Solar Powered Japanese Garden Lantern - Using Dollar Store Items As Molds
by danthemakerman in Workshop > Molds & Casting
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Solar Powered Japanese Garden Lantern - Using Dollar Store Items As Molds
I have always loved the look of Japanese Garden Lanterns. Even though I live near a very large city in the US, no one in the vicinity makes or sells these. And unfortunately because of their size and weight they can be expensive to order online. So in true maker fashion I decided to try my hand at making one.
I had a rough idea of what I wanted and I figured I could find some materials at the dollar store to use as molds and while I was at the dollar store I saw that they had solar garden lights which would allow me to light up the lantern at night. Originally I didn't even think about lighting it I just liked it for its ornamental value. After wandering around the store I purchased several items as potential candidates for the different sections. I wasn't sure what was going to work so I gave my self several options since everything is one dollar it was easy to splurge. However I did stick to buying larger plastic pieces that could possibly work as the different sections of the lantern. I ended up going to 2 different dollar stores for supplies.
These are a few of the items I purchased at the dollar store. After mocking up a few of the pieces and trying different pieces together in different configurations I decided on the look and shape I was going to try and make. At this point I am thinking I am only making 4 pieces, this will change as I get deeper in to the build.
Disclaimer, the red step stool was $2 at the dollar store the dollar store I went to also sells items for more than $1.
Prepping the Molds
Unfortunately the underside of the step stool was not perfectly flat and there were some tabs that protruded from the base so I used a Dremel tool fitted with a cut off disk to remove the offending tabs.
Making a Pattern
Since I will be pouring concrete in to the step stool I had to make sure it would be flat, as this would become the top of the lantern base. So I first traced the top of the step stool on to some thick corrugated carboard and cut it out with a utility knife. I checked the fit and it was not good; it had a lot of gaps around the edge and corners so I cut a few scrap pieces of cardboard and taped those pieces to the carboard to fill the gaps. Next I traced this modified template on to some a fresh piece of cardboard and cut it out. I checked the fit again and it was nice and snug all the way around. I wanted to limit the gap as much as possible so it wouldn't fill those areas with concrete.
Sealing Off Holes
I needed to seal off the holes in the step stool so I used some packing tape and taped off the inside and outside of the holes in the stool. I wanted it to be fairly strong so it could withstand the weight of the concrete. I also hot glued a piece of scrap PVC pipe to the cardboard that will create a hole in the base and allow the solar light to shine through.
More Mold Prep
This box was made of paper so I thought it would be a good idea to clear coat it in the hopes that it would help waterproof the mold. This didn't work, the water in the concrete soaked in to the paper. The shape of the box held up but I would have to consider these a one time use as they will not survive the concrete curing process.
Window Section Prep
In order to make the center part of the lantern, I'm calling this part the window section, I used a hexagon shaped gift box from the dollar store. To make the windows I used some small wooden blocks that I cut from some scrap plywood and screwed them to the inside of the box. I centered the wood pieces on each side to create a negative in the mold. I also screwed a small wood scrap to the bottom to act as a depth stop for the vessel I would use to create the void in the center of the mold. The plastic vessel, which was from a kids science kit is touching the wooden blocks on all sides. My plan here was that this would create the window effect and allow for a gap to create the window. I would have to make the holes larger post concrete curing but I was up for that challenge.
All the Molds
Here are a few pics of the molds. The cardboard tube was a last minute addition as I needed a spacer that would go in between the window section and the top. The clear plastic piece is the top I did no prep for it. Also I decided that I would use the hexagon box top as another mold. I thought I could use it as a top for the window section. The order and fashion in which I use all of these will be clearer in a following step.
Mixing Mortar
I used Quikrete Mortar Mix instead of concrete because I wanted a cleaner look and didn't want any aggregate poking through the surface of the finished pieces. Mortar Mix does not contain any aggregate. I setup all my molds and mixed up a small batch of mortar. I just mixed what I thought would be enough for each mold. I probably could have done a larger batch but I was afraid of mixing too much. Its hard to get rid of leftover concrete.
Filling the Molds
I tried to shape the base of the lantern as best I could with a garden trowel. I realized that I needed an indention in the bottom of the top section so I used a piece of carboard tube for this. I taped off the opening in the cardboard tube and placed it in the center of the mortar. This indention would receive a cylinder spacer to give it the right height and or spacing from the window section. Again I understand this may seem confusing but once it all comes together it will make sense. The last pic shows the baby bottle filled with mortar, originally I had planned to use that as the topper for the lantern but ultimately changed my mind.
A lot of improvising went in to this, somethings I thought I was going to use I didn't and vice versa.
Demolding
I gave the pieces 24 hours to cure. Most of the pieces turned out fine and fell right out of the molds or required a little prying to release them. I did notice that the topper section was too shiny, this came out shiny because the mold was glossy, so I used some 80 grit sandpaper and sanded off the sheen. You don't have to scrub very hard with the sandpaper to remove the shine, this took me maybe all of 5 minutes to sand.
Fail, Rinse, and Repeat
The window section was a little troublesome. The wood spacers did not release cleanly and ended up causing some cracks and then some breaks in the piece when I tried to remove them. Also the round center plastic spacer did not come out easily and caused some damage as well. So I had to toss that in the bin.
So I regrouped and bought two more hexagon boxes from the dollar store and made two new molds. This time I made one mold using rectangle wood pieces and I also made another mold but added bevels to the sides of the wooden spacers. The bevels would result in larger amounts of mortar mix in between the windows and would pop out of the cured mortar easier as the shape acts like a relief of sorts. This time I also covered the entire inside of the box with petroleum jelly to act as a relief agent.
I mixed up some more mortar and I also mixed up some regular concrete with aggregate. I figured the aggregate would add strength to the piece. I used a cardboard cylinder as a spacer for one mold and a paint can for the other mold.
I let the pieces cure for 24 hours.
Demold Part Deux
I demolded the first piece and all the paper portions came out very easily. The wooden spacers were another story they took quite the effort to remove which resulted in another broken window section.
Lets Try This Again
I removed the paper box on the second or actually third window section without any issues. But again the wood was reluctant to come out. So I used a screw and pair of pliers to gently pry the wood pieces out of each section. I was able to remove most of the pieces without any issue save for a few cracks. However removing the paint can was another story.
Even though I slathered and when I say slathered I mean really laid on a thick coat of petroleum jelly on the entire outside of the paint can it did not want to budge. So I used a small nail setter to clear out the thin layer of mortar in each window hoping that this would free up some of the surface tension between the mortar and the paint can. Removing the small layer of mortar helped but not much so I used my thumbs to press on the paint can in an effort to slightly bend the metal and release it from the mortar. Again this worked but not much. Eventually I used a wooden block to hit the can from the bottom which caused the piece to break apart.
Construction Adhesive to the Rescue
I was out of hexagon boxes and didn't want to try making another window section again so I decided to glue the piece back together. I have used this construction adhesive on stone before with really good results. Luckily the piece broke in to large chunks. So I applied the adhesive and reassembled the pieces and taped it together. It cures fairly quickly but I let it cure overnight. I checked it the next day and it was one solid piece.
Drilling a Whole New Hole
I made two of these flat hexagon pieces to act as the top and bottom of the window section. Basically these two pieces would sandwich the window section. Except I forgot to make a mold with a hole in the center of the bottom one so that the solar light could shine through. So in order to make a hole I drew a circle in the center and used a masonry bit to drill several small holes around the perimeter of the circle I had drawn. Then I was able to use a screw driver to snap the center out thus creating a hole. I used a cheap wood rasp to clean up the drill marks in the hole.
Solar Light Mod
To make the solar light fit flush in the base I had to cut off the shroud on the top. I used my portable band saw table for this but you could use a hack saw for this as the body is made of plastic.
Solar Light Disassembly
Because the solar light panel is on the body of the light and would not be able to recharge if it was inserted in to the base of the lantern I had to use two solar lights to make one working light. Basically I am going to use solar panel from one light to charge the battery in another light by extending the wires. Extending the wires will allow me to place the solar panel away from the lantern and in the sun so it can recharge the garden light.
First I opened up the lights and cut the two wires going to the solar panels making sure to leave myself some wire to solder the extension wires on to.
Solar Light Wiring
With both lights taken apart I could begin to add the extension wires. I used two pieces of wire that were about 3 feet long each. I soldered each wire to the solar panel as seen in picture #4. Next I soldered the other ends of those wires to the matching wires on the little circuit board of the actual light that will be installed in the base of the lantern. I made sure to use heat shrink tube on all the solder joints.
Solar Light Test
Next I screwed everything back together and tested the light. You can see I am holding the one light in my hand it is covering the solar panel which tricks it in to thinking it is night time and it turns on the light. So now that I know it works I can insert the light in to the base of the lantern and I can place the solar panel off to the side to get charged.
Light Cleanup
The new wires were getting in the way and wouldn't let the solar panel compartment close so I used a small blow torch to heat up a small screw driver shaft and melt some holes at the base of the compartment. This captures the wires and allows the compartment to be screwed back together with now gaps around the edge. I also ran the exposed wires through some shielding just to give them some protection from the elements.
Mock Up
These next pictures show how the lantern is assembled and in which order the pieces will go. The solar light will slide in to the hole in the base from the bottom. Since the PVC pipe has a larger diameter than the solar light I will secure the light in place with a screw. I'll show how I did that in another step.
Fixing My Mistakes
I added this step after posting my Instructable because in my excitement to post it; I hadn't noticed how lopsided the curve at the base was that spanned from one foot to the other foot. Using a pencil I sketched out how I think the curve should look and used a cheap rasp to remove the material to make the curve look better and more even. Removing material with the rasp goes fairly quickly considering its mortar. I repeated this for all four sides.
Glue Up
I was debating as to what pieces I would glue together using the construction adhesive. I decided to glue up the four pieces that make up the center window section together (Hexagon-Window Section-Hexagon-Cylinder) and then glue the three pieces that make up the top section (Roof-Small disk-Topper) together. I feel like that will allow me to take it apart for any maintenance needs. I will let this dry over night then stack the pieces together. All in all the lantern is made up of 3 subassemblies, the base, the middle section and the roof.
Installing the Solar Light
In order to secure the solar light in the PVC tube I pre-drilled a hole on one side and then using a screw with a flattened tip I screw that in to the hole part way. Next I placed the solar light in the PVC tube and then tightened the screw until it secured the solar light. I did not puncture the body of the solar light I just made sure that it secured the light in the PVC tightly without damaging the light.
Here are a couple of beauty shots. In the day light picture you can see the cable and solar panel charger behind the lantern. Despite having to glue up the window section I am really happy with how this turned out. When my wife saw it she asked me how many I was going to make, so I new it was a winner for sure. Originally I just wanted one but since a 60lb. bag of Mortar Mix is only about $5 I will probably be making at least one more.
Thanks for taking the time to look at my Instructable, I hope you find it helpful and maybe spark a little inspiration to make your own Japanese Garden Lantern.