BritBike Forum logo
BritBike Sponsor BritBike Sponsor BritBike Sponsor
BritBike Sponsor

BritBike Sponsor

BritBike Sponsor
BritBike Sponsor BritBike Sponsor BritBike Sponsor
JWood Auctions JRC Engineering dealers JWood Auctions
Home | Sponsors, Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons, "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Member Spotlight
Hector Catre
Hector Catre
Toronto/Ontario/Canada
Posts: 106
Joined: August 2008
Show All Member Profiles 
Shout Box
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
Who's Online Now
34 registered members (998John), 193 guests, and 392 spiders.
Key: Admin, Global Mod, Mod
Newest Members
Andrew Fallo, Zack Banks, 1966g10, Tacet, Joe Bruney
10416 Registered Users
Top Posters(30 Days)
btour 84
Rohan 76
reverb 75
Triless 75
Stuart 70
Popular Topics(Views)
708,169 mail-order LSR
Forum Statistics
Forums34
Topics68,287
Posts664,831
Members10,416
Most Online3,995
Feb 13th, 2017
Like BritBike.com on Facebook

Previous Thread
Next Thread
Print Thread
Rate Thread
Glassfibre tanks - an unnecessary question #720775
01/01/18 6:49 pm
01/01/18 6:49 pm
Joined: Dec 2017
Posts: 209
England
F
ferretjuggler Offline OP
BritBike Forum member
ferretjuggler  Offline OP
BritBike Forum member
F

Joined: Dec 2017
Posts: 209
England
I'm just asking this out of idle curiosity.
I've never had to deal with a glassfibre petrol tank or oil tank (yet) but I may soon have to, as a unit single project has come onto my radar recently.

Now I've studied engineering and manufacturing technology to a point, so I've got a very good idea of how most components are produced.
I can understand the virtues of making something like sidepanels out of GRP, using female moulds.
A little labour intensive (using hand lay up) but very low tooling costs compared to injection mouldings.

But how do you make something like a fuel tank out of GRP ?
Are they moulded in separate sections and then bonded together ?
Or is some special technique used to produce the hollow moulding in one piece ?
I'm genuinely clueless
But I think that if I know how something is made in the first place, I might gain some insight into how to do repairs etc.

Support your #1 BSA Forum and our favorite sponsors

Check out BSA on e-bay: BSA Parts in UK, BSA Motorcycles in UK, BSA Parts in North America, BSA Motorcycles in North America

 
Re: Glassfibre tanks - an unnecessary question [Re: ferretjuggler] #720809
01/01/18 10:07 pm
01/01/18 10:07 pm
Joined: Mar 2011
Posts: 215
netherlands
L
lemans Offline
BritBike Forum member
lemans  Offline
BritBike Forum member
L

Joined: Mar 2011
Posts: 215
netherlands
the GRP-tanks are made in two parts. top half and bottom half, then bonded together.
and that's where mine split after using modern fuel and leaving it in the tank for a rather long time.

so I bonded it back together again and use the modern fuel, only when the bike is not used for 2 days or more I'll drain the tank.

regrads A

Re: Glassfibre tanks - an unnecessary question [Re: ferretjuggler] #720828
01/02/18 2:06 am
01/02/18 2:06 am
Joined: Dec 2017
Posts: 209
England
F
ferretjuggler Offline OP
BritBike Forum member
ferretjuggler  Offline OP
BritBike Forum member
F

Joined: Dec 2017
Posts: 209
England
Thanks for that.
I did a bit of Googling myself and learned that you're supposed to carve out a replica of the shape you want from Green Floral Foam.
Yes they do sell it on eBay but only in house brick sized lumps its going to take about £20-30 worth all glued together for a decent size tank.
After that it's a case of making a pair of female moulds around it.
Exactly how to split the moulds and how to join together the two tank halves seems to be shrouded in mystery.
Loads of issues with resin types that are fuel resistant and ethanol is the villain of the piece as usual.
I see that BSA soon returned to steel tanks after a couple of years of GRP.
I wonder if this was due to practical issues or done on the advice of the lawyers ?

It has occurred to me that it might be a useful way to get a spare export tank for my OIF A65.
I've got a rough original that will filler and paint up OK.
But I've always been told that these tanks have a terrible reputation for splitting.
I really wouldn't want to pay £300 for an Indian made tank just to find out that it's true.

Re: Glassfibre tanks - an unnecessary question [Re: ferretjuggler] #720848
01/02/18 1:35 pm
01/02/18 1:35 pm
Joined: Oct 2009
Posts: 496
new jersey usa
P
pushrod tom Offline
BritBike Forum member
pushrod tom  Offline
BritBike Forum member
P

Joined: Oct 2009
Posts: 496
new jersey usa
One of my pals recently made a f/g tank using special epoxy. Lots of work. Beautiful result. started to leak soon after putting fuel in it. Do not waste your time/money going down this path. Or, use only non ethanol fuel. PRT

Re: Glassfibre tanks - an unnecessary question [Re: ferretjuggler] #720849
01/02/18 1:43 pm
01/02/18 1:43 pm
Joined: Oct 2006
Posts: 2,873
Elburn, Ill. USA
I
Irish Swede Offline
BritBike Forum member
Irish Swede  Offline
BritBike Forum member
I

Joined: Oct 2006
Posts: 2,873
Elburn, Ill. USA
"Or use only non ethanol fuel."

OR. use an aluminum or steel fuel tank.

Re: Glassfibre tanks - an unnecessary question [Re: ferretjuggler] #720856
01/02/18 3:08 pm
01/02/18 3:08 pm
Joined: Aug 2005
Posts: 1,499
melbourne florida
B
bodine031 Offline
BritBike Forum member
bodine031  Offline
BritBike Forum member
B

Joined: Aug 2005
Posts: 1,499
melbourne florida
My B-25 Starfire ethanol melted tank was a 2 piece. Like the others go with steel or alloy

Re: Glassfibre tanks - an unnecessary question [Re: ferretjuggler] #720864
01/02/18 3:59 pm
01/02/18 3:59 pm
Joined: Dec 2017
Posts: 209
England
F
ferretjuggler Offline OP
BritBike Forum member
ferretjuggler  Offline OP
BritBike Forum member
F

Joined: Dec 2017
Posts: 209
England
Thanks for all the good advice.
A quick browse on eBay shows a nice selection of steel Starfire tanks (presumably made in India)
TBH I'd rather go for an original BSA item and spend a little more time on refurbishment.
At least the supply of cheap Indian tanks keeps prices down.
I suppose that if you want the correct '67 - '69 oil tank you just have to have GRP and like it.

Re: Glassfibre tanks - an unnecessary question [Re: ferretjuggler] #720870
01/02/18 4:44 pm
01/02/18 4:44 pm
Joined: Dec 2004
Posts: 9,549
Scotland
kommando Offline
BritBike Forum member
kommando  Offline
BritBike Forum member

Joined: Dec 2004
Posts: 9,549
Scotland
Steel oil tanks were definitely on the 69's, they had a fibreglass cover over the steel oil tank, so that would give the look of the earlier FB oil tank.

Re: Glassfibre tanks - an unnecessary question [Re: Irish Swede] #720881
01/02/18 5:43 pm
01/02/18 5:43 pm
Joined: May 2013
Posts: 4,999
Rotherham - S. Yorkshire
Allan Gill Offline

BritBike Forum member
Allan Gill  Offline

BritBike Forum member

Joined: May 2013
Posts: 4,999
Rotherham - S. Yorkshire
Originally Posted by Irish Swede
"Or use only non ethanol fuel."

OR. use an aluminum or steel fuel tank.



Just given me an idea, I'll need a fuel tank for my A50 racer (when it eventually happens) Option being that I could metal bash a tank of sorts and make a fibreglass cover, didnt the hurricanes have something like this, or was that the aftermarket version?


beerchug
Re: Glassfibre tanks - an unnecessary question [Re: pushrod tom] #720891
01/02/18 7:12 pm
01/02/18 7:12 pm
Joined: Sep 2013
Posts: 1,731
Pacific northwest
Q
quinten Online confused
BritBike Forum member
quinten  Online Confused
BritBike Forum member
Q

Joined: Sep 2013
Posts: 1,731
Pacific northwest

Originally Posted by pushrod tom
One of my pals recently made a f/g tank using special epoxy. Lots of work. Beautiful result. started to leak soon after putting fuel in it. Do not waste your time/money going down this path. Or, use only non ethanol fuel. PRT

did he hand lay-up or use a vacuum bag ?

Re: Glassfibre tanks - an unnecessary question [Re: ferretjuggler] #720894
01/02/18 7:37 pm
01/02/18 7:37 pm
Joined: Aug 2015
Posts: 1,266
Bolton Lancs UK
A
Andy Higham Offline
BritBike Forum member
Andy Higham  Offline
BritBike Forum member
A

Joined: Aug 2015
Posts: 1,266
Bolton Lancs UK
Fibreglass is the least suitable material for a fuel tank. The resins dry out over time and the tank becomes porous, Fibreglass is prone to weakening through vibration. Just look at any fibreglass car a few years old, the bodywork is full of cracks.
A fibreglass tank is easily damaged in a minor accident spilling fuel

I bought a Greeves challenger a few years ago, it had not been used for many years (long before ethanol in petrol), The tank was mushy and leaky underneath


BSA B31 500cc "Stargazer"
Greeves 200cc "Blue Meanie"
Greeves 350
Greeves 360 Challenger
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500cc sprint/LSR bike "Deofol"
Jawa 500cc "Llareggub"
2003 Aprilia RSV Mille "Lo Stregone"
'35 OK Supreme
'36 OK Supreme
Re: Glassfibre tanks - an unnecessary question [Re: ferretjuggler] #720895
01/02/18 7:57 pm
01/02/18 7:57 pm
Joined: Dec 2017
Posts: 209
England
F
ferretjuggler Offline OP
BritBike Forum member
ferretjuggler  Offline OP
BritBike Forum member
F

Joined: Dec 2017
Posts: 209
England
Obviously buying a used GRP tank for my unit single project would be a false economy unless it was virtually free.
Far better to save up for a good steel one instead.

However I would still consider a GRP tank as a stop gap measure.
I've seen rusted steel tanks with rust perforation patched up with tank sealant (masking tape across the holes until the resin cures) then given a very expensive paint job.

A fools paradise.
I think that I'd put my faith in a GRP copy rather than do something idiotic like that.

Re: Glassfibre tanks - an unnecessary question [Re: ferretjuggler] #720897
01/02/18 9:36 pm
01/02/18 9:36 pm
Joined: Oct 2009
Posts: 496
new jersey usa
P
pushrod tom Offline
BritBike Forum member
pushrod tom  Offline
BritBike Forum member
P

Joined: Oct 2009
Posts: 496
new jersey usa
Q, It was hand laid. They loved the shape and are making an aluminum fuel cell and will use the Fg as a cover.

Re: Glassfibre tanks - an unnecessary question [Re: pushrod tom] #720908
01/03/18 12:12 am
01/03/18 12:12 am
Joined: Sep 2013
Posts: 1,731
Pacific northwest
Q
quinten Online confused
BritBike Forum member
quinten  Online Confused
BritBike Forum member
Q

Joined: Sep 2013
Posts: 1,731
Pacific northwest
Originally Posted by pushrod tom
Q, It was hand laid. They loved the shape and are making an aluminum fuel cell and will use the Fg as a cover.

they may have have had better results with one of the various vacuum bagging techniques.
The process sucks the air out, during the wet phase, for a dense void free product.
... Or may not... At least not on the first try.

There are some Excellence composite tanks being made.
[Linked Image]
But at a price that may make a custom aluminum tank price reasonable.
I think you have to have a serious weight savings Reason
Or a Passion ...to go the composite route

Re: Glassfibre tanks - an unnecessary question [Re: ferretjuggler] #720920
01/03/18 2:55 am
01/03/18 2:55 am
Joined: Nov 2012
Posts: 680
Isle of Wight, UK
K
koan58 Offline
BritBike Forum member
koan58  Offline
BritBike Forum member
K

Joined: Nov 2012
Posts: 680
Isle of Wight, UK
If you have an original (no matter what state it is in) make a mold of it. You only need any bath, tub, box, whatever, full of plaster.

Re: Glassfibre tanks - an unnecessary question [Re: ferretjuggler] #721022
01/04/18 4:15 am
01/04/18 4:15 am
Joined: Mar 2011
Posts: 215
netherlands
L
lemans Offline
BritBike Forum member
lemans  Offline
BritBike Forum member
L

Joined: Mar 2011
Posts: 215
netherlands
ducati endurance racer

https://www.flickr.com/photos/scurvyknaves/8393434173

love these grp tank, with fuel gauge


Last edited by lemans; 01/04/18 8:02 am.
Re: Glassfibre tanks - an unnecessary question [Re: koan58] #721095
01/04/18 8:17 pm
01/04/18 8:17 pm
Joined: Dec 2017
Posts: 209
England
F
ferretjuggler Offline OP
BritBike Forum member
ferretjuggler  Offline OP
BritBike Forum member
F

Joined: Dec 2017
Posts: 209
England
Originally Posted by koan58
If you have an original (no matter what state it is in) make a mold of it. You only need any bath, tub, box, whatever, full of plaster.

I'm going to do that with my OIF export tank before I paint it.
Judging by the prices being demanded for some very dodgy used ones I believe that it might be prudent.

Come to think about it, I don't see why I shouldn't make a set of female GRP moulds direct from a prepared metal tank ?

Re: Glassfibre tanks - an unnecessary question [Re: ferretjuggler] #721163
01/05/18 3:50 pm
01/05/18 3:50 pm
Joined: Dec 2017
Posts: 16
Toledo, Ohio
C
Charlie Hawkins Offline
BritBike Forum member
Charlie Hawkins  Offline
BritBike Forum member
C

Joined: Dec 2017
Posts: 16
Toledo, Ohio
Originally Posted by ferretjuggler
Thanks for that.
I did a bit of Googling myself and learned that you're supposed to carve out a replica of the shape you want from Green Floral Foam.
Yes they do sell it on eBay but only in house brick sized lumps its going to take about £20-30 worth all glued together for a decent size tank.
After that it's a case of making a pair of female moulds around it.
Exactly how to split the moulds and how to join together the two tank halves seems to be shrouded in mystery.
Loads of issues with resin types that are fuel resistant and ethanol is the villain of the piece as usual.
I see that BSA soon returned to steel tanks after a couple of years of GRP.
I wonder if this was due to practical issues or done on the advice of the lawyers ?

It has occurred to me that it might be a useful way to get a spare export tank for my OIF A65.
I've got a rough original that will filler and paint up OK.
But I've always been told that these tanks have a terrible reputation for splitting.
I really wouldn't want to pay £300 for an Indian made tank just to find out that it's true.


Once you lay up the fiberglass matte and resin over your green floral foam, and roll out the bubbles, there is a whole tank, one piece with your filler cap also bonded in during this process. Then once you have the petcock areas reinforced with a steel plate, also embedded into the fiberglass bottom, you can let the whole thing cure. Once that is done, you dissolve the green foam with a solvent and pour out mess and rinse well. I can't remember which solvent, but you can use alcohol, or some type of solvent that leaves no residue, test it on the left over foam. Your tank is now one piece, and no worry about bonding top and bottom together. shape, sand, and give it a protective coat in the tank! Gel coat the inside and outside, prime and paint...
Charlie


Moderated by  Allan Gill, Jon W. Whitley 


Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Powered by UBB.threads™ PHP Forum Software 7.6.2