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Question on oxyacetylene aluminum welding and brazing
I know this isn’t metal shaping but I was wondering if it would be possible to weld or braze this with oxyacetylene. It’s an aluminum Vespa engine case.
I would like to build up the case with welding around the cylinder spigots so I can add/enlarge the transfer ports. A lot of Vespa tuners use JB weld if porting breaks through the case, often with good results if it is prepped properly. I would rather use metal. I don’t usually weld aluminum so I don’t have a TIG welder. Is this possible? EC119290-6258-4438-8CD7-03729A8EC512.jpg 4597953C-9C4B-4FB8-80BA-6C8E9905C25E.jpg Thank you for the help
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James Last edited by Steve Hamilton; 11-11-2021 at 09:09 PM. |
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It's an alloy, but I don't know the constituents. I'd caution against using a torch. One of my brothers had a Husqvarna, which had a case of either magnesium or a high enough magnesium content that the "welds" were quite spectacular. The weldor pretty much destroyed it, though that was electric welding. That may be why JB Weld is used?
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~Steven |
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It’s definitely aluminum, but I don’t know the specific alloy. It’s from the early 60’s and was successfully TIG welded recently. These cases are routinely TIG welded for port work and rotary pad repair. I was hoping to be able to do it myself, though getting set up for TIG isn’t worth the expense for me. JB weld or a similar type epoxy is actually recommended in factory manuals for rotary pad repairs. I just never liked the idea of using JB weld on an engine case. They are very sturdy cases. I recently split one with seized internals that looked like it had been a doorstop for a barn door for decades. I heat and beat the snot out of it as it owed me nothing. Lo and behold, it didn’t crack, no real corrosion of the aluminum inside, rotary pad was fine. It’s a keeper!
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James |
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It can be done with flux. But if you dont have a lot of experience with Oxy Aluminum welding I would suggest some of the lower temp fillers. They will probably work if epoxy is holding up for others.
Sorry I dont have any experience with them so cant tell you any brand names. If the case was magnesium you could weld it with Oxy also. In WWII they did not have TIG for Magnesium so used torch.
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Greg |
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Yes it's possible, I have welded aluminium engine blocks using oxy acetylene and preheat. But if you get it wrong you could melt the lot. I should practice on some scrap before even thinking about it.
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David Hamer |
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Quote:
Maybe better to just have it TIG welded. The gentleman who did the crack in the cooling vane did a nice job. Sometimes it’s better to hand it off and admit that you can’t do everything, though it’s worth trying out on something easier to replace than a 60’s engine case.7770CCDB-37D2-4478-9CE4-5A8CC91495EA.jpg Thanks for all the helpful replies.
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James Last edited by Steve Hamilton; 11-12-2021 at 05:02 PM. |
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It's do-able. You are right - the MAPP gas fixes are done with ALUMINUM SOLDER, low temp, soft, - but they do not admit it because they prolly don't know. Students of mine have learned and practiced enough to report their successes using O/A and aluminum welding on Castings .... auto tans cases, engines, saws, etc. etc. Lots of misinformation out there. But it is free info..... gotta love freebies. Vespa is what year?
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
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Hmmm,
I'm seeing one tig weld on the rim, right side. What goes in the rotted-out center - a machined plug? I think 4043 filler and Super Premium flux, and some .edu would get this done.
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
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Thanks! Vespa is a 62 VBB. The running engine is from a 65 Super. The rotted out plug is part of the old bearing seal for the crank. It was rusted to the crank. The main bearings are roller type and fit into a brass bushing in the case. Heat the case on a hot plate a little and it just drops right in.
I will check out the 4043 filler. The areas around the transfer ports are low compression/pressure.
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James |
#10
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Roller crank bearings = cool stuff.
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
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