COB LED DIY Build Journal

BM9AGS

BM9AGS

Well-Known Member
Yeah aluminum gets eaten by a lot of other metals or chemicals. I'm sure it's fine, AS website might mention it. I know the liquid silver pro would eat the fuck out of it.
 
PDX Joe

PDX Joe

Well-Known Member
BM9AGS said:
Yeah aluminum gets eaten by a lot of other metals or chemicals. I'm sure it's fine, AS website might mention it. I know the liquid silver pro would eat the fuck out of it.
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I just found this post from Robin at Northern Grow Lights.

https://www.rollitup.org/t/diy-passive-cooling-with-pin-heatsinks-sst120-and-sst140.906729/page-11#post-12754700

The pads I have from Cutter are graphite. I'm wondering if I might have a corrosion issue now with the raw sanded heatsinks. I wonder if I should let the heatsinks sit out for awhile before mounting the COBs, that way it would give the raw aluminum time to develop a layer of aluminum oxide, which would protect it from corrosion.

Or I could look into anodizing the aluminum. I think you can get DIY anodizing solutions.
 
PDX Joe

PDX Joe

Well-Known Member
I just spoke with an anodizer here in town. It sounds like they can anodize four heatsinks for around $30. That's not terribly expensive. I might go ahead and do that for some additional piece of mind. I'm putting in all this effort to build this light and it would be good if I don't have any corrosion in the near future. That would completely piss me off. I like doing things right better than doing things over.
 
Airwalker16

Airwalker16

Well-Known Member
PDX Joe said:
I created a heatsink drilling template cutout with AutoCAD. It made setting the holes to drill a bit easier. They're drilled and ready to be hand tapped.
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Using electronic self tappers is much easier. 5/64" bit and m3x6-10mm and boom
 
PDX Joe

PDX Joe

Well-Known Member
Well, no surprise that I've run into a few minor issues with my build. As a first build and one-off design, I was bound to run into some problems. I cut my fan holes a little bit too large and was having some trouble aligning the fan holes with the COB holes. They were slightly misaligned. So, I needed away to adjust the COB engines and get them centered between the two holes. I decided to use some scrap 1/8" acrylic sheets and bolt the COB engines to the acrylic. This allows me to adjust the location of the COB engines. I'll bolt the acrylic sheets to the fan grill bolts in order to fasten the COB engines to the metal enclosure.
 

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Airwalker16

Airwalker16

Well-Known Member
PDX Joe said:
The acrylic plates really helped me be able to center the COBs properly in the holes. I cracked one plate as I was drilling it, hence the one plate in a different color. The COB, heatsink, fan assemblies are now all bolted to the metal enclosure. Time to wire everything up now.
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As far as cracked plates you mean on the fan?
 
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Airwalker16

Airwalker16

Well-Known Member
PDX Joe said:
The acrylic plates really helped me be able to center the COBs properly in the holes. I cracked one plate as I was drilling it, hence the one plate in a different color. The COB, heatsink, fan assemblies are now all bolted to the metal enclosure. Time to wire everything up now.
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You've got your fans sucking air from the top ON TO THE heatsinks right?
 
Airwalker16

Airwalker16

Well-Known Member
That light should be an ass kicker. The spacing is how a fixture actually Should Be. Haha. You'd really killed it with 72v cxb3590's.
 
PDX Joe

PDX Joe

Well-Known Member
Airwalker16 said:
That light should be an ass kicker. The spacing is how a fixture actually Should Be. Haha. You'd really killed it with 72v cxb3590's.
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Thanks. I actually drafted out the closet size, fixture height and light pattern in AutoCAD to figure out the light spacing. I wanted to try and get the most even light coverage possible in a 3'x3' closet.

I thought about trying the 72v, but I think at the time I bought my driver there weren't as many driver options for four 72v versions. But, I may be misremembering, because I bought the driver about 8 months ago.

Summer has slowed me down a bit. But, I'm hoping I'll have the closet up and running this fall.
 
PDX Joe

PDX Joe

Well-Known Member
I've completed most of the wiring. However, I had some trouble soldering wires onto the IEC 320 plug module. The lugs are just too close together for soldering easily. So, instead I think I will use crimp on female terminal connectors for this portion of the wiring. I soldered a 10k resistor to the dimming pot and that went okay. I'm very close to firing this thing up.
 

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nevergoodenuf

nevergoodenuf

Well-Known Member
@PDX Joe it looks like you didn't tin the wire on the resistor. Get a good amount of solder on both before you try to solder them together. Also make sure the tip of your soldering iron is very clean. I found even a slightly dirt tip doesn't transfer the heat well.
 
PDX Joe

PDX Joe

Well-Known Member
nevergoodenuf said:
@PDX Joe it looks like you didn't tin the wire on the resistor. Get a good amount of solder on both before you try to solder them together. Also make sure the tip of your soldering iron is very clean. I found even a slightly dirt tip doesn't transfer the heat well.
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Thanks for the tip. This was my pre solder mockup. The soldering went well and I got good solder coverage across the entire wire connection.
 
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