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Engine basics => Engine set up tips => Topic started by: Brent Williams on November 07, 2020, 12:09:22 PM
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My brother and I are making ourselves a couple of headers for VF40-46's and are curious what methods and materials folks have used (successfully) to braze or weld the aluminum flange to the aluminum pipe and for it to withstand heat and vibration.
Aluminum material is 6061 for both the flange and the header pipe.
Brazing seems like the easiest way to get the two pieces joined and have a complete joint. 4047 filler material seems like a good choice.
I am interested to learn what has worked for this application.
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Thanks Lauri! Are you using MAPP gas or oxy-acetylene?
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My brother and I are making ourselves a couple of headers for VF40-46's and are curious what methods and materials folks have used (successfully) to braze or weld the aluminum flange to the aluminum pipe and for it to withstand heat and vibration.
Aluminum material is 6061 for both the flange and the header pipe.
Brazing seems like the easiest way to get the two pieces joined and have a complete joint. 4047 filler material seems like a good choice.
I am interested to learn what has worked for this application.
I haven't done it, but if I was going to, I would think that contacting Scott Dinger would be my first step. I don't know what he would charge but I know he has done a lot aluminum welding for modeling applications.
I have "successfully" used the "magic" eutectic rods for welding aluminum, but, it is extremely difficult and the end result was a complete mess. It stuck two pieces of aluminum together, that's about all I can say for it.
Brett
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I'm sure there is an US equivalent, but let me know if you need help with getting the Castolin. L
Castolin is easily available here.
Brett
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Lauri,
Is the flux you are using the Castolin 190-NHR https://www.castolin.com/product/190-nhr-brazing-flux
There are a several options in the Castolin 190 range of products. Can you specify which Castolin 190 material and what size you are using for your mufflers?
https://www.castolin.com/en-US/product/eutecrod-190
Castolin has some interesting flux core rods in the 190 series, 190cw / 192cw(higher silcon content).
I mentioned 4047 brazing material earlier. 4047 used with an appropriate flux looks like a possible good choice as well. https://www.brazing.com/products/Welding_alloys/alloy4047.1.aspx
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For actual header flanges and case repair, I've only ever tig welded. But, my experiences with the 4047 brazing has been pretty good. I've only used it on low stress, relatively thicker materials though. Where there was little chance to destroy it. Like Lauri said, the parts must be heated near melting point, making it a sensitive operation. Not that you'll blow a hole through, but you could make little pits and puddles. Just take your time and go for it!
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Im glad this thread opened up the last few years I've messed with the idea of brazing & soldering Aluminum . I will need a lot of practice because most my stuff is a mess also. I'll probably come back with the setup I have tried.
John L.
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Like Lauri said, the parts must be heated near melting point, making it a sensitive operation.
Exactly, this is always the issue with any of the aluminum brazing/welding I have attempted - you are always a few seconds away from going over the top.
Brett
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Exactly, this is always the issue with any of the aluminum brazing/welding I have attempted - you are always a few seconds away from going over the top.
Brett
Many years ago an old craftsman told me: "the right time is when the aluminum turns pale pink". Once I think I had a hallucination, I saw the pink and the solder was perfect. Unfortunately it was the only time, I have never succeeded before or after.
Massimo
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Exactly, this is always the issue with any of the aluminum brazing/welding I have attempted - you are always a few seconds away from going over the top.
Brett
Especially when your little butane torch is below half full and you get those inconsistent pops! I guess if you practice frequently, you'd get good. But how often could one practice?
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https://www.alumiweld.com/
Works for what we need, just remember you have to heat the heavier material first. Of course you need a jig to keep everything aligned during the process. I am looking into having a run of these done over seas but need interest in quantity as minimums would be 50 to 100 pieces. If I was still traveling into the region I could find a small mom and pop that would do these but I no longer travel to south east Asia any longer for business.
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I inquired with the product manager at Castolin USA-MG Welding. He confirmed that the Castolin 190 rods are the same material as 4047 filler material. Castolin 190-FP is the USA designation for the flux.
He mentioned that their alternate brand line, Messer Weld MG-410 rods are the same product as the Castolin 190. The appropriate MG brand flux is MG-410.
http://www.messerwelding.com/Product%20PDFs/by%20part/MG%20410.pdf
Castolin and MG can be obtained through AirGas, Praxair and other larger welding suppliers.
These are professional, high grade aluminum brazing products, not gimmicky low temp magic rods. 4047 is very commonly used in TIG, MIG and was originally developed as a higher silicon content aluminum brazing material.
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Looks like you have 2 good options, Brent. That's nice.
Now, where can you get the thin walled tubing used in headers? I could use some.. L
McMaster-Carr has tubing with a wall thickness of .028, sounds about right to me.
Brett
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Looks like you have 2 good options, Brent. That's nice.
Now, where can you get the thin walled tubing used in headers? I could use some.. L
https://www.mscdirect.com/browse/tn/Raw-Materials/Aluminum-Round-Tubes?navid=4287924315+4288236647&searchterm=aluminum+tube#navid=4287924315+4288246872&searchterm=aluminum+tube
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Fill the tube tightly with fine silica sand and cap the ends. Make a jig out of hard wood to the radius you need. Heat gently and evenly as you bend around the jig. Old school method, but holds up.
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My brother Curtis is a great machinist. He made these header parts. Next step is to purchase the braze materials and fire up the torch. (braze and flux are rather expensive!)
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Obviously not everyone has the same tooling, but that's the point I get to, and then tig weld it. To me, it's easier to control the bead welding. But, if you aren't set up... then brazing its wildly cheaper. Lol
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Pardon my ignorance, but does TIG have similar capillarity of molten filler as with brazing?
Brent's joint is just a butt joint so it propably doesn't make a difference.
For brazing, that needs a good jig to keep pieces still.
I am far from an expert at TIG welding, but the arc is merely a heat source with a passivating gas (argon), you use a filler rod just like anything else, and it works a lot like brazing. The only real distinction is that you intentionally melt the substrate, where in brazing or soldering you only melt the filler.
Brett
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Yep, that's how I understant it too. But in brazing the filler kind of follows the heat. It wicks through seams when you apply heat to the other side. I never do butt joints, that's why I ask. L
There is such a thing as TIG brazing, just like brazing with a TIG torch instead of an oxy-acetylene torch use it as heat, use a dissimilar material with a lower melting point as a filler. I don't know how well it flows into joints, I have never attempted such a thing.
I think your aluminum braze is a fine solution, and plenty good enough.
Brett
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If youve a welding outfit nearby , which arnt turd , theyed do it in a few minutes while at it on something similar . Near the coast , a marine outfit , or a bull bar shop ( Mnfr ) .
Dunno how the alloy brazee'd go. With the heat & vibration . Almost as bad as a Triumph. They recon . S?P H^^
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I spent a few days googling and calling flux manufacturers. Castolin, Messer, Vulcan, Continental, Superior, Forney, ect. Many of the fluxes out there are over $100 and some were $150 for 6-8oz. Too expensive to consider, for me. I found Tin Man Technologies in my searching and purchased the "Super Premium" aluminum flux from them. It was reasonably priced and had good reviews for torch brazing. TMT described its product as having been a preferred flux used by aerospace companies, ie. Boeing, Douglas, ect. Neat company as well. They did a replica of the Hughes H1 racer aircraft among many other cool projects.
https://www.tinmantech.com/products/welding/welding-flux/aluminum-welding-flux.php
I purchased 1LB of ER4047 .047" as well. Under $20 on eBay. As mentioned above, the Castolin rod that Lauri used is 4047, so this should hopefully suffice.
So, it will be fun experimenting with this stuff before I make attempts on the real projects.
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Oh yes, I realize mixing products can be a gamble. I enjoy the hunt. Based upon your great results, we know that Castolin works extremely well. Hopefully my experiments will also work satisfactorily. If these alternative products prove to be lacking, I will know conclusively that there are superior products that should have been paired for optimal results. Before the end of the month I should have all the materials to begin testing.