Wednesday, January 17, 2018

Blending in With Solar

I grew up a farm kid.  People in that demographic tend to have a pretty wide skill set.  But for those of us who have moved off, it isn't a skill set we have maybe used in a while.  In theory anyway, one of those skills I have is welding.  But the last time I welded anything was 30 years ago.  Building a grid work of pipes so a movie production company could hang lights over a set.  It was up next to the ceiling on a hot summer day and after the first few welds I was totally overheating.  Taking full advantage of my maleness I whipped off my shirt and spent the next several hours finishing the job. …not to mention getting easily the worst sunburn of my life.  Ah but isn't all education expensive in some way?  Welding puts out a ton of ultra violet light.  Pipes never fell down.  That’s the important part.

I have my solar panels, I want to mount them to the roof of the van.  But I don’t really want them visible because that breaks stealth.  I have to have a couple of pretty good sized (Number 4 gauge) wires coming down from the panels and going into the van.   It would be very nice to disguise those wires in some way as well. 

Underside of a frame corner.
What I came up with as an idea was to build a steel frame.  I would paint it white so it would blend in and cover the black edges of the solar panels.  The frame would have some sort of textured metal that would cover part of the underside to provide some busyness the eye would tend to just flow over.  But most importantly it would hide the middle part of the backs of the solar panels where the wires attach.  The last design feature I wanted was to have the frame hinged in some way so if I was really desperate for electricity and didn’t need to be stealthy I could tip the panels up and increase my solar collection.

On the side of this frame I wanted a bracket that would hold a six inch PVC pipe.   If you start to watch cargo vans you will see them all the time.  I think carpenters use these long pipes on their roof racks to hold thin pieces of wood trim.  Well I wanted a pipe just like that.  Behind it, the wires could drop down from the solar panels and enter the van through two holes I will cut in the roof.  My PVC pipe will hold folding chairs and maybe a tent. :-)

Tacking the weld on hinges.
During this van building work I gave really serious consideration to doing this job of building the solar frame myself.  The shop that I am working at has a full metal fabrication area with welders and the like.  But I don’t really like working with metal as much as wood.  I would have to do some cutting and I am not very familiar with metal cutting band saws.  The shop offers training on all this stuff once a month so I could have done it.  But, did I really want to?  This is to be a frame, holding something expensive, on the top of my van.  A weld breaking loose at speed could be way more excitement and cause way more damage than what I really need at this point in my life.  I decided against it.

I got in touch with number one son and he, in touch with his redneck network.  As it turns out I ended up going with the same guy I hired for cutting the hole in the floor of the van and building the basket for the propane tanks.  I got him a drawing of what I had planned and we setup a Saturday to do it.  The really great thing about working with one of these young, positive thinking kids is they are really open minded to building something non standard.  And, even more important, they have already built lots of custom stuff.  They have a lot of really great ideas on their own.

The first thing we looked at was the bracket to hold the pipe and the hinge.  My original idea was to use two pipes of the diameter they could nest together.  I would have the smaller diameter pipe attached somehow to the van at the edge of the roof rack. I would have the larger pipe attached to the solar frame.   The frame would extend out beyond the hinge point and to the under side of this extension would be this custom pipe holding bracket to be built.

My original design for the custom pipe
holder bracket and frame with pipe hinge.

But I had to concede two points.  First off this bracket was going to be a tremendous amount of effort to produce.  The only way I knew to cut a 6 inch radius in heavy steel was to cut it with a torch. Then grind it smooth, but that process could run an hour per bracket.  I felt like I needed three of them.  The second point against my design was with the hinge point back at the roof rack. Tipping the solar panels up would cause the pipe to strike against the side of the van if tipped more than about thirty degrees.  At my latitude I have to tip my panels up to about 66 degrees in the wintertime.   My design accounted for this by making the bracket swingable.  I would be able to unhook something or other and let the bracket swing down and not hit the side of the van.

In the summertime, sun bright in the sky, I am not going to have a shortage of solar problem.   The time I am going to need to resort to these extreme measures to gather electricity is in the dead of winter on one of those bright clear twenty one below zero Fahrenheit days.  Those days, am I really wanting to be diddling with some kind of (frozen) fastening system on my big white pipe?  Something I am going to only really be able to access from an icy stepladder?  No.  No, that is what you call a design weakness right there.

Cutting sheets of expanded metal.
The Welder took one look at this and made an immediate design change.  He had some weld in hinges.  What he suggested was to move the hinge point out to the outside edge, we would double up the frame and let attach back at the roof rack via some two foot long “ears” from the frame.  It solved the whole pipe hitting the van problem because the pipe would never move.  It would be below the hinged frame.   No fuss, no muss, I would just be able to tilt the panels up without having to touch anything about the pipe.  This was a fantastic idea.  Exactly why I like going to guys like this.

For the under part he had some “expanded metal”.  Imagine taking a sheet of steel and cutting a whole series of little slits in it.  Then, pull it from the end and the slits open up to form holes.  This is what expanded metal is.  I picked out some that had the added feature of being flattened.   They take the expanded metal that has sort of a twist to it that leaves lots of exposed sharp edges and run it through some sort of roller that flattens it all out.

The underside of the solar panel frame before the pipe
holder and attachment ears are welded on.
It was really interesting watching the whole fabrication process.  Number One son and The Wife were both there as well so it was a fun time.  The Wife is a townie and had never been in a metal shop before, let alone seen the entire process of building something.   Before the day was over she had a welding mask on and really seemed to have a good time.

The frame came together well and I think it took us maybe five hours all told.  But one thing to factor in, this was one guy working and three people asking him questions.

Here is where I made a little bit of a mistake.  Number One Son said, “I know a guy who can powder coat it.  You want me to run it over there?  Take a couple of weeks...”  Powder coating is when you take plastiscised paint particles (dust) that have a positive charge to them.  Then you take your object, in my case a solar panel frame, and you put a negative charge on it.  The dust sticks to the object due to static electricity and some long forgotten property described to me in a college physics.  Then you run the object into an oven and you bake that paint right on.   It makes a great finish.  Really hard and long lasting.

This is a weld on hinge at the edge of the
solar panel frame.
Two weeks?   Nahhh, I’m gonna paint this whole thing this afternoon!   I confess, this is the largest object I have ever spray painted.  I didn’t realize how little actual paint is in those little cans when it comes to covering something of this size.  I figured a couple of cans of primer.  It was more like five.  Must have taken six or seven cans of white and three weeks.  Really it could have used a couple more.  I totally should have had it powder coated.

The frame is all built, the next step is to mount it on the van.

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