White Death Corrosion Experts Needed

[Agrarian]

I got what I thought was a great deal on a Husky 268xp Anniversary edition (1989). From the outside it looked like the the saw had only been used a few hours - hardly a mark on it. I looked at the piston through the muffler before I bought it and it looked great. Paid $125 with a 20" ok bar and new chain. Guy said he picked it up at a yard sale and had it running but it would not idle. He bought some Chinese parts for it (carb, coil, sparkplug, fuel filter, fuel line) and when it still would not work, he gave up.

Anyway, I figured I would tear down the top end, clean it up and have a very nice 268xp - maybe even my first shelf queen. Dreams were dashed when I removed the cylinder though. White death.



So, is there any hope to save this? I've cleaned it with a small Foredom wire brush. I was thinking that I would get a small abrasive blaster and use some baking soda to get into the pits better. The bearing and gasket surfaces are clean but you can see where it is eating into the magnesium right at the gasket edge.

Given how nice the case is on the outside, I would really like to save this. What suggestions do you guys have? How can it be sealed or does it need to be? I was thinking that once it is coated with the fuel mixture that maybe the corrosion would be stopped?

 

[jacob j.]

That looks worse than it is. The rule of thumb I got years ago from Husqvarna is to make sure that the corrosion doesn't go through more than half the thickness of the material.

I've filled in corrosion like that before with JB Weld and that worked pretty good. You could just run it as is.

 

[Jon1212]

I would think that there is a way to chemically neutralize the corrosion, and then seal with some form of epoxy.

 

[jacob j.]

The big thing is keeping water out of it. Saw mix can protect crankcase corrosion but eventually new moisture will find its way in there.

 

[Duce]

Looks like your case on flywheel side has enough material left to seat a seal. I would check for pin holes, put it back together, vac and pressure test, run it.

 

[Cut4fun]

I got a 505 from KY that had that from water in it.

 

[jmssaws]

That looks worse than it is. The rule of thumb I got years ago from Husqvarna is to make sure that the corrosion doesn't go through more than half the thickness of the material.

I've filled in corrosion like that before with JB Weld and that worked pretty good. You could just run it as is.

I'm with you, I have fixed worse with jb weld.

 

[Duce]

I'm with you, I have fixed worse with jb weld.

Not trying to start anything, but if it seals, why put JB weld in it?

 

[Barneyrb]

How would powder coating work on that?

 

[jmssaws]

Not trying to start anything, but if it seals, why put JB weld in it?

I do so I can keep case capacity as small as possible. Don't have to at all if it's not leaking.

 

[Duce]

^^^ Understood. Thanks

 

[Ikeholt]

I have used rust stop from NAPA. It stops further oxidation. 5 Bucks, cheap and easy. Never had any white rust return.

 

[Tor R]

only way to stop corrosion is to use a strong primer , epoxy type, and preferably with a bit etching effect.
It has to be thin, the one we used only build 30-40 my.
Normal epoksy grounding build 150-300my but doesnt have the ability come down in cracks and pin holes.

 

[Glock37]

How would powder coating work on that?

Blast and powder the case will stop the white death

Blasting will erode the material around the affected area you have to inspect really good after blasting because it will be thinner




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[panteliss]

The corrosion is something that can not control at leats easy , so all theese jbwelds or others epoxies cant help i will agree with Glock37 that you need heavy blasting until you find new clear metal and in our case clean magnesium and then the only cure is to refil the areas using TIG welding with magnesium and milling -grindind until you have the best results that you can

 

[Glock37]

If inside crankcase we powder right over after blast if outside we have a filler epo strong takes heat and conductive to make things smooth again


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[DSS]

I'm with JJ, I'd run it the way it is. I just put together a 272 that was worse and I figure it should go for years.

 

[Agrarian]

I have used rust stop from NAPA. It stops further oxidation. 5 Bucks, cheap and easy. Never had any white rust return.

What prep work did you do before applying the Rust Stop?

 

[Agrarian]

I've filled in corrosion like that before with JB Weld and that worked pretty good. You could just run it as is.

I've never used JB Weld inside a crankcase before. Should I be concerned that it can come loose over time and destroy bearings or worse?

 

[Agrarian]

I would think that there is a way to chemically neutralize the corrosion, and then seal with some form of epoxy.

I looked that up and the most promising I found was for reconditioning early airplane parts made of magnesium as follows:

Chemical Removal of Corrosion

• Mix a chromic acid solution. The solution should contain 24 oz. of chromium trioxide mixed with 1 gallon of water in a stainless steel, lead-lined steel or 1100 aluminum container.
  
  
• Apply the chromic acid solution with a nonmetallic bristle brush. Allow the solution to set on the area for 15 minutes.
  
  
• Rinse the solution off the treated area. Use clean water and rinse thoroughly.
  

I'm guessing the quantity could be reduced considerably for my needs but now I need to be a chemist to get this done. And this stuff sounds nasty.