Monday and Tuesday - finishing touches : )

The final layers of paint have been applied by Angel. We have decided to give the model a slight speckle rather than it appear perfectly smooth and glossy as the steel on the real bridge has a textured appearance and is a more matted silver. We have all been cutting, gluing and re-gluing the meshed fencing as it was very difficult to maintain its curved shape whilst sufficiently holding it in place on the posts. Similarly, ensuring the holes in the front fence have gone all the way through has proved to be a very fiddly process. Once these were clear, I threaded fishing wire through to represent the railing. The ends of the wire were secured with glue and the clear thread was sprayed silver to match the steel finish.

One small mistake we made was securing the meshed fence before the wooden walkway, which then made it more difficult to attach this to the supports from underneath. However, once this was weighted to lie flat and set, we could bolt both parts to the base. I then stuck on the scale ladders while Angel and Paul applied the final adjustments such as the scale figure and clean and polish using T-cut.

The whole model is now completed three days before the deadline !

Wednesday and Thursday

Removing the fast cast resin from the mold proved difficult due to the excess resin spilling over and covering the whole surface. I therefor had to cut into this with a scalpel and sand the remains flush before the cast would pop out. Any cracks and breakages caused during this removal were fixed up with super glue and fine filler. I then glued both sides together and sanded the shape as smooth as I could before painting with acrylics. For the supports attaching these to the island, I bent small strips of brass left over from our netting order and painted these silver. These were then glued into place to hold the rings up.

Angel has been sanding and gluing the cable supports up the support pylon. He used dyclo to attach the styrene pieces together and a drennel for the small holes. Paul has decided to provide a cleaner alternative to our hand cut veneer strip to run along the bottom of the walkway. This needs to be laser cut from more veneer as the hand cut piece flexed when I cut it with a scalpel.

Friday:
Working on finishing touches before spray painting, Angel has been filling in any gaps between the cable supports and pylon with putty. Paul has found a way of creating a fine mesh for the wind break fence by flattening two strips of larger mesh together so that they criss-cross to make smaller holes. He has then cut this into panels to be glued between each pillar. I have been guillotining 2mm strips of aluminium to cut and shape into supports for the bumpers. I could then glue the bumpers onto these upside down so that they hold them in place when upright. The supports for the top ring were not quite in-line with the pillars running down so I re-glued these onto the island before re-attaching the top ring. We believe that most components are now ready to be sprayed once it is less crowded in the Spray Room.

Mondays' madness

Today I fixed the split in the island as best as I could using fine filler and sanding blocks. Once this was primed and painted, I was pretty happy with the result although the paint gets right in the groves running round the top band of styrene and takes away some of the detail.

As the workshop currently has no fast cast resin available, we have tried filling the molds with car body filler. Even though we primed these with releasing agent first, the filler was very reluctant to be released from the mold and was cracked accidentally. I feel the filler is too brittle for this job, although once released and backed with the other half of the mold produces a nice finish. To compromise, we are trialing the filler again but leaving out the little rivets that would meet the island. Once this is set we can try easing it from the mold with strips of card more gently.

Meanwhile the pylon, triangular piece and circle were glued together. A bolt was drilled into the bottom of this ready to fit into the island and baseboard. The support was then glued to the walkway. Paul has also been redrawing the walkway on Rhino to make it wider. We were initially adding another plain strip along the bottom of the walkway as in one of the computer images but we found the completed design does not feature this.

Thursday and Friday

This image shows our CNC molds for the bumper pieces complete with supports to attach to the island. We resolved the issue with our initial Rhino drawings but copying them on a flat plane before attempting to import this to Excalibur. Once the Excalibur software demonstrated a correct tool path we could set our work up on the machine. The groves at the centre of the object show where the tool needs excess material to start off it's cutting path. A very thin excess strip runs around the middle of each ring where the tool didn't cut all the way down so we later removed this with a scalpel. Each grove will be filled with fast cast resin and laid out to set with a piece of acrylic on top to keep dirt and air bubbles out and to keep the surface flat. Once these have set, each half of the cast will be glued together.



Today the old issue of fitting the styrene strips around the island reemerged. As the gap between where the styrene ends and the pillar cuts through is fairly big I used more styrene and filler to try and cover this. Finally, a mix of fine filler, styrene, car body filler and spray paint covers the cracks adequately as we no longer have time to remake this piece again. If we do decide to re make it, then we would cut the styrene into the sections between each post before wrapping this round the chemi wood and gluing it to leave a much smaller gap. There would still be the issue of a small gap left though.

Wednesday 25th

Using clear acrylic, I have drilled the hole for the beam to come through the top ring and applied a speckled effect with white spray paint the represent the grill. During the morning I also stuck twelve of each railing post to it's reversed pair with the cutouts sandwiched between to create the gap. The angle on the triangular piece has been corrected and resprayed along with the final coats for the support beam.

Having looked at my bumper pieces, Paul has suggested using the CNC machine to make these shaped from a block of wax instead. Unfortunately, our drawings once again did not work in the Excalibur programme as they do not originate at point 0,0 and lie flat on the plane. Paul suggests correcting this by tracing the existing drawings on the correct plane in Rhino before attempting to CNC this again tomorrow.

After a discussion, our group has decided to change the method of constructing the pier. We will make the shape one millimetre smaller around it's circumference before applying the textured styrene around the top ring and plain styrene around the bottom. This should mean the whole piece will be flush, ideally with the join lines for the top ring of styrene disguised with the beams running down this.

Mon and Tues, 23rd and 24th

After trialing segments of mesh around the curve of the island's walkway, I found the appearance was not satisfactory as the silver spray paint pealed away and the mesh wouldn't fit properly. An alternative representation of this mesh will be speckled clear acrylic. Similarly, I found that my initial tubing for the rubber bumpers was too thin to fit around the lip of the wood whilst maintaining it's roundness. I have had to buy thicker plastic tubing and paint this with black acrylic as the spray paint would not stick to it's surface. Another issue we found was with the thickness of our acyclic rod as it is one millimetre out, affecting the size of the holes through the walkway support beams and the triangular piece at the centre. This means the support beams plans had to be re-drawn and the triangular piece re-made.

Successes so far include cutting the redrawn clear acrylic walkway supports on the laser cutter and fitting them into place along the rod. We then glued strips of styrene along the bottom of these pieces to re-create the t-bar shape along the edges. half of the walkway fence pillars have also been cut into veneer as they are far too delicate to cut accurately by hand. Once these pieces have been reversed on the computer drawings and laser cut, we will stick them back to back with the others, leaving a small gap between by inserting one mm of veneer between them as on the real ones.

Things that are not going accordingly to plan include the number of layers of primer on the support pillar, requiring over ten coats before the wood grain has started to fade from sight. Another set back is the styrene strip I glued around the island as cracks appeared in the filler before it came completely away at the end. Paul has resolved this by sawing this top half off and making another segment altogether one mm smaller than the bottom parameter. The styrene strip will be glued to this to sit on the bottom half and will hopefully not come away again.

Mon, Tues, Wed 16th,17th,18th

Having used Araldite glue to stick a styrene strip round a chemiwood base, I found this went too lumpy and would not hold the curve of the styrene as I wanted. A better method proved to be the use of contact surface adhesive, which I secured in place with masking tape. This adhesive also worked to stick back sprayed acrylic to the baseboard without eating away the paint. Much of my time this week was dedicated to sanding and spraying the concrete pieces of the model with the support beam requiring several coats of sand sealer to make the wood appear smooth without a grain showing through the paint.

As a group we have come up with a rough time plan of our remaining tasks to complete. This includes working out how to make our brass mesh order fit around the top strip of flooring. So far I have cut this to waste as little as possible and I have used 3mm high blokes to raise up the "metal" paneling to the correct height.

Thursday, 19th:
Me and Paul were interested to see if we could cut out the walkway's support beams on the CNC machine as they are not in fact flat but T-bar shaped. However, once our drawings were converted into Excalibur the closed lines no longer joined up and overlapped ever so slightly. This meant that when the machine was asked to show a tool path, the path was all over the place, missing out parts and cutting inaccurately. We now have a choice to try and make the drawings work for this software or to stick to the original plan of laser cutting.