First time using Fertan tank sealer & rust converter - 1957 Douglas Dragonfly / ep137

[@jonneville2287]

I recently de-rusted an old DKW fuel tank on a Honda CB 750. Step 1- Two tablespoons of caustic soda, fill tank with cold tap water, leave overnight. Step 2 - Pour out soda, fill tank with cleaning vinegar, let sit for several days. Step 3 - Pour out at least half the vinegar, add two handfuls of small nuts, bolts, screws, etc., and shake well while tipping tank over and over, upside down, etc. Step 4 - Pour out vinegar and screws, rinse tank well with demineralised water. Step 5 - Heat tank with heat gun as soon as possible to avoid flash rust. Inspect with bright torch to make sure all water has evaporated. Step 6 - Add rust converter, about 200 mil, and tip tank in all directions to ensure even coating. Step 7 - Rinse tank with warm water and allow to dry. (the tank had no rust or converter residue by this stage, the metal was clean and bright). Step 8 - Add tank sealer and tip tank in all directions to coat evenly. The process took about two weeks, and cost about $60 AUD, but the tank is now clean, rust free, and sealed.

[@theworkshopuk]

Great tip - thanks for posting!

[@adelejones3746]

Nice one, just got a 1990 BMW R80 and it needs doing. I'll be using this stuff, it comes highly recommended and you confirm that

[@EnlightenedPatriot1]

Good info with this video. I have 2 Dragonflies, one I rebuilt and ran about 35 years ago, and one still all in bits, all parts painted/lined and ready to assemble - but sadly not by me. This classic biker is 75 next month, so all has to go but, if I (unlikely) or any buyer find the tank insides need treating (been garaged many years) this will be a good help, thanks. Like mine, it is missing the green stick-on, pimpled knee pads. Black were available and later, I think, the green ones I never got. I even have tank panels tracings (for my tank sprayer/hand-liner guy) from the original on clear plastic film somewhere that I hope someone can make use of one day. By coincidence, having just watched your video about welding up the splitting Earls forks, I happen to have a spare set, minus dampers. Fair surface rust in places but, with that filler shown being used, I hope they may be useful to someone in need who cannot source any better ones. I recall reading about that outfit (unless it is a copy) being built on the I.O.M by, I think, someone called Heatherington. There was also a 'DragonFour' special with another pair of cylinders/inverted crankcase placed on the top as a 700cc engine. Thanks for showing.

[@Bernard-l8j]

I have tapox kit at home i dont have an oven ti put the tank into i was wondering if i left the rust converter for longer would it be ok ,? How has the tank held up after three years ?

[@johnhickey1128]

How did this treatment hold up?

[@theworkshopuk]

Excellent!

[@bernardmccann1640]

Good video

[@theworkshopuk]

Thanks!

[@piperdoug428]

No open flame or cigarettes.......Ash quits

[@theworkshopuk]

Ha ha ha ha

[@johnirwin6087]

yep looks like u were paid bad vid and who the hell was the voice in the back ground bad

[@theworkshopuk]

It's hard to make a video like this without looking like it was paid for. But I can only promise you that it wasn't. And that's my voice (Stuart) behind the camera, thanks!