mercury racing lower unit alloy grade.

[lcp8410]

anyone know what grade of alloy using to cast the mercury lower unit? and what type of tig welding most suitable to weld there lower unit? hope someone will help....

[Mike45]

Noy sure of the chemisty of the aluminum the early ones were cast then later they forged them, but I do know depending on where it needs welded it is very diffucult to do it and have it not break again. I had one welded that I broke (on a rock) that split from the gear housing bolt at an angle of about 11:00 and it was not good. it started to crack again and it is now just used as display because I do not want to lose a gear foot and prop.

I had this done profesionally by an excellant welder. If it does break in the mentioned area sometimes it is better to weld it up then weld some plates of aluminum over the repaired part.

[Guest]

Foot repair

Doug Kay can repair most any damage to a gear foot. If you need new treads installed welding is not the best way to go. When welding a gear foot it is best to preheat the foot to minimize distortion. Heliarc is the best welding process I believe for unit. New threads are best installed by inserting a sleeve made from 6061T651 and then machining new threads.

Alan

[lcp8410]

tig weld mercury gearcase

im about to tig weld the skeg.anyone know which tig rod to use? i just wonder what material the factory use to cast those gearcase housing.

[Guest]

Maybe

Just a guess but it could be a 50's series casting alum.


"
5xxx Wrought Alloys and 5xx.x Casting Alloys. Wrought Alloys of the 5xxx series (aluminum-magnesium-manganese, aluminum-magnesium-chromium, and aluminum-magnesium-manganese-chromium) and casting alloys of the 5xx.x series (aluminum-magnesium) have high resistance to corrosion, and this accounts in part for their use in a wide variety of building products and chemical-processing and food-handling eguipment, as well as applications involving exposure to seawater. "


Alan

[Fast Freddie]

Which Racing Gear Case?

Which Merc gear case are you welding? Is it die cast or 44XS/25XS which were lost foam?
Fred

[Guest]

Lost Foam

The casting process is independent from the alloy used. Weather it is a sand cast, die cast or lost foam casting the alloy chemistry used is not related to the casting process. Over time I am sure Mercury has changed the alloy to improve the corrosion resistance of their engines in salt water.

Alan

[trident]

Alloy

And, if anyone would know, it would be Fred.

Jerry

[lcp8410]

44XS/25XS gearcase alloy

fred, it is 44XS/25XS lower unit im talking about ....mind to shared which alloy these gearcase is cast...and what is best tig rod to weld these lower unit?

[Steve77t]

fred, it is 44XS/25XS lower unit im talking about ....mind to shared which alloy these gearcase is cast...and what is best tig rod to weld these lower unit?

Yup 5056 is harder and will pull more, 4043 is a little better for less pull but is softer. When you heat this aluminum hot enough for welding it becomes soft, so retreating is a big help here. When aluminum is heated and then machined it is also gummy, That is why a retreat is done. Steve

[spud62w]

I know if I was welding it i'd use 5356.

[lcp8410]

5056 filler

steve,what do u mean by retreating? are u mean the 5056 filler works better on there lower unit?

[Steve77t]

No!

I would use the 5356 as well but when you weld the case and it gets hot enough to melt the two pieces together, and it then cools the area and some of the case will be softer as it has lost it's heat treat. It is enealed or made soft. This is why the material is gummy when machined. So a simple retreat is done and all is good again.

[jeff55v]

If you're welding a 44xs skeg, let me know your boat number. I want to be on the inside of you when you go into the turn. Or so I can have my camera focused in on you for some dramatic shots.

[foot_doctor]

I just checked my drawings for the "Quicksilver" gear case castings. They specify Alloy K360 that was changed in 1955 from ALCOA 380. I have no info re. the later Lost Foam castings. R.T.