Open Source Maslow Solar Collector

I hope this is the right place to post this:

Alright folks. If I’ve learned anything it’s that Maslow users are creative engineer types who generate awesome ideas from nothing! I’m not an engineer and I’m not proficient with 3D software yet (I can do Sketchup really well but am slow at learning Fusion 360). However, that doesn’t stop me from dreaming - I have about a million ideas for Maslow! One of the biggest one is to create an easily assembled solar water collector.

A few years ago a good friend and I built a couple of these collectors for his house:

They perform really well and were pretty cheap to produce but those two panels were tedious to build! We had to cut all sorts of small pieces, and use a lot of caulk to seal gaps. I’m pretty sure Maslow could cut a more useful panel in a fraction of the time, and it would be with tighter tolerances. I imagine Maslow could print the frame, as well as jigs for making things like the aluminum fins and such.

The other thing it (Maslow) could do is build water storage tanks on the cheap (another thing we had to build), but that’s for another day.

Anyway, this post is more of a call-out to the smart Maslow peeps! Would you be willing to work together and create an open source CNC-based solar collector based on the link above? I’m willing to help in any way I can, but I fully recognize there are far smarter, more talented people on this forum.

Not sure what next steps should be… ideas?


I should note I’ve considered the idea of building jigs for bending aluminum to create the frame. The idea is to create a frame from the same aluminum stock that the fins are made from. It could be riveted together with a simple rivet tool, and the frame could be made rigid by lining the interior with foam board (and maybe a plywood/OSB bottom). Again, I know nothing of how to do this… I just have lots of ideas…

I have seen where some people are cutting thin aluminum… could the whole aluminum frame + bending/brake jigs be made with Maslow?!..

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Sounds like a great idea. I’m not interested in building one myself for the time being, having too many other projects already. But I’m happy to follow along and add suggestions.

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I’d be happy to use my Maslow for creating/testing. My big weakness is in design! Would you be interested in helping to engineer a solution?

Sure. I do most of my design work in OnShape, which is a very collaborative environment.


I’ll be really transparent here… I’ve never really been part of open source design and have no idea how to organize it, or what process is involved. Any suggestions on how to get all of this started?

In truth, I haven’t done open source hardware either. However, I’m an engineer, so I’m going to fall back onto the traditional way of designing/building hardware.

  1. Start with your objectives (for example, are you just trying to automate the production of the “stock” design in your link, or improve the design?)

  2. Define your requirements. What elements need to be designed? What is needed from the designs? This can be as simple as “I’ve got the dimensions and just need to turn it into a form that can be compiled into g-code”, to something more complex if you are trying to re-design or optimize a design.

I have looked over the pages linked above and I may be over-engineering this, but having a good process means that we all know what’s needed. Besides, I’m an engineer, so over-engineering is what I do. :slight_smile:

The other issue we should consider is what sort of open source do you want to use. Are you just trying to make the design a freely available as possible, or do you want to put restrictions on it to, for example, prevent commercial use, or require attribution, or require any design that uses this design as its basis also be open source?

Let’s discuss these things and see where we are after that.

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Excellent thoughts @jwolter I’ll see if I can provide my perspective below:

1.) Objectives: to design a solar collector that’s similar in style and performance to:
but produced on a CNC router, thus making production easier and faster than the hand built design listed above.
Defining “similar in style and performance”: a solar collector which is constructed of similar components (especially the poly roof panel as the top). Each of the components should be easy to locate and purchase from a typical hardware/big box store (i.e. no special fabrication). The exception would be, the constructed frame would not be made from dimensional lumber but from exterior grade plywood that is cut from a CNC router.

2.) Requirements:

  • We need to identify the ideal size of collector which can be cut with a CNC router (Maslow) and house the solar collector parts with minimum waste (the one listed above seems to allow for some extra waste in exchange for ease of assembly - I think we can find the ideal size for both Maslow, and the finished collector).
  • We need to design the parts to be cut by CNC router, and how it will be assembled. We should also consider how the internal parts will be made (there’s a chance Maslow can create templates and tools that can assist in constructing the “plumbing” parts on the inside)
  • An optional part to be designed: a modular water tank (a CNC router version of this: )

Regarding open source licensing… honestly I think it should be as open as possible.
The only real restriction I’d want is to have attribution go to the Maslow CNC community. Does that seem reasonable? I mean, I just can’t see any downside to having more solar collectors around the world.

Does this seem like a good starting place? Do you (or anyone on the forum) have suggestions? I’m new to this, so, I’m kind of flying blind here.

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I think you probably want CC-BY-SA

-BY means that anyone making a version of this needs to give you credit as the
original creator

-SA means that any modification needs to be licensed under the same terms (they
can’t take your design and make a modification and license the result under a
more restrictive license)

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what part are you going to make with the CNC? are you planning to cut aluminum
or wood?

I would suggest that you use onshape or fusion360 to create the design, so that
people can directly copy the CAD work. personally I prefer onshape, but others
like fusion360x

I’m thinking the easiest and most likely to be used by others is creating parts from wood. In my mind there are only a couple parts that need to be designed:
1.) a frame that can be cut out, easily assembled, and will fit nicely/simply with the poly cover, mounting hardware, and the internal components.
2.) Tools/jigs that can be used to assemble/build the internal components (the copper or pex water lines and fins that fit over them). I think it will take a lot of creativity and art to design things which will make this part of the process easy.
3.) a strong but easy to build/move/assemble water storage system. I’m guessing this will be easy, but one must make sure it’s plenty strong. Hundreds of gallons of water in someone’s house/basement is a big problem.

I’m slowly learning Fusion 360 and it seems to have good collaboration options. Shall we proceed with using it? I don’t know the first thing about OnShape… but I’m willing to try.

FWIW, you can make a quick hot air collector with beadboard. Masking tape to define the non-depressed areas, spray with lacquer thinner for the channels, paint with BBQ black, unmask, and your cover of choice, cut the air plenums on the Maslow and smile as the fuel truck drives by. Read it in Popular Mechanics maybe 30 years back.

A quick rule of thumb, from some random source, is a square foot of collector area will displace a gallon of LP or fuel oil. Obviously that’s pretty rough, more sun in, say, Florida than Moose Swamp MI

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I’ve seen those and have heard they’re great!.. as long as the sun is shining. Problem is, they can’t buffer the cold nights and such. The idea of heating water is to make btu’s available at any point. But I do like the solar to air designs. They’re efficient and simple. :slight_smile:

In the olden days they used rock beds. They’re not just for sleeping on

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Sorry I’ve been silent for the last few weeks. Things got busy.

I’d suggest we start with the collector design, leaving the templates, tools, and water tank for later. I’m already proficient in OnShape and would prefer to stick with it. I just don’t think I’ll be able to contribute much design work if I have to learn a new program before I can be useful. Alternatively, I can contribute ideas and calculations if you or others want to do the CAD work.

I’m game for using OnShape, but I have to warn you I’ve never used it. It’ll take me a bit of time to understand how it works.

What would the next steps be? I could try to sketch out what I imagine the frame/collector could be, either on paper or Sketchup. would that help? Or is it better to start by identifying the goals/priorities of the collector?

onshape has a set of tutorials in the app that they direct you to, and on
youtube as well.

They do a pretty good job of explaining things.

it’s always good to list the reasons for things so that others can make
suggesions to improve the design. If you don’t agree on the reasons, suggesions
can contradict each other.

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I’m with David. Both the goals/priorities and the sketches would be useful, but I think the former should come first.

I’m sorry I’ve been so silent on this but I’ve had ideas swimming in my head and I’ve tried to spit them out using new (to me) tools like Fusion 360, etc… but I just haven’t been able to get myself proficient in a different software. Because of that I decided to lean toward what I know and start working in Sketchup. I hope someday to do this in a proper software but for now this is what I need to work in.

So, here’s what I’ve come up with so far. It uses Maslow to cut the ends (the complicated parts of the design) and a support piece for the bottom. Then standard 2x4’s for the sides (to reduce cost, and because it’d be hard for Maslow to cut a 8’ piece). The top should be a standard poly-carbonate roof panel, and the lower section is set up for 1/2" insulating foam.

I should note I built this to only be a (roughly) 2’x8’ panel. Figured that would be lighter and easier to work with, but this could easily be doubled so that it’s a full 4’x8’ panel.

This is just a concept, I’m hoping it’s a good enough starting point that someone who know’s what they’re doing can make things more professional and appropriate.

Please let me know what you’re thoughts are and where we should go from here:


P.S. The file contains an assembled panel (without the collector parts inside) and an “exploded view”.