Nerd Shed Observatory Introduction

[gazza25]

Wow Beautiful build wish i had the skills 

[Nicola Fletcher]

Thank you for posting all these fantastic photos and the description- I thoroughly enjoyed reading about the build and the end result is jaw dropping - I hope you have many happy years in it!

[skybadger]

Very nice. The feet for the dome shed is a lot like my first one, so a word of caution, over time they will sink unevenly and the top ring will deform to match. 

I really like what you've done with the thin ply. 

Did you consider fibre glassing the outside Vs 2-part epoxy paint ?

Very nice construction . Well done. 

 

[PXR5]

That's absolutely beautiful ❤️

 

A job well done!!

[ItsmeMaw]

Your skills are very impressive. I've tossed around the idea of a dome, but just cant make the leap!

Be proud! Just dont throw a shoulder out patting yourself on the back!

[VaguelyAmused]

markse68 thats really interesting about the papier-mâché, quite ingenious. Funnily enough when I had the main skeleton of the dome done, I did wonder about a similar approach to old planes, some sort of cotton skin stretched over and then doped in something like epoxy. I couldn't find anyone who had done anything close online as a reference, and had spent so much time getting to the point of completing the skeleton that I didn't want to tread completely new ground and have to wind it all back if it didn't work out.

Security was a slight concern as well, I mean plywood isn't going to put up much of a fight, but probably more than cotton, even doped in epoxy. 

scotty1 thanks! Both yourself and Mr Spock have similarly keen eyes I really enjoy them, though bought long enough ago that they weren't quite as wallet draining as they look to be now. They are quite understated, most people would just pass them by, but put them on in the background and at some point guests usually stop talking and comment on them, once their subconcious catches up with what they are hearing  I promised myself no more projects for a bit and to think about getting a pet kitten, but I look around my place and it really isn't inquisitive claw friendly! 

 

[VaguelyAmused]

Thanks again for all the nice comments. I hope to get many years use out of it - though I did come outside after fireworks night to find a rocket buried in the ground like an arrow only 10ft from the dome... hopefully they would just bounce off if they did land on target but hopefully odds mean I never find out! Just finishing off odds and ends like a little arduino focus controller and arduino dew controller, but I've had moments of standing back now and it is starting to sink in what now exists in my back garden and the fun it should bring.

skybadger, you are at risk of hearing the squeaky hinges of pandoras box open with those sorts of questions  

Initially, I was all set for polyester fibreglass over the plywood skin and then a final white flow coat. Truthfully, if I was to do it all again I think I would go straight for this choice. From all the copious, copious reading I did, I think polyester fibreglass would give the longest life, is the most UV stable and would need pretty minimal maintenance over the years. There were reports of it not bonding well to plywood : polyester fibreglass is great at bonding to itself, but not much else. However I think these comments are more in regards to "below the waterline" boat building, and not more "domestic" applications. I think the key is to wet out the plywood with slightly thinned polyester resin first, let that soak in then fibreglass over the top.

However, as the build progressed, and the skin went on looking better than I thought it would, my mind started to lean towards keeping it as a bright finish and using something like yacht varnish. So this is the direction I started to go, which was silly. I made sure all plywood edges were sealed with thickened epoxy, and all joins were taped with fibreglass tape and epoxy. 

The problem with the tape, is on one edge of it where it is stitched, it has a ridge. I wanted a really smooth finish, so sanded the stitched ridge out. This lead me down a path to some "can it just end now please" decisions.

What I should have done at this point, is carried on with the epoxy fibreglass encapsulation. I had the twill weave cloth and the epoxy ready to go, but by the time I'd finished sanding (there were at least 200 hours of sanding in this thing!) I was so utterly sick to death of it that I just couldn't face fibreglassing the whole thing and another round of sanding.

So, the decision was still between a bright, varnished finish or paint. I did a few samples using yacht varnish, and two weeks later it could still be scratched off by a finger nail (even now, about 3 months on it can be). So I went with a paint solution instead.

The first coat of white primer going on I was a bit heartbroken, I'd had my mind so set on a natural wood finish that painting just felt like defeat. However, now its done, I think it looks great and the white dome has a very traditional look to it. It also keeps the insides cooler than a darker wood finish wood, and should last longer than yacht varnish needing less maintainance. I came to the conclusion that the dome's primary purpose is to protect the stuff inside it, and white paint in the end was the best of the options I had left.

With the paint, I am hoping maintenenace every so often shouldn't be too problematic, but I do wish I had just that extra bit of patience and will power to have done the epoxy encapsulation. Before this project I would have said "harsh weather" meant ice, rain that sort of thing, nope - the sun appears to be by far the harshest weather, pretty much any finish it seems is going to degrade over time, its then down to how easy the maintenance is.

In regards the pad stones and sinking, that sounds like something "fun" to look out for over the coming months and years. I had heard of ground heave with frost, so have made them reasonably deep but definitely not house footing deep so I'll wait and see. Thanks for the heads up!

All the best
Chris