Reflection - Fuel Tank

The fuel tank brought upon many challenges and was a great way to combine the skills learnt from the previous assignments projects being the bowl, tray and torus. during the process of making the tank there were many successes and failures/things that could have been done better or approached differently.

The biggest issue the group had trouble with was trying to marry the 3 pieces of the tank together. Similarly to the tray the approach in creating the tank was to use the template and marked up paper to form a outline for a metal cutout. When this was done with the tray my partner and I cut the tray tight to the marked out line which worked well as the tray stretched and gave as the perfect amount of tolerance when forming the shape, which was then cut off with tin snips as we worked. 

On the other hand a different approach was chosen for the tank which I think was our downfall. Unlike the tray when cutting the pieces the we decided it would help if we cut the pieces larger than what the finish piece will be to give us room for any errors that may be cause during the shaping (see image below). This approach did not help as by doing this it created more work in shaping each piece than cutting it down again. It also did not assist in ensuring the pieces lined up as the original marked out lines had faded and therefore our pieces were marginally different and therefore not meeting up at the edges.

Using the original option utilized with the tray I feel would have achieved a better result with the lining the joints up.

Another issue the group faced was in relation to the finish surface of each piece. In comparison to the bowl I completed early in the semester the finish was not the same. When finishing the bowl i used a cloth methylated spirits and the English roller. The process was to roll the bowl, then take it out and wipe it with the cloth and spirits, and then to put it back in the roller and repeat the process.

Alternatively with the fuel tank the group decided to use a very fine steel wool (see image below) with methylated spirits. This worked ok but not as well as the bowls method. I feel that the finish was not the best because we didn't use the English roller during the polishing of the tanks pieces lack of an English roller made it look a lot worse than the bowl. See photo comparison below.

The Fuel Tank

Brief

In teams create a 1:1 scale template replicating a motorcycle fuel tank. once created create an aluminium skin that adheres to a third of its contours.

Process

Step 1 - Choose desired fuel tank you would like to replicate, and take as many photos possible at a wide range of angles. Note: The more photos and angles the more closer the replica will be.

Step 2 - Next is you will need to have sufficient skills in the program Rhino. To allow the tank to be modelled in Rhino and ins step 3 the tank was measured so that sizing was correct.

Step 3 - The next stage is to transfer the model into slicer for fusion 360 which is a program that slices the 3D model into individual parts. firstly the file needs to be exported from Rhino as a STL file. The dimensions set for our fuel tank sheets in slicer was 400x800mm.

Step 4 - In total we had 16 segments which were to be cut onto three 400x800mm plywood sheets 3mm thick. Export the file to illustrator to laser cut the skeleton.

Step 5 - Using illustrator set the thickness you want your skeleton connecting cuts to be, initially our group chose it to be 3mm but this was too thin and a re-cut at 3.05mm was required.

Step 6 - Once all the pieces of the template is laser cut its time to assemble it. Using the numbers and letters etched into each piece start piecing together the template.

Note: Our group found it quite helpful to use a couple of pieces in one axis then once a solid frame is built start placing all the opposite axis on leaving the small pieces to the end.

Step 7 - Once the template is assembled we decided to give it extra strength by gluing each joint on the template on both top and bottom.
Note: ensure that when gluing the tank template is straight as there is a chance it may shift and not be aligned/skewed one way.

Step 8 - While gluing the group decided to cover the template in masking tape which created a surface that wrapped around the template, this combined with the applied glue gave the template a solid base to form the sheets around. The masking tape was placed in both directions of the template with the whole tank being covered in the end.

Step 9 - Next step is to create an outline of the section that you will be moulding, what we decided to do was wrap the template in paper and draw our sections onto the paper. There were multiple ways which the group was going to split the tank but in the end it was decided to have split the tank longitudinally with the left and right pieces being symmetrical. Once the sections were drawn on the paper these were cut and then transferred onto the aluminium sheets.

Step 10 - Using either tin snips or the lever shear cutter, cut out your piece staying tight with your marked out line on the sheet.
Note: Once the piece is cut out it is advised to ensure that all the edges are filed and any sharp pieces on the edge of the sheet are removed, this can be an annoyance when moulding the sheet to your desired shape and by doing this will also make the piece a lot nicer.

Step 11 - Now you should have 3 your aluminium sheets split into 3 parts, choose one which you will begin to mould.

The piece I was tasked to do was the middle piece of the tank.


Step 12 - Take your cut out piece to the aluminium roller and feed the sheet through the roller. The curve you are trying to create in this step is the long curve of the tank. Adjust the rollers angle and repeat this step until the curvature of your piece matches your part of the template.

Note: When rolling the sheet through ensure that you have both sides of the roller adjusted evenly, if not even your sheets curve will vary from side to side and be not symmetrical.

Step 13 - Next is to try and form the short curve of the your designated section. This step requires multiple tools and techniques which I will discuss. Please note that these techniques can all be used with no specific order needed to complete this step repeat the techniques below as required.

Technique 1 - Nylon mallet, small wooden mallet and sand bag
Using your mallet strike the sand bag to create a curve in it. Now place your sheet on top of the sand bag. Using the pointed end of the nylon mallet strike the of the sheet to create the curved lip of the piece. work your way around the sheet striking at even intervals with an even force.  once completed using the small wooden mallet do the same thing but this time use the flatter more rounded edge of the small wooden mallet.

Technique 2 - English roller
To smooth out the piece whilst also create a desired curvature run the piece back and fourth through the English roller ensuring that the piece is rolled evenly.

Technique 3 - Template and nylon mallet
Using the laser cut template place the piece on the template and use the nylon hammer to curve edges down flush with the template.
Note: By having the template glued and taped securely it was able to withstand the force of the mallet hitting it.

Technique 4 - Curved metal forms with mallet
To get a tighter curve on the edge your sheet place the edge on the curved metal form shown below. once on use the nylon mallet to strike the edge down and around the form creating a lip.

Note: You may notice that by completing step 9 you may have lost some of the shape you created in step 8 along the long curve of you sheet. To rectify this apply technique 1 down the middle of the long face of the sheet until your curve is back to where you need it to be.

Step 14 - Your sheet should now fit to the mould quite well with some of the edges potentially being to high or too long, If so use the shears to cut these back and get the edges flush.

Step 15 - Using methylated spirits and fine steel wool scrub the finished pieces to get a nice polished finish and to remove any dirt from the surface.

Pre polished piece

Final Product

Group members sections

When piecing all of the tank together the group came across issues involving the joints of the pieces. Along the edges the group as a whole found it hard curving the edges flush with the skin, this in turn meant that our pieces did not line up as well as we hoped. 

Overall each individuals piece adhered to the skin of the fuel tank quite well as you can see from the pictures below. 

The Blister

Materials/tools 

- 200 x 200 annealed aluminium sheet

- Plastic mallet

- Sand bag

- Mineral Turpentine

- Cloth

- CNC blister template

- Tin snips

- Screws and nuts

- Small wooden mallet

- Timber corker

Procedure

Step 1 - Choose template of what shape your blister will be the larger and more broader the blister the easier it will be. The templates cut using a CNC. template photo below.

Step 2 - Sandwich the aluminium sheet between the two templates and drill through the holes in the template to create holes in the aluminium. Insert screws and screw nuts on ensuring they are tightly fixed.

Step 3 - Using the plastic mallet photo below strike the aluminium through the template. ensure to start you use the flatter and more round face of the mallet to ensure you keep a smooth face on the blister. Tip: place a sand bag under the template when striking with mallet too ensure the base of the blister stays rounded.

Step 4 - Using the more pointed side of the mallet strike the edges of the blister. This will give the blister more depth closer to the edges. While doing the use the small wooden mallets flat edge to smooth out any large dents in order to keep the smoothness.

Step 5 - Using a piece of timber disc sand it to create a pointed edge, this will be used as a corker. What this does it help in getting depth and sharpness to the edges and pointed end of the blister. Using the corker place it on the edge and strike it with the mallet. Work your way around the blister and pointed end until you have your desired edge sharpness. Note: the corker will go blunt and will need to be re sanded to hold the original shape.

Step 6 - Using tin snips or the sheet metal cutter cut evenly around the blister following the outline.

Step 7 - Now complete polish the aluminium with some mineral turpentine and a cloth. This removes and blemishes, dirt and oxides in the metal giving it a nice shine.

Final Product

The Tray

Materials/tools 

- 200 x 200 annealed aluminium sheet

- Plastic mallet

- Mineral Turpentine

- Cloth

- Timber tin template

- Tin snips

- Vice grip

- Sanding block

- Marker

- Ruler

- Radius stencil

Procedure

Step 1 - Using a marker and the radius stencil mark on the timber template the desired curvature of your tin. once template is marked use the disc sander to create curves on the edge of the timber.

Step 2 - Cut the aluminium to the same shape as the timber template but add an extra 5mm approx (depending on how deep you want your tin) of aluminium around the template. Then cut aluminium neatly with the tin snips. 

Step 3 - Sandwich the aluminium sheet and the timber templates to in a vice. what you should see is the two timber templates hugging the aluminium with the over cut of the aluminium (5mm) sticking out all the way around.

Step 4 - With the rounded plastic mallet start to strike the aluminium overhang to form a 90 degree angle around the timber template. work your way around the tin until you get to a corner. Once you get to a corner strike it to the template but be cautious not to create a fold in the aluminium. The aluminium will stretch and any excess metal that is not needed cut away with the tin snips. Repeat above until all 4 corners are complete.

Step 5 - Repeat steps 1-4 with second sheet of aluminium to form mirrored piece

Step 6 - Now complete polish the aluminium with some mineral turpentine and a cloth. This removes and blemishes, dirt and oxides in the metal giving it a nice shine.

Final Product

The Torus

The Bowl

The Bowl

 Materials/tools 

- 200 x 200 annealed aluminium sheet

- Plastic mallet

- Sand bag

- English roller

- Methylated spirits

- Cloth

- Marker

- Radius template

- Tin snips

Procedure

Step 1 - Using the radius template and marker, draw concentric circles on the aluminium sheet.

Step 2 - Using the tin snips cut tightly around the circumference of the largest circle

Step 3 - Using the plastic mallet and sand bag strike along the marked line of circle using the pinted side of the mallet. 

Step 4 - Using the plastic mallet again strike the same line all the way around but this time with the broader side of the mallet.

Step 5 - Repeat steps 3 and 4 for the inner circles 

Your piece of aluminimum should now be resemblant of a bowl with vaious highs and lows in the metal.

Step 6 - To smooth out these highs the english roller will be used. With the aluminium bowl push and pull it through the roller making sure not to make sharp movements. your movements should resemble a lawn mowers systematic direction in order to cover all areas of the bowl.

Step 7 - Repeat step 6 until you have your desired shape and gradient of the bowl. In order to get a polished finished on the bowl clean the bowl with a cloth and methylated spirits as often as possible when using the english roller.

Final Product