A sample “brick” in fiberglass that can be assembled with many others looked good! Thanks Rustin for that effort.
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Thanks, its definitely been an incremental process.
The first brick came out too heavy at 510g (1 1/8 lbs), but the 2nd one feels significantly lighter, but i’ll have to weigh it thursday to find out how much lighter.
I hope to have a new mold printed by the weekend to try a layup of half a row of bricks to see if it’ll be quicker.
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Was just looking at what it would cost to make the wall-jack-like tools to lift the current castle one last time. At about $300 I think it’s a bit more than we want to spend on a one time solution to easier lifting.
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The one layer mold came out to .75 lbs. I am happy with that weight, especially with the tinfoil still on it.
I showed the work to the renn fair coordinators and they’re excited to see how this is turning out, and might be up for having us crank out a project for next year.
Also, the first half of the nee mold has printed. There are 2 layer mishaps on it that i think i can fix, but i think it will work with this tinfoil mold release trick.
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From a distance, it looks like the villagers are holding up the wall.
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Dave and I have done some more experimenting.
We’ve pulled a panel off of that new mold and it’s turned out alright. We hit the weight we were hoping to get (be under 4lbs, we got 3.7ish), but found a flaw in the layup process of manually adding resin to that round of a mold. It’s difficult to get sheets of fiberglass to hold in place vertically as well as apply resin. And with only 20 - 30 minutes to apply resin, that means it has to be done quickly. We still got a decent part out of the mold, but it’s one of those situations where it would take extra skill for beginners to pickup.
The weight of the new test panel means it is very possible for us to build each 12ft tower and be under 100 lbs (and possibly transported in the back of a sedan).
BBQ tin foil was used as a mold release, and the layer shift did end up being visible in the mold, but as a cheap alternative to spray on PVA, I think it did pretty good.
So instead of doing a round, horizontal mold, we’re looking at doing thinner, horizontal molds. This will allow us to do large layups with less struggling to apply plies. Unfortunately, this does mean the edges of panels will have to be covered somehow. I think we can get away with making a ‘vanity’ panel (or maybe even a tapestry?) to go over the seem of the panel that serves a double purpose of being covered in symbols representing each of the major spaces we have at the makerspace.
Round horizontal segments:
Narrow vertical segments:
With the limits of my printer, it will probably end up being 4 stacked prints to make the final mold, but hopefully that will mean it will be pretty quick to design and print them, and finally be at a point where we can go into production mode…
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Is it possible to make a um zig-zag edge? like only do whole stones?
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Yeah, it’s possible, but I think it adds a lot to the complexity, not just for construction but also for erection at the faire. I do want the joints to line up with every other tier though and split the other tier at the middle of a block.
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Yeah. If you can add a fillet or radius at the bottom of those grooves, it should be easier to get the glass to conform
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Finished printing the first quarter of the mold…
I switched to a different filament supplier for the top half since they offered 5kg rolls of PETG. I definitely need to come up with a way to dry larger rolls of filament.
There are 3 more chunks of the mold to print, but i may try to refine the print file a bit to see if i can get it down to 3kg of filament instead of slightly over 4. We’ll see if reduce number of walls on the supports and number of layers for the top and bottom help, i’m okay with the 5% infill. Though i wonder if 1% would still be strong enough at this size.
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That is…weird. It reminds me of spooky trees in a spooky forest. Are we sure we want a new castle, instead of spooky trees in a spooky forest?
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I think we would be better off planting some trees and weaving them into a tent for that. Not sure if we would want to wait 5 years for a tent. 
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You could recycle it into pellets for injection molding
Only question I have is how its going to hold up against a 70 mph wind? Like the ones that blow over a semi-tractor trailer.
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The same way we kept the old castle up - with lots of ropes, stakes, and vampires. (Cannot confirm if ninjas were involved)
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Another 50hrs of print time remaining which i think works out to 57hrs of human time remaining for the last chunk.
The last roll of PETG was slightly more damp than the others for some reason, so i’m going to have some mold cleanup to do, but i’m hoping after bolting the 6ft x 3ft panel together, that we’ll be ready to start laying up parts on Sunday.
We have a enough fiberglass left from prototyping to hopefully do one full tower, but we’re also dependent on getting in more resin. I should have a gallon of resin showing up tomorrow to play with, but its going to take 4 gallons per a tower.
We also have this wonderful constraint to deal with called the weather. If the temperature drops below 70, thats going to limit where we can do the panel layups, especially with all of the resins being pretty high on VOCs (so indoor spaces are a bit of a no-no).
We should be able to prep, layup, and cure a panel once every 3 hrs, so i think it is possible (a bit ambitious) to create the panels for an entire pillar with less than 20hrs of effort, and possibly 2 or 3 people.
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6ft tall, 15kg of PETG, and about 250 (human) hrs of printing later. The last couple rolls of PETG were a bit moist, but hopefully the cleanup will be quick with a sanding pad on a die grinder. An angle grinder might be too aggressive for this project.
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