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Message started by uigiroux on 04/16/14 at 16:11:20

Title: Building a fiberglass gas tank.
Post by uigiroux on 04/16/14 at 16:11:20

I've been planning a lot for modifying my rear seat and was going to build a fiberglass seat, I think I easily am capable of making a seat that looks great, but I've heard that gas tanks are a whole different thing given the gas factor and air tight, etc... but I've gone through many threads on fiberglass gas tanks and I really think I can pull it off. My main questions would be what are the exact resins/hardeners, types of fiberglass (or even a thin layer of carbon fiber) and others things necessary to make this work. I know I need the inside with a protective coating against the gas of course, but I guess I'm just asking, outside of a normal fiberglass build, what do I have to do extra or different?

Title: Re: Building a fiberglass gas tank.
Post by blueknight on 04/16/14 at 17:00:29

Give the folks over at http://www.uscomposites.com/ a call I use them for all my carbon fiber needs and they are very knowledgable. Also their prices are competitive for high quality products

Title: Re: Building a fiberglass gas tank.
Post by Kris01 on 04/16/14 at 17:15:30

I'm a complete noob with fiberglass but a fiberglass gas tank sounds dangerous to me. Do they actually exist?

Title: Re: Building a fiberglass gas tank.
Post by oldNslow on 04/16/14 at 17:26:50

6C554E541716270 wrote:

I'm a complete noob with fiberglass but a fiberglass gas tank sounds dangerous to me. Do they actually exist?

Used to be pretty common on dirt dikes back in the day.

Title: Re: Building a fiberglass gas tank.
Post by Kris01 on 04/16/14 at 17:30:27

That sounds even MORE dangerous! One rock with an attitude and you've got a crack and a fire. :D

Title: Re: Building a fiberglass gas tank.
Post by blueknight on 04/16/14 at 18:01:48

I have taken some pretty nasty rocks to my Arai helmet and it has suffered nothing more then a minor paint chip. When you think about it the gas tank would be constructed in the same manner, multiple layers of fiberglass, carbon fiber in opposing directions, and kevlar. When built correctly it would be darn near bulletproof

Title: Re: Building a fiberglass gas tank.
Post by uigiroux on 04/16/14 at 18:07:05

That seems to be a large portion of the aftermarket new cafe racer style tanks I find. For instance Dime City Cycles has probably more fiberglass tanks then metal ones.

I mentioned using a thin layer of carbon fiber also. Wouldn't that also make the tank more solid or safer? Like sandwich it in between the fiberglass?

I really want to make this work I just can't pay $400-$500 for a new tank.... And that's for a fiberglass one. I'll see the same tank made of aluminum or something for $700-$1,100!?

Title: Re: Building a fiberglass gas tank.
Post by v-pilot on 04/16/14 at 18:09:54

Yes there are a multitude of fiberglass and eve carbon fiber tanks out there but they all have a disclaimer stating for racing use only

Title: Re: Building a fiberglass gas tank.
Post by uigiroux on 04/16/14 at 18:22:20

7F24796065667D090 wrote:

Yes there are a multitude of fiberglass and eve carbon fiber tanks out there but they all have a disclaimer stating for racing use only

Title: Re: Building a fiberglass gas tank.
Post by oldNslow on 04/16/14 at 19:09:38

4D164B5257544F3B0 wrote:

Yes there are a multitude of fiberglass and eve carbon fiber tanks out there but they all have a disclaimer stating for racing use only

Of course if we're gonna worry about the fine print everybodys gonna have to put the stock pipes back on their Harleys ;D

Title: Re: Building a fiberglass gas tank.
Post by ToesNose on 04/16/14 at 19:26:12

Yea some BSA tanks were fiberglass from the factory in the 60's as well as a bunch of Ducati street bikes had fiberglass tanks in the 70's early 80's, along with a lot of after market café style tanks. From what I understand based on my knowledge of boat fiberglass tanks it's the ethanol that actually eats away the resin. The hardest part is sealing the tank lining properly at any egress/ingress points, once any gas/ethanol was given the opportunity to leach in behind the lining it would wreak havoc on the actual tank from the inside out.

Expand your search of knowledge on fiberglass tank building to the marine community as well, most tanks are plastic or aluminum now on boats, but there are plenty of older boats with fiberglass tanks which people are maintaining still ;)

Title: Re: Building a fiberglass gas tank.
Post by WD on 04/16/14 at 23:35:10

Had a fiberglass tank on one of my 1964 Triumph T120C projects. Unless you line it with ethanol proof Red Kote, modern fuel will eat the thing pretty quickly. That said, Red Kote is not that expensive, so, go for it. Florist foam makes a decent shaping buck.

Go read the bodywork section of www.dotheton.com for glass tips. Those guys crank out some insane kitchen table made parts...

Title: Re: Building a fiberglass gas tank.
Post by justin_o_guy2 on 04/17/14 at 08:20:05

I wont address the "It cant leak" part of it, but just the finishing of the surface to prep for paint. If you dont have experience in working fiberglass & sanding it, then before you spend the time & $$$ building a tank, I'd suggest you get some fiberglass & resin & make something, a box, heck, maybe just glass a cardboard box up. YOu can slice a coupla places on one side & glass hinges onto it, finish the cut, drill & bolt the hinges, make a little parts box or something,, But lay glass on thick enough to make it solid enough to sand on & learn a little about how glass acts. Keeping fresh paper on your sanding tools is important with that stuff,,
I guess something more or less the shape of the tank would teach ya more..Flat surfaces are the hardest, because any distortion will show up with a light across it, Compound curves are challenging too. & the tank has plenty of those,
Finding a high spot is part of it,, knowing which way to move the sandpaper to kill it is crucial. Sand Off of the high spots & onto the low spot youre blending to,Dont lay a sanding block on top of a high spot & scrub back & forth, Push the block off the high spot & do that in every direction that it needs blended. Once youve got it all "made" & out of the forms, remember how thick the walls are. Dont go sandin it too thin,, There is a "Bondo"( NEVER buy Bondo products made BY Bondo) type product specifically for glass,Youll need to practice mixing & getting the hardener right,,When you have "Bondo" mixed differently they are harder or softer & sand differently, BEGGING to create wavy places. Mixing the hardener for the glass,, dont want it too "Hot",, I think it makes it more likely to crack,,Like epoxy, you can determine the Set time by how much hardener you use,,Too little = a MESS,, So, Buy enough glass & Stuff to play around & learn, play with the filler
You can use a paint paddle to Spank the sandpaper & unclog it, but once its tired, ditch it,, youll be pushing too hard to smoothly blend.
Early on,you can get away with using tired paper,, but once it is getting close, you gotta keep sharp paper on it,,

I Never liked working glass,, especially patching on old glass. Fixing a "Vette" is a Huge pain,,

Title: Re: Building a fiberglass gas tank.
Post by uigiroux on 04/17/14 at 09:11:31

That's exactly what I plan on doing. I have a thread going to start by making an underbelly air scoop. I'm going to give that a try, and for all my projects I'll be using female molds so the outside will be the smooth side and then just work on smoothing out the inside, or if possible have both female molds for both sides and sandwich them in so when I pop it out both sides will be smooth. Is that possible?

Title: Re: Building a fiberglass gas tank.
Post by v-pilot on 04/17/14 at 18:58:09

3A2628263D203A374F0 wrote:

[quote author=7F24796065667D090 link=1397689880/0#7 date=1397696994]Yes there are a multitude of fiberglass and eve carbon fiber tanks out there but they all have a disclaimer stating for racing use only

I've rarely seen that, in fact I just went to Dime City Cycles website and looked at their fiberglass tanks and not one has that disclaimer. They are made specifically for a custom build for street bikes. I don't even see one of them that specifies it's for racing applications only.
[/quote]

If you check out Airtech Slipstreaming they say that about all their tanks. They make some really nice stuff. I'm building a Dicati 250 as a Paul Smart Imola tribute bike and what I've gotten from them is nice

Title: Re: Building a fiberglass gas tank.
Post by Gyrobob on 04/18/14 at 20:33:49

You must use ethanol-resistant resins in your handcrafted gas tank, and then coat it inside with one of the ethanol-proof liners.

AOC F764 resin is a new one sold at http://expresscomposites.com/resins.html

Another one is R&G Epoxy-c, and I don't know where you'd buy that.

Title: Re: Building a fiberglass gas tank.
Post by justin_o_guy2 on 04/19/14 at 13:52:03

706C626C776A707D050 wrote:

Sure,, look at how they do boats, gel coat,,slick as glass,, hmm,, no pun intended.. anyway, you make the mold like ya want, smooth as silk, use a release agent, lay what ya want in & finish up with the ethanol resistant stuff. The inside you can still make "smooth", but the mold determines if its finished or not,, Done right, you could do gel coat & pop a finished product out,How youd hide the mold lines, I dunno,, I guess if ya did a left & rite side you could hide the joint under some kinda stripe,,

Title: Re: Building a fiberglass gas tank.
Post by uigiroux on 04/19/14 at 14:19:29

I guess it just depends on how easily it pops out, but the ends I guess would just be the one part I would be trimming up and have to make look like the rest finished product. For a gas tank, I got this idea from someone else's build, but have an 2 inch indent all around the track where I plan on cutting and splitting the tank out and then once all the parts are in the tank I'd combine by adding strips of fiberglass and resin to fill it in and then have another female mold ready that I could put it in which is smooth and even. Or do that but then once it's all evened out do a whole nether female mold, similar to the other idea just with one more layer over the whole tank.

Title: Re: Building a fiberglass gas tank.
Post by gizzo on 04/19/14 at 15:45:19

Good luck with the project. It's a big undertaking to make your own tank. Hope you'll keep us updated on your work (I'm a RC model flyer and we love a good build log on the RC forum). I guess you've already learned that making a moulded part from scratch is a lot of work, and not cheap, either. I build my own moulds and airframes but it's only because I wanted to build something unique and completely mine. If I just want a nice moulded plane (especially a competitive one), I'll do a few overtime shifts and buy one from a manufacturer. If you use polyester resin, it still could end up being in the ballpark price wise but until you do a moulding project you have no idea how long it takes and how much effort is involved. But like I said, good luck, you'll learn a lot. And it's a great feeling cracking open the mould and seeing your part come out, for sure. IMO, YMMV, FWIT etc.
Cheers
simon

Title: Re: Building a fiberglass gas tank.
Post by uigiroux on 04/19/14 at 15:48:00

7C666260615F6E7D7B7D666B686A0F0 wrote:

Thanks, I'm looking forward to that feeling! Just working on getting the money and parts at the moment but I will keep track of it with lots of photos.

Title: Re: Building a fiberglass gas tank.
Post by uigiroux on 04/24/14 at 12:47:36

Before I do my tank, I'm going to start by making an under engine air scoop for practice. I have my design all planned out and the lower mounting worked out, but I'm trying to figure the best way to fasten the top part to the frame. I figure I could make a bracket for the frame and connect them with a thick strip of metal and find a way to fasten the air scoop to that, but what I think would work best and be the easiest is while I'm applying the fiberglass to the female mold, fit in some straps, either metal or some sort of fabric that would cinch tightly to the frame. I am leaning towards this idea as it would be a much quicker, and easier method of keeping it attached. I'm just stuck on whether to use a metal, rubber, or fabric fastener. Once it's layered in the mold, to even out along with protecting the paint on the frame I'll use a one sided strip of neoprene foam and stick that to the finished product along where it hugs the frame, and I could just thin it where the fastener is so it's completely even. Any thoughts on how well this might work, or ideas of how to better fasten it? I saw this pic and I want to create something like this, just the front part, not going all down the bottom.

Title: Re: Building a fiberglass gas tank.
Post by ToesNose on 05/04/14 at 08:54:55

Hey Uig here's a link for a step by step beginners fiberglass tank build I came across, thought you might like to check it out ;)

Title: Re: Building a fiberglass gas tank.
Post by justin_o_guy2 on 05/04/14 at 09:39:59

WOW! That was very informative Toes!

Title: Re: Building a fiberglass gas tank.
Post by uigiroux on 05/04/14 at 10:48:56

Lol yeah, forgot to post the link...

Title: Re: Building a fiberglass gas tank.
Post by Sej on 05/04/14 at 15:03:46

I was thinking of making a fiberglass tank as well, but came to the conclusion that it would simply be too much work for me to do anytime soon and so instead picked up a GS450e tank to clean up and use.

Not sure if this is the same link as ToesNose tried to post, but here is the most helpful link I found in my research:
http://crecca.wordpress.com/category/i-composite-gas-tank-fabrication/

And for female mold making, this is a great link:
http://www.dotheton.com/forum/index.php?topic=26144.0

As far as fuel safe epoxies, look into novolac resins (epoxy or vinylester), which should hold up fine (they're used for sealing fuel reservoirs at gas stations). The only downside being that they are fairly expensive and not too easy to get in small amounts.

Title: Re: Building a fiberglass gas tank.
Post by uigiroux on 05/04/14 at 16:56:40

4C7A757E716A6C1F0 wrote:

Sej, thanks for those links! I have seen similar versions of the tank building, but the female mold thread was very inspiring. I have been thinking about making my female molds in a similar fashion, split down the center, and this really gives me a lot to think about. Really glad you linked that. One thing that is bothering me is in that, the guy used a Pro Autocad and CNC machine to make his mold perfectly symmetrical. I don't have access to that and though I am using my skills with math, and the use of a protractor (I've had to make a ton of maps as part of my Geology Degree and have gotten very good at making 3-D geometric shapes. In this case though, as much as I can do to ensure the sides and edges and corners are symmetrical, the parts that get curvy I'm having to eye as best as I can. Granted this is a small piece, but I've stressed before I'm rather a bit of a perfectionist, and I'm curious if there is a way for me to (cheaply) produce a mold on the computer and get it CNC'd somewhere. I have been getting a good amount of people expressing interest in wanting one If I can make it look professional and so on. That's cool and all, though my first priority is getting my bike fitted with this part, and should others like it and want one, well that's just a bonus. Anyone know how I could get access or where I'd go to have my mold copied to a perfectly symmetrical design and fabricated so I could make my female molds.

On a side note. I realized that there is essentially 3-5 variations of the mold I plan on making.

1ST: stock bike with no modification

2Nd: bike like mine, rear shocks are stock, but the front has a 2 inch lowering causing the bottom of the design to be a bit increased in degrees to keep the air scoop level with the ground.

3RD: bikes with rear sets (such as RYCA builds), which basically would make installation a while lot easier as the stock position of the pegs and rear brake and got controls would be gone and would give me much easier access to the area.

4TH: bikes with both rear sets and different rear shocks and front such height, really not a huge issue, would just need to adjust my mold to be level given the dimensions, though this could end up being more costly for some of they have some unusual dimensions, basically making me have to build a one time only mold/part.

5TH: This would be basically a custom requested build specifically for someone. The difference between this and the last being that people add I've pointed out have done crazy creative things with our bike, and some massive modifications to the frame and other such things, so this would be an even further custom job if not requiring a completely different design altogether. I think though I would mainly focus on 1-3 on this list and if really compelled, possibly 4. I'd really need some free time to just completely try and fabricate a piece for someone else's totally moded bike, and in all honesty, if there capable of doing all the things the have so far, chances are they'd not need me to create something they probably easily could themselves.

Ok well I am off to study for my last final, Calc 3 so gonna try and focus on that. Thanks again for the links, very helpful!

Cheers

Uriah

Title: Re: Building a fiberglass gas tank.
Post by ToesNose on 05/10/14 at 18:12:47

ROFL sorry man!!! :o

Here it is.....
http://www.hondabrat.com/2013/01/diy-fuel-tank-5-big-posts-in-1-giant.html

Title: Re: Building a fiberglass gas tank.
Post by paulmarshall on 05/10/14 at 18:30:45

This guy made a fiberglass tank for a Honda Sabre which he made the tank from foam. Then put the fibreglass over the foam and used a solvent to evaporate the foam inside leaving a fiberglass shell.
Well worth the watch.
https://www.youtube.com/watch?v=-bHv8hUwE5k&list=PL8SLiVEQM9KNBccNx4p2W9W5ggKPFy30w

Title: Re: Building a fiberglass gas tank.
Post by justin_o_guy2 on 05/11/14 at 08:49:29

Well, DUUUHHHH!!! How obvious is that? DANGITTT! I just hate missing such obvious answers..

Title: Re: Building a fiberglass gas tank.
Post by old_rider on 05/12/14 at 00:42:12

Durn burn it Paul.... I went to that link at noon on sunday and its now 3am Monday morning... I could not stop watching that guys build!
He is a very clever videographer and a likeable fella..... I have subscribed to his site and will keep an eye on his next build.

Title: Re: Building a fiberglass gas tank.
Post by paulmarshall on 05/12/14 at 00:54:06

Yes mate he is very talented. I have learnt a lot from watching his videos.
Since watching his videos I have pulled my Savage off the road and have been playing with fibreglass myself. Its a great product to play with, you can make all sorts of stuff.
I will post picks of my new project soon :)

Title: Re: Building a fiberglass gas tank.
Post by jcstokes on 05/12/14 at 01:24:00

We await with interest.

Title: Re: Building a fiberglass gas tank.
Post by LANCER on 05/12/14 at 05:20:47

Yep, having fun watching the video's; some good tips in there.

Title: Re: Building a fiberglass gas tank.
Post by justin_o_guy2 on 05/12/14 at 07:35:58

Okay,, now Im all mad at you guys.. Yea,, I messed up, I WENT there,, now Im stuck,,
Coupla things Ive noticed.

I see why he works alone, no one can stay outta his way. He must drink those 5 hour energy drinks or sumpthin..

YOu guys notice the bench in the BG? 3 tubs or small barrels, trash cans maybe? Laid down & stuck in,, Man,, pretty good materiel storage,

ETA

Too long on the GO button w/o letting the starter cool.
Id use ether to get it fired.
& He has an Extinguisher handy,, I set 2 out any time Im using the torch or welding, or doing anything like what he is doing,, I set them up away from the work area, just a little ways, along the line of retreat.
I know human nature, see a fire, back up, so, set extinguishers up along any line of retreat from the work area,

Again, ETA

Did you see the GACK in the carbs? Wow..

Title: Re: Building a fiberglass gas tank.
Post by paulmarshall on 05/12/14 at 17:18:14

You Sir are very observant. I am going to watch them again. :)

46595F5845427343734B59551E2C0 wrote:

Title: Re: Building a fiberglass gas tank.
Post by justin_o_guy2 on 05/12/14 at 17:46:19

When Im watching a movie I look away from the main scenes very often.. I look for details,, Ive been "looking away" from the main stuff for decades. Thats how I catch the details,,

Title: Re: Building a fiberglass gas tank.
Post by WD on 05/12/14 at 23:41:32

FYI, any REAL boat supply shop is going to have gel coat kits and fuel safe resins... don't buy the generic hardware store or big box chain junk.

Gel coat kits: http://www.westmarine.com/gelcoat-repair-kits

Glass and resin: http://www.westmarine.com/resins-fiberglass

That's just one source for DIY hull and tank repair supplies, there are dozens of others.