Diff case reinforcement?

rtj

rtj

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I'm attempting to build up a toms 12 bolt. After the case grinding, a region on the top of the case is thin.

I was thinking of applying a coat of hardblok to the outside. This product normally is used to fill water jacket to increase block strength. Any body have any suggestion? There are several similar block fillers, but this seems to be the most used.
 
HARD BLOK WATER JACKET FILLER is a specially formulated, cement-based product with refined, size-graded iron particles combined at an optimum ratio to provide maximum strength, vibration dampening, and heat dissipation required in high performance race engines. Its coefficient of thermal expansion is identical to cast iron engine blocks. Product has been tested and proven effective in aluminum blocks.


Manufacturer info above.
 
When you use this stuff in a block it really cannot go anywhere because you're filling a cavity (water jacket). Outside of the diff case you would rely on this stuff bonding properly.... IMO it won't hurt, worst case it comes loose and falls off like stucco.....

I'd be concerned about this statement:
Its coefficient of thermal expansion is identical to cast iron engine blocks. Product has been tested and proven effective in aluminum blocks.
Click to expand...

As far as I know cast iron and aluminum are quiet different...... :suspicious:
 
MYBAD79 said:
When you use this stuff in a block it really cannot go anywhere because you're filling a cavity (water jacket). Outside of the diff case you would rely on this stuff bonding properly.... IMO it won't hurt, worst case it comes loose and falls off like stucco.....

I'd be concerned about this statement:
Its coefficient of thermal expansion is identical to cast iron engine blocks. Product has been tested and proven effective in aluminum blocks.
Click to expand...

As far as I know cast iron and aluminum are quiet different...... :suspicious:
Click to expand...


Good points, thanks. I've got an iron case. I was going to coat the entire top 1/3, right down to the top rib/reinforcement.

I sent their tech support a question.

Others are saying devcon might work.
 
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Reply from company below. I like honest vendors. Internal use only.


Guaranteed not to work on the outside. Do not try it.


But, thanks for thinking about us.
 
HEY, my UNION welder buddy can weld aluminum OR steel to concrete and make it stick.....I don't see the problem......


:tomato::twitch::)
 
Don't even think about welding cast iron .... If you use some gorilla glue to glue a piece of material to cast iron it'll be stronger than an attempted weld LOL ....

I heard good things about Devcon - but again I'd be more concerned about adhesion, outside the diff casing it's (lacking a better description) "unsupported"

You could very likely use it to fill a deep groove in the mating surface to the diff cover, file it down even with the surface and since it's sandwiched between the cover and diff casing it would probably stay there forever....
 
MYBAD79 said:
Don't even think about welding cast iron .... If you use some gorilla glue to glue a piece of material to cast iron it'll be stronger than an attempted weld LOL ....

I heard good things about Devcon - but again I'd be more concerned about adhesion, outside the diff casing it's (lacking a better description) "unsupported"

You could very likely use it to fill a deep groove in the mating surface to the diff cover, file it down even with the surface and since it's sandwiched between the cover and diff casing it would probably stay there forever....
Click to expand...

Good suggestions, never thought about bonding a second piece on top.

Devcon steel and devcon titanium go to 250F and 350F. Web site says it is machinable. Cost is double for the titanium.

I'll post some photos of what I've done. Mostly shade tree mechanic stuff.
 
JB Weld?
http://www.jbweld.com/know-your-bond/

I repaired a thermostat housing (water neck) on my Yanmar (in the boat) while stuck in the Sea of Cortez - in 1997. Its still there and holding fine. Not the same application - but neat stuff.
[Oh yeah - I bought a spare/replacement - it's still in the box!]

Cheers - Jim
 
MYBAD79 said:
Don't even think about welding cast iron .... If you use some gorilla glue to glue a piece of material to cast iron it'll be stronger than an attempted weld LOL ....

I heard good things about Devcon - but again I'd be more concerned about adhesion, outside the diff casing it's (lacking a better description) "unsupported"

You could very likely use it to fill a deep groove in the mating surface to the diff cover, file it down even with the surface and since it's sandwiched between the cover and diff casing it would probably stay there forever....
Click to expand...

Well, for the typical guy, that is true, to a certain extent.....

but years ago I ran into a company called Pre Heat Welding in Gaithersburg Md.....they fixed....RAILROAD DIESEL engines.....

I needed something welded, and they didn't even charge me, but I got a cooks tour of this impressive plant they ran.....there was this RR engine block that a rod had gone through the side, and to there was this bare block on wood, and was going into a furnace to be pre heated, and so welded back together, the cylinders bolted to the block, crank outta there....interesting little lesson for me.....NOT what I was expecting....

I assume most of you know that RR Locos are all Diesel Electric these days....;)
 
welding cast is pretty easy. Preheat to more than 450*, weld either with MIG stainless wire, or TIG using stainless rod.... don't let it cool too fast. Simple
 
SuperBuickGuy said:
welding cast is pretty easy. Preheat to more than 450*, weld either with MIG stainless wire, or TIG using stainless rod.... don't let it cool too fast. Simple
Click to expand...

Interesting, but I think I'll stick with a coat of deacon titanium.

Guys have been doing these for years I've heard of one drag car splitting a case. Just figured for $100 I'd try it.
 
Looking forward to your report on it. At a one pound container - that would be a lot of JB Weld tubes!
But, I note the Devcon references a very high Compressive strength - but no details on tensile strength (what you'll want in a case application.)
JB is at near 4000#'s tensile strength - not so great - but there is no matrix per se, so it is just the chemical bond.

Anyway will follow with interest.

Cheers - Jim
 
phantomjock said:
Looking forward to your report on it. At a one pound container - that would be a lot of JB Weld tubes!
But, I note the Devcon references a very high Compressive strength - but no details on tensile strength (what you'll want in a case application.)
JB is at near 4000#'s tensile strength - not so great - but there is no matrix per se, so it is just the chemical bond.

Anyway will follow with interest.

Cheers - Jim
Click to expand...

I dropped the case off with a machinist. He will drill and tap one side for a steel cap. He looked at it and said devcon would come off.

I'm impressed with your jb weld success story.
 
Here's a what I bought from Tom's, he tuned the posi and fit the side axles.

kitfrtm-1.jpg

Assembling the TA's:

DSC_0721.jpg

Grinding fixture, this bolted to the old posi case, so no worries about grinding dust in the new bearings.

fixture1.jpg

fixture2.jpg

fixture3.jpg
 
Grinding set-up. The Harbor Frieght borescope worked great.

grindsetup.jpg

Roughed out case. I need to install the real ring gear and touch it up.

grndcase1.jpg

grndcase2.jpg

grndcase3.jpg
 
MYBAD79 said:
Nice work :thumbs:

Did that Harbor Freight borescope come with a tripod ?? LOL
Click to expand...

No, I got a very expensive tripod from a pawn shop for my photography, so my old tripod is now on borescope duty.

I went to buy their 80$ model, but this borescope was way better at 180$.

For the amount I use stuff, the HF tools are great. That milwaukee grinder is better than the HF, but 5x the price (photo above).
 
HF - I bought a buffing side grinder from HF, it lasted exactly one day. The next day I went to use it, it was dead. I bought a Makita to replace it.... it'll outlast me. 5x more expensive, yep, but how much time has it saved me not having to drive back to HF and replace the buffer after every use?

HF makes great dollies, stands, tables, even toolboxes.... but electronic stuff, not so much.
 
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