Petrol Tank

[florence]

Very shocked to find that after 46 year's service the petrol tank has developed a rust hole behind the Honda badge.  I thought I would get the bike going after a winter rest, and given that we can't go anywhere seemed like a good way to spend time.  Does anyone know where I might find a reasonable/useable replacement that won't cost silly money, assuming people are allowed to sell such things at the moment with this crisis and all that.  I have thought about patching but always found this to be unreliable in the long term.

I suspect that alcohol in the fuel might be to blame, does tend to attract water.

[Erny]

This back luck. if that hole is just tiny maybe proper liner applicaton can fill that hope safe?

[Johnwebley]

Can you solder a small patch



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[Moorey]

Solder it. if its done properly you will have no problems. Tanks were been soldered long before they were been welded. 

[florence]

Soldering, now that is a good idea.  I've soldered land rover radiators but that is easy because they are made of brass.  Will I need a special flux being steel or will Bakers no.3 be OK?

[royhall]

I wouldn't solder it the ethanol likes to eat solder. Will only hold for a short while.  I can say from bitter experience it needs to be brazed. Trigger will probably back me up on that.

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[florence]

is that modern low lead solder that is the problem?  I have some old lead/tin solder, will that be OK?

If not what about epoxy resin?

[Bryanj]

If ethanol attacks fibreglass tanks i dont hold up much hope for epoxy. Not sure if i still got the tank from my burnt No 36, if so you may have to take an "essential" drive to Gloucester!!

[Moorey]

Its now going up to 5 years since i soldered the bottom of my tank and it is still good so are others i have done. It may well be possible to do a repair at the back of the badge without destroying the paintwork not so with brazing or silver solder. Soldering will certainly be your cheapest option. I use a coroline paste flux as it is easier to keep it exactly where you want it to work. The bakers 3 been a liquid acid could possibly damage your paint if not very careful but as a flux would be ok. I have soldered stainless using Bakers 3 and many think you cant solder stainless steel.
I think Ethanol to be far more problematic with rubber parts rather than the metals. After all Ethanol also corrodes brass and copper, but hay ho.

Remember cleanliness is next to godliness as far as soldering is concerned. If its not clean it will fail.

[Moorey]

is that modern low lead solder that is the problem?  I have some old lead/tin solder, will that be OK?

If not what about epoxy resin?

The lead free solder is more prone to cracking where vibrations come into play. Old solder is fine also.

[florence]

I'll give it a try, nothing to lose after all and the paint is not a problem, it is just Smoothrite black, hand painted.  Thanks for all the advice, I will drin it and give it a go tomorrow.  What's the best way to get rid of the petrol as I will be using a blow torch?  Just empty and leave it in the sun with the lid open?

[Bryanj]

Steam clean the inside and a good air flow through it

[Moorey]

I wouldn't use a blowtorch at all. A big copper iron. A soldering iron is quite capable of igniting petrol vapour never mind a blowtorch.

[florence]

I don't have a steam cleaner so will fill up with fairy liquid and hot water, give it a good wash then leave it in the sun for a couple of days, then see if I can get it to light! 

[matthewmosse]

Hot soapy water and then braze weld worked with my landrover diesel tank. It was originally soldered at the joints and that was easy to re flood with solder when I found out about the soldered joints the hard way. Definitely have both cap, and tap off the tank, probably worth flushing with hot soapy water a few times, I'd not be that worried about drying it out before soldering, the heat from soldering should dry the relevant area, and the evaporating water from the rest might help reduce any fume build up from heat and fuel residue. I think there was a good 3 inches of water still in my landrover tank when I braze welded some pitting on it. It stood up to 6 or 7 years use before the weeping of fuel alerted me to the pitting probably having got deeper probably elsewhere - plenty of time to have sourced a spare tank, which as a bonus came half full of fuel.