Forum

[Chris Tindal]

Hi, does anyone know and recommend where I can get a broken cylinder barrel fin welded back on in the Yorkshire area?. Despite very carefully tapping off a stuborn barrel with a piece of wood at the very base of the lower fin, it went 'ping' right at the last moment before the barrel came off!

Also anyone that can braze a leaky petrol tank?

Cheers

[Les H]

Hi Chris. Sorry to hear that you've broken a fin, I hate that on an engine. I recently renovated a twin cylinder with broken fins on both barrel and head (not guilty). I had the broken pieces and was advised to have them brazed on but found someone who said they could be welded on, which sounded better. However, I was not overly impressed by the finished job and wish I had them brazed which I'm sure would have been neater and sufficiently strong. As your broken fin is at the bottom of the barrel where the temperature usually does not rise to any extremes, I would be tempted to use a resin like JB WELD. Cast iron is very grainy so the surfaces of the broken edges are absolutely ideal for any resin to key to. I would also imagine the broken edge is crescent shaped rather than a straight line? If it is, there is a natural bolstering or support to the broken piece. JB weld is extremely strong and if you also left a very slight extra cover smeared over the line both sides of the crack to give support, I reckon it would last for ever and once painted would be invisible. If you use the resin make sure you don't buy the "Instant or fast" version as they are slower. You will need to have a piece of wood to support it for around 12 hours for it to set and it hardens for many days after that. Worth considering I think as it's a simple job to do. As far as the tank, soldering is often used if the metal has thinned. Don't know any services up your way though.

[Les H]

DoH!...just spotted a mistake..I said: "If you use the resin make sure you don't buy the "Instant or fast" version as they are slower"....that sounds very funny though and made me laugh....I meant to say: "If you use the resin make sure you don't buy the "Instant or fast" version as they are WEAKER"......

[JOHNNY SINGLES]

Hi Chris, personaly I would go down the welded route, It is fairly easy to do on both alloy and iron barrels. I have welded a number of fins on both types, a good welder would have no problem.

[simon]

I've brazed them successfully a number of times. You need unity flux for cast iron and to finish a cost of VHT black hides the brass seem.

[Alan R]

Hi CHRIS---I had exactly the same last Winter -----the very last gentle "tap" to free the barrel and "PING"---away goes part of the top fin !! Reverting to early, Anglo-Saxon lingo I said}----OH DEAR, and }---THAT'S A PITY. The cat was deeply and emotionally moved by all this and promptly ran away !!!!........My local engineering firm (Bradbury Engineering...http://www.classicandvintageengines.co.uk/...) have DAVE, an ace lad with the welding stick. With my approval he did a series of long, "Spot" welds. Over 1,000 miles of riding so far and all is well. I had considered fitting some purpose-made rubber bungs between the fins to give extra support but this has not been needed. As regarding your fuel tank---if a naked flame is going to be used then the tank MUST be TOTALLY cleared of any petrol fumes at all. I've done this in the past by repeatedly filling/emptying with cold, fresh water---then filling the tank to the brim before commencing any work. I agree with LES H that soldering can be used----but you still have to consider that there may be some residual fumes present so that rather limits the type of heat source to do the soldering with.ie an iron will not be hot enough with the water present. TIG Brazing might be useful here.

[Chris Tindal]

Thanks for all the input, I have a think about JB weld or real weld. Someone has welded a fin on the cylinder head in the past and has done such a good job you can barely notice it.

[Les H]

The cylinder head is alloy though Chris, the barrel cast iron...just something to bear in mind.

[Chris Tindal]

Yes thanks for your post Les, much appreciated. After 54 years the barrel gets into the hands of a neaderthal (me!)

[grunda 12]

mr tindal why don,t you ask knowledgeable club members DOH!!SPEAK TO PAUL NICELY he may weld it for you!!