Wednesday, June 4, 2014

Adding cold fire to the van

If you got here through my other blog then the title of this entry might make more sense, if you got here direct then not so much.  For those getting here direct, I was attempting to add a little evening ambiance to the van's interior with this project.

It all started when I rediscovered some battery powered LED tea-lights we had laying around. There is a very tiny chip in there that causes the yellow LED to flicker like a flame.

After messing around a little I figured out that if I deconstructed the tea lights, threw away the excess and got down to their working parts I'd have a pretty small package. To make it even better, the flame shaped diffusers were easily separated from the body of the tea-lights and fit over the LED snugly enough to stay put. The deconstruction might look a little drastic but the price sticker on the bottom of each tea-light said we paid 58 cents apiece for them. If it all blows up in my face I'm only out a few bucks. (OK, worst case, if the failure is spectacular enough, a few bucks plus the cost of a new face shield. . .)

Since I really didn't want to be dealing with those little button batteries I needed to figure out some other way to power my 'flame'. Two button batteries = 3 volts. If I string 4 of these LED assemblies together in series, end to end as it were, that would = 12 volts which is exactly what the house batteries in the van deliver! (OK, someone check my math here! Serial readers will remember that I've shot myself in the foot with sloppy math more than once. . .)

Anyway. . . I wasn't going to need the switch on each of the tiny boards so off it came. I bridged what used to be the switch contacts by soldering in a piece of wire and threw the switch into the project bin to be used on something else in the future. The button batteries went into the battery box where they'll get used up next Christmas in one little sparkly ornament or another.

 Next step was to solder the black wire from the LED on the left into where the red wire is currently attached to the LED second from the left and so on down the line until I end up with one red wire on the left and a black wire on the right. This turned out to be a delicate process because the little printed circuit boards were really cheap (Hey, what do you expect for 58 cents?) and even my little 30 watt soldering iron was enough to destroy them if not applied very carefully. With only 4 tea-lights to work with and a 12 volt target to hit I didn't have any room for screw-ups.

Even with extreme care it was a near thing on a couple of the solder joints and I was pretty stoked  to see them light up when I temporarily hooked the assembly up to a small 2 amp battery charger. To make sure everything stayed functional, especially since a couple of my solder jobs partial delaminated the foil contact from the fiberglass PC board, I mixed up some 5 minute epoxy and encased all the important bits just like in military electronics.

While all this was going on I was taking frequent breaks out in the van to see where I might put something like I had in mind; or at least sort of had in mind. I selected the circled area for a few reasons. It's in view of either seating area, is up out of the way, is close to a 12 volt power source (The under-cabinet light over there is 12V) and there's about 2 inches of clearance between the wall and the far right edge of the cupboard door which is plenty for my tiny fire to fit into.

So now that I had a fire source and a location for it I had to figure out what to build around it. (If you get the impression that some of my projects are not really fully planned out so much as just evolve as I go along, you might be right. . .) At first I was thinking some sort of carved wood sconce, but before I got there I saw a piece on PBS about hand made paper piercings, (These are extremely popular in Hispanic communities and are strung up thickly at any self-respecting fiesta, just like used car dealers here in the US string up plastic flags; although there's a lot more fun to be had at a fiesta than there is in a used car lot.) that got me to thinking about pierced tin lanterns which got me thinking. . .
Which is always dangerous!

Anyway, I did some measuring and cut a piece of tin from a roll of roof flashing (Doesn't everyone have one of these laying around???) and, rather crudely with my limited tin-working tools, folded a hem around all four edges.

I then drew up an equally crude pattern on some paper that I stuck to the tin with spray adhesive. Grabbing an inexpensive gouge and a small hammer I went to work and discovered it was pretty easy to create the little football-shaped piercings.

The results are not exactly machine-age quality but then I was thinking hand made, more along the lines of a family recycling a tin can into a candle lantern. (Fill the can with water, freeze solid, pierce with a hammer and nail to the pattern of your choice, dump out the melted ice, insert wire handle and a candle.) Actually, the truth is I was screwing around to see how I might do something like this but it all went much better than I expected so I just kept on going. Frankly if I had known I was working on the finished product I might have taken a little more care in manufacturing it. Instead, I tell myself it has character.

Next I turned the tin over on a hard rubber mat and with the handle end of a grinder wrench (If you don't know what that is it's not important other than it's steel, has a 1/2 x 1/8th inch slightly radiused end and can be whacked on the other end with a hammer.) added a few 'rolled beads' like the kind you see around a tin can to make them stronger.

At this point it was clear I wasn't going to be able to easily abandoned the work I'd done so far so I fashioned a couple of wood blocks that would help the tin hold it's shape and act as mounting points. Once again, for mounting I turned to the Command strips and you can see the recesses I cut in the wood blocks so everything would sit flush against the wall once the strips were in place. I also drilled some random holes at random angles through one of the blocks, thinking that light would shine up through the holes and create a pattern against the ceiling. (It does a little bit but not much. the block is too thick, therefor the holes too long, to let much light make it all the way through.)

Being more of a copper man than tin man (There's a joke, or at least an insult, in there somewhere but I'm not going to try to find it.) I layered on a base coat of black paint, covered that with a coat of copper paint, then randomly ragged on a touch of deep red to give it character and some antiquing black (Dark walnut stain would have worked just as well.) for soot and wear. And finally a shot of satin clear-coat spray to give it a metallic sheen.

Next step was to fasten the wood blocks in place with some silicon calk. I recessed the bottom block up high enough that it can't be seen when sitting down across the room from it. In this photo you can, just barely, see a strip of some opaque paper I cut from scrap in the recycling bin that I added to cover up the three lowest piercings in the tin after darkening the visible side with a black marker. Testing revealed that these three piercings went just a little too far (Piercing run-amok!)  and allowed a direct view of the flickering LED's in there, and it was too distracting to leave that way.

Here you can see that I mounted the LED's on a small strip of wood, again using silicon calk as the glue. (This stuff sticks to just about everything, including your hands and tools!) With another Command strip, I mounted the mounted LED's in place in such a way that I can remove the whole mess if something goes wrong or needs to be changed. This photo also shows the hole I drilled into the face of the adjacent cupboard for the electrical leads. The hole is large enough that I can shove the small connector I attached to the LED leads through it. Don't worry, (As if you were. . .) the hole will be hidden by the sconce.

The second Command strip showing above is one of two that the sconce will mount to.

Now it was time for more electrical work. After removing all the contents and a couple of panels from the cupboard the existing wiring was exposed, including that of the under-cabinet light. All I had to do now was splice into those leads, add a switch and plug in my LED's. Mounting the switch was not technically difficult but it was a little nerve wracking to mark

 and then cut into the nice pristine headliner covering the cupboard bottom. A good sharp #11 Exacto knife made short work of the vinyl and foam. (I wonder if surgeons also have the jitters when making that first cut??) The top side of the cupboard bottom (Huh??) is also covered with the same padded vinyl so I carefully drilled a small hole in each corner of my initial cutout, making sure to go all the way up through the vinyl on the other side. This marked the 4 corners so I could make the same cuts on the top side knowing everything was going to line up properly.

With a Forstner bit just a bit larger than the switch-body is wide chucked into my drill I went to work. Contrary to what may seem like the right thing to do, don't spin Forstner bits at high speed. this makes the cuty parts fly around so fast they don't have time to - well - cut. Instead they burnish, which makes making a hole a whole lot tougher. (You like that last sentence? I though it was pretty good!)

Using a slow speed and keeping a close eye on the other side of the wood, I was able to spot the pilot spur of the bit as it broke the surface. This let me drill the last little bit out from the top, eliminating blowout and splinters.

When drilling out an opening like this never drill out both ends then come back to the middle. It will be nearly impossible to keep the bit from wandering off in undesirable directions when trying to remove the middle part. Always start at one end and work your way sequentially towards the other end, attempting to space the holes out such that you are drilling through no less than 2/3rd's wood and no more than 1/3 air. This will keep the bit on track and the left over points can be removed with a few passes of a rasp.

 With the switch in place I made the final connections

and put the panels back in the cupboard. There's one on the back which covers the wire runs and another fitted padded square, that sits over top of the wires seen the the second photo up. Here the lidded sauce pan and small mixing bowl are sitting on top of that one.

With the sconce in place and the cupboard door closed, all is ready for the big test. All except the sun. I had to wait a few hours for that to finally get in position, namely a whole lot closer to the horizon.

Without any fancy camera gear this is the best shot I was able to get of the sconce all lit up. Since the flicker program is identical in each of the 4 LED assemblies and they all start at exactly the same instant when I throw the switch on, they flicker in sync which gives the illusion of one large flame in there.

All in all, this is a project that worked out pretty well and I can imagine myself sitting in the van in the evening mesmerized by my cold fire.

I tried for a 10 second video of the lit sconce but that's even worse that the photo above!  I include it here only because it gives a vauge sense of the 'flicker effect'.


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