Tag Archives: transport design

MODEL MAKING PROCESS- PRIME AND PAINT ( PART 4)

Since the Model was back from paint, the final bits to go on where the 3D printed parts. These parts as shown by a previous post ( scroll down) were cleaned and sanded slightly to prepare the surface for priming. These parts while small needed a lot of sanding to get the surface smooth for painting.  I used 240 grit sand paper here and had to be extremely careful as the parts were quite small and fragile. With the Objet Printed parts ( yellowy plastic) you can actually paint straight onto these parts however applying a layer of primer is important to get a smooth even surface as primer just helps to fill up any inconsistencies you may not see or feel. 

All the smaller parts you see here are for the headlights and taillights of the model. The larger solid parts are the Z-Corp Powder prints and these have been soaked in Epoxy Resin for Strength and sanded down ready for priming. Image

You may not be able to see it from the picture but all the parts above still don’t have extremely smooth surfaces. This is because some of them were so small and fragile that I didn’t want to risk breaking a printed piece since I didn’t have any replacements. After this photo was taken I did however sand them down a little further and then the Acrylic Primer Surfacer was applied. This Acrylic Primer Surfacer was made for use on plastics meaning it will adhere to the surface better than standard Primer Putty. The Primer Putty is then applied over the Surfacer to give the pieces that extra layer to hide any surface roughness. Once the Primer Putty is applied twice the pieces were given a light sanding back and then the chosen paint applied . I glued the pieces down to a wooden box and just sprayed them outside in my garden. I coated them with at least three layers of Automotive Acrylic Paint ( Purchased at Autobarn) and then a coat of the Acrylic Clear Gloss to give the pieces a bit of a shine. The pieces were then ready to be glued onto the model.

Image

 

Advertisements
Tagged , , , , , , , , , , , , , , , , , , ,

MODEL MAKING PROCESS- PRIME AND PAINT ( PART 3)

The day after I saw the first coat of paint being applied ( Strato Grey) the final body colour was put on just the next day and the model was ready to pick up within 36 hours. The main body paint I chose was a Toyota Pearl White. This colour contrasted well with the dark grey windows and was a colour that reflected luxury and wealth and looked good in almost any light. Through some research over the last couple of days, I had narrowed the colour choices down to a range of metallic colours such as beige gold and bronze and also a number of different shades of white. This Pearl White wasn’t something that i was able to render too well in KeyShot ( CAD program for rendering) but after seeing a new Toyota 86 on the road in pearl white I knew that was a colour that would work really well. As mentioned in the previous posts, using Adams manufacturer swatches I was able to choose out the exact Pearl White that I wanted. Pearl White is a tougher paint than most to apply because it is applied in 3 layers. These are the base colour ( very light off beige white) then the Pearl Sparkle ( in White) then the clear coat. Three layers means three layers of paint to be applied, three times the drying time making it quite a tough job to complete properly. Thankfully Adam was experienced in this area and the paint job came out really nice, really contrasting the windows well.
Image

The final stage of the process was to add on the 3D printed parts for the small details such as the suspension arms and head/taillights and the model was ready for presentation.   

Tagged , , , , , , , , , , , , , , ,

Model Making Process- Prime and Paint ( Part 2)

The next day I popped back to Hi-Gloss Bodyworks to see how Adam was doing with my model. He had finished the primer layers then night before, let it dry and then applied a coat of the window paint, “Strato Grey”. This paint looked really nice, had a dark metallic grey colour which really worked well against the Pearl White swatch. The model, being made from Renshape ( A chemical Wood) was unable to baked due to it being part wood. This meant that drying times took a bit longer than expected. Luckily though the Strato Grey was a easy paint to apply compared to the later coat which was in Pearl White ( 3 Individual Layers of paint) . The model began to really look like it was coming to completion here and I was really happy with the progress. The only issue I saw was a join that hadn’t been quite covered up by the primer and had still come through in the paint near, part of the front recessed area for the headlight. This goes to show how hard it is to smooth out joins before primer, no matter how much bog or putty you put to fill up the gap. Luckily this join was going to be hidden by a 3D printed headlight so it was not a big issue.

Image 

The next step was masking off the grey paint to ready the model for putting on the main body colour, Pearl White. Watching Adam apply the blue masking tape you could see that there was a real art in masking off the curves to the exact radius’s and angles that you had on your model.  He completed the roof section first and then moved onto the side windows.
Image

The windows were the tougher bit to mask off with sections that were obscured by other parts of the wheel hub making them hard to mask accurately. Watching Adam apply the tape though, none of these sections seemed to bother him in the slightest. Within half an hour the model was masked up and the masking tape was being applied readying it for Pearl White paint.

Image

Tagged , , , , , , , , , , , , , , , , ,

Model Making Process- Prime and Paint ( Part 1)

The first couple of photos were taken just before loading the model into the car to be taken to the painter. The model was finally all put together and ready for paint. The painter that I had chosen was one which did a lot of automotive restoration jobs. I dropped him an email about two weeks before i was expecting to finish the model with screenshots from my CAD files and he was able to give me a rough quote on how long it would take allowing me to work that into my schedule.  I found Adam’s shop ” Hi Gloss Bodyworks” through the internet, browsing places that did custom paint jobs and his came up with some recommendations from a forum. Not new to student work Adam was really understanding about my time lines and enthusiastic about what I had planned for him to do.

Image

Located out in Knoxfield, we arrived at his Body shop and took the model out and put it on a tray. Being a proper automotive body show he used two pack paint which is illegal to spray without a fully vented spray booth in Australia. Two Pack is better than Acrylic paint to use on models as you are able to get a thicker coat than acrylic and are able to layer the paint with ease. We went to the paint room and I was able to pick out a paint choice from his large collection of swatches that were all sorted by Automotive Manufacturer which was really helpful as the colour for the body that I wanted to match was a pearl white that I had recently seen on a Toyota 86. The window colour was an older Mitsubishi Gun Metal Grey which was easy to get from swatches too. After a couple of minutes choosing colours and comparing them to existing swatches that I had, I decided on a Pearl white( 1 of many shades) and he was ready to prime the model.

Image

We then moved the model into the paint room, placing it on a barrel with a stand so that he could get primer onto the top and bottom of the model even though people wont see the bottom. Adam informed me that some of the really tight areas would be very hard to get into as when you apply primer you have to do it in a smooth slow fashion. This I assume meant you couldn’t stay in one are to fill it up as this would apply too much primer to one area leaving an uneven coat. He did what he could and it came out really well, this was the first time I could see the reflections of light on my model similar to the ones that I had in CAD.

Image

After the first coat of primer was done I walked in to see the model. I was both shocked and surprised at how it came out. Surprised because finally i could see the models reflections and shocked because of all the part lines that stood out! This was really worrying as every little area that had been joined together with glue has a part line showing even though we sanded it down and filled it up with bog and spot putty. Luckily Adam was planning to apply more than 1 layer of primer and by the 3rd the part lines had been mostly covered up. Over the next day, Adam sanded back my the primer and rubbed down the model getting it looking as smooth as possible on the sides. He even added some auto bog on one of the part lines that he couldn’t smooth out and then sanded it back further.

Image

Tagged , , , , , , , , , , , , , , ,

MODEL MAKING PROCESS -PUTTING THE PIECES TOGETHER ( PART 4)

By this time, most of the body had been glued together and the sanding was getting to a point where i was just getting the joins as flush as possible. Here I moved onto getting the front wheel hubs stuck on and bolted in for strength. I thought that epoxy would be enough to hold the hub in but since Renshape was such as heavy material and the join was such a small area, my dad suggested a bolt to hold it in would be a good fail safe. This was a bit daunting as no one wants to make changes to the final model at the last second. We glued the hubs on and then chose an  area where people couldn’t see bolt sticking through which would also provide the most support. Using the cordless drill with one of us holding down the model as the other drilled we began. The hole went through both the wheel hub and the body. We then filled this hole with a bit of epoxy resin and then dropped a bolt in there to hold the body together. This hole was later to bogged over and sanded clean.

Image

The next stage involved putting together the rear wheel hubs of the model. Due to time constraints and machine failures in the final weeks I had to get a rather large part of the inner hub 3D printed in Z-Corp Powder Print. This cost quite a bit ($240) but saved me crucial time as it meant the other half could be CNC’d with on a 3 axis machine saving me time. Like the other Z- Corp part, this was brushed in West Systems 105 Resin and Fast Hardener and put in front of a heater to dry up. This was then glued to the other half of the wheel hub and the join cleaned up with a bit of bog and spot putty. The left Wheel hub was a bit of a nightmare. After not having time to finish to complete it on the 4 Axis machine, it had to be sliced up to be put onto a 3 Axis machine. This machine then broke down for 5 working days so the parts that made up this part were the last to come out, a mere week before the project was due. As you can see by the pictures a lot of sanding and bog was put on and this part took quite a while before it began looking remotely like its opposite side.

Image

Once the rear wheel hubs had been sanded down and the joins tested against the body to make sure they were flush, they were attached to the body. We used the same procedure as the front hubs by first gluing into place with 5 minute epoxy then drilling a bolt through for strength. These were tough to line up as they had to be done by eye.

After the final bolts were in, bog put on to cover the holes, we did a once over on the model to make sure it was all in good shape. A good clean with methylated spirits and an air gun brought up any holes in the joins or the bog. These were then sanded back or had spot putty or bog added depending on the size. These were the crucial last hours getting the model prepped for paint. I did a once over with 240 grit paper and a final wipedown with methylated spirits as well as a pressured air gun and the model was ready to be sent to to paint.

Image

Tagged , , , , , , , , , , , , ,

MODEL MAKING PROCESS -PUTTING THE PIECES TOGETHER ( PART 3)

After gluing most of the main body parts to my model bar the rear parts i began filling up gaps left by glue and general gaps left by parts not fitting in perfectly. I used a combination of auto bog and spot putty which helped me to fill up gaps quickly with minimal sanding. This part was crucial as all these joins had to be completely smooth so that come priming, the model hopefully wouldn’t require too much coats from the painter ( more primer, more cost) . The parts at the rear of the model required quite a bit of bogging and sanding back to get them to be flush with the other parts. 

I began working on the outer sections of my model here, the wheel hubs which due to limitations in the CNC machines I had , had to be cut up into a number of small parts. Once put together, I had quite a bit of fine sanding to do to get into the small radius’s left by the drill bits. Some of the wheel hubs needed a lot of sanding due to errors in the programming of the CNC but after a bit of sanding they were good to go. 

Image

After sanding the front wheel hubs down till they were smooth i began sanding down the parts where the body and the hub join. This part needed to flow perfectly as it was a major part of the side graphic of my design. 

Image

Once the front parts were sanded flush, I went back to prepping the rest of the model for paint. The painter had requested I get the model sanded back to between 180-240 grit so I had quite a bit of work to do to. In between sanding or gluing I wiped down the model with methylated spirits to keep it clean of any foreign objects to ensure a clean and strong adhesion. Any parts which had small areas to sand down i masked off with tape so that I had clean edges that would show up in paint. 

The 3D printed suspension housing was sanded down here to fit with the model. It was important that I get both the wheel hub and the suspension arm to fit snug or else I would have alot of issues sanding down the 3D printed part which is not something I wanted to do due to its brittleness. To make the 3D printed part harder we coated it in a 2 part epoxy resin by West Systems. This was brushed on and soaked straight into the Z-Corp Powder Printed parts. After sitting it in front of a heater to speed up the drying process, the part became almost marble like with a grayish hard finish.  This made the part even harder to sand hence why I wanted to get the wheel hubs fitting as best possible at this stage. 

Any gaps in the model such as the ones that appeared in the rear were being polished off here and sanded down as flush as possible. 

Image

Tagged , , , , , , , , , , , , ,

Model Making Process -Putting the Pieces Together ( Part 2)

After gluing together most of the sides i began to place in sections such as the base, back and some roof parts to see how they fit. It was important to keep checking this as each of the parts were machined to slightly different tolerances. 

Overnight i clamped the sides together to a roof section to pull the side sections into the shape I was looking for. In the morning i took off the clamps and this resulted in a shape which fit the roof section almost perfectly with a friction fit. Before putting in the roof section, starting from the front so that any errors in measurement would appear at the back i placed in some wooden support pieces which i glued to the inner sides of the model. These supports would make gluing the roof in place easier as well as give strength. 

The joins between the roof parts was really good, they were very small and were easily fixed with bog and spot putty. By working from front to rear, the main errors, one which i expected due to a mistake in CNC’ing appeared only in the rear area meaning the rest of the model went together easily. The mistake led to a gap almost 3 mm wide on the roof section and also about the same on the right side. It was a matter here of choosing whether to sand back, or bog up to fill the gap, I chose to sand down as bog, as easy as it is to use, is very tough to sand back if you add too much.

 Image

 

This was the model after placing the remaining roof pieces, you can see clearly here where the errors were and how many pieces were required to join the roof together. Running on little sleep and high stress levels discussing with my dad the best strategy to glue this all together was crucial in not making any mistakes and creating the most even finish.

Image 

 

Tagged , , , , , , , , , , , , ,

Model Making Process- Putting The Pieces Together ( Part 1)

After sanding down what I could with the 20 or so parts, I began mocking up the final shape of my model with just masking and double sided tape. On the final day of CNC’ing, while I was waiting for  one of the machines to finish with my parts i decided to cut out a foam block which at the time i assumed would make up the internal structure of my final model. Using the dimensions from my CAD file which was basically what was left of my model once i took off all the parts that were to be CNC’d i had basic dimensions of the shape I needed. I gathered some scraps from the workshop, printed out the technical drawing and got to work. Using scraps from around the RMIT workshop, epoxy glue and double sided, the hot wire and the band saw, i was able to get a pretty accurate shape going for the inside of my model.  When i got home I sanded it down a bit more and was able to place the parts around it to get a good idea of the shape that the model was taking and where the possible areas for bogging would be.

Image

These images are were the first stages of putting the parts together. I decided the order to put the parts together were the sides, then work from the front and across the roof towards the back. This mean that if there were any mistakes they would be pushed towards the back of the vehicle rather the front. Using a bunch of g clamps and lots of 5 minute epoxy i got to glueing the parts together and the parts started to take shape. Some parts required more sanding than others so I pulled out the dremel tool to speed up the process. Image

Tagged , , , , , , , , ,

Model Making Process- Final CNC’d Parts

After about 3 Weeks the majority of the parts for my model had been CNC’d out from 4 different  CNC machines. While relieved that I was up to the final part of the model making process, the issue that I had to face here was that because each machine worked to different tolerances ,y used different drill bits, not all the pieces would match up perfectly. This was also the case for the pieces which required more sanding than others, human error being the main problem here from sanding too far.

I ended up with quite a large number of parts, a lot higher than the others in my class due to the size limitations of the machines as well as the number of undercuts the parts I had contained. Throughout the process i attempted to put these pieces together to see my model coming together.

Image

Through the following images you can see the sanding that was required on some of the parts. Some came out with very little sanding needed (>10 min) some needing small bits of dowel to get into smaller radius’s.  The hardest parts to sand where the ones which joined onto others through flimsy joining areas, these were only able to be sanded properly once the parts were glued to each other and required very careful handling to minimize bogging later. I sanded here using 80- 240 grit paper. 80 grit for the really rough stuff and 240 for getting the parts ready for paint.
Image

Tagged , , , , , , , , , , , , ,