Screened porch build, LED waterproofing and advice?

[Illum]

I'm curious why you epoxied the end cap to the bracket and the LED to the end cap instead of tapping screw holes in the bracket and using a pair of screws to hold the whole assembly together.

Granted, epoxy is a little more weatherproof than heatsink grease but I suspect it would be preferred if the ambient temps drop very low in winter, a large rapid thermal expansion of the end cap might be hard on the epoxy unless you use a type that remains flexible.

too bad the inside of the brass cap isn't flat, at all...the LED was seesawing around rather than staying still. My tap and die set was borrowed but never returned so I don't have tapping capabilities. As far as thermal expansion is concerned, if the LEDs are left on 24/7, chances are the temperature will be constant most of the year, but yeah that's something to think about

You mentioned having a drill press... you might get the holes started easier without skipping if the cap were put in a vise.

it was in a vice, it wasn't the cap rolling around, its the drill bit being pushed away as I lowered the chuck. the shop was designed as a wood working shop, I have plenty of drill bits but none designed for metal. :candle:

It's hard to tell but it looks like the edges of the star are resting upon the corner of the end cap where it starts to curve upwards, I wonder if the LED would sit lower, more flush with the cap if the edge all the way around the back of the star was ground or filed down a little bit. Then again, the picture might just be an optical illusion.

Good observation, the star is being held up by the sides as well as by the "hill" in the center of the cap. I used epoxy to fill the gap between the corner and the center.

drilling would require at least two screws for it to sit flush and if I was able to tap it, I don't have screws that I could guarantee won't short a couple pads together through the copper material its standing on.

The orange glow is a nice effect, but outdoors I doubt it will be long till the copper oxidizes and that glow is gone.

yeah, but until then its icing on the cake. :twothumbs
Its an unintended effect, from the looks of it I might actually do away with the copper cap and use hot glue instead over wire contacts:candle:

 

[J_C]

To keep the screws from shorting pads you can put insulating washers under them. I have often used old paper ones from earlier computer days but since they can absorb water, I'd probably go with nylon ones at the local hardware store.

 

[Illum]

To keep the screws from shorting pads you can put insulating washers under them. I have often used old paper ones from earlier computer days but since they can absorb water, I'd probably go with nylon ones at the local hardware store.

:huh2:, so such things do exist, in the past I've tried everything from masking tape to plastic sheeting...often with disasterious consequences once everything is in motion and heat is applied. to date the most successful material I've used is a plastic cutting board, but theres not much in that little copper bucket that I can drop things in without having to modify them

no go on the plexiglas yet...from the amount of temperature measured on the surface of the copper cap after a 14 hour test burn I'm inclined to use cellulose wrap over plexiglas. Its winter now, outside temperature is about 66F ambient at night, so its a bit distorted to suggest the heatsink temperature would not be higher once we return to summer with a 80-85F ambient and a 80-90F day temperature. For now, cellulose film will do.

Sometime this week I'll start on a 2 LED assembly. From field evaluation I noticedthat while the pretty glow of copper looks pleasant indoors, it'll wash the plant leaves into this rust color
I might have to wrap the inside of the copper cap with some green electrical tape as a cost to reflectance.

Single LED at 700ma is sufficient to hint vegetation, it did manage to light up a trail of ants on the floor which appeared to be disorganized and scurried along the shadow of a length of water supply pipe on the floor. If these critters are photophobic at night I might actually have a legitimate reason to line the house with LEDs
It did not, however, create the perspective I had when I tried out the lighting locations with my MCE modded L4 driven on a single half-dead CR123A...I'm guessing its due to reflector nature of the L4 in contrast to the imitation using a 3/4" cap

I hope two LEDs will be sufficient. :candle:
I'm awaiting funds to acquire another Xitanium 700ma driver for the other side, but as things look at this point I may only have time to build one side before the end of November, which will initiate final exam season and the headstart of a road trip to California shortly after.

 

[J_C]

so such things do exist, in the past I've tried everything from masking tape to plastic sheeting...often with disasterious consequences once everything is in motion and heat is applied. to date the most successful material I've used is a plastic cutting board, but theres not much in that little copper bucket that I can drop things in without having to modify them

I do wish they'd start making more stars where the wire pads aren't so close to the screw slots.

Paper washers would work, just coat them with some silicone caulking and let that dry before use, so they don't absorb moisture. Plastic should work but would need be need some with high melting point like polycarb or teflon and not brittle like plexiglass. There are a lot of different materials that should work, but finding them or the rising cost of the project could be factors.

Another option would be polycarbonate discs where you don't necessarily try to make a tiny washer, instead make a disc with outside diameter = inside diameter of the copper end cap, drill an oversized hole in the middle where the emitter is and small holes where the screws go. One problem is you'd need a more uniform path for the wires and then dremel out a channel for them on its underside.

Another option might be nylon screws though I don't know how they would hold up over time. Another option might be taking an X-acto knife or similar, or dremel, and sever the wire pads in the middle so the half adjacent to the screw is not live anymore but you'd need to check that there was no continuity to the star's metal base when finished.

no go on the plexiglas yet...from the amount of temperature measured on the surface of the copper cap after a 14 hour test burn I'm inclined to use cellulose wrap over plexiglas. Its winter now, outside temperature is about 66F ambient at night, so its a bit distorted to suggest the heatsink temperature would not be higher once we return to summer with a 80-85F ambient and a 80-90F day temperature. For now, cellulose film will do.

There's always glass, held in with caulking or since you are epoxying these to be permanent you could cut a small ring from pipe and spot-solder that at the top of the end cap as an inner ring that holds the glass lens. Not sure how bad the artifacts in the beam would be from that.

Sometime this week I'll start on a 2 LED assembly. From field evaluation I noticedthat while the pretty glow of copper looks pleasant indoors, it'll wash the plant leaves into this rust color
I might have to wrap the inside of the copper cap with some green electrical tape as a cost to reflectance.

If the heat is enough to effect washers or a lens you will probably find it too much for electrical tape, especially the vinyl type. One thing you might try is plumber's tinning flux, smear it liberally on the sides of the copper end cap and heat it with a torch producing a silver colored plating, or it's possible some HVAC duct tape (aluminum metal type) might work, I don't know what it's adhesive is rated for temperature-wise. Stove paint that gets baked on should also work but is typically black, seems like a large loss of light.

Single LED at 700ma is sufficient to hint vegetation, it did manage to light up a trail of ants on the floor which appeared to be disorganized and scurried along the shadow of a length of water supply pipe on the floor. If these critters are photophobic at night I might actually have a legitimate reason to line the house with LEDs

I know little about ants but we are invaded by them a couple times a year and find they start to scurry from vibrations of people coming and going more than anything else.

 

[usLEDsupply]

I do wish they'd start making more stars where the wire pads aren't so close to the screw slots.

Paper washers would work, just coat them with some silicone caulking and let that dry before use, so they don't absorb moisture. Plastic should work but would need be need some with high melting point like polycarb or teflon and not brittle like plexiglass. There are a lot of different materials that should work, but finding them or the rising cost of the project could be factors.

Another option would be polycarbonate discs where you don't necessarily try to make a tiny washer, instead make a disc with outside diameter = inside diameter of the copper end cap, drill an oversized hole in the middle where the emitter is and small holes where the screws go. One problem is you'd need a more uniform path for the wires and then dremel out a channel for them on its underside.

Another option might be nylon screws though I don't know how they would hold up over time. Another option might be taking an X-acto knife or similar, or dremel, and sever the wire pads in the middle so the half adjacent to the screw is not live anymore but you'd need to check that there was no continuity to the star's metal base when finished.

There's always glass, held in with caulking or since you are epoxying these to be permanent you could cut a small ring from pipe and spot-solder that at the top of the end cap as an inner ring that holds the glass lens. Not sure how bad the artifacts in the beam would be from that.

If the heat is enough to effect washers or a lens you will probably find it too much for electrical tape, especially the vinyl type. One thing you might try is plumber's tinning flux, smear it liberally on the sides of the copper end cap and heat it with a torch producing a silver colored plating, or it's possible some HVAC duct tape (aluminum metal type) might work, I don't know what it's adhesive is rated for temperature-wise. Stove paint that gets baked on should also work but is typically black, seems like a large loss of light.

I know little about ants but we are invaded by them a couple times a year and find they start to scurry from vibrations of people coming and going more than anything else.

i like the glass idea better then the plexi glass but i would just use clear silicone or epoxy and only fill up to the bottom of the glass lens on the emitter so the important parts are sealed (you could hot glue an empty pen barrel onto a silicone tube to get a more precise applicator) if you are worried about getting it on the lens you could have someone hold a large straw over it till you are done

 

[Illum]

I do wish they'd start making more stars where the wire pads aren't so close to the screw slots.

they really should remind themselves that a star does not need so many pads

Paper washers would work, just coat them with some silicone caulking and let that dry before use, so they don't absorb moisture. Plastic should work but would need be need some with high melting point like polycarb or teflon and not brittle like plexiglass. There are a lot of different materials that should work, but finding them or the rising cost of the project could be factors.

well, I try to keep things simple and down to earth, that includes not buying new material and use what I have available and modify them.

Another option would be polycarbonate discs where you don't necessarily try to make a tiny washer, instead make a disc with outside diameter = inside diameter of the copper end cap, drill an oversized hole in the middle where the emitter is and small holes where the screws go. One problem is you'd need a more uniform path for the wires and then dremel out a channel for them on its underside.

so in essence windows held in by "set screws" on the side?
that sounds interesting, I've never considered something that fancy:devil:

given the copper cap diameter I can probably cut out 3 or so from a mag D cell stock window

 

[lonesouth]

Kapton Tape

http://www.dealextreme.com/details.dx/sku.21351

we use the stuff daily in military grade electronics

 

[JohnR66]

I'd loose the cap if the LEDs don't fit down inside flush. It is poor thermal contact even with thermal epoxy/paste. It might be good enough if the LED's junction temp remains in the safe limit.

Mount the star right on the aluminum plate and be done with it. If they are tucked under the fascia board like that, They should be fine.

 

[Illum]

I'd loose the cap if the LEDs don't fit down inside flush. It is poor thermal contact even with thermal epoxy/paste. It might be good enough if the LED's junction temp remains in the safe limit.

Mount the star right on the aluminum plate and be done with it. If they are tucked under the fascia board like that, They should be fine.

thankfully I only implemented the brass cap with one LED...
after a 24 hour test the LED was fine, but I did notice a noticeable difference in temperature between the copper end and the aluminum, which whacked me in the face when I was being optimistic the epoxy would suffice.

the other areas are still in the design stages, and yes, from the looks of it the copper caps out of the loop. :shrug:

 

[J_C]

While there may be better options than copper caps, leaving a bare LEDs exposed outside is probably not a good idea. The dome and gel underfill is relatively fragile and as mentioned previously bugs, then spiders, etc will tend to gravitate towards light. At the very least I'd want a way to clean them periodically without subjecting the dome to it.

 

[lonesouth]

JC did you see the aquarium torture test? I'm now thinking about just mounting the LEDs on some 1" angle aluminum and running them unprotected under my soffit.

 

[Illum]

away from angles, channelsdo exist. I'll see if I can conjure up some pictures this weekend:thinking:

I think from a purely experimental standpoint wrapping duct tape on the side opening of the channel should be more than adequate to keep water from flowing into the assembly from the top, though mounting ability might need some looking into. Granted I can drill holes on the side and mount it in that manner, but having a nail or a lag screw head stuck out within the emitter's viewing angle may introduce unwanted artifacts:thinking:

Kapton tape is nice, but I'll check for local availability of teflon washers before I go about testing the waters in DX or KD.

 

[J_C]

JC did you see the aquarium torture test? I'm now thinking about just mounting the LEDs on some 1" angle aluminum and running them unprotected under my soffit.

Yes, but 2 years is only a fraction of the service life you should expect from a reasonably designed LED lighting fixture.

The dome did come off when cleaning was attempted and look at how filthy and poor the light quality must have been at the end. Granted, it's likely out of and away from water an LED won't get that bad that fast, if ever, but it is reasonable to think they could need cleaned one or more times within their viable lifespan. I've torn domes off XR-E's just barely wiping around the dome.

From a construction/materials cost and design/build time perspective I accept running bare LEDs could be desirable to some people, it is up to each to decide for themselves. I would want something that resists damage if someone not acquainted with how fragile the dome is, tried to clean it.

 

[Illum]

the LED enclosures are underway, for now I'm surprised no enclosures exist for the xitanium, either too big or too small:shakehead

Its thanksgiving week/Exam review week so I had made no progress on the build. the power system is under way but water proofing the concept still proved to be an obstacle. I used paper twoel wadding stuffed to sides of holes around the experimental boxes then sprayed water all around after the glue is dry. No go, there were no stock on three gang exterior junction boxes [dunno if they even exist] and the three gang interior junction boxes had so much holes on it its impossible to waterproof for outdoor use:shakehead

 

[Mr_Light]

If you haven't bought the Xitaniums yet, another option might be to use an exterior 12V lighting power supply (Malibu ...) and then use individual 12V drivers at each LED. You should be able to drive a lot of leds off one power supply. These DX drivers have been well reviewed and cost under $2 when you buy more than 3.

MR16 1*3W 320~350mA Constant Current Regulated LED Driver (8~40V Input)Price: $2.40
http://www.dealextreme.com/details.dx/sku.13557

 

[Illum]

If you haven't bought the Xitaniums yet, another option might be to use an exterior 12V lighting power supply (Malibu ...) and then use individual 12V drivers at each LED. You should be able to drive a lot of leds off one power supply. These DX drivers have been well reviewed and cost under $2 when you buy more than 3.

MR16 1*3W 320~350mA Constant Current Regulated LED Driver (8~40V Input)Price: $2.40
http://www.dealextreme.com/details.dx/sku.13557

I've bought the xitaniums for an earlier discontinued project, I have currently 2 700ma and 2 350ma drivers sitting idle on my desk:shrug:

Given the location of the light is primarily outdoors, designing seperate enclosures for drivers for each LED [6 on one string, 12 total] sounds like an addition expenditure I can afford to do without

 

[Illum]

All this L and U stuff here started getting confusing, as some people can't understand the figurative speech. L is for aluminum angles, U is for Aluminum Channels.

Here's my "workbench" lit by 3 LuxVs on the front driven at 700ma, a central overhead "75W" CFL and flanked by three RX1H Luxeon stars [350ma] above my LM317 voltage regulated power supply.


I set up the central bus that connects the two Xitaniums to a central junction that plugs in into the wall. I found an AC pull switch for a florescent fixture that was thrown out and decided to use that for the main switch.

I resized pictures at 640x480 because when I previewed this post sized at 800x600 was way too slow even of my broadband

the enclosure shown here is a Radioshack 4" x 2" x 1"


It cannot be an easier build, find a 6 row bus bar, inter tie 3 channels to each, 1 for power the other two for the two xitaniums, drill a hole where the pull switch will sit, mark the holes on the side to drill out for power chords, put it together with a wiring diagram





It will be mounted upside down from the first picture.

I found a box big enough to hold the xitanium, but from the looks of it, I could fit TWO xitaniums and then some. 0.o

[FONT=&quot]
[/FONT] Okay, now for the LED modules...

Grab a bar of 1-1/2" x 1/16" Aluminum Angle and start marking the pieces. Each 12" partition will suffice the thermal output of two CREE XREs at 700ma.




Cut the Angles to spec, the first partition on the picture from the top is more another project, driven at 350ma. It is what you in the first picture of the post where the luxeons are shining from



With the placements now marked and stamped, it's chucked and drilled, bore at 1/8" for both mounting and wiring


With the holes bored we can now get to work epoxying the LEDs down:devil:





Now that its epoxied, we can go about soldering in the connecting wires, I'm using 22 Gauge AWG for the long distance ahead:shrug:






With All three modules connected between LEDs, I connected all three modules together with some scrapped 24 gauge wire to do an overnight test run and determine what will go wrong before I go about installing it outdoors



In my room, pre-test

Post-test


The output is incredible, no words can I describe how bright my room is at the moment, it was previously lit by 3 fenix lightbars at max, and this blew that out of the water!

I'm really looking forward to putting it outside and see it from the outdoors perspective:nana:

 

[Illum]

Re: Screened porch build

There's some minor delays until it can be mounted to the porch

for now, there's some weatherproofing to do

Had some medical grade tubing to spare, decided to use that to link up the wires






I decided to tie everything in the negative line and leaving the positive wire in a straight run, but as it turned out to run the tubing I had to cut them open and resplice/solder them :shakehead




I dropped some elmer's glue where the wires perforate to the other end. I'm out of candles or else melted wax will do



For the central junction box, there's tubing for that as well the tubes from the connecting module will be taped to the extensions being a little offset for proper strain relief and allow a little "give" on the tube channel





I have already set up the mount placements, once this is all done the third and fourth module will be installed in a similar manner, hung up, and energized

 

[J_C]

You're not going to make the switch pull chain a piece of fiber optic cable lit by an internal blue led? :devil:

Looks good so far, am anxious to see the finished result.

 

[Illum]

You're not going to make the switch pull chain a piece of fiber optic cable lit by an internal blue led? :devil:

Looks good so far, am anxious to see the finished result.

LOL, that would be cool, but what will it do? a circuit that turns on when it senses pulsed light? Where I can stick my flashlight on the fiber optics, flash it three times to turn on the fixture?

As for the LED moisture barrier, I've finished cutting pieces of cellophane film and stretching them over the LED dome. Lay on 1-2 layers and pushed down to stretch over the LED yielded much needed rain protection without artifacts. Its not waterproof, but droplets of water from the gutter and mist will take sometime to get near the LED

If I must "waterproof" it, I suppose a square cut film flanked by tape on all four sides could be an option

They don't look too fancy looking at it but at night I doubt anyone would look for it.

The best "caps" I've found thus far is the left over plastic carton from radioshack's button cell cartons