Cast iron question.

[Fixer]

Many of you have added to iron with welding and brazing so can anyone tell me if it would be possible to
cast additional molten iron around an existing cast iron object and have a bond or fusion rather than just encasement?
I this where surface prep, preheating the object comes in? flux? ideas appreciated as always.

 

[brightspark]

no chance nuff said in order for fusion both metals would have to be melted to the same temperature. impossible

 

[Pete.]

Never heard of it attempted but I can't see it working as Brightspark said. It would be interesting to find out. Is this a sculptural thing or a casting repair? Decorative piece or structural?

 

[Fixer]

Ok fusion is out, fair enough but can I get a solid molecular bond like with galvanising, flame spraying, brasing and soldering? what if I had the thing bras plated first? like chroming? just asking!

 

[Paul.]

Its possible to oxy acetylene weld cast iron using special cast iron rods and a flux, the rods are actually cast iron, the flux is Borax based and comes as a powder which is mixed with water into a paste and painted on the joint and the rod, It used to be a part of the City and Guilds O/A welding course, I used to teach it many years ago, its a horrible, hot, uncomfortable, messy job, which requires a lot of pre and post heat, and unless the part is quite small is very hard to get hot evenly.

 

[brightspark]

he said cast around it not weld to it

 

[Fixer]

Never heard of it attempted but I can't see it working as Brightspark said. It would be interesting to find out. Is this a sculptural thing or a casting repair? Decorative piece or structural?

Its to reinforce an engine block prone to putting rods through the sides. The block is thin there.

Any additional stength is worth having even if its not ideal.

 

[Paul.]

he said cast around it not weld to it

Welding is just a crude form of casting, practice for the test piece consisted of running beads on cast plates effectively building up the thickness, I wouldn't recommend trying it on an engine block, though, the stresses created by the localised heating will likely cause all sorts of stresses in the casting,

 

[anto44]

If the rod is going through the block then the rods are breaking and hitting the block, reinforcing the block won't stop the rods from breaking. What engine is it?

 

[Fixer]

Its possible to oxy acetylene weld cast iron using special cast iron rods and a flux, the rods are actually cast iron, the flux is Borax based and comes as a powder which is mixed with water into a paste and painted on the joint and the rod, It used to be a part of the City and Guilds O/A welding course, I used to teach it many years ago, its a horrible, hot, uncomfortable, messy job, which requires a lot of pre and post heat, and unless the part is quite small is very hard to get hot evenly.

That might be what i have to try instead. Its not a broken thing that will depend entirely on the repair, rather any additional strength is a bonus.
I could use the methods and things you taught to add fillets and just build it up. As long as it not all bitty and porous it will do. I may consult you in due course

 

[tom2207]

Its to reinforce an engine block prone to putting rods through the sides. The block is thin there.

Any additional stength is worth having even if its not ideal.

the problem then isnt the block ,,, its the rods , if you made the block twice as thick all you have is a 200hp rattle

 

[mr haynes]

Crank bolted strengthener?

 

[Fixer]

If the rod is going through the block then the rods are breaking and hitting the block, reinforcing the block won't stop the rods from breaking. What engine is it?

No the rods don't break on Alfa boxer flat fours. My engine builder raced them 30 years ago and never broke one but done all the blocks with them.

 

[mr haynes]

No the rods don't break on Alfa boxer flat fours. My engine builder raced them 30 years ago and never broke one but done all the blocks with them.

Is it flex then from crank or block?

 

[tom2207]

Crank bolted strengthener?

its the rods , so better rods , carillo or the likes , whats the engine , is it worth the expense, if its breaking rods its either crazy levels of performance or somethings tragically wrong with the build

 

[Fixer]

Crank bolted strengthener?

Main cap girdle thing? no need with a boxer, never breaks anywhere but the weak sides. Thats where they break when everything else is bulletproof.

 

[tom2207]

Main cap girdle thing? no need with a boxer, never breaks anywhere but the weak sides. Thats where they break when everything else is bulletproof.

does no one make better rods for them ..

 

[Fixer]

Is it flex then from crank or block?

Flex in the crank? maybe. Ill have to ask him if they put rods through the block with with steel cranks or factory cranks. Thanks for raising that question.

 

[tom2207]

Flex in the crank? maybe. Ill have to ask him if they put rods through the block with with steel cranks or factory cranks. Thanks for raising that question.

is there no centre main bearing on them .

 

[Fixer]

does no one make better rods for them ..

The rods dont break, the block does. Its a boxer, the pistons come together, horizontally opposed. under enough load, something goes sideways, through the block. The rods survive it but the block doesn't. Mabe a brace around the sump flange plasma cut from 10mm steel or something would add something.