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higgy wrote:alumalloy works like solder but is for aluminium parts. All you need is a butane or propane torch. Normal JB weld won't hold up to ethanol but Devcon of the proper blend will and so will alumalloy. In the mean time I just fired off an email to one of my Maserati guys bought a carb from me a while back and I seem to remember he was replacing one that had other issues so he may have a good top for you

http://www.youtube.com/watch?v=TZ5sD9hQTyw

Higgy, thanks for the information. I have a butane torch and I would love to try this repair. However, I would rather have one that has not been broken. Thank you for taking the time to try and find me a new top. Just let me know when you find out. That would be great if your friend had one thanks for the help.
PS. Where can I get some alumalloy? I am going to give this a try I think it looks fun
Interesting JWilliam,"I recommend creating a Zinc powder from a Lumiweld rod and coat the fracture surfaces with it. Got a lot of cavitation within the parent metal so a Zinc powder will fill nicely. Then accurately and gently jigging the pieces together, heat the break area until the Zinc powder melts and joins." I would be interested to know more about this process. How do you create a zinc powder from the lumiweld? Thanks for all the help.

[quote="JWilliam"]You can make very fine 'welds' with Alumalloy / Lumiweld etc. It is a Zinc alloy and has a lower melting point than Aluminium. The only drawback being when the working temperature is reached the Aluminium will be soft as it is now near to its own melting point. What this means is you cannot clamp the Aluminium with any force since this will push the Aluminium out of shape. That looks do-able, I'd be tempted to have a go. I recommend creating a Zinc powder from a Lumiweld rod and coat the fracture surfaces with it. Got a lot of cavitation within the parent metal so a Zinc powder will fill nicely. Then accurately and gently jigging the pieces together, heat the break area until the Zinc powder melts and joins. Don't use a plumbers blow-torch but a butane micro / pencil torch. Its scrap otherwise so what have you got to lose (apart from $500)? The picture here shows the join of two pieces of Aluminium by a single stroke of Alumalloy rod along the weld site. Not the method you should try at first with your repair but what it shows is that very small and intricate welds can be made

Interesting JWilliam, I would be interested in knowing more about this process how do you create a zinc powder from lumiweld? I have never worked with this type of material before. Thanks bender

Sorry for the delay, its the time zones. Anyway, to make a zinc powder you have to do it the hard way, secure the rod in a vice (they are about 4mm dia), file an end down and collect the powder. You need more than a pinch. The rods are quite bulky and trying make a pass over such a delicate repair will push it out of alignment. I'm at a loss to think of another way, if the powder really doesn't work then a basic melt onto a wall will have to be tried. Don't 'clean up' the edges of the fracture with a file or abrasive at all, you need them for accurate realignment. To remove the JB Weld, burn it off and scrape away the carbon. Place the powder along the fracture, put the piece onto it and assuming it is secure, apply the heat, Soon as the zinc melts kill the heat and leave for an hour. As for jigging the break into place - try a few paperclips - that the Aluminium softens is a huge problem, if you used crocodile clips they would bite into it once hot! The smaller break with its end gap looks like a challenge too but if you are successful with the bigger break it shouldn't be so daunting.

JWilliam wrote:Sorry for the delay, its the time zones. Anyway, to make a zinc powder you have to do it the hard way, secure the rod in a vice (they are about 4mm dia), file an end down and collect the powder. You need more than a pinch. The rods are quite bulky and trying make a pass over such a delicate repair will push it out of alignment. I'm at a loss to think of another way, if the powder really doesn't work then a basic melt onto a wall will have to be tried. Don't 'clean up' the edges of the fracture with a file or abrasive at all, you need them for accurate realignment. To remove the JB Weld, burn it off and scrape away the carbon. Place the powder along the fracture, put the piece onto it and assuming it is secure, apply the heat, Soon as the zinc melts kill the heat and leave for an hour. As for jigging the break into place - try a few paperclips - that the Aluminium softens is a huge problem, if you used crocodile clips they would bite into it once hot! The smaller break with its end gap looks like a challenge too but if you are successful with the bigger break it shouldn't be so daunting.

Thank you for the information. These are really small pieces, but I am going to try this process when I have time. I am still going to try to find a new top plate for my carburetor so if anyone reaches has one I would be extremely grateful for the opportunity to obtain it. I'm not completely sold that this will work I think it will be hard to do without getting alignment.

Another product that might help is 'Weld putty'. The professionals joke about it but here it could be of use, if one side was packed out with the putty to hold the piece and the other side alloyed. The other property of Alumalloy is that it flows when hot, so to braze a wall it has to be flat to aid pooling. You also get a stainless steel brush with the rods for final cleaning, but that is the least of your problems.

This guy was selling top covers cheap on ebay recently,he had 5 or 6 at the time,try contacting him,they were very cheap $50-60 australian dollars ! J.

http://www.ebay.com.au/usr/continental_spares

jayh wrote:This guy was selling top covers cheap on ebay recently,he had 5 or 6 at the time,try contacting him,they were very cheap $50-60 australian dollars ! J.

http://www.ebay.com.au/usr/continental_spares

Thanks I appreciate the help I have sent him a message and I'm waiting to hear his reply

so to braze a wall it has to be flat to aid pooling

actually it is quite easily held in place with tin cans cut up and used as forms very much like concrete

I forgot to mention that there are two types of top cover (different amount of bolt holes),be carefull if you do find one that the number of holes matches yours.He is also selling the plastic weber floats,so I assumed
that the top cover also matched the paso weber.This may not be correct,so check. J.