Saturday, 22 May 2010

Didnt finish on time! Not happy!

Attaching the bottom and top part of the cabin was fairly simple and then filling it and creating it seamless was pretty simple too. I then went to prime with lots of time left to sand and then spray final coats.
The primer was too thick and cracked and started melting into my styrene vacuum formed cabin. I quickly sanded the primer off with wet and dry and water. I was very annoyed as it had ruined all my work the previous day making it sooo smoooth and sleek. I quickly tryed to sand it out, but unfortunately my time was running low.
I decided to spray plastic primer on both the hulls and cabin as i was too worried that the normal primer would ruin the surface even more. I then sprayed two layers on both the cabin and hull of white paint. This was definitely not enough for the final coat. The grey plastic primer was still slightly visible underneath. I attached two 0.5 mm pieces of acrylic for the windows.Time was up and I temporarily assembled my model.

This model should have been complete yesterday and today should have been allocated for finishing touches.
I feel that If I had had one more day the model would have been completed to a much higher standard. And I also feel that If posed with a situation like this in industry, I would be able to stay through the night working on finishing the model.
I am happy with how the model has come out with the slight exceptions for the damage done by primers. I think it could look much better with the final coat and some added details, such as its thin blue stripe on either side of each hull and small hand painted detail on cabin. And scaled items bought from a model boat shop to add detail.

Filler spray!!!!



I have yet to attach the bottom and top part of the cabin. But I did use filler spray on my hulls (orange colour). I sprayed a thin layer every hour for five hours. I then sanded down after 24 hours as it takes ages to set. It has removed nearly all blemishes.

I think it looks cool!

Cabins bottom and top!


I used two layers of styrene to vacuum form both bottom and top cabin parts.
I sanded the bottom cabin part with the wooden former still in as I could sand perfectly around the former giving maximum accuracy.
I also kept the top cabin with the chemi wood former in but I then marked out the cut lines for the windows and the cut lines for the open back. Using my Vernier gauge and a small metal ruler I marked out the dimensions from my rhino drawings. Using the metal ruler with a bit of tack on the back and a shape blade I cut the windows and back exit out. It was fairly clean and needed a little bit of a sand
I then used Dichlo to bond each layer of styrene together on the cabin parts. I then sanded and primed.
I also decided to attach the supports to the bottom part of the cabin and used a thin metal rod and filler to create a nice smooth joint between the supports and cabin.

Update!

I have also made a small seating area in the back of the boat with small blocks of chemi wood rounded off. and sprayed with added matting agent.

I will now joint both the bottom and top parts of the cabin together with super glue and use filler to seal the gaps.

Cabin formers

Using these drawings on rhino I began making my bottom and top parts of the cabin out of wood and chemi wood.

Here are my two separate formers together to reveal the shape of the cabin. I have drilled holes through the top back part of the top of the cabin this is so that when vacuum formed it will pick up the line I have carved into the back to show guidelines for where to cut to make it a hollow object.

I first began researching vacuum forming as I havnt used this process in ages. I can remember it being very simple to use but I do also remember various flaws, such as webbing and plastic over heating.

I wanted to have a clear plastic to vacuum form with but using clear PETG and Acrylic seemed so much harder to use on the vacuum former than i thought. Petg produced lots of heat bubbles, which made the material look wierd. And even if I left it under for less time the bubbles would disapear but the material wouldnt form all the way round my formers and left lots of webbing. Acrylic was the worst to use as it always produced heat bubbles when heated and always webbed.

I talked to my tutor and he recommended using styrene and working out a new way to produce windows. Styrene definitely vacuum formed the best. I double vacuum formed 1mm styrene on the each former to make it a little bit stronger and rigid.

How to make the Cabin?

I have been brainstorming ideas on how I can make the cabin.
I had an idea of milling out the bottom part of the cabin and then building the rest up on top of that.
I milled out a perfect size of chemi wood and lay it on the hulls and realised I had wasted valuable time as this could have been done in minutes with some acrylic.
I also felt this was too rigid and boxy like the previous design. I decided to make a very simple blue foam model, which you can see to the top right of the photo above. I then realised I could produce a bottom and top part of the cabin in a solid material like wood or chemi wood and then have these vacuum formed to produce a nice hollow cabin shell.

Cabin design



The main cabin of the Power Cat is quite straight edged and boxy. I want to make this cabin smooth and sleek. I have decided to do some simple re designing to produce something that would look cool to this day. I did some planning on Rhino and made a few drawings. I think it now should look more fun, speedy, smooth, sleek and extreme.

Hulls!



Once both sides the sides of the hull have set, I attach them to a former I made from MDF and then mix up a small amount of fast cast and let it go off slightly. I then use this solution and slowly pour it between the two sides of the hull and then push together. This works very well and all that is left to do is give it a final sand. I repeated this process for the other hull and then primed.

Sunday, 25 April 2010

Fastcast!


The moulds worked extremely well. I used fastcast to produce the casts of the hull. I have attached both the ends of the hull and sanded, filled and primed three times so produce the best finish. I have now cut the hull in half once again to produce two final moulds.

Moulding


I have now decided to cut the hull in half so that I can easily mould and cast it. My tutor suggested using some tubing, which worked very well and also used minimal silicone.

Foam and Resin


Here I have filled the skeleton with yellow foam and painted on the resin. I have then sprayed the hull with primer to work out what areas need to be sanded to save me on sanding later when it has been moulded and casted in fastcast.

Acrylic Former


Here I have the acrylic former assembled and ready for the yellow foam to be added and sanded.

Lots of drawings


After lots of measurement converting and small redesigns on the main boat, i can now start on the making of the hulls. I have decided to laser cut small formers that will create the skeleton of the hull. I will then fill in the skeleton with yellow foam so that I will be able to sand it into my required shape. I will then paint on resin to block the pourous yellow foam and create a thick layer so that it can be sanded down and moulded in silicone.
Once the silicone has set I will cast using fastcast and fill and sand to give it a much nicer finish. I can then repeat the moulding stage again so that my nexts casts will be cleaner and smoother.

Drawings!

I have aquired some drawings for my boat from an old boat building handbook. I have found the correct scale for the drawings, but it is taking some time to convert all measurements to my chosen scale of 1:25.

UPDATE!

I have had quite a lot of trouble finding any information on the power cat 28 online, but I luckily found a website with a diary of the build and some drawings that will be of massive help.

Power Cat 28


I have decided to build a 1:25 scale model of the Power Cat 28. I will be modernising the original design to create a more sleek and sporty look. This model could have various uses, such as being used as a sales tool for prospective clients, on display at a boat or catamaran museum or simply used as a prop.

I will be using this blog as a logbook for my project. Anything that I use for research will be logged on the right hand side of the page.