I would just leave it. It is on the outer edge and maybe not even in the usable range of the reflector (and also only slightly different angle than the rest)

well guys, this elliptical reflector is very promising, but its not going to be a quick "slam dunk". Quick playing around I found the focal point to be a couple inches out from the rim. I was using a cardboard box to play with focusing etc and found that this thing is burning the cardboard after about 4-5 seconds! So she is definitely concentrating A LOT of that light. I held the assembly in place and tried to put its focal point about where the fresnels FP is, but wasn't able to get an evenly lit screen. I am guessing we will need a condenser for this baby, but I have much more playing to do. The other cool thing is that it isn't as big as I expected and it is easily vented at its base opening around the base of the bulb.

Sunlight averages 1KW per square foot...maybe we should come up with a periscope to bring light to the box through a window.

Well.At least you got a hell of a focus on the reflector so I guess,congratulation.
And how wasit in temp?Isi´t safe to put in a box?I have seen a reflector on another
page and hi as done what I think i almoast rigth(exept for the front reflector).
Otherways I have another idea.What if the reflector where made rectangular insead of round but still elleptical?That sounded stange.... No i´ll build the thing and post pictures later on.Here´s the page whith the reflector:http://www.hommie.net/parts.htm

The reflector is similar to that, but it is designed for a HID bulb like ours. I'll take some pics soon here. I am sure a condenser is needed like used on the link you posted. I am curious what kind of results that guy got. He didn't show or write much. I don't know how transparent the "made for overheads" LCD that he used is, but I am very suprised he would want a brighter bulb than a 400W using such an efficient reflector. Maybe he didn't focus it correctly? It is touchy.

Hmm.Guess you´re rigth.Focusing migth have been wrong(sense he later on gave up).But the idea seams nice anyway.I still think that done rigth the elleptical
reflector is the way to go.Just look at the amount of ligth we are making here and
only use a little of it.So there must be a better way.Look at the commercial
projectors and how little ligth they are making(compered to us).Don´t belive me?
Just try a projector lamp outside the projector and compare it to our 400W mh.
Biggest different I saw was concentrasion(and price).

Hey all,

I've finally finished building my projector (still have a lot of tweaking to do) and will have my plog up soon. I do have a question. I'm using this bowl double wall insulated bowl that I got from LNT. Basically, I cut the outside of the bowl off leaving about .25" lip on it. However, I don't think the inside of the bowl is perfectly spherical. I'm getting pretty even lighting but it looks like I have a large 'hot dog' shaped bright spot in the middle of my image.

If anyone has used this bowl as a reflector, how much of it did you cut off? BTW, I'm using the old, large ED28 size bulb (the old lighting unlimited package with the old ballast).

This is a great community, I've gotten all my questions answered and have successfully made a projector! Thanks, Brain!

Jason

I found a cheap source for the Steeltek ice cream bowls and was wondering if anyone had luck with them. They look rather small, but may work with the DD style of bulb. At $1 each I'm going to give it a try.

Me again,

Don't mean to bug, but hasn't anyone used the steeltek double was insulated bowl from LNT? I'd really like to see how much of the bowl they had to cut. Like I said in my earlier post, it doesn't seem to perfectly spherical. Any help would be appreciated.

I don't know if this has been brought up before, but I was wondering if anyone's used ceramic or porcelain floor tile to build their light box. I was gonna throw my precondensor, double ended HQI, dichroic reflector, and AC crossflow fan all into an old CD-ROM case, but I started thinking that the tile would be a better insulator and would be much easier to work with than metal.

If it is ease of construction that you’re after you might want to consider a product called “Hebel” used in the construction of houses instead of bricks. Its aerated concrete block that is very easy to saw, drill and sand by hand. Because it has air trapped inside of it I think it would make a good insulated light box and it is very light as well. Hebel is it’s brand name here in Australia but you should be able to find it if you do a search for “autoclaved aerated concrete “.

DJ

I googled for the AAC and still need to look into it some more. It's very interesting. Thanks for the info DAZZZLA. I'm gonna run to my local hardware store and see what I can find readily available for now as I need to get this project completed before next weekend when the kids come over.

If you are talking about insulating heat that is not a good idea. You want to dissipate heat as much as possible. The best design I have done so far (for dealing with and getting rid of heat) has been the PJ with the aluminum light box and aluminum hood. That thing is always just over room temp and runs a small quiet fan. I would think ceramic/cement would be much more difficult (and heavy) to fabricate a box out of then easy to bend aluminum.

I'm just having a hell of a time working with the CD-ROM case. I figure I could get all the heat dissipated with my crossflow fan. My lightbox will be really small so weight isn't a concern. The biggest problem I'm having is mounting my precondensor and dichroic reflector. I'm somewhat of a perfectionist.

I am sure the CD-ROM case is no fun. You will love sheet aluminum if you try it.
Dichroic reflector? have a link to what you are using? Is it hemispherical?

Does anyone know a lot about precondensing? I have this elliptical reflector that is definitely very efficient, but it is not sending light out in the correct way. I know I need a pre-condenser, but I don't know the technicals of what I need. Is it only what you are sending the light to that needs consideration? Is it the angle or focal length or both that needs consideration?
Dying to harness this concentrated light and blast some video!

I am and it works fine. You can look at it here in my PLOG.

For anyone who has trouble getting the napkin rings, these steeltek bowls are available at any Kohls. They seem to always be in stock and cost 8:00 (US).

Thanks Dergrin. Your lighting looks nice and even. Which bulb are you using? I'm really not sure why I'm getting this strange bright spot. I'll try to take some pics of it (my dig. camera doesn't have a night mode) sometime this week.

I am using the S400DD.

Hey, how about this mold.

It seems very spherical..

Here is the link,

http://www.dr.ca/e_pcercle.html

you can find it under Stainless steel half sphere moulds.

What do you guys think?? It doesn't look too much polished though...

I may order one just for the sake of it.

BTW, as I haven't received my LL lightkit yet, I am not sure of what size I need the reflector to be. Does 16 cm sound right? That is about 6 and 3 eights...

That would be about the right size. Will need cutting and possibly a polishing.
The IKEA deal seems to be the best option these days for size, manuverability, no cutting, easy mounting, polish, price etc. Unless you are in Canada, that might be cheaper for you and buying it through me might take 2 weeks+ to get it.

That would be about the right size. Will need cutting and possibly a polishing.
The IKEA deal seems to be the best option these days for size, manuverability, no cutting, easy mounting, polish, price etc. Unless you are in Canada, that might be cheaper for you and buying it through me might take 2 weeks+ to get it.

[/quote]

Well I am in Canada.. but wich one are you selling anyway? I assume you are not selling the Blanda one but the napkin holder right? And how well are they doing, I guess you don't have too much cutting to do...

Let me know...

Thanks
JF

I checked a "super quartz halogen spot light" in Costco today in Canada diameter of the reflector should be 7-8", 12,000,000 Candle Power, bulb was Philips H4, price was under CAD$40.00

looks similar to the picture but one in Costco looks diffarent. was trying to search the web cant find the same thing I see in the store

Can we use this light in LL PJ? How much light is halogen H4 light 12,000,000 CP compared to S400DD?

H4 is normally an Automotive bulb number and they are typically 50 watts or so.
Being that its halogen you could probably see about 35 lumens/ watt.
Based on this you would need about 24 of them to equal the output of the s400DD.

Kirk

= one big ligt box

I've read and searched through this thread but still need some clarification; for those of you who are using the scubby holder form LnT, is it NECESSARY (I understand about useful part of the reflector) to cut/notch the bowl if using the s400 bulb? I'm thinking I do not, but will feel much better hearing from someone who has direct experience with this setup. Approximately how far away are you placing them from each other for the best light transmission (I'm planning to tweak and adjust once everything is installed but a ballpark distance gives me somewhere to start)

Thanks in advance guys!

Basically yes.

In order to be effective the lamp has to be at the center of the sphere. For the scrubby holder, the onl way that it's possible to do that is to notch the bowl so that the lamp's arc envelope can be at the geometric center of the sphere. If you place the scrubby holder further back, it will not reflect the way that we want it to.

Thanks Supraguy! I think I get it now.

http://store.yahoo.com/patiofurniture-supe...lbeatbowse.html

A wannabe Norpro, someone wanna try it?

This also might be worth checking out-
http://www.arjanimpex.com/mainframe_kitchenwares.htm

Scroll down to Hand Grip Mixing Bowl (With convenience ring)

Hi guys! I've got most everything I need to build my enclosure, but I can't find where I read a while back about the placement of the IKEA napkin holder. Can someone who knows post a link to that post, or just reply with the info? Thanks


Josh

http://www.lumenlab.com/forums/index.php?s...indpost&p=58048

Hope thats what youre lookin' for.

A couple of months ago you would have been a hero for finding those bowls... I guess everybody has moved on to the Ikea napkin holder now. There was so much panic that there would never be a reflector as good as the Norpro.

Don't worry, the IKEA is working just as good as the Norpro. The idea of useable reflection is proving to be correct in the testing I have done.

Anyone notice the model number of the bowl in the second link is MH-400?

I use IKEA Groggy ash tray as reflector. It's not as large as the napkin holder but it's much more reflective. If you aren't using pre-condenser you don't want to use bigger one.

Thanks MadMoose!!!! That is the exact post I was looking for. I was so worked up about not being able to find it that I took some rough measurements and found a way to calculate the radius from the measurements that I had. Due to my rough(and I mean rough) measurements I was off by 2.5 mm. Still close enough to be in the ball park, but I had no real idea if I was even close.


Josh

I was searching like crazy a couple months ago, best I found was another norpro source (the canadian one that went sold in within a day). I really think someone should give those a try though. The second link looks like its the OEM. Maybe they can be ordered in mass quantitys @ whole sale and resold? Maybe not

Hello everyone. I know it has been answered before but i'm a little drunk right now. What is the best way to polish the ikea napkin ring.I was thinking of using my dremel and wanted to know if i need any kind of paste.

Just polish it with Wenol fine cut.

I used the chrome wheel polish compond at autozone. Be very careful when using the dremel though, you don't want to nick and scratch the surface. It's polished pretty well as is, I think that a good hand polish with would be just a good.

[/quote]
A couple of months ago you would have been a hero for finding those bowls... I guess everybody has moved on to the Ikea napkin holder now. There was so much panic that there would never be a reflector as good as the Norpro.

[/quote]

These bowls still would be very useful (if tested and seen properly working) for those that have larger lamps (like myself) because those Napkin Holders are way to small for the bigger lamps!

Has anyone out there tried the IKEA napkin reflector with a larger bulb yet? Imagining it in my head it seems that it would work fine with all but the gigantic bulb (which only a very large bowl of any type would work with). Its all about whether it fits where it needs to be in relation to the gas pocket of the bulb. It would fit no better or worse than a bowl that needs to be cut to fit. The reflection surface needs to be where it needs to be no matter what you start with to make the reflector.

Stebooks, do you have the huge bulb?

Has anyone compared the difference between using an unpolished reflector and one polished with one of the products that has been mentioned?

Joe:

I looked into the napking ring with my BT37 bulb. No dice. The bulb glass it too large to allow the napkin ring to get to the correct focal distance from the bulb.



Yes. I just finished polishing mine up. Although there was a time difference between seeing the results with and without, I'd have to say that I didn't see any difference at all. There may well be one, but I don't see it as being a signifgant improvement. To summarize, that's a half hour of my life that I'd like back!

So what did you use for a reflector and why did it work in a way the IKEA doesn't? Is the hemisphere dimension bigger than the IKEAS "would be" total hemisphere dimension?



Well put and 'nuff said!

I sold the BT37, along with the coil 'n core ballast, and the Ikea BLANDA bowl that I was planning to use to another fellow who'll be using it instead.

I'm using the napkin ring, along with the LL light kit. (Good thing, too, that box was getting HEAVY.)

Hi guys this is my first post here.

I am usually one for contraversy so why not start with my first post

Reflectors are a waste of time.

Let me explain.

The fresnel will only make the light paralel so long as the the light is coming from a specified point. Lets say the fresnel was designed to paralell the light from a point source of light 30cm away. Then thats only how it will work.
If you then start gathering light from other sources, ie the reflector, that means the light is hitting the fresnel at the wrong angle, hence it will also exit the fresnel at the wrong angle.

The choice is yours, you can deside to either only use the reflector method, or only the direct method, but not both

Sure, by having both direct and reflected light you will get more light through your lens, but it will be mixed angles of light and only serve in bluring your picture and just making a nicley lit wall.

I can hardly wait for the savaging

Oh and just one other thought. Why are we using metal halide lights with the big protective bubble on them? The bubble serves no purpose other than protecting the inner tube where all the action is. We can easily smash off the bubble.

There is a good reason why professional lamps are more expensive than what we are using here. They are deigned to put more light into a finer point source than the metal halide lights we use.

Let me be the first to welcome you and, at the same time, the first to correct you. :)
The reflector designs presented here are mainly based on a spherical surface that reflects the rearwrd arc light directly toward the origin point and onward to the fresnel. Because the fresnel lens is focused on the arc point and the reflected light is also headed back to that same point the reflected light is properly oriented for use by the collimator. It is very useable and makes a noticable increase in net output. The excess potion of the rear reflector that is larger than the front included angle is of course not useable but that then becomes a matter of mounting feasability, availability and ease of installation.


Kirk

I haven't seen anyone list this before, so please let me know if I am reposting this item.

Calphalon Soup Ladle



It's $10 at Bed Bath and Beyond and has one hell of a polished finish to it already. I got one yesterday after I thrashed my Ikea reflector. The only drawback to this item is that it is very thick and heavy. Using my Dremel with steel cutting disks, I spent 2 hours to get the grooves cut out. It is 88mm across and as far as I can tell, is pretty close to spherical.

It comes ridiculously shiny, but I went at it for 30 minutes with some Mothers and it is just flawless.

If you're in a pinch, or don't have an Ikea near you, this could be a good option for you.

You haven't done much searching through the forums have you?

The reflectors bounce the light back to the source which makes the source brighter, so it doesn't send light through the fresnel at a wrong angle.

The protective bubble is there for a purpose, to stop most of the UV light getting out, without that protective bubble you'd get severely sunburnt.

Professional lamps are expensive because yes they're smaller for a finer point of light but from what I gather the bulb manufacturers have contracts with the projector manufacturers so they have the market cornered and can set the price as they wish, subsidising the cost of building the projectors by keeping the bulbs expensive (like printers and ink).