Norton Fiberglass Tank Expansion

mschmitz57 · Apr 8, 2015

I have been thinking about using aluminum pieces on the inside epoxied in to hold it in place, than fill the exterior with epoxy resin fiberglass.
My plan is to now cut the tank in half vertically and widen it by at least 2"-3". It will have to be sort of pie shaped so I can keep the back tank mount area pretty much the same, maybe 1/2" wider. Than when that's done I will cut it again vertically and raise the top half of the tank up about 1".

Used fiberglass Roadster tanks are cheap as chips. I'd buy another donor tank and cut it up and use the sections as fillers to expand your tank horizontally and vertically. That way you have the correct shape already in the new filler piece. And you would be grafting a finished surface onto the tank which requires less filler afterwards. If you have access to a band saw you could slice both tanks precisely and end-up with minimal gaps to bridge and join with fiberglass mat. Use some cardboard to make templates of the sections and wedges you want then just transfer them to the donor and slice away. When I repair fiberglass I use clear packing tape on the exterior gel-coat surface to hold things in place, then I wet the reverse side and apply the mat, and wet the mat. The resin usually leaks through the mat and fills in behind the tape. After the resin has cured I remove the tape and I have a nice smooth finished surface that requires minimal filler.

Just my $.02

Cheesy · Apr 8, 2015

mschmitz57 said:
I have been thinking about using aluminum pieces on the inside epoxied in to hold it in place, than fill the exterior with epoxy resin fiberglass.
My plan is to now cut the tank in half vertically and widen it by at least 2"-3". It will have to be sort of pie shaped so I can keep the back tank mount area pretty much the same, maybe 1/2" wider. Than when that's done I will cut it again vertically and raise the top half of the tank up about 1".

Click to expand...

Used fiberglass Roadster tanks are cheap as chips. I'd buy another donor tank and cut it up and use the sections as fillers to expand your tank horizontally and vertically. That way you have the correct shape already in the new filler piece. And you would be grafting a finished surface onto the tank which requires less filler afterwards. If you have access to a band saw you could slice both tanks precisely and end-up with minimal gaps to bridge and join with fiberglass mat. Use some cardboard to make templates of the sections and wedges you want then just transfer them to the donor and slice away. When I repair fiberglass I use clear packing tape on the exterior gel-coat surface to hold things in place, then I wet the reverse side and apply the mat, and wet the mat. The resin usually leaks through the mat and fills in behind the tape. After the resin has cured I remove the tape and I have a nice smooth finished surface that requires minimal filler.

Just my $.02

For a tank I would want at least a 12:1 scarf and then tape it with woven cloth. You have to be very careful with chopped mat as it usually has the wrong binder and sizing for use with epoxy, which leads to my second poiint, you have to make sure that the resin will have a sufficently strong secondary bond with the original polyester, epoxy will but polyester will not.

Hobot · Apr 8, 2015

OH yeah JBW cold weld has saved my buddy Hi Rider tank and my IS fb tank permanently a long time and booze proof to boot. I'd epoxy straps of thinnish drilled alu strap across the gap for the real strength with some in seam to ooze smoothly under the exterior tape back up and masked pretty close to minimize finishing.
Corvette body fixers like JBW if ya can stand how snotty kid level it is.
http://knowhow.napaonline.com/fantastic ... ic-bonder/

RennieK · Apr 8, 2015

Are you going to install baffling inside to cut down on the movement of fuel? Also some way to strengthen the front mounting fixtures as they often spin on fiberglass tanks. Lastly if you ever considered using clip-ons you may require dents along the front of your wider tank to accommodate them. It sounds like it wouldn't be too much more work as you're adding an expansion strip in the general area.

Hobot · Apr 8, 2015

Good point about baffling slosh of extra gasoline when half full but not really and issue unless wildly tossing on or off road. Also might add a couple plates of mild steel plate so maybe magnet tank bag would stick.

snortonNorton · Apr 9, 2015

Finally got around to cutting tank. All as planned so far.

2.5" gap at front and 1/2" gap at back.

Before I re-fiberglass it I will check for triple tree clearance.

snortonNorton · Apr 10, 2015

Lesson learned. I should have left the front lip on the tunnel. The back one had to come off. To get the front curve to follow the contour of the tank I had to pull it back about 1.5" as you can see in the next photo.

I am OK with that. I was planning on stretching the tank back towards the seat at least a 1/2" but now it is going to be at least an inch. The early Commandos always had a bit of a gap there and the knobs for the rubber straps were always visible. The seat mount can always be moved back a bit. I am planning on getting a Corbin seat made, so they can match it to the extra width as well.

You can see in this picture how much I have to bring back the mounting knobs to line up with the tank.

lcrken · Apr 10, 2015

Looking good , Steve. I'm following this with interest. I recently picked up a glass roadster tank with the intention of either modifying it or using it to make a buck for a later attempt at an aluminum tank, but it was in such good condition that I haven't had the heart to start butchering it. I won't get to it until after the rally in July, and by then I'll probably benefit from the results of your experiment. Thanks for posting it.

Ken

Cheesy · Apr 10, 2015

Thats looking better than I thought, might have to re think mine. I basically added 30mm over the top and down the back and the sides at the front back to the knee indents. At the front it blends into lines of the existing tank. I might have to try and sneak 1/2 hr to do a bit more on it so I can compare it to yours.

L.E.N. · Apr 10, 2015

Thanks for posting and for being the first to break the ice (glass). I'm watching this thread with keen interest and hoping it all works and never has a problem with the "booze" as hobot might say. I have a fiberglas tank with a failed KBS epoxy coating, shoulda' coulda' used Caswell if I'd known.
Lance

Hobot · Apr 10, 2015

Damit snort what a mood swinger to follow for uplifting punch line. There are intelligence tests based on ability to mentally slice up a shape to change it into something else. Of course you can cheat by adding pieces. But as universe is based on one part fundamental principles and all the rest pure random chance, you get a passing grade lucking out on Norton unsightly groin gap. Would it be that hard to picture arranging baffles so light shines through fake bullet or arrow holes? Maybe mount a self winding watch?

snortonNorton · Apr 10, 2015

Hey that's an idea. Glowing bullet holes at night time!
Here I just put a single fiberglass epoxy layer on to hold it all in place until I make the front pieces.

I had to reattach the front piece to get the contours correct. I have it all planned out for reassembly. I think?

snortonNorton · Apr 10, 2015

Cheesy said:
Thats looking better than I thought, might have to re think mine. I basically added 30mm over the top and down the back and the sides at the front back to the knee indents. At the front it blends into lines of the existing tank. I might have to try and sneak 1/2 hr to do a bit more on it so I can compare it to yours.

Is yours a roadster tank? Can you post a pick of what you have done?
Sounds interesting.

Bruce

snortonNorton · Apr 10, 2015

Hi Would you mind telling us what is the brand and formulation name of your resin. I have been researching on and off for years to find a fully appropriate gasoline AND alcohol epoxy, polyester, or vinylester resin that meets the necessary UL1316 approval. Several novolac formulas come close but "so far" none of the engineering application sheets confirm suitability for both. I am homing in on a formulation by a large US national chemical company. It so far is the ONLY UL certified gasoline AND alcohol proof formula that I have found. Now I will have to find somewhere I can buy just a 5 gallon pail to do trials.[/quote]

Sorry I missed your question earlier and I was just rereading some of them tonight. I have been researching epoxy resins for quite a while as well and haven't settled on one yet. But in the mean time I am using 3M panel bonding epoxy to tack everything in place and get all the contours lined up. I have a friend working in the Chemical industry who is looking into the product they use at work which has to be brushed on and is almost bullet proof.
When I find out I will put it on this blog.
Bruce

snortonNorton · Apr 10, 2015

I am looking at a couple different types of Epoxy Resins:
Vipel F085 High Temperature Epoxy Vinylester .
http://www.compositescanada.com/product ... vinylester

Master Bond High Performance Alcohol Resistant Epoxy Systems
http://www.masterbond.com/properties/al ... d-coatings

Also Hobot mentioned one earlier that has good reviews , Novalac Vinylester Epoxy Resin.

snortonNorton · Apr 11, 2015

Removed plastic sheild, Tank shell spread about 3/4" when tape removed but will be adjusted when fitting front pieces.

I am not going to split the tank horizontally now. I don't think I need to and it would be very difficult to raise the tunnel lips tops at both ends. Just by moving it back and out I think has given me a minimum 3 liters and probably 4. In the 2 spaces at the front of the tank I can just about put a one liter oil bottle in each hole.

Cheesy · Apr 11, 2015

Ill see if I can dig mine out of the garage and take some pictures of it.

Before you start glunig it back together you really need grind back the surfaces you are gluing with a coarse grinding/sanding disc or similar, the strength of your tank is entirely dependent on the mechanical bond between the epoxy and old polyester. You should also taper out the edges of the joins, I would be going 50mm-75mm on each side with maybe a mm or two of thickness left at the edges. All of the ground out material is replaced with cloth cut to appropriate widths to build up the thickness again. Im not sure the tape in your pictures above will be suitable for the job.

snortonNorton · Apr 11, 2015

Cheesy said:
Ill see if I can dig mine out of the garage and take some pictures of it.

Before you start glunig it back together you really need grind back the surfaces you are gluing with a coarse grinding/sanding disc or similar, the strength of your tank is entirely dependent on the mechanical bond between the epoxy and old polyester. You should also taper out the edges of the joins, I would be going 50mm-75mm on each side with maybe a mm or two of thickness left at the edges. All of the ground out material is replaced with cloth cut to appropriate widths to build up the thickness again. Im not sure the tape in your pictures above will be suitable for the job.

Yes I am going to sand back all edges in at least an inch or 2 before I permanently epoxy both side. For the whole top skin I was going to wrap it in one layer of carbon fiber when finished to tie all the pieces together, just a little extra insurance.

Snorton74 · Apr 11, 2015

Nice work! Your gas hole looks like it's about to slide off the right side of the tank though.?!

Why not center it? Just a thought...

snortonNorton · Apr 11, 2015

Nice job. Did you make that tank and is it Fiberglass or steel?

Norton Fiberglass Tank Expansion

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