Aluminium welding

[Cap'n Jack]

Has anyone used either of these before..............

Durafix Easyweld

OR

HTS 2000

They appear to be the same thing under different names. Basic make up is Aluminium with a Zinc content to help them melt at around 200 degrees lower tham Aluminium. I bought some Durafix from Ebay and tried it on an Aluminium extrusion, drilled a hole and sure enough it worked, filled the hole no problem. Tried to repair my bell housing lip where the bellows fit, unfortunately my torch couldn't heat it sufficiently to reach the 400c temp to melt the rod. Need a hotter torch!!

Welded Extrusion.............

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Bell Housing

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The Torch

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[Gazjen]

That's the problem with alu welding the heat just dissipates through the material, you may find you will need two torches just to get the local area to temp, but be careful as rubber nearby will melt even if its quite a distance from the area your heating.

When tig welding steel you can get away with around 80amps, with alu welding you need at least 130 amps and that's with the lower melting point.

[Cap'n Jack]

Just added the pictures, not sure if you saw them Gazjen?

Ali sure does dissipate heat, funny though the ali extrusion only heated by about 6" down its length, but I suppose it is quite thin in comparison. The bell housing heated up and had burned the paint all over so will need repainting, there is no rubber, just the housing. In the demo they brazed a cylinder head so I assume its the torch.

[Gazjen]

What about pre-heating the whole lot in the oven first (assuming it will fit)

[Ed]

Just to say be carefull with that stuff as it will be impossible to tig normally with it after you have done that, as the melting points will be all over the place. Having said that, I have some of that stuff and it has been useful, but I taught myself to tig weld alu after I go a myself a tig (Im no expert) and have successfully managed to do what ever I have needed to thus far with that method instead.

BTW I'm happy to have a go on that if your willing to accept total loss if it goes all wrong lol,!!!

[Ed]

Another thing, if you want another go see if you can get some MAPP gas for your torch, it burns much hotter, and may help.

[jamie1131]

Cap'n,
Would you be better off getting a new spigot turned up, cut the old one out of your bell housing and pressing the new one in? A machine shop should be able to do that pretty easily I would think. Only thing I'm not sure about is if there would be enough material in the housing to take a press fit. If you fancy that I can do some calcs on sizes/press fits for you.

[Cap'n Jack]

Hadn't thought of that one Jamie. Good call.

This is a little project for me now, originally I was going to buy a new one and just bolt it in. However, I've discovered that it may also be possible to repair the Gimbal Housing too, if so this is quite a common occurance worldwide and could be an answer fo a permanent repair for many a boat. The only alternative is a resin kit called a GHR kit which is very expensive in comparison to the cost of the kit and when resined in the bellows may not be able to be replaced.

I have talked to several welders who say that welding aluminium is a difficult job as it oxidises easily. This was the metal is heated to 400c, 200 below Ali melting point and makes a permanent repair.

I am really surprised that Mercruiser don't make a cost effective way in which to simply repair this part, it would be so so easy.

Ed many thanks for your offer and maybe I'll take you up on it, thats if you have forgiven me for making you our official weatherman for the trip.

[Ed]

haha no problem. I'm a storm chaser at heart anyway. Looking good for the weekend now

[salamis]

Last year on my Volvo Penta AQ131B engine the number 4 exhaust port became eaten away by sea water after the manifold inner seperation shelf failed due to corrosion.
This is a known problem with the 2.3ltr cylinder heads being automotive ali. The engine has to have a closed water system with a radiator, or heat extanger much like a car.
After removing the head I took it to John Cunningham engineering in Storrington, Pullbourgh Sussex, John Cunningham rebuilt up the whole exhaust port and mechined the face flat and made new threaded stud holes, cost £75 and I only had to wait three days.





PM if anyone needs a phone number.

[Ed]

Thats a bargin!!!! He could have easily charged more for that, nicely done!

[salamis]

You're right Ed he could have trippled the cost and it would still have been a bargain, but John Cunningham is well known in the boating world. It is'nt his normal type of engineering business as he makes cargo hold containers for airlines, but he likes working on boat projects and actually made and fitted many of the Round Britain Powerboat race engine mountings on boats for the 2008 race.

[Cap'n Jack]

So, the story goes on. I've done some welding and brazing before and brushed up on it for the past month to refresh the old memory. The durafix seemed like a good idea and works very well on aluminium, I know because I did a test piece first. Having asked Mercruiser (Brunswick actually) what there castings are made from, they confirmed they are XK360 Aluminium low-copper alloy, XK360 is their own name for it.

I've tried to heat the casting with a Go Torch but without success, Gazjen suggested I heat the casting first or try two torches and Ed suggested Mapp Gas. I bought a Rothenburger torch head (2100c at the flame with Mapp) and some Map Pro the second generation Mapp Gas.

All aglow he he!! I was excited to think I could do this job myself...........wrong!!

The last thing to try was the two torches which succeeded in melting the tip of the housing but still not allowing the "Durafix rod" to flow. As Gazjen says the casting must be disSipating heat faster. However this sort of brazing is used for cylinder heads which are much larger so I'm really puzzled now.

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[Gazjen]

Seems odd doesn't it

it must be because of the thin section you are trying to weld/braze losing heat so quickly, but If it won't flow directly in the flame that is strange, can't really think of anything else. preheat the rod maybe?

[Cap'n Jack]

That's the thing Gazjen, the rod will melt in the flame every time but crumbles and doesn't weld. This type of rod brazes by melting into the metal,to get a good weld the metal is first cleaned with a stainless steel brush and then tinned, the metal is cleaned again through the tinning and the brazing commences. Aluminium melts at 600c and any item being worked on only needs to reach 400c for the rod to melt.

As you say it may be that the thinness of the lip is dissipating heat to the rest of the casting, or to the air. I have also tried to heat from the other direction to push heat through, that didn't work either.

I'm wondering if there is a high Magnesium content, Brunswick didn't mention it. I have noticed that the ring on which the bellows sits, seems to have a weld connecting it to the main bell housing, I'm now wondering if it is impossible to repair this item.

Ed, I may have to take you up on your offer.