Bultaco footpeg replacement

Twin-shocker · 03-26-2012, 12:14 AM

The only sure way you will be able to ensure your tank is ok to use with modern fuels, is to section it and install a chemical resistance layer using novalac vinyl ester resin and surfacing tissue, then bond back together. None of the sealing products such as Caswell can be seen as anything other than a short term fix, as firstly they are very brittle when cured, and secondly it is very difficult to key the inside surfaces of a used tank properly, not least one which has contained 2T fuel over many years!

However you can greatly increase the chances of any of the sealing products working for longer, by making the effort to key the inside of the tank properly (carefully fixing the tank inside something which can revolve it at slowish speed, and putting a couple of handfuls of crushed glass inside works well). Also the addition of something to make the very brittle cured sealer a little more durable and less likely to crack is a very good idea, and if you add something like chopped glass fibre strands and mix in very well, this will certainly help.

There are industrial sealing materials such as polysulphides, which I would imagine would work perfectly as tank sealers due to them remaining flexible when fully cured, and in effect forming a chemically resistant skin inside the tank, but I guess profits are much higher selling repackaged (500% markup) epoxy laminating resins (such as Caswell), so dont think any of these will be cooming onto the home user market anytime soon!

Finally to have any chance of success at all with a sealer, you must be 100% certain that any fuel which has leached into the lay up of the tank itself is gone entirely before you try to seal it. Leaving outside for a week say if the weather is very hot will help with this, but if the tank has actually gone soft to any extent, then it wont be possible to seal it, and you will need to look for a replacement.

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03-26-2012, 12:14 AM	#15
Twin-shocker Studly Adventurer Joined: Jan 2012 Oddometer: 993	The only sure way you will be able to ensure your tank is ok to use with modern fuels, is to section it and install a chemical resistance layer using novalac vinyl ester resin and surfacing tissue, then bond back together. None of the sealing products such as Caswell can be seen as anything other than a short term fix, as firstly they are very brittle when cured, and secondly it is very difficult to key the inside surfaces of a used tank properly, not least one which has contained 2T fuel over many years! However you can greatly increase the chances of any of the sealing products working for longer, by making the effort to key the inside of the tank properly (carefully fixing the tank inside something which can revolve it at slowish speed, and putting a couple of handfuls of crushed glass inside works well). Also the addition of something to make the very brittle cured sealer a little more durable and less likely to crack is a very good idea, and if you add something like chopped glass fibre strands and mix in very well, this will certainly help. There are industrial sealing materials such as polysulphides, which I would imagine would work perfectly as tank sealers due to them remaining flexible when fully cured, and in effect forming a chemically resistant skin inside the tank, but I guess profits are much higher selling repackaged (500% markup) epoxy laminating resins (such as Caswell), so dont think any of these will be cooming onto the home user market anytime soon! Finally to have any chance of success at all with a sealer, you must be 100% certain that any fuel which has leached into the lay up of the tank itself is gone entirely before you try to seal it. Leaving outside for a week say if the weather is very hot will help with this, but if the tank has actually gone soft to any extent, then it wont be possible to seal it, and you will need to look for a replacement.