The Pinawa Heritage Sundial

Pinawa Heritage Sundial Conceptual Design

The construction of the gnomon took place in the Bldg. 412 machine shop located at the AECL Whiteshell Laboratories outside of Pinawa, Manitoba. Without the use of this shop and all the tools that we had access to, the gnomon would not exist. And of even greater importance, without the help of the volunteers, the gnomon would not exist. Although the tools are there, they are useless without the specialized skills of all those who helped in making the gnomon a reality. Thank you!

The following photographs attempt to illustrate some of the phases of the work that was involved in the construction of the gnomon. Unfortunately, photographs do not exist for every stage of the job. Other than hiring a welder all the work was done by volunteers. In fact, Glenn Graham did a fair amount of welding when tacking all the pieces together in preparation for the welder, Fred Betker. To get the gnomon to the stage it was in the last photograph on this page, it took at least 175 hours of work of which 23.5 hours were the welder. Then it still had to be sandblasted and erected.

Gnomon structural steel. These are the various structural members cut to length using the bandsaw shown in the back. Clive Schultz pushed this saw to its limits to get the critical angle cut in the 12 inch square hollow steel section. It was amazing to see!

Gnomon plasma cut insert.
The photograph above shows the gnomon sail as it came from the steel supplier. The sail is made from 0.5 inch mild steel. The plasma cutter is capable of handling a sheet of steel 6ft. wide and 24ft. long. This meant that the entire sail could be made from two pieces. The curved cut of the second smaller piece is visible at the lower left. The four icons laying on the sail and on the floor in the back are made from 0.25 inch mild steel. They will be welded to the surface on both sides of the sail. The tabs on the curved back will have 1 inch by 3 inch mild steel bar stock welded to them.

Gnomon construction - welding. Gnomon construction - cleaning welds.
To get to this stage, a lot of volunteer effort has taken place. Bill Macdonald, Glenn Graham and I spent until midnight one evening putting the pieces together in preparation for the welder. Here we are in the process of putting a continuous weld on both sides of the base between the 4 inch x 8 inch and the 6 inch square hollow steel sections. This had to be done in short sections to minimize the stress on the steel and prevent warping.

Completed gnomon in the shop prior to sandblasting.
It's done! Now outside and fire up the sandblaster.

Here the gnomon is basically completed. A lot of work has taken place.

After the sail was secured to the 6 inch square hollow steel sections the continuous welds described above were completed. The two pieces of the sail were welded together from both sides and 0.5 inch mild steel end plates were also welded where required.

The 1 inch by 3 inch bar stock was bent to shape and attached along the back of the sail. The long curved piece was done in two sections. The first was a piece from the semi-circle to the second tab from the top. This little job was undertaken one evening by Clive Schultz, Glenn Graham, Steve Berry and myself. We had every big clamp available from the tool crib and two acetylene torches. Two on the torches and two working with about 4 to 6 clamps. For almost 5 hours the torches were heating the bar stock and very slowly we were able to pull the bar into the tabs along its length. That steel was red hot and there is evidence of this in a couple of places where it started to puddle. Fortunately for those of us who were working the clamps, we had high temperature insulated gauntlets which came up to our elbows. I know I saw mine smoking more than once. At the end there were well over a dozen clamps holding the bar against the tabs so that it wouldn't move away while it cooled.

Another evening Clive Schultz, Glenn Graham and I finished the remainder of the bar stock. The semi-circle was bent using heat but because the top piece was so short and there was rather a sharp bend in it, Clive shaped it using the hydraulic press.

To finish the transition between the 6 inch square hollow steel sections and the 1/2 inch sail plate, 1/8 inch mild steel plate was used. This plate was cut to 3.5 inch widths and 4 ft. long. It was then rolled to a radius by making successive passes through rollers. It took 5 passes to get each piece of steel to its final curvature. With each pass the rollers were tightened a bit more to increase the curve of the steel. Ervin Hemminger and I performed this task. What was really nice was that Ervin came in one evening while he was on vacation to help with this part of the job.

How were the four 1/4 inch plates attached to each side of the sail? Initially they were to be tack welded along the edges in a few spots. The welder suggested that we use plug welds and this was a great idea. I drilled a number of 1/2 inch holes in each of the 1/4 inch plates. The plates were then positioned and the welds were made in the holes. The weld material was brought up above the surface of the 1/4 inch plate. This excess weld material was then sanded until flush with the plate. At that point the weld disappears as it becomes part of the main plate. It's impossible to tell where the welds are.

This describes some of the major tasks performed during the constructing the gnomon. There were many others.

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