D.I.Y. 900-watt CF Lighting Units

[Martin Catt]

Richard:
Terminology difference, I think. Round here, when people say "plaster," they mean plaster of paris. I suspect the "plaster" in the article is actually an investment compound, which is intended for use as casting. My background is in watchmaking and jewelry, and one of the things we were told was to NEVER use plaster of paris for casting molds because it wouldn't stand the heat and often would pop or "explode" when filled with molten metal. Of course, jewelry alloys melt at around 1800 degrees F. Lower temp alloys might work in regular plaster. My information is slightly dated.

Martin

[Richard Andrewski]

Yeah, no way would plaster of paris work. I think they mean products like Ultracal 30 from US Gypsum:

http://www.plaster.com/Ultracal.html

Or the dental grade molding stones which are all super hard and dense.

[Greg Boston]

Originally Posted by Martin Catt

Now, if I was REALLY dedicated, I'd go out and get them black anodized.

There are kits you can buy online for small volume anodizing. Not too expensive. I was looking into it awhile back for something unrelated to video.

As to painting, I was talking more about the baking pan exterior than the barn doors. Sounds like you did okay with the cooling requirements by creating that airspace.

-gb-

[Gary Moses]

Sure Martin, building is much more fun, that's why I built my own LED lights that are extremely powerful. When it comes to putting 9 or 16 bulbs (they make a 16 also) in a small case, it was much easier to buy. By the way, I don't use barn doors I made a shield around the entire box, mostly for protection of the bulbs.
Gary

[Brian Luce]

Originally Posted by Gary Moses

Wouldn't it have been a lot easier and less expensive just ot buy one of these?
http://cgi.ebay.com/Continuous-Light...QQcmdZViewItem

I bought 2 and have been using them for almost a year. It has 2 circuits, one I use for 5500 degree CFL's and the other circuit for 3500 CFL's.
Just a thought.
Gary

I emailed the seller about this and they said the fixture is 8"x8". Isn't that a bit small for 9 bulbs?

[Gary Moses]

Yeah Brian, it sure seems that it is, but 9 bulbs fit perfectly. What's nice is that 2 of these fit in an old gym bag and weigh only a few pounds.
Gary

[Mark Sasahara]

A Matthews TVMP adapter might be helpful.
http://www.bhphotovideo.com/c/produc...P_Adapter.html

http://www.msegrip.com/mse.php?show=...ducts_ID=24180

Get a small Matth T handle to replace the thumbscrew. The TVMP adapter has a 5/8 female receiver and the outer diameter is 1 1/8" so and it will fit in a Jr receiver, when you remove the T handle. You may also want a slightly beefier yoke.

Increase the size of the "pan" and the addition of Miro covered reflectors will also increase the size of your light. I believe that would also increase the output. You would have to fiddle with the angle of reflection and maybe also figure out an optimal placement distance. You could probably find a metal fabricator to help you make your parts.

Does the light cause multiple shadows? That would be one concern. a little bit of light diffusion should cure that, if there are.

Nice rig.

[Martin Catt]

Originally Posted by Mark Sasahara

You may also want a slightly beefier yoke.

The current 1"x.125" aluminum yoke seems to be sized just right for the weight of the head. My only concern was the mount hole at the bottom of the yoke would weaken it, so I went with the wide bar stock reinforcement. Plus. it made it simple to do the mount for the stand. There is no wobble, rock, or droop. It locks up nice and solid.

Originally Posted by Mark Sasahara

Increase the size of the "pan" and the addition of Miro covered reflectors will also increase the size of your light. I believe that would also increase the output. You would have to fiddle with the angle of reflection and maybe also figure out an optimal placement distance. You could probably find a metal fabricator to help you make your parts.

No plans to go into production any time soon. At the most, I thought I might do up a PDF file with plans and instructions and make them available for download.

Originally Posted by Mark Sasahara

Does the light cause multiple shadows? That would be one concern. a little bit of light diffusion should cure that, if there are.

Because of the compact size of the heads, the close lamp spacing, and the diffuse nature of CF's, you only get single shadows at normal working distances. As a wild-hair experiment, this worked out pretty well.

Originally Posted by Mark Sasahara

Nice rig.

Thanks.

Martin

[Tsu Terao]

Martin

If you were to do it again, would you use double pans, or would a single do?

[Martin Catt]

Originally Posted by Tsu Terao

Martin

If you were to do it again, would you use double pans, or would a single do?

You really want to use two pans. The two pans nested together form the housing and reflector assembly, giving a bright aluminum reflector behind the lamps and completely covering the sockets and wiring.

The pictures below show how it's built. The first picture shows the back pan, where all the sockets and the yoke mounts are attached. Everything major attaches to the back pan. In the center are four 1.25" aluminum hex spacers used to mount the second pan in front of the first.

The next picture shows the second pan, removed from the lighting fixture. It serves as a reflector and a place to mount the barn doors. Nine large holes are drilled in it for the lamps to screw through. It mounts to the back pan with four screws into the four hex spacers.

The last picture shows the two pans assembled , without the CF lamps.

You could replace the back pan with a box or plate of some kind, but using two identical pans is the easiest way to make the fixture.

Hope that helps.

Martin

[Richard Andrewski]

No question that is the easiest way. The harder route would have been to make a Alanod MIRO reflector box that went on top of the sockets. The reason I say hard is because its not such an easy trick to cut the reflector out of the aluminum and do it right the first time--making it look good and professional too.

[Martin Catt]

Richard:
I agree completely. This was an exercise in producing a solid, reliable light unit on the cheap, using locally available items. I'm really happy with how things turned out. The lights look good and perform better than I expected. Unless you get right up on the back of the unit and see the Nordic Ware stamp, you can't really tell it's made from two brownie pans. I suppose I should make a custom nameplate to cover the stamp.

BTW, I enjoy reading your site and how you develop your product line. I think you understand what's needed to come up with a profitable design and bring it to the market better than most, especially when it's a product that may sell only in the hundreds or thousands of units. I thought about making and selling lights like these, but there's really no way I could compete with the imports selling for less than $90 on eBay.

Regards;
Martin.

[Richard Andrewski]

I know what things cost and I thought it was ridiculous what an aluminum fixture was costing--especially long after all the tooling costs have been paid for. I also know what ballasts are and what components are in them. It's hard to imagine the collection of components that warrants a price tag of $4000 to $8000 for an HMI for instance. Actually, I think its not that I know more than most because I don't. Many people understand manufacturing processes. Frankly, I think its a question of business plans, honesty, size of companies, overhead, momentum in the market, and what they can get away with based on what they have done in the past. It's mainly the lengths I've been willing to go to that many others might not be willing to do to make all this happen.

On the subject of what you choose to be your "project box" as I call it --borrowing a term from the electronic hobbyist world and applying it to the lighting experimenter: that's easily the hardest part IMHO. You can search for weeks for a suitable enclosure and baking pans are about as good as it gets for many of these kinds of things. When I wanted to move up to the 55w tubes, there really wasn't anything of the size necessary so it was time for more serious measures--like going to a sheet metal fab shop....

[Martin Catt]

Got a question via PM about the lights, and thought I'd attach the PDF showing how the hinges are made and the wiring diagram.

Regards;
Martin

[Chris Barcellos]

I made this unit as a prototype using 3 4-bulp bathroom fixtures bought at Home Depot for 9 bucks each. Backing is a cutdown foamcore poster board I got at Staples. Kids use them for the science presentations, etc. With this set up, the you just have to wire tie three units together, and tie them together with wood slats, and design a mount for whatever you are goint to hand them from. In this case I had a shop light go back so I used the encloser for the the wiring. No switch right now but the concept will work...

By the way, those shop lights in background are used to sit on either side of my green screen....