at HomeDepot for $29, i cant find 1000Watt bulbs ANYWHERE locally, and the fact that i wont be able to go down to the store for a replacement bulb is steering me toward the more available 400watt metal halide bulb.....unless anyone thinks 400 watts isnt enough........anyone?


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## macmiller (Jul 23, 2007)

ebay. i actually got my 1000w bulb for $1, $15 to ship!


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## inky (Jul 6, 2007)

hello neato,.. here is a pic of my homemade exposure,1000 watt metal halide,18 in. from glass burn tim 40 sec's,qtx...on my metal halide and my old work halogen (i found out the hard way...the glass or bulb or lens cover are actually uv filters take them off...) and your burn time will change drastically...actually the box has no floor....


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## SurfMobile (Apr 11, 2008)

Awesome! thanks for posting the photos inky!! ....What is the metal rectangle + welded handle in the last pic?


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## inky (Jul 6, 2007)

the metal rectangle has a black sponge like material on the bottom,it weighs about 30 pounds,it is a weight to sit on top of screen to hold positive flat on glass ,more less use it instead of my vacuum lid...


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## inky (Jul 6, 2007)

oh and they are two 4x10 register covers on the sides one on each side,but heat is no issue..the pine smells good ....i could put a flourecent above where the shutter shuts then i would have a light table as well..but really don't need the light table....


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## neato (Mar 21, 2006)

Looks great! Looks a lot like mine actually. The only concern I would have is the 18"distance. It seems a little close, but I may be wrong. If you're burning screens, it's working.  Good job.


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## inky (Jul 6, 2007)

neato said:


> Looks great! Looks a lot like mine actually. The only concern I would have is the 18"distance. It seems a little close, but I may be wrong. If you're burning screens, it's working.  Good job.


phillip,casey from the forums,yep 18in, will do it..


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## sg613 (Jul 19, 2007)

Here is a great example of another home built unit. If anyone is interested. Mine is very similar minus the vacuum top. Its hard to get pond liner up here during the winter so i haven't made the vacuum top for mine yet but since it went from winter to summer pretty much, they finally opened the garden centers at home depot and i can get my pond liner now. Enjoy guys.

So I built my exposure unit... (pics!)

And here is the discussion I had with macmiller in another thread. He was a great help.

http://www.t-shirtforums.com/screen-printing/t39684.html

I got my bulb and ballast brand new for $150 at Litemor up here in Ottawa. They have a store in boston I think but thats about it for the USA. So if any Canadians are interested they should go to that website to find the closest one to them. Oh and it was a Sylvania bulb and ballast.


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## inky (Jul 6, 2007)

looks nice,glad you shared your pic's i might get to making my vacuum blanket one of these days but the weight works well...


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## ftembroidery (Nov 25, 2006)

I know of a fellow screen printer that uses a 400w H bulb successfully. His is suspended above a workbench with a wood shutter that slides in & out affixed to the lamp housing. It shines down on his screen which is in a compression lid case kept closed by "lunch-box" latches. I don't know what his exposure times are, but it works well for him.

My 1000w MH exposure unit is "semi" home-built. I built the table with vacuum blanket and put together the brackets to hold a commercial OLEC AL-9 unit over it. 

Most of the time, you will see the suggestion given that the light be placed 1.5 times the diagonal measurement of the screens to be exposed as the distance from the glass when building the exposure unit. It is sometimes cited that going too close to the screen will cause a "hot spot" and expose that spot more than the surrounding area. When I built my unit, I called and spoke to the engineers at OLEC about the proper distance from the target and they were very insistant that I place it 85% of the screens diagonal measurement above the glass. I use Murakami TXR pure photopolymer emulsion and it doesn't seem to matter whether I'm exposing a 110 or a 305 screen as long as the screen is coated 1/1. I get excellent screens in about 19 seconds. 

One of the most important things is the glass used. 99+% of glass has some kind of UV protection in it (usually advertised as prevents fading of furniture and carpeting). Glass that is optically clear and flawless with absolutely no UV protection or tint is necessary, otherwise you are just slowing yourself down and "muddying" your results.


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## MotoskinGraphix (Apr 28, 2006)

Are those height specs more for this type lamp and not a uv tube type exposure box? I really dont know which way I am going to build.


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## ftembroidery (Nov 25, 2006)

The 85% and the 150% are for single-point metal halide type exposure units. Units using fluorescent tubes usually have the tubes about 2-4" below the glass. Fluorescent units use several tubes and therefor do not cause a single, distinct shadow to be cast upon the screen from the positive. Each tube causes a shadow to be cast by the positive. The more tubes, the more shadows. Fluorescent units will work nicely on screens for distinct spot colors, but fall short for half-tones because of the indistinct shadow/multiple shadows. That's why single-point units are preferable for high detail, since they can only cast ONE shadow.


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## joseramos (Apr 16, 2008)

Hi all, I finally finished my exposure unit and it works pretty good. Now I expose my halftone screens in 30 seconds. I took me sometime but I finally found the right time. Now I am ready and working in some orders I got already. 
Probably my next buy will be a good quality press since the one I have is a little hard to get good registration but for now it is okay. Al least I save a bunch of money with my exposure unit: 1000 W metal halide. Total cost: around $400, it could have been less cause I spent $200 in bulb and ballast, I could have found it cheaper on ebay, but I just couldn't wait.

See the pictures yourself in this link Untitled Document , my friend helped me a lot building it.


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## dmarshall83 (Apr 3, 2007)

what store did you find your metal halide bulb and balast at because everything that I'm seeing online is very expensive.


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## MotoskinGraphix (Apr 28, 2006)

dmarshall83 said:


> what store did you find your metal halide bulb and balast at because everything that I'm seeing online is very expensive.


Look on e-bay at the metal halide grow lite systems. They arent anywhere near as expensive as a web search.


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## SOBER (Aug 6, 2007)

macmiller said:


> it's about 34" from the center of the bulb. glass is about 2x3 feet


so you can burn screens or images pretty 
close to 2x3 ?...thats good thats about the size of area i want to work with, its what i have now but with 48' fluor.lights...and i'
just ordered a 1000 watt set-up also ..so 
i want to gut that out and replase it with the 1000 wtt.


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## SOBER (Aug 6, 2007)

macmiller said:


> i have those same exact parts. with ulano qx-1 i can burn screens from between 50 sec to 2 min, depending on mesh color and count.
> 
> have fun w/ your project!


i just bought the same set-up ..and was wondering how long your exposure times were?


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## dmarshall83 (Apr 3, 2007)

How long do you let your bulb warm up before you pull the shutter?


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## macmiller (Jul 23, 2007)

about 5 minutes. it will stop humming as loud once it's warmed up


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## C-DUB (May 7, 2008)

I finished mine a few months back from info I found here and around the web. It's a 1000w metal halide I picked up at a hydroponics store for about $200. It has a shutter, fan and a neoprene vacuum lid powered by a hacked up vacuum I found at a garage sale. The glass is 24" x 36" and 1/4" thick. My exposure time are around 3 minutes. Warm up time is about 5 minutes.

This thing works way better than I expected. Easy to operate, no ghosting or shadows, everything nice and sharp. I researched all of the home built exposure units from this forum and others suggested on the net. I picked out all the features I wanted and just went for it. This forum is invaluable! Thanks to all who posted their information!


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## RickB (Jun 15, 2007)

Very nice rig, Chris! Have any of you fellow DIY exposure unit guys ever wheeled out the ol' light cannon on a foggy night?


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## buckcreek (Aug 13, 2007)

Jose,
Did you have to pay a lot for shipping on the press you bought on ebay? That really increases what you pay for the item. Also, was it in a crate or anything when it was shipped or were you able to pick it up?


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## Soulstack (Jan 8, 2010)

Hi, i recently went to home depot to buy the glass for the exposure unit i plan to build but was told they no longer sell sheets of glass. does anyone know where else i can find non uv-treated glass? (i live in san francisco)
i was also wondering if anyone who has built some of these 100 watt metal halide units might have plans? Chris your unit looks amazing but i'm not quite sure if i have the measurements down. 
any help will be greatly appreciated.


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## chard (Oct 14, 2008)

which among these metal halides floodlight would you recommend?
Industrial Luminaires
these were the only ones available in my place..aside form different wattage, what concerns me is which kind of lamp..there's a tubular and linear..which one do you recommend..thanks


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## chard (Oct 14, 2008)

when building exposure unit, does it really have to be enclosed in a box?cant you just build it like this one on youtube.. http://www.youtube.com/watch?v=VsA1q0ejA4I&feature=related


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## hdem (Mar 1, 2008)

You don't have to enclose the light in a box by why would you want that really bright UV intense light showering everything in the shop? It will turn the place into a tanning salon lol.


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## edward1210 (Nov 7, 2009)

Great info! I'm getting ready to build my exposure unit, here is what i planing to buy.
M1000/B/U/BT37/HTL Eye Hortilx 53967 | 1000 Watt M47 Mogul Lamp | BallastKit.com

MH-1000A-P-CA Keystone | 1000W Metal Halide Ballast Kit | 5 Tap | BallastKit.com
What do you think? is this good choice?
Can I put two of this ?
Thank you


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## amdivoff (Jun 6, 2012)

Working to finish mine. Heres a vid 
https://www.youtube.com/watch?v=rNhsNG6k060&feature=youtube_gdata_player


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## edward1210 (Nov 7, 2009)

nice, what is the distance between the glass and the light?


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## reugenio (Sep 20, 2008)

message me if you need help. I built mine and it turned out perfect. I have a vacuum seal (pond liner), shutter, fan (to control temp when it gets really hot). try to keep the bulb and glass about 40 inch. I bought my fyi my bulb was a phillip 1,000 watt halide and I got the ballast for growing weed. when I bought my bulb I tried to research what type of bulb I needed so I did further research and found out that the phillip bulb has really good sun burning credentials compared to others, so I decided to use that. I use Ulano QX-1 for halftones (180-305) and ChromaBlue for spot colors (white mesh). With Ulano QX-1 hybrid my burn time is 35 seconds and with chromablue its 30 seconds with a 2/1 coating. Personally I love QX-1 over chromablue because I have never had problems washing out halftones with QX-1. In Fact even when I did test runs to calibrate the timing it always came out perfect. Plus QX-1 has more durability over chromablue to where it wont break down early.


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## reugenio (Sep 20, 2008)

amdivoff said:


> Working to finish mine. Heres a vid
> https://www.youtube.com/watch?v=rNhsNG6k060&feature=youtube_gdata_player


With my vacuum unit, it does not seal when vacuum is off. It needs to be on till you are done. I bought a $20 1 gallon shop vac. I also drilled holes into the wood and put 4 air lines into the wood. What I did different was paint the whole inside white (sat on the phone with Richard Greaves and debated that whole issue) and bought me a reflector because reflectors have complete science to it rather than me trying to figure it out myself and creating unwanted undercutting. the vacuum reduces it but doesnt minus out the equation. Jus my input.


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## reugenio (Sep 20, 2008)

edward1210 said:


> nice, what is the distance between the glass and the light?


It needs to be 1.5 times diagonal of your biggest image you will burn. NOT the size of the screen, "the image". Always go bigger and thats why I went with 40 inches and it turned out perfect. my image max size is 26 inch Diagonal and its perfect for automatic screens. Remember to put a fan so it doesnt get too hot in the box. It can manipulate ur timing if its too hott. Make sure the fan blows the air out not in. This will help when needing to do multiple screens at once because when ever you turn off your ballast and halide light, you will have to wait 10-15 minutes in order for it to turn on again. Unless you buy the quick strike ballast and bulb. jus my insight on this hope it helps you


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## edward1210 (Nov 7, 2009)

reugenio said:


> It needs to be 1.5 times diagonal of your biggest image you will burn. NOT the size of the screen, "the image". Always go bigger and thats why I went with 40 inches and it turned out perfect. my image max size is 26 inch Diagonal and its perfect for automatic screens. Remember to put a fan so it doesnt get too hot in the box. It can manipulate ur timing if its too hott. Make sure the fan blows the air out not in. This will help when needing to do multiple screens at once because when ever you turn off your ballast and halide light, you will have to wait 10-15 minutes in order for it to turn on again. Unless you buy the quick strike ballast and bulb. jus my insight on this hope it helps you


I’m building my exposure unit, with 1500 watt mh, by box is around 29x31 and 36d
Metal Halide Lamp Ballast Kit 1500W 4Tap 120V 208V 240V 277V + 1500W BT37 Bulb
I know they said 1.5 times diagonal of your biggest image you will burn. NOT the size of the screen, why not the screen?
So let said my biggest image is 13inch diagonal x 1.5?, so this will be =19.5 inch
So my 1500 watt mh will be below the glass 19.5?


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## amdivoff (Jun 6, 2012)

I would go by screen size diagonal length, that way your entire screen is getting optimal light.


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