Kz1000 Carbon Fiber Fuel Tank

I can imagine how it would be more appealing to replace a tank that has difficult to repair damage. It is much harder to shrink metal than it is to stretch it! It's possible to do, but requires skills I never really honed. At least you got a replacement and are working on assembly..... I'm still having fun building :whistle:

porchev914 wrote:

otakar wrote:

Her's another angle.

It looks great cut and buffed otakar, but do you have any pics during layup? It's hard to see the composite construction under all that shiny paint :woohoo:

Unfortunately I did not take any pictures while I was building it. Because it was a one of that I did for my brother I built it over a foam plug that i carved. I started by laying a layer of 8oz Glass followed by one layer of Kevlar followed by three layers of Carbon followed by two layers of Kevlar and two layers of glass. The reason I used the glass at the top layers is because it is much easier to sand. I used Ester resin and allowed the unit to age for 90 days on the plug. Than I put a layer of "Fetherfill" allowed to cure for a week and than baked it at 140f for six hours. This process almost completes the shrinking of the resin and prevents it from showing threw the paint in the future. Epoxy would not have shrunk as much but "featherfill can not be used over it with any safety.

Excellent memory otakar. May I ask why you chose to use kevlar in there? It is my (limited) understanding and experience that kevlar adds abraision resistence. It doesn't add much rigidity to the composite, those qualities are taken care of by the carbon and the fiberglass. I am also curious why you didn't just mold the entire part out of fiberglass. If I was going to paint it, I'd probably do that just to save the cost of materials! But then you can't tell people you have a one off, kevlar reinforced carbon fiber fairing
:woohoo:
I only ask because you may have excellent reasons for doing what you did, reasons that I may not have anticipated and need to take into account.

(youtube)

That's right Craig, my bullet proof Kawk :laugh:

adam,
if you do have to remove the lip you could cut it out in small sections and weld the gaps,then keep cutting small sections of it out and welding until you had it all gone.
keep up the good work,

leon

That's a good idea Leon, thanks for the suggestion. I could do that on the bottom of the tank, but I still need the lip up around the front of the tank to seal the halves together. I need to look at it some more to see how I would do the transition.

OK, I must be temporarily stupid, because I can't seem to figure out how to mod the steel tank to transition from a flat bottom to the flanged front and top, have the two pieces fit together properly AND have enough area to seal the halves together in the transition area. After mulling it over while I worked on it, the best solution I have is to simple mold off the tank as is. After making a tank with the mold, spreading a black epoxy fillet around the flange to blend it. Then if I get really ambitous I can make a fiberglass tank and modify it to be seamless and take a mold off of that. We'll see :S
I haven't been too lazy, I did get some more body work done on the tank. I figured out how I want to keep the stock emblems with the composite tank, and part of that plan required the area around the stock emblem mounts to be filled and blended. Of course, if I had planned to eliminate the emblems I would have had to do the same thing I put a small wire wheel on a die grinder and removed the paint from around the emblem mounting brackets

I filled the seam in with body filler, careful not to get it into the teeny tiny little emblem mounting holes. At some point I'll need to make some emblem mountint tabs that will be embeded in the epoxy during layup of the tank. I sanded the filler down and viola! Smoothed out emblem area.

Some of you might be thinking why didn't I leave it alone if I planned to put the emblems back on, it all gets hidden by the emblem anyway, right? The simple answer is that when I cast the mold of the tank, gelcoat would get into those litle seams and locked in I could have used modeling clay, but you get a smoother, more uniform finish with body filler. It's not perfect, since the emblem mounting tab isn't always absolutely flush with the surounding tank :laugh:

In that previous pic you can see where I stripped the paint from the edge of the seam. I will be spreading some body filler or spot putty on there tomorrow and sand it down so the seam is smooth for molding. The rest of the body work is pretty much rapped up

Those of you that are experienced will notice a no-no, and that is to put body filler over paint (around the filler neck). Always remove paint from an area to recieve body filler. I didn't in this case because I did not think the filler would need to stay in the area around the filler neck, and it didn't matter. I using this as a master plug; this isn't a prep to paint so errors like this can be tolerated. I still need a right angle drill to remove the front tank mounts, and I'm still working on smoothing out the bottom. So far, so good!

Get four 3mm nuts to use for your tank emblems. After you are done molding the tank, you can drill some shallow holes and epoxy the nuts in place to use the original emblem mount screws. Just make sure to check that everything fits right before you glue them in place.

Actually Josh, the plan is to mold the mounts into the tank during the layup. I need to find a die to cut those tiny theads on some turned down 1/4" stock, and thread them into to the tank when I layup the mold. Then I'll use those same pins to hold the new mounts in the exact same location. It's clean and simple..... in theory :laugh: