welding alum

[phillip garrett]

I HAVE A SEADOO JETBOAT THAT HAS A CRACK IN THE EXHALST MANIFOLD THAT IS WATER COOLED. IT IS MADE OF SOME KIND OF CAST ALUM. IT HAS A CRACK IN THE WATER PASSAGE. MY CERTIFIED WELDER HAS TRIED TO WELD BUT DID NOT WORK.
IS THERE SOMETHING SPECIAL TO FIX IT!
THANKS!
PHIL

[Engloid]

I'd suggest a different welder. The fact that he's certified dosn't make him the "end-all" of welders. Actually, I've seen more good welders without certifications than I have good welders with certifications. The fact is that many jobs don't require certifications, so no matter how good the welder is, he won't have the cert unless he pays for it himself.


Whatever you do, don't resort to JB weld...that stuff was made by the devil.

[bruisermac]

try Super Alloy 5...type that into google. its a alum brazing rod.

[TRG-42]

Hi Phillip, most cast aluminums are readily weldable. The problem usually encontered is contamination ( especially in a engine manifold )

The perfered filler for most cast alloys is 4043 first choice. Exception is 7XX alloy castings where 5356 is suggested

I agree with Engloid...find another welder

Make sure the welder die grinds / chemically degreases the crack properly. Bevel crack ( open it up )

If you are using TIG ( best choice ) make sure you have AC balance to more DC+ ( more cleaning ) . Also ensure you have a big enough welder to so you don't get a cold weld

Normally you shouldn't preheat aluminum but in this case it would help

Last resort is to use a aluminum brazing rod

Did the weld crack again, or did it just leak ??

[Rocky D]

IN any situation where the casting is used to transfer water, you will find it saturated with moisture....aluminum really sucks up moisture, so a good preheat till the moisture is gone, is in order.

Also, a brazing operation will best work only when you have a metal to metal tight fit. Brazing has little strength by it self, like when you have a gap. (and this is true with most all brazing alloys). Alladin makes a great brazing rod, to use with acetylene. I don't think I would use it in this instance, tho.

[Brand X]

TRG-42,
Wouldn't 4047 be a good choise too?
I have not used it on cast aluminum but I have heard it works well.

[Engloid]

I havn't ever used 4047..actually havn't heard of it. I use 4043 on nearly everything I can that's aluminum. If it has to have more strength, I'd look into other types, but 4043 is kinda like the generic that will do nearly anything aluminum. It's good for most applications.

[Jerry]

There are many aluminum filler rods and yes 4047 is for cast but 4043 is also. I use 4043 for cast aluminum and 5356 for other.

I do weld many repaires on cast alumnium and removing the contaminates is the key to a good weld. In a enclosed area that needs a weld crack or hole repaired it is impossible to get the area inside clean. The unclean area seems to suck into weld puddle, therefor laying down of filler can be almost impossible. Weld may blob onto and area may be black in color. A fix or way around this is to weld a couple beads along the edge of area and then connect over your beads. You can also try to grind away the bad weld you just placed down and keep cleaning off with wire brush and rewelding area and repeating till you close crack.

Remember in welding repair of aluminum it must be clean and you will probably find yourself welding and cleaning and welding again. Almost everytime I do a repair job on aluminum its going to be welded twice. The first usually gets most of the junk out, I clean everything again and weld again.

[drizler]

Don't get to laughing too hard now but I have fixed all sort of stuff like that with the stuff. Rather than rip the thing apart you can likely clean it out with a brush, vee it some, stop drill the ends and put some on. It will likely hold up as long as a weld will unless it gets too hot which I doubt. At any rate its real easy to grind off if it doesn't work well or fails.
If it was mine and I wanted it welded I would look up the local guy who fixes props. Don't go to the marine, rather find the welder who does them for the marine who then charges you double what the welding cost. Its a pretty specialized art and theres likely only one guy around who does it. Find him and he ****ed well will be able to fix it for you and I bet it won't cost much either. I get all my dinged props done that way and have been pleased every time.
How did you crack it anyways, I have a similar rig om my 585 Bombadier spi and it stays bone cold as far as I know. FWIW I fixed a Mercuriser water jacket which had been frozen and welded using JB. The JB held up better than the original nickle weld did. They have some better stuff that I just used to fix a slightly weepy cracked head on my mercuruiser, its called DEVCON. It has ceramic base and is for hi heat apps. Like JB on steroids but not easy to find at retail places.

[cnslmva]

Saw a similar post on Miller's forum. They advised 350 degree preheat and 5356 filler metal due to strength reasons. Above all, clean, clean, and clean some more! It can never be clean enough!

Good Luck!:)

[reedfish]

I used JB weld on a friend of mine's Minnapolis-Moline tractor engine block 10 years ago and it still is holding and it doesn't leak. Last week, I used in on a Homelite chain saw housing to redrill/retapp for threads on a plastic housing and it works GREAT AGAIN . I used it 2 years ago to reform a pillar block on a custom .243 rifle and low and Behold it worked great again. I used it on a Rockwell Harness tester's precision load cell to save the machine since the load cell is no longer made and heat would have rendered this load cell to a worthless 1600.00 chunk of aluminium.........and what do you know the tester is still working after 3 years doing 300 rockwell "c" tests per day 24/7 at a major heat treating company. If JB weld is made by the devil then the devil had a great chemical engineer on his staff because this stuff has NEVER failed me yet.

[drizler]

That stuff is worth its weight in gold. The Devcon I got is experimental stuff they are floating for test purposes. A guy on a boat board said he would send me some and all I had to do was let him know how it worked on what application ect. His municipality uses it to fix broken sewer and water castings ect. You should see the jar he sent me overnite mail and won't take a dime. Its the size of an old fashioned cold cream jar. Christ there must be at least $50 worth there. I told him next time his *** needs kissin I am all puckered up. This stuff is the cats *** for bedding and vertical surfaces. It has the consistancy of frosting. Really stays put.

The other thing I swear by is that majic aluminum rod they sell in Harbor freight. It may not be the tensile,rockwell nothin of the industry but it is flat easy to use, doesn't require much heat at all and is hardern a *****s heart. I filled and redrilled the cowl holes on my Cessna that got wore down over time and it worked fantastic. It drilled about like a piece of mild steel. Nice stuff which would probably work well on that aluminum casting in the seadoo as well.

[SuperchargedS10]

Originally posted by drizler
I told him next time his *** needs kissin I am all puckered up.

LOL

i have used JB many times. sometimes it works good, other times not good at all.