Today I completed the last bits to finally have the dome frame fully covered. This led me to do a bit of a clean-up and pack some tools away before I started the sanding.
Trimmed and sanded back all-over hanging plywood and lightly sand all joins. Now currently filling all joints with Builders Bog before some more sanding.
That's looking very nice Anthony!
Bunnings do cut but locally none of the guys bar one I spoke to the other day understand kerf thickness, 3mm for the saw blade. I wondered for years when every job was 3mm short till I picked up on the guy reading the tape measure equally right to left and left to right. His answer was "none of the tradies complain" and I explained it wasn't their own project and what's 3mm to them or the customer but went on to explain at well over $100 for a single sheet of 12mm marine grade play I wanted it cut accurately, not 3mm short (which it was).
I guess I studied fabrication engineering along with a lot of other subjects (too much time on my hands on disability pension) and my teacher would have failed me if I failed to allow for the kerf when cutting and welding materials.
What sort of bog are you using?
Are you going to tape it first with the fibreglass tape (self adhesive) like what is used to join gyprock?
It holds the filler in much better and isn't overly expensive.
So, since yesterday the dome joints have been filled with builder's bog and allowed to set. From lunchtime today I have sanded all the joints down to a nice smooth finish ready for fiberglassing, may wait for the holidays before I start that process.
Other than the fiberglassing the shutter is the next major task. So, the plan for this stage is to cut out the appropriate quantity of plywood arcs to form the frame for the two shutters, top one rolling and the bottom one connected by a hinge, simpler to the Sirius observatory dome.
For the tracks which the top shutter will run on I plan to lay aluminium flat bar along the shutter frame opening, then a strip of timber then another layer aluminium flat to create the track for the shutter to roll on. As for the roller, I have a quantity of 20mm Flat rollers for the job.
I'm not sure if it's of any benefit to you in any way but the timber sandwiched between 2 strips of aluminium may be a little restrictive, then again it may not and I may well be misunderstanding the design you've described, it happens with my brain or what's left of it..
In the past with a sliding timber surface I attached the tongue out of yellow tongue particle board flooring and it gave it a nice smooth surface for the panel sliding movement up and down. It was only a sliding shelf in a complex computer table I designed and built but with the plastic or whatever it is it made for a very nice sliding finish. Bunnings sell the tongue on it's own, worth keeping in mind.
It's a polypropylene strip: https://www.bunnings.com.au/poly-eig...eeder_p4430566
Are you going full fibreglass shell over the dome?
I don't like playing with fibreglass but have canoes and have had no choice in the past, good luck with it.
So to Leo.G for this part of the project. I have been considering various options for creating the tracks for the shutter to roll along when opening and closing.
These options included using aluminium flat bar laminated together. Example, one piece of 25mm wide flat bar then several 10mm wide flat bar stacked to give a track width of 20mm then finished off with 25mm wide flat bar. Probable would work but costly.
Other option was again using a piece of 25mm wide flat bar but instead of 10mm wide flat bar I would be using timber then finished off with 25mm wide flat bar. Problem here is finding a suitable piece of timber fit for purpose.
The final option which I have gone for is to use a strip of 30mm colour bond steel scrounged from a building site, 5 strips of yellow tongue, stacked and a piece of 25mm wide flat bar to top it off. All up a cost-effective solution to a problem.
The Yellow tongue was Leo.G idea
Cheers
Last edited by anthony2302749; 23-06-2024 at 06:17 PM.
I'm glad to be able to help Anthony!
I've found it to be a valuable resource in the past for multiple purposes and always used to salvage it when given the opportunity, it allows other materials to slide nicely and if it does become a little stiff a little dry lube stick will help.
The weight of this thing... gotta be a bit on the heavy side! How are you going to lift it out? Or are you going to build up a brand new obsy out from underneath it?
The weight of this thing... gotta be a bit on the heavy side! How are you going to lift it out? Or are you going to build up a brand new obsy out from underneath it?
Hi Adam
Put the dome through a lift test this afternoon with me on one side and my son on the other, surprisingly not that heavy, so it could be a two man lift. But the plan is to call in some help and with the help of several dollies to wheel the dome around section of flat yard and the lever it up onto the observatory. Propping the levers with ladders once level and then slide the dome on to the observatory. Shouldn’t be too difficult.
So, for the pass week been routing out the bits and pieces to construct the Sliding Shutter for the observatory. You would think after the number of cuts I have done with the router this would be straight forward. No, had to recheck my math to get the right radius. Once that was done everything fell in place and I am happy with the results.
This piece of Sliding shutter runs on the inside of the tracks, still finalising the roller bearing design. Kind of leaning towards two more plywood arcs outboard of the inside frame which will be fitted with the roller bearing. These will be affixed to the plywood cover via screws so to be able to remove shutter when need be. A future photo of the idea probably will clear up any miss conceptions.
Cheers
Last edited by anthony2302749; 28-06-2024 at 04:22 PM.
Same day different task, Fiberglassing. Back story here is the ability to find a suitable local supplier of fiberglass and epoxy resin in my local area other than Bunnings, after countless hours on google came up zip.
End result purchased a roll of 150mm x 50m fiberglass tape from a company up in Sydney, more then enough to do the job. It was on special for $15 which is a bargain, but postage was $38. Still, three days later it was on my front doorstep which was very quick delivery. As for epoxy resin I caved in and got two tins from bunnings for $37 each.
Fiberglassing, like sanding probably is not the most favourite part of the construction. While I have fiberglass before it's still a learning curve and after reading the instructions and guesstimating the quantity need to do one strip it turned out I made enough for two.
So, from this little exercise I will assume that 200ml of epoxy will cover at least two joints. I will do some more math and test the theory next week. Plus, I need a lot more rubber gloves as well.
Cheers
P.S. 7.00pm Just checked the fibreglass and the epoxy resin is going off nicely.
Last edited by anthony2302749; 28-06-2024 at 06:09 PM.
I learnt a long time ago some of the boating supplies and spa places (manufacturers) have the best prices on glass and resin. I guess they are buying it in bulk and pass the savings along. It's coming along very nicely!
As for lifting, while as you say your son and yourself can comfortably lift it if you still have to get something underneath it can be a pain. Do you know anyone with a Ute with a hyab?
A lifting eye on the top of the dome and it's up with a few pumps of a handle, that or make a tripod with some 4x2 timbers or steel pipe if you weld and use a pulley system to lift it. That would depend on how high it has to go, I'd probably shove a flag pole in the ground, lol.
I'm somewhat of a lazy mongrel so I always look for the easy option.
I learnt a long time ago some of the boating supplies and spa places (manufacturers) have the best prices on glass and resin. I guess they are buying it in bulk and pass the savings along. It's coming along very nicely!
As for lifting, while as you say your son and yourself can comfortably lift it if you still have to get something underneath it can be a pain. Do you know anyone with a Ute with a hyab?
A lifting eye on the top of the dome and it's up with a few pumps of a handle, that or make a tripod with some 4x2 timbers or steel pipe if you weld and use a pulley system to lift it. That would depend on how high it has to go, I'd probably shove a flag pole in the ground, lol.
I'm somewhat of a lazy mongrel so I always look for the easy option.
Not a lot of boating supplies in my area. As for my backyard no vehicle access so no Hyab, so muscle power all the way. I will come up with the best solution to the problem. Only need to move it about 10m and up one level of about 0.4m and then lever the dome up onto the observatory, so I have a few ideas.
After a lovely weekend away touring the silo art with my wife it now back to work on the observatory project.
Last week I did two seams, and it was a bit of a mess as I didn't have the correct tools. This time around I used a 100mm roller with a 5mm Nap roller to apply the resin to each side of the seams then laid the fiberglass over and the applied more resin to full wet the fiberglass. Then roller out the bubbles with a Fibreglass Compression Roller. I found that 200mL of resin was the right amount to cover three seams, only mixed up three batches.
No mess no fuss.
With this method I quickly covered 10 seams. Only have two larger seams to do.
Fiberglassing is complete onto the track for the shutter.
So, over the last couple of days, I have been Fiberglassing the dome, this task is now complete. Today, I have installed the track for the shutter to slide along. Task was simplified by using the yellow tongue strips, 5 on each side.
The process was to place a strip of 1.5mm metal front to back for the rollers to run along. This was affixed to the back of the dome, then a stack of 5 strips of yellow tongue which were also affixed to the back of the dome. All were stretched across the dome and clamped and aligned with the shutter opening then affixed to the dome, repeat for the other side.
While not finished it seems to work quiet well. Tomorrow will be adding the rollers on to the shutter frame and then aluminium flat bar to cap of the track.
. As for my backyard no vehicle access so no Hyab, so muscle power all the way. I will come up with the best solution to the problem. Only need to move it about 10m and up one level of about 0.4m and then lever the dome up onto the observatory, so I have a few ideas.
