I have searched this forum without much success. Chat on this subject has left me still asking "what about????" Since replacement of my flawed 3x2 intake is not possible, (no longer made) I need to discover a satisfactory repair. Welding on the sand cast aluminum is an option however, I worry about #1) difficulty of getting a suitable weld on the sand cast substrate and #2) warpage. My problem;...the wall between the intake chamber below the carburetor and the exhaust heat chamber on the manifold has developed a hole. I will need to cut away part of the bottom of the manifold to access the hole. Once I get there and clean everything up, I'm thinking, "why not High Temp Epoxy?" Googling that subject gets me "JB Weld EXTREME HEAT" good to 1000 degrees and "Blue Magic Metal Repair HIGH TEMP" good to 2400 degrees. Has anyone experienced a similar issue and what was their solution?
I would grind it, epoxy it and then block off the exhaust cross over with metal shims so it doesn’t get that hot.
If you have a cast iron intake, I'd try using Silicone Bronze tig filler rod. Works great for these applications. Cast aluminum is a bit trickier, since cleanliness and porosity becomes a greater issue. I've used the high temp/pressure epoxy and works fine on these kind of cases, tried it on an exhaust manifold and the extreme heat and pressure blew it out within a week.
I’m assuming the problem is to the right of the X,,,lower leg area of X ? Epoxy or welding,,,whichever you prefer . I had a sand hole come into a blower intake,,,,flaw from the casting process . Ground it,,,had a friend tig it,,,,,no problem ! Just like Serv Pro,,,,,Like it never even happened ! Tommy
"Labmetal" is good stuff. They offer high heat rated and the regular Labmetal rated to 450 degree. Its a one part, no extra mixing. Contains mostly aluminum. Better than JB Weld and most other epoxies. Can be cut, drilled, tapped, machined..........
Awhile back, my brother had an issue w/the exhaust manifold on a mid60's chev 6. Exhaust leak ate part of the sealing surface away of the cast iron. So he cleaned it well, used the JB(?) hi-temp stuff(iirc. I can check if you'd like) to seal the pits & damaged surface. He got it a little hi, & had a tough time sanding it down flat. Tough stuff, ;D . But he eventually got it, installed, & no troubles after that. Since the manifold is Alum, Tig would be nice, but if not, I'd cut out what I had to, clean everything surgery-clean, & use the Alum "soldering" sticks. There are a few different versions, some better than others, I'm told. You do need to properly clean the Alum, & especially the corrosion off w/a new SS-"toothbrush" just before application, & sometimes partway thru the repair, so the alloy sticks. Need to preheat the casting, but can & should use something like a propane torch or other clean heat, then use a propane torch to locally heat the repairing-area & the sticks are used like, well, solder(ing) -> the heat from the casting melts the alloy. Or it won't stick or bond properly. Which is ~600*F. So very little warpage should occur. If that didn't work, then the epoxy, again after proper cleaning. I repaired an alum manifold for a guy using this Alum "soldering" stuff, but it wasn't as involved. Worked well. FWIW. Marcus...
Several years ago I needed to TIG weld a crack in an aluminum '32 Ford oil pan. The biggest issue I had was that I could see oil bubbling out of the porous aluminum every time I started to weld. Even when the owner took the pan to an aircraft repair facility and had the pan, hot vapor degreased, I still got some oil. If you can get it clean, it can be welded.
Find a machine shop with a hot tank and have it cleaned. Use a propane torch and a brand new stainless steel bristle wire brush. V-groove the crack a little. Torch and scrub the crack area until no more oil wells up. TIG weld it while still hot.
Check this out: Ceramic and Aluminum-Filled, Two-Part, Water-Based Paste. For Applications to 1/2” Thick. Repairs Cast Aluminum Parts to 1400 °F. https://www.aremco.com/ceramic-metallic-pastes/
Well boys,....I was able to avoid the High Temp Epoxy issue. A good friend, who has done other projects for me, said, "no problem". He's done similar repairs in the past. Yes,...extreme scrubbing and cleaning of the weld area is important. And, he warns that still with the cast aluminum and shit that comes to the surface, it won't be pretty!!! Not worried about appearance. The repair area will not be visible. He preheats the manifold in his back yard BBQ, carefully welds small areas, and does a cool down in the BBQ to finish. Y'all might enjoy seeing my journey even tho it doesn't include HIGH TEMP EPOXY! View attachment 6023834 Cutting away the floor of the preheat chamber revealed the suspected hole. Obviously it was a production flaw as the molten aluminum never completely filled the mold. This hole will be welded up as well as the part removed for access. All this not visible when the manifold is back in place.
Nice work! I would have removed the sender and cleaned the whole thing before repair. Reason being, that if I got that kind of work done, then finished prep, it would need some other new repair! Murphy's Law and all...
Forget JB Weld, Gorilla stuff, etc. They are retail common formulations. I had a similar project where I cast an aluminum individual runner intake manifold for the Chey 230/260 series of engines. To take advantage of the individual runners I had to divide the 3 Siamese intake ports in the head. I studied the problem and finally settled on using Devcon Plastic Steel. This stuff was the real thing. It is a two part epoxy that sets extremely hard and impervious to everything, chemicals, heat, you name it. stick to metal like weld. It is pricy, cost the national debt but well worth it for tough apps. https://www.amazon.com/Devcon-10110...id=pla-4583657836144251&psc=1#customerReviews
Got 'er done! A whole lot nicer than I could have anticipated. Good friend Mike popped it in the "barbie", laid down some pretty nice beads and returned it to the barbie for cool down. Thanks to all who offered advice and experiences, good and bad, with epoxy.
Real nice! People get very weird when you mention welding aluminum, it's really no big deal. Much of the theatrical truss work and scenery we did was TIG aluminum. Your manifold is as good as new.
Probably better, as pointedout, a casting flaw from original. Your buddy is truly a craftsman worthy of the title!
if you call some the companies that make stuff, they will give all sorts of info. a lot of neat stuff nowadays. i built a single plane, cut up mopar m1, intake for my 350 buick about 15 yrs ago. used it on the racecar. intake was held together with j-b weld. and they said it wouldn't work......went 6200 rpm on d/p. went 7500 rpm on s/p. big difference
Some strange things have been fixed with Pratley's (our version of JB Weld). Oddly, the more it has the character of a scandalous bodge job, the more likely it is to hold up!
Just do it. I remember when I crashed my dirt modified about 30 years ago, I busted two of the three tabs on the side of the early hemi I ran. I was able to find one broken tab on the track, but not the other. I was in a dither. A couple of weeks later I was talking to a friend who was a union pipe fitter, He said "Bring it over". He looked it over, grunted, and went out in a field behind his house and used a hammer to break a similar piece off of an old harrow. It wasn't quite "Hold my beer", but he had me hold an oxy-acetylene torch on the side of the block to pre-heat it. He then proceeded to use nickel rod and an old arc welder to weld the pieces back in the block. Everything turned out great (I am still running it that way). The only problem was when he was done, he had a couple of beers, while I was occupied holding the torch to allow the whole area to slowly cool down. I did end up having my share, but looking back it was a great experience. As you found, if you can find the right guy, this kind of thing is a non-problem.
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