Following discussions at North West meetings, I offer my personal experiences on Petseal removal etc.
In the early part of the year I noticed slight lifting of the 30 year old Petseal lining in the filler mouth of the tank on my 1929 Flyer, as it succumbed to the 5% bioethanol in most petrols. Wanting to postpone any significant work until Winter, I siphoned off the alcohol containing fuel and started using Total petrol as recommended in a previous posting, but the damage was already done, causing major carburation problems by June. With hindsight a fine gauze on the petrol tap, or in-line filter might have given me the postponement I was looking for.
REMOVAL of the OLD PETSEAL
Bearing in mind all the safety issues about gloves, goggles, good ventilation, as well as protecting the exterior paint work with cling film, then polythene & duct tape, I used 300 ml of Nitromors liquid (Yellow can), shaken with a hand full of gravel every few hours over a 24 hour period, letting it rest in various orientations. The tank was then washed out with 2 or 3 tankfulls of warm water plus a few mls of washing up liquid, then several of plain water. I used a small LED torch to peer inside to confirm the Petseal had all gone.
For recoating I bought a ‘Motorcycle Fuel Tank Repair Kit – POR15’ (now approx. £35) from Frost Auto Restorers (sometimes available on Ebay), which starts with ‘Marine Clean’ solution, then ‘Metal Ready’ solution to prepare the metal surface. Safety issues still apply.
The tank must then be completely dried out before recoating with the liquid ‘POR15’, which then needs 4 days to cure before use.
The fuel filler on my vintage Flyer has a screw on cap, so is really easy to seal by cutting a full circle of gasket material for the cap, which will completely seal the tank including obstructing the cap air breather. Tanks with other cap types will need a bit more ingenuity.
Plumbers merchants stock blanking plugs for the petrol outlets. Long bodied ones will keep the threaded holes free of coating. PTFE tape will help.
Nitromors in green or brown cans are viscous products for brushing on, and will not swirl around the tank interior.
Wickes offer a “safer” (non-methylene chloride) product, but again this is a gel, so not suitable. I tried dilution with iso propyl alcohol (or industrial meths) to make it more fluid, but was not satisfied with the results.
Nitromors is not miscible with water and will float on top of the water, preventing it from maintaining contact with the metal, when not shaken.
Avoid heating the sealed tank whilst Nitromors is inside it as this will pressurise the tank, so any tank perforations will leak Nitromors under the cling film/polythene and damage the exterior paint.
The Petseal came away mainly as coarse granules in the process.
‘Marine Clean’ may not have been necessary after my Petseal stripping process, but I chose to follow the instructions to the letter.
As the tank was well & truly free of petrol by the time drying out prior to recoating was required, I found that threading a vacuum cleaner pipe into the recesses of the tank and switching on the vac. for a minute every hour was useful. Sitting the tank on a windoow ledge in the hot sun (if we get any) and rotating regularly will speed up the drying – but do not be too impatient, it must be perfectly dry.
My tank needed no patching.
POR15 gives a bright aluminium silver looking finish.
The process not only coated the inside of the petrol tank, but also the exterior of the oil tank within, except for the oil tank base, but that is not a petrol contact part.
I am happy with the results, albeit only a few months down the road, of using various brands of unleaded petrol, assumedly with 5% bioethanol.
Incidentally, I understand that Total fuels are no longer guaranteed to be alcohol free. Murco fuels may still be alcohol free, at the present time.
Other comments appear in the posting “Petrol Tank” by Dicky which commenced 18 Jan 2011.