Below are 1/6th scale models, two of the "tooling" blocks we found, and one of the more complicated blocks with many different shapes on it. I wanted to see if this tooling block could be used to make the molds to fill the cavity of this more complicated shape.
My theory is that balsa wood was used to make all of the patterns and molds for some of these "molded" looking blocks. A little research shows that the Inca used balsa wood to make rafts. If the Inca had balsa wood and were used to using it, chances are it was there for the builders of Puma Punku thousands of years earlier. Though it is rumored that there are no trees at all up in the highlands, a quick look of the area on Google Earth reveals trees all around lake Titicaca some 10 miles away. On this trip I had planned on taking a drive around the lake to see if any of these trees could have been balsa trees but due to altitude sickness I really didn't have the time to properly document the few stones I wanted to, let alone take a trip down to the lake; but make no mistake about it, there are trees only ten miles away.
Balsa wood is very easy to sand, shape, carry, work with etc. It would be the perfect material to make the molds out of. For blocks that have under cuts in them, it would be very easy to remove the balsa the way I did on the arrow rock after it was done being molded.
After de-molding the blocks, the balsa would have disintegrated not long after, leaving absolutely no signs of how they made their molds.
Below is a picture of how the tooling block could have been used: by having the wood fence pushed up against the steel pin, it would allow for various sized squares and rectangles to be sanded too. Moving the pin to different holes would allow you to make any length you want for different mold segments.
Although balsa is not very strong along the grain, by using end grain balsa you could pile a bunch of cement on top of it without crushing it.
By using this technique you could make almost perfect parts with no other tools needed. After the parts are de-molded, they would be ready to use with no further work required.
If you were to place a fence made out of wood against the pins, you could use this to set different lengths and widths so that they could be sanded to make different shapes. I use the term fence as this is something you would find on a band saw or table saw, used to butt wood up against.
It's hard to know how wide to make this fence, but with a little experimenting I found the slightly wider one was better and seemed to match the pin holes with the cavity segments on the block with all of the art work on it.
After about an hour I had all the segments sanded to shape. These were all done on this tooling block.
I was going to post more pics of each segment but you get the idea of how it's done.
Unfortunately there were a few dimensions I had to guess when making the 3D printed part; I tried getting all of the dimensions by day at Puma Punku and spent evenings in the hotel room doing the drawings on Auto Cad, but between trying to get dimensions when the guards weren't looking and not feeling well I did miss a few measurements. I need to go there again with permission to study and document these blocks and try my theory on the full sized stones.
After all of the segments were glued together I lightly sanded all of the faces before gluing the 3 pieces on top of each other. Doing this sands the pieces to the right thickness and removes the glue that oozes out, making it impossible to see if each level was one piece or three.
Here's the finished part. Even with the fine cement I used you cannot see any signs that these wooden segments were glued together. This process does work.
While sanding some of these small pieces of wood I noticed that even the smallest side forces on the wood being forced up against the pins would leave small indentations in the balsa. These dents would be seen in the final block when cement is poured over it. I thought you could put more pins in it to reduce the force that one pin would put on the balsa in one area, but I remembered that the holes were a little out of alignment side to side on the actual stone so some of them would still leave impressions in the balsa. Then I thought it needs to have something flat to butt up against and at that point it struck me: is this what the 6mm grove was for? After cutting a thin piece of aluminum to fit in the grove to butt the balsa up against, the indentations stopped and perfect pieces of wood could be made from this tool. Maybe my theory is incorrect on these stones, but is sure does work. They did have copper tools to work with so they could have made copper strips to put in the groove to butt the balsa up against.
Below is a picture with the wooden segment butted up against the pins, I marked the wood with blue lines to show where they lined up with the pins for the next picture.
Here is the model with the aluminum strip slightly press fit into the tooling block. After this was done the dents stopped. Is this the reason for the 6mm groove?
So the big question: what is the composition of this stone? Is it man made or natural? This is out of my league and seriously needs to be looked into a little more with open minds. The theory cannot be discounted just because some people "don't think these look like a cement type slurry."
There is one theory that the stones could be softened to a slurry or puddy state and re hardened. I did not believe this theory until I was down there and saw how these blocks fit together, anyone with extensive sanding and fitting knowledge will see that these stones fit together to well, especially with all the odd shapes and how they fit together. It was at this point that the stone softening also seemed like a possibility. See this article.
Also I get a lot of comments that the quarry was ten miles away and this proves that they were not molded, if the stone softening technique were used to make the slurry they would still need to get the rock from somewhere so this does not prove that these stones were sanded and carved to shape.
I must make it clear, I am not saying I have solved this by any means, I am just offering an idea that shows molding these stones with what they had at the time is very possible and does not need complicated molds and/or tooling to make them. They may have had knowledge we don't have today!
If you have expertise in this area please email me.
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