CSR1000 Project Build

Davido, just a random thought (I have lot's of them) with regards your filler cap recess - if you are not going for a bare carbon finish could you mould the recess slightly undersize with the radius as suggested by Doctorot, but with a couple of extra layers of material in that area and then "final trim" the recess opening with a router to get the "square profile you are looking for so the cap is a snug fit ?

Sounds like a good idea. I also thought of using the practice mold I made to make the fuel cap recess as a separate part and join it into the main tank later. This will give me the time to get it right without messing up the main top half casting.
 Maybe even a combination of both processes.

My head is still in the XT though. Engine is finished and back together. Just got to get it back in the frame, connect all the bits and bobs,then its that terrifying first press of the button!
Depending on what happens then, I'll either be back on the Z tank, or I'll be trying to get the XT engine out again through a wall of tears!!!




















 

Happy to say all went well with the XT. Got it sorted,back on the road and bimbled around Spain during the summer So,that's done and out of the way (though I will need a new rear shock and a fork rebuild for next year but....one thing at a time.)
 Getting back to the carbon fiber tank business. After a lot of thinking (and I mean a LOT of thinking).I have decided to change direction. The molds I was making,though a lot of work, didnt fill me with confidence. There seems to be two ways of going about this. The first being the ZRX guys method,which is what I was busy with. Making a mold of the outside of the tank then laying  up the carbon fiber on the inside of that to give a true replica of the original tank.This means,although you get a great copy of the tank, the finished product comes out in two (or more) parts and you need to join these parts. I was going for a cast of the top part of the tank and one of the under part. Giving a joint or seam the same as the original steel tank. The original seam is only about 6 to 7mm deep, which is not a lot of surface to rely on.I thought of making it a bit larger and adding rivets which would beef it up a bit but at the end of the day it would still be a joint. A weak part. Right along the bottom of the tank.

  The other way of building it is a method I got from the Hackaweek guy. He made a tank for his Honda Sabre build.
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Though his was fiberglass,not carbon fiber, the method was interesting. He made a copy of his tank from insulation foam, Fiberglassed over it, then dissolved the foam out with acetone.The problem with this method is that you don't get an exact replica of your tank. The shape,size,look and fit of it are dependent on how good a foam tank you can sculpt to begin with. The big advantage though is that the tank is one piece. No joints. No weak points. I was planning on changing the area around the fuel cap anyway and maybe some knee indents,so I don't need an exact copy. Just something reasonably close.

 So, I'm going to have a go at this method and see what happens. To start with,I'll just be concentrating on shaping and sculpting the foam. Getting a look that I like and making sure that the hardware all lines up and everything fits and sits well on the bike. The whole resin/ carbon fiber side of things will happen later as I'm still looking into what I need and how best to do it.
 I've already made a good start,I just have to shrink the photos file sizes to be able to post them.Should have something up in the next day or two.
AND, I know this build has gone on long enough.I do a bit,leave it a year then do a bit more etc. My goal is to get the tank done over the winter and have it fitted and holding fuel by the spring. I think that's realistic.
 

Sounds like a plan, here is a guy doing a similar thing with carbon, great to see you still persevering with this idea. Loved your original build (I have told my wife you are responsible for my current Ltd build as you showed me what a Ltd could be)
Building a Low Cost and Simple Carbon Fibre Moulding : 10 Steps - Instructables
Could you use the moulds you have already made to make a foam "former" for the new tank ?
 

Yes,I've watched this video. It was exactly what I was looking for. One off molds without vacuum bagging.Very informative. Easycomposites is the company and they have a load of really useful tutorial videos.They also have a branch in the Netherlands,so I'll be looking to them for supplies when the time comes. I did think about using the other mold to make the foam tank. The only foam I could think of which is unformed is builders foam.There are problems with that though. For a start, it expands.With quite a bit of force.I would need to seal the molds very tightly to avoid it pushing out of shape.I don't know if that would work. Also, it needs air to react and harden.If I taped everything together to hold the shape, the air couldn't get to it and it would take forever to cure. Another thing is that it wont dissolve with acetone. Or with anything. I tried.I tested it ages ago with 5 or 6 different chemicals. Nothing would dissolve it. Not even the cleaner you buy to clean out the foam gun. Once it has set.That's it.
 (However.There might be a way of doing it gradually. I suppose it could be done.I might have a go.Just for shits and giggles).
I went with the insulation foam,as that will dissolve. Not with the acetone that I have but with petrol for sure and probably other stuff. There is a problem with acetone in this country at the moment.I don't think its been banned but its not so easy to get hold of anymore. I think because its used to make party drugs and its sale is now being controlled. The stuff you buy off the shelf is a very weak version.it wont melt foam.That I know.
 The dissolving process is a fall back issue anyway. The stuff I dissolved (with petrol) didn't totally dissolve. It left  a gooey mess in the jar. I don't fancy having that in my tank so I plan to break out the foam in chunks and only if there's bits left  that I can't get to, will I resort to chemicals.


Apologies to your wife Wookie58

Not sure if you can order the below from amazon, I use it to dissolve ABS plastic into a paste to use as a filler so it's fairly strong (takes around 18 hours to fully dissolve) if not your friendly local beautician may be able to supply you  

Another reason to use acetone as a last resort is that I have no idea how it might react with the resin that I use.I need to experiment with it first before throwing it into the tank.
Here are a few pictures of whats been going on so far. I built a hotwire cutter on the worktable and sized the plates of foam;
 
I marked out the tank shape on the top plate and on the bottom plate;
 
Glued up all the plates into a block of the right height (more or less) and squared it off;
 
Cutting the tunnel was a bit of a challenge. Its not a straight line from back to front.It sits at three different angles.I took the line at the middle of the tunnel as the base line and cut some templates for the front and back'
 
This allowed me to cut a channel  following the basic shape of the original. I made a different hotwire cutter for this part;
 
 

Really nice work, looks like you are all over it

The channel/tunnel widens out towards the back and I wasn't able to do this bit with either of my hotwires. They are both tensioned between two points. I needed a free standing wire. It needed to be thin enough to allow the resistance to create heat but thick enough to hold a shape. This was trickey. I managed it, though the wire still moved around a bit too much and gave a very wobbley cut;
 

An addition to the template allowed a shallow to deep cut;
 


Next was the hardware (Front ears,tailpiece and fuel tap mount). Positioning this properly is very important. Everything has to be in the right place in relation to each other.If its all a little bit forward or a little bit back,it shouldnt be a problem,so long as each bit is the proper distance and position from the other two bits as on the original. I hope this makes sense;
 

I made a frame on the original tank,connecting all three points together;
 



As the tank is such a rounded shape,I've taken all the measurements from the bottom of the seam/flange/lip on the bottom of the tank. This is the only straight line on the tank and I've used it as a constant. As a zero point. I wont be able to mold the seam on the final model so I will probably shave 6 or 7mm off the bottom of the foam when all the shaping is finished.Its a lot easier than subtracting the mms for every measurement. Less chance of messing it up.

 

Impressive!

Thanks Mikaw,Though I have no idea if or how this is going to work out. I can make all the molds and templates I want for the hot-wire but when I've got as far as I can with that,then its down freehand work to get the shape right. I'm reasonably confidant that I can do a reasonable job but..... we will see!
 So the basic tunnel is done for now.I will probably have to fiddle around with it to get it to fit right.I need to sit it on the frame and see what the clearance is like.But for now it will do. This was the most awkward part to measure and cut. The reason I did it first. Also,easier to do with a square block of foam. If I cut the profile first,it would have been a bugger to set up for cutting the tunnel.
The next is the circumference.The outside lines.Going up from the bottom seam,the tank bulges out then comes in again on the top of the tank. So I'll mark two lines.The first will be the seam itself,all the way around as far as I can,(as it lifts up at the front and a bit at the back).The other line to mark is the tank at the widest part. The bulge.To do this I made a pen holder at 90 degrees to the table top;
 
So the inner line is the seam.This is just for reference for now but you can see how much the tank bulges out. I will cut two MDF templates following the outside line which I will glue to the top and bottom of the foam block (making sure to keep all the center lines lined up) Then I'll go at it with the hot-wire. Which should give me the outside shape of the tank at its widest.Later I will re-mark the seam line and this will give me a line to carve/scrape/sand into.

New templates for the outside (circumference) line glued to the top and bottom of the foam block;
 
 A handy spray for giving a bit of slip to the worktop and allow the foam block to glide by the hot-wire a bit easier;
 
It goes very slowly as the power pack doesn't put enough heat through the wire;
 
But taking some time, it comes out well;
 
Side by side the foam looks a lot bigger than the original tank but in reality the front to back dimension of the foam is the same as the tank-minus-the seam at either end and the width is the same as the original-plus-half the thickness of the pen that I used to scribe the line.(maybe 3mm max). Happy with the result so far.