Liquid Cooled Projector

[joesgarage11]

It will stay polished for a while. When it oxidizes, polish again. Should be much easier to repolish once you get the first polish done. Or you could try to find a highly reflective white paint. At work, we switched over most of the specular (special reflective coating) aluminum reflectors to the white paint. It reflects ~95% and is cheaper.

Just by coincidence I had to light up a 400W metal halide lamp today to see how it performed in a light fixture. Even through a white acrylic cylinder the lamp was almost too bright to look at. I thought of you guys.

joesgarage, watercooling a HID bulb takes away about 40% light intensity. Also, you dont want to use a HPS light for this application. Stick with MH.

True, the color would be bad and the price is outrageous. Close to US$1000 for the whole setup! HPS for growing, MH for projecting.

[superart]

what about a murcury vapor HID light? Or is that too much toward the blue spectrum for projecting?

[joesgarage11]

Go with the MH. You're right about the color of the mercury lamp. The pulse start MH system that killnernoodle is using is about the best you can get right now. Use an open fixure rated lamp if you can so you don't have to shield it in case of the rare explosion when the lamp reaches the end of its life.

From the Venture Lamp Brochure:

Venture's open rated MP and MPI lamps contain protective quartz shrouds which helps contain hot particles in the lamp in the event of an arc tube rupture.

[bigben2k]

Originally Posted by killernoodle

Not really, that would cost far more than the actual reflectors. I'll just have to live with it. What is a good way to keep them polished and still heat resistant? If I polish it with that brasso for aluminum stuff, will it keep shiny for a while?

I'm really not sure. Someone else probably has a better answer than me. (looks like joesgarage11 has a good answer)

One thing I know for sure is that if I was in your shoes, I'd be *issed; I wouldn't consider using an Alu reflector for this project (sorry).

(looks like joesgarage11 has a favorable answer)

[superart]

Why whats wrong with Al?

Al is more reflective than stainless anyway.

[JWFokker]

I'd just polish it and spray a couple layers of clear coat on it to prevent oxidization. Have you checked Linens N Things for a stainless steel mixing bowl? They're supposed to have good ones similar to the Norpro.

Of course, this is assuming that the clear coat sufficiently prevents oxygen from reaching the surface of the aluminum, which I have no idea whether it does or not. It could be entirely oxygen permeable for all I know.

[JWFokker]

Lenses, ballast and bulb are on the way. Next week I'll order the LCD and build the box. I should get a couple of those squirrel cage fan case fans too while I'm at it.

What do you think I should do with the box? I was thinking of using poplar or red alder for the main construction (keep it as light as possible) and then using a nice cherry burl or redwood lace burl veneer and a basic oil based finish. Brass fixtures of course.

Then again, lacewood would look good too with a light stain....or maybe a quilted maple/ebony combination. Crap. Time to dig out the catalogs.

[lolito_fr]

spray a couple layers of clear coat on it to prevent oxidization

Won't that stuff get hot?

[JWFokker]

Very. I wonder what the max temp is for something like that. They do make high temp engine bay paint. I would hope they made a clear coat version.

But honestly, I'd ditch the aluminum and buy something stainless steel. Linens N Things has a full hemisphere bowl for $8 if I remember correctly.

[superart]

can you anodize clear the Al after polishing to prevent oxidation?

[Senater_Cache]

Originally Posted by killernoodle

Well, we are looking at ~30,000 lumens from the 400w, so they are already very effecient. Plus, they need to have nearly perfect white light and must also be durable. The most important thing, however, is that they are a point light source, which is necessary in a projector.

Hey Killernoodle,
My friends MH bulb (400w) puts out light that is extremely greenish, (moreso than his Flourescents even, but much brighter)
Have you looked into HPS at all?

[JWFokker]

HPS is too orange. I think your friend's MH bulb was a low temp bulb. We're talking 4000K bulbs with a CRI of at least 65, it may have been 3200K or lower. Ideally, we'd use 5200K bulbs but they aren't very common. However, Ushio does make a 5200K MH conversion bulb (85 CRI) that is intended for HPS ballasts. It's the best available right now, but it isn't easy to find. I'd use one but I've already got an MH ballast on the way so I'm stuck with a 4000K for the time being. I've been told the 5200K Ushio is compatible with MH ballasts too, but I'll wait for a definite answer on that.

[joesgarage11]

I got a 6" dia. aluminum half sphere to try testing instead of the dog bowl . I'd like to check the light output and lamp temperature with no reflector, a white sheet reflector, a spherical reflector, and a parabolic reflector.

The picture from left to right shows the ballast and 150 watt metal halide lamp, a light meter that measures lux and foot-candles, the parabolic reflector, a thermometer, and the spherical reflector. All are sitting on top of the white sheet reflector.

killernoodle - the aluminum half sphere was in bad shape inside. It was spun from aluminum sheet. It had a hole in the center so I put a 2" long 1/4" carriage bolt through the hole from the inside and used two washers and a nut on the other side to make a pin I could put in the chuck of an electric hand drill. While the drill was running, I went from sandpaper to 0000 steel wool to automotive polishing compound on the inside.

[superart]

JW,
You got that kinda right. MH bulbs are compatable with HPS ballasts, but not the other way arround. However, to put an MH bulb into an HPS ballast, you need to diconnect the sparker. They have dual ballasts on the market like that. All it is is a HPS ballast with a switch controlling the sparker.

[JWFokker]

I'm not talking about the ballast. This bulb works with all HPS ballasts. It's a modified MH bulb designed to work with HPS ballasts because HPS bulbs are traditionally orange-ish in hue. This bulb is white. Whiter than most MH bulbs in fact.

It turns out the guy who was telling me the Ushio 5200K bulb is compatible with MH ballasts is flat out wrong. This bulb is HPS only. Good thing I ordered the right one. Unfortunately, it's only 4000K. Maybe when I've got everything up and running for a while I'll buy an HPS ballast and get the Ushio 5200K bulb. It's supposed to have better whites. I can compensate to a degree with video card controls but I'd rather just have a better bulb.

[superart]

What's the wattage on that 5200k bulb?


btw, when a MH bulb is built to go into a HPS ballast, thats called a "conversion bulb". They make them for people who are growing plants with a HPS ballast, and need a MH or MV bulb for a short while. That way they don't need to buy a whole new ballast. Their not very good for growing, but aparently really good for projectors. Good find.

[JWFokker]

Dude, that's exactly what I said.

"However, Ushio does make a 5200K MH conversion bulb (85 CRI) that is intended for HPS ballasts. It's the best available right now, but it isn't easy to find."

It's 400W btw. I have no idea why they don't make a dedicated MH version of it.

[killernoodle]

Alright, just thought I'd give you foolz an update.

Now projecting on the crappy pitted and discolored cement wall in my dorm room: Family Guy! Also showing is Gladiator of course and some itunes to show the clarity of it all. (and my hands are freaking huge BTW, so that makes the comparison in size even better). The image takes up an entire wall of my dorm room, some of the ceiling and part of a pillar thing It needs to be moved much closer, but suspending it from the ceiling is not an option.

And for more size reference, that is a 2001fp monitor, and 4 HTD level 3 speakers on the shelf there that I just picked off ebay for cheap.

[superart]

sweet. How much did everything cost you?

[killernoodle]

I wasnt really taking a tally:

170 for the lcd
100 for the lamp+ballast+accessories
70? for the lenses
free wood
free wires and paint
10 for random radio shack stuff

So I was at my target of $350 for everything.

[bigben2k]

Sweet!

How long would you say this setup is going to last?

Is there enough info in this thread to replicate it? I've always wanted a projector, but never had a budget for it. It looks like an interesting project.

[killernoodle]

Not enough in this thread. I suggest you first buy the $20 lumenlab manual. More importantly, this lets you access some very nice parts of the forum which answer all the questions you may have. Trust me, without the forum I'd be lost.


The lamp is rated for 40,000 hours, so I'd say it could go for years. I'll upgrade to a WUXGA screen sometime and a better lens kit and make a folded projector sometime, but not anytime soon. I'm very impressed with the quality of the picture from this one alone.

[Etacovda]

Ive just started designing mine, glad to see another person with good results. Good little project, beats paying 5k for one

[bigben2k]

Done. Looking forward to it, thanks!

edit: link to manual purchase: http://www.lumenlab.com/
(I'm assuming that everyone is cool with this?!?)

[killernoodle]

Yeah, thats the place. The forums are definitely worth it. The guy who started it all posts regularly there and gives tips, ect. Tons and tons of information. Lots of math too (you'd love it ) about lumen output ect.