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SV Carbon Tank project for Zoran

lizard said:
hmm, maybe I could fab a larger capacity gas tank for my Monster for sport-touring purposes. An extra gallon would make a big difference.

hmm...
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As Yoda might say, "There is no 'maybe', there is no 'hmm...'. Only 'do'..."

Of course you could make a monsterous Monster tank. That's half the purpose of this thread - to encourage others to give this a try. The hardest part for you would be modifying your plug to make it the size/shape you want. Which is the same thing I have to do here - I'm just going the other way in that this tank will be narrowed and capacity is not an issue.
But with regard to your Monster tank, I say go for it.
 
Just print this thread when it's done and you'll have a hell of an instruction booklet to make a tank with :thumbup
 
Plug coming to life!

The clothes pins worked just fine and the waxed popsicle sticks came right off, as planned. (I love it when things go the way you hoped...)
I pulled the top part from the mold this afternoon, did a quick, rough trim and...Presto! One plug top piece!

2202632-pc270001.jpg
 
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Here's the initial fitting of the underside. I still have to trim it to fit better then bond it into the top.
Essentially, we now have a fiberglass replica of the dented tank with which we started.
Once the top and underside are bonded together, I think I'm going to fill the tank with expanding foam so that when I start to narrow the tank and reshape the top/underside junction, I'll have something solid behind the 'glass.
I hope to get the underside bonded and the foam poured in the next day or two.
Once the plug is shaped and prepped, I start the entire process you've seen so far over again in order to make the production mold. This time, however, 'Neatness Counts'.

Total time invested to date: ~15 hours.

2202642-pc270002.jpg
 
:thumbup For your MV/SV tank, I'm guessing the plug is where you blend the top from the MV with the SV bottom?
 
question. if the fiberglass mold is made by placing fiberglass on top of the existing tank doesnt that make the fiberglass one slightly larger, by about the thickness of the fiberglass?
 
kurbycar32 said:
question. if the fiberglass mold is made by placing fiberglass on top of the existing tank doesnt that make the fiberglass one slightly larger, by about the thickness of the fiberglass?
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Read back a few steps and you can answer the question. You make a mold, then a plug. Then the rest of the steps will be up soon :p
 
drizz said:
:thumbup For your MV/SV tank, I'm guessing the plug is where you blend the top from the MV with the SV bottom?
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Short answer is yes. And thanks for the well timed question, Drizz. It gives me the excuse to talk about the top/underside interface that I keep mentioning as having to modify on this plug.
Below is a pic of the underside of my SV/MV plug next to our stock SV underside. (Geez, can you believe how well an SV underside can be made to fit the top of an MV tank...? What are the odds?!?!)
You see that nice big flat area running around the outside of the bottom of the SV/MV plug? That is the 'interface' I have to develop for this stock tank plug.
When I lay up the underside mold using this plug, I lay it up such that this flat surface is part of the underside mold. Then, when I lay up the top mold on this plug, I wrap the lay up around and again use this flat surface as part of the top mold. When I make the production parts, both parts have this flat section in common. These flat surfaces get bonded together to join the top and underside. It does make the tank 'taller' by the dimension of one of those flat surfaces, but that has virtually zero impact one way or another.
Also, you may notice that I modified the shape of the underside - I eliminated a lot of the details as they're just more work during lay up. I'll likely do the same on this project.
BTW, those holes are where, after making the production underside mold, I mounted a bracket to the plug to allow me to hold it in a vise while doing the layup of each side of the final production mold. Makes things much easier. You'll get pics of the fixturing as I reach that stage.

2202758-pc270006.jpg
 
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kurbycar32 said:
question. if the fiberglass mold is made by placing fiberglass on top of the existing tank doesnt that make the fiberglass one slightly larger, by about the thickness of the fiberglass?
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You are correct; the MOLD is thicker by the thickness of the fiberglass. - but the INSIDE of the mold is the exact dimension of the outside of the tank. When we use that mold to make a part, we're building 'in' from that exact outside dimension. When done, the part taken from the mold is the exact dimension of the tank from which the mold was taken.
Simple, no?
 
Question: Why make a glass plug to modify in the first place, if you're going to fill it with foam? Why not just make a foam plug from your original mold, modify it, then seal it and finish for your production mold?

Great thread!
 
GetaGripGreg said:
Question: Why make a glass plug to modify in the first place, if you're going to fill it with foam? Why not just make a foam plug from your original mold, modify it, then seal it and finish for your production mold?

Great thread!
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Thanks for the kind words. I suppose I could make a foam plug, I just haven't ever gone that way. I'll learn a bunch about working with expanded foam here in the next few days and may very well come away with an updated method.
Having never worked with foam, I've got no idea what the 'right out of the mold' foam surface is like. If it's totally smooth and essentially 'done', I'm all for it - that's what the 'glass is like. I can get a surface that's perfect with no additional work. If foam can do that too, sign me up!

Thanks for jumping in and making a suggestion. That's what I hope happens in this thread.
As I've said all along, I don't profess to be expert at this - I just do what I know and try to learn new techniques along the way.
 
HAving had quite a bit of experience with foam, I can tell you that no, it wont have a smooth finished surface after it cures. The denser foams will be closer, but still not quite right.

To get a smooth surface out of foam you're going to have to coat it and sand it.

Back when we'd make styling bucks at AAC, the general technique was to make a rough shape with foam, poke a bunch of holes in it, then lay down styling clay. Paint the clay, and you've got a great surface for making a mold.

Alternately, instead of coating the foam plug, you could make a cast copy from resin, and finish the surface in the (much easier to work) resin. Of course, for a plug the size of a gas tank, you'd have some serious issues with molds warping, etc.

I think your hybrid glass/foam plug idea is a good one. Just be aware that you're going to have to bondo the foam and do some serious sanding to get it as smooth as composite gel coat. :)
 
tygaboy said:
You are correct; the MOLD is thicker by the thickness of the fiberglass. - but the INSIDE of the mold is the exact dimension of the outside of the tank. When we use that mold to make a part, we're building 'in' from that exact outside dimension. When done, the part taken from the mold is the exact dimension of the tank from which the mold was taken.
Simple, no?
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yup makes perfect sense, thanks:teeth
 
i have been wanting to do this with my practicly priceless 1987 ex250 body panels so i would have a set of spares in the event of an accident. thanks to your thread that idea will soon become a reality! should be alot easier since the general shape is flat i will be able to do it in one peice
 
Yeah, that seat I showed was shaped completely with expanding foam. The foam is easy to shape, but it does require a surface coat of something.

Bondo- the cheapest, but a major PITA. It just never comes out right the first time, so you end up spending TONS of time sanding/reshaping bondo. And if you sand through the bondo, you have to start over because you can't sand both the hard bondo and soft foam at the same time.

Putty- we also used a bit of some other crap, I don't remember the name but it was like a 1 part air-curing bondo. Much easier to sand, came in toothpaste-like tubes. If you want, I can get the name in a few days when I get into my shop.

UV Smooth Prime - This stuff seems to work very well. I can't say for sure, because I havn't actually pulled a part from it yet. I have two plugs literally ready to go using it though, and it seems GREAT. You brush/spray it on, its nice and thick so it sort of self levels and then you sand it down smooth, which is easy. The second mold I did I learned to spray the stuff, it works 10x better and requires much less sanding. It is kind of soft, so I recomend coating it with some sort of sealant before use. I used epoxy based black rattlecan paint. We'll see how well it works, but I think it will be good. The downside to this stuff is that it's EXPENSIVE. 1 can should be plenty for the tank I think, assuming you don't waste a ton.

If you find something better, please let me know. I use hotwire or hand shaped foam for the majority of my molds so I'm always looking for a better method.
 
tygaboy said:
Thanks for the kind words. I suppose I could make a foam plug, I just haven't ever gone that way. I'll learn a bunch about working with expanded foam here in the next few days and may very well come away with an updated method.
Click to expand...

Two-part urethane foam is great to work with, IMO. I've used it for a variety of things, mainly racing seats (cars and karts). As long as you mix it right, you end up with a consistent texture that shapes easily and quickly.

Watching your steps so far, I think I would have just made a splash of the tank base, then built a box on top of it to pour the foam into, sized to allow you to shape the tank without any additional filler.

Urethane foam can be coated with cheap polyester resin, and finished with a skim of bondo.

Looking forward to seeing your home vaccum bag setup. I just might get around to making a new tank myself.

:thumbup
 
I want to start playing around with this stuff, too, with a little bit of trial and error. Where do you pick up the cloth (both fiberglass and CF) and the rest of the chemicals?
 
HellFyre said:
I want to start playing around with this stuff, too, with a little bit of trial and error. Where do you pick up the cloth (both fiberglass and CF) and the rest of the chemicals?
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Check out Tap Plastics in Dublin.
 
Will do! Thanks, Dan.

BTW, I saw you at the IMS show, but there was a huge crowd around you and I couldn't get close to say hi. Next time, please leave my name with the bouncers/entourage. :)
 
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