Fixing hole in side of block

[jaxs]

A first time fix, by a brazing neophyte is not likely to go well.

He'll "figure it out" !

 

[joesmith123]

Trying to get the patch to stick

angle grinder, discs and grinding wheels

bucket of water close by for safety

cut square in cast iron skillet

cutting bucket to make patch

practice patch

Hit iron skillet with grinding wheel

held down patch with clamp, hit it with grinding wheel

patch ready for brazing

small neutral flame in right hand, bronze rod dipping in flux in left hand, patch did not stick

2nd run with torch, messier, still trying to understand where to point the flame and how to successfully bond the two entities

Next step: hit everything with grinding wheel and start over, fixing to try what greenville said: put beads in the corners, then try solid beads half of each line to distribute heat, give big heat to the cast iron skillet, then push the rod into the area, melt the bronze, let it cool solid

New attempt: point the flame on the cast iron skillet, push the bronze rod exactly where you want the bead to form until it liquifies, move down the line forming a bigger bead and waiting longer for the bronze to melt, make the bead form at the intersection of the two entities big enough to encompass the 1/4 steel patch...

 

[hagrid]

Brazing works via capillary action. If there is any filth then the filler will not flow into the joint.

 

[GreensvilleJay]

OK, those parts are NOT clean enough to braze !
You NEED shiny, well ground, CLEAN metal. Can be 'rough' but has to be clean.
BTW the coating on the bronze rods IS flux. I never used anything BUT the rods.

Hottest part of flame is the blue-blue transition.
You need to preheat the point where you want the bronze to go
THEN place rod there and heat will melt a small amount of bronze and it'll flow a bit
REMOVE the flame !
Now go to the opposite side of the patch and repeat the process..
preheat,add bronze, move to another corner..
Once several corner are attached, go 1/2 the distance and
preheat,add bronze, move away....
After an hour or so ,you should be able to get the timing right of applying the correct amount of heat, dab of bronze, cool and continue

You ARE wearing 'brazing googles' ?? Mine are a dark blue tint.

 

[joesmith123]

The 'trick' to understand is cast iron takes heat AWAY from the heat source real fast, so you need a lot of heat BEFORE you can start brazing the patch.

brazing is just 'high temperature soldering', the way I look at it. Get the parts hot and bronze flows,remove heat and you're done.

This is the comment I am using to figure this out

Point the flame on the cast iron, get it super hot, then push with left hand the bronze on that area until it flows, enough to encompass the 2nd entity, if the bronze rod is sticking, the area is not hot enough to melt the bronze (that happened on the last attempt)

Other details: the bronze stuck way better to the steel patch, none of the bronze stuck to the cast iron

Now I go experiment: how much heat can I give cast iron before damaging it? And I try to do the tack welds, give big heat to the edges, melt a bubble that would hold the patch on, then try to do like I am outlining

OK, those parts are NOT clean enough to braze !

Ok yes, hit the cast iron way harder with grinding wheel, and the patch

BTW the coating on the bronze rods IS flux. I never used anything BUT the rods.

I know what you are saying but: at the weld shop, i intentionally got rods without flux to keep them separated like the guy did in the video I am trying to emulate

You need to preheat the point where you want the bronze to go
THEN place rod there and heat will melt a small amount of bronze and it'll flow a bit
REMOVE the flame !
Now go to the opposite side of the patch and repeat the process..
preheat,add bronze, move to another corner..
Once several corner are attached, go 1/2 the distance and
preheat,add bronze, move away....
After an hour or so ,you should be able to get the timing right of applying the correct amount of heat, dab of bronze, cool and continue

Yes this is the advice that I am following from the other post (I did not try this yet)

You ARE wearing 'brazing googles' ?? Mine are a dark blue tint.

They had chinese lenses for $7, I did get them because I need to be close to the flame to see exactly what it is doing

 

[DustyRusty]

This is the comment I am using to figure this out

Point the flame on the cast iron, get it super hot, then push with left hand the bronze on that area until it flows, enough to encompass the 2nd entity, if the bronze rod is sticking, the area is not hot enough to melt the bronze (that happened on the last attempt)

Other details: the bronze stuck way better to the steel patch, none of the bronze stuck to the cast iron

Now I go experiment: how much heat can I give cast iron before damaging it? And I try to do the tack welds, give big heat to the edges, melt a bubble that would hold the patch on, then try to do like I am outlining



Ok yes, hit the cast iron way harder with grinding wheel, and the patch



I know what you are saying but: at the weld shop, i intentionally got rods without flux to keep them separated like the guy did in the video I am trying to emulate



Yes this is the advice that I am following from the other post (I did not try this yet)



They had chinese lenses for $7, I did get them because I need to be close to the flame to see exactly what it is doing

Are you aware that many of the Chinese lenses give virtually no protection? Spend the extra money and get a US-certified and made product. If you harm your eyesight, it isn't like getting a cut or burn that heals. Eyesight damage is for a lifetime. Looking at that flame is like looking at the sun during the eclipse. It was reported that many of the people who bought cheap Chinese counterfeit glasses got permanent eye damage.

https://aas.org/press/american-astronomical-society-warns-counterfeit-fake-eclipse-glasses

 

[joesmith123]

Bronze sticking well to patch but not to the cast iron skillet

Hit the cast iron and steel patch real hard with grinding wheel

Second try with new data,
Forming beads around the patch trying to get it to stick, Hitting the cast iron with flame using right hand, Then coming in with bronze rod using left hand mounting a small puddle, attempting to make the bronze hold the cast iron and the steel

The flame being used

No bronze wants to stick to cast iron skillet, Bronze sticking very well to steel patch

My theory: not enough heat on the iron skillet to allow it to bond to the bronze

My next experiment: Hit the cast iron with the flame until you noticeably see the cast iron melting, I need to get it to that point so that the bronze can bond with it

This weld I am showing: Hit it with sledgehammer thinking it would break, nope, it is fully bonded to the patch, most of them are

 

[Jim L.]

Some thoughts.

Beads show that there is not enough heat. Try preheating the pan in the oven and see if that helps in your test case.

Cast iron needs to be clean. When you get to the engine, you may need to bake out the engine oil and other contaminants prior to grinding.

Rods will work better when coated with flux. Before brazing, also apply flux everywhere you will be brazing to prevent metal from oxidizing and blocking braze.

Eye burn is forever.

 

[ken erickson]

Some thoughts.

Beads show that there is not enough heat. Try preheating the pan in the oven and see if that helps in your test case.

Cast iron needs to be clean. When you get to the engine, you may need to bake out the engine oil and other contaminants prior to grinding.

Rods will work better when coated with flux. Before brazing, also apply flux everywhere you will be brazing to prevent metal from oxidizing and blocking braze.

Eye burn is forever.

Good advice Jim!


"My next experiment: Hit the cast iron with the flame until you noticeably see the cast iron melting, I need to get it to that point so that the bronze can bond with it"


I do not think you want to to see the "cast iron melting". Admittedly it has been a long time since I did any brazing but I did spend a year going to WCTI and received a associate degree in welding right out of high school.

I think what you want to see is a cherry red heat zone and you might see just a small circle of the cast iron right at the center of the heat zone start to get what I call a "wet" look.

I agree with Jim L that the pictures you posted all look too cold for the brazing filler rod to flow correctly. Pre heating the pan will help for sure along with pumping in more heat and moving at a quicker pace as you add filler rod.

 

[RCW]

I did some brazing decades ago and have long since forgotten how to do it.

I’m learning along with Joe…..you guys are great.

 

[PoTreeBoy]

I'm the least qualified on this thread, but we all agree the cast skillet is not hot enough. The block wil be more of a challenge.
* You could try preheating with a propane torch like people use to burn weeds. Preheat a large area and maybe keep heating while you braze. This is where a third hand might be useful. This will take a lot of propane, but it is cheaper than acetylene.
* Insulate the outer part to reduce the heat loss and keep the object at as constant temperature throughout as possible.

 

[RCW]

I'm the least qualified on this thread, but we all agree the cast skillet is not hot enough. The block wil be more of a challenge.
* You could try preheating with a propane torch like people use to burn weeds. Preheat a large area and maybe keep heating while you braze. This is where a third hand might be useful. This will take a lot of propane, but it is cheaper than acetylene.
* Insulate the outer part to reduce the heat loss and keep the object at as constant temperature throughout as possible.

One of those burners might be very handy. I don’t have one but think they put out some serious BTU’s.

Might create some soot if air mix not calibrated well. Soot could deter adhesion.

 

[Sidekick]

Years ago I had a cast iron manifold brazed and he used a special flux filled rod. Heated the parts in an industrial oven, brazed, and then slowly cooled it in the oven overnight. I would look for a local welder for a repair like this if you only want to do it once.

 

[DustyRusty]

I did some brazing decades ago and have long since forgotten how to do it.

I’m learning along with Joe…..you guys are great.

Brazing is just like having sex. Once you have the torch in your hand it will come back to you. Just like sex, you won't be good at it the first time, it just takes a lot of practice. When you get old, brazing is just like sex, you have the desire, but sometimes it is just too much work, so you don't bother. YMMV

 

[fried1765]

Bronze sticking well to patch but not to the cast iron skillet

View attachment 135737

Hit the cast iron and steel patch real hard with grinding wheel

View attachment 135738
View attachment 135739

Second try with new data,
Forming beads around the patch trying to get it to stick, Hitting the cast iron with flame using right hand, Then coming in with bronze rod using left hand mounting a small puddle, attempting to make the bronze hold the cast iron and the steel
View attachment 135740


The flame being used


View attachment 135741

No bronze wants to stick to cast iron skillet, Bronze sticking very well to steel patch


View attachment 135742

My theory: not enough heat on the iron skillet to allow it to bond to the bronze

My next experiment: Hit the cast iron with the flame until you noticeably see the cast iron melting, I need to get it to that point so that the bronze can bond with it

View attachment 135744

This weld I am showing: Hit it with sledgehammer thinking it would break, nope, it is fully bonded to the patch, most of them are

Clue: YOUR amateur brazing ain't gonna work on the frying pan, and even less so on your engine block!

 

[GreensvilleJay]

forget about the patch for now
instead get the heat on the cast and see if you can get a small pool of bronze to attach to it.

in 'soldering' this would be called 'tinning'.

yes, you'll require practice maybe 1-2 hours before you get the process down.

 

[jaxs]

Brazing is just like having sex. Once you have the torch in your hand it will come back to you. Just like sex, you won't be good at it the first time, it just takes a lot of practice. When you get old, brazing is just like sex, you have the desire, but sometimes it is just too much work, so you don't bother. YMMV

Speak for yourself, if the first time had been any better I might not have lived through it. As for practice, I must have been born programmed for success or maybe the central nervous system handles it same as heart beat and digestion.
I'll have you know it might take this old man all night but he can still do what he once did all night.

 

[jaxs]

Clue: YOUR amateur brazing ain't gonna work on the frying pan, and even less so on your engine block!

Haven't you "figured out" that Joe has to "figure that out" for himself ? Reminds me of something dad once told me "you can tell a woman Joe but you can't tell her him much".

 

[North Idaho Wolfman]

My next experiment: Hit the cast iron with the flame until you noticeably see the cast iron melting, I need to get it to that point so that the bronze can bond with it

You can not put enough flame to it to melt cast iron!

You need to take your pan and throw it on a BBQ grill on high for a min of 15 min.
Your patch needs to fit into the hole ( like a plug not a patch) so not over it the cast.
You need plenty of flux and a good rod, heat both materials till the Brazing rod flows to it.
You can use mutiple passes to build the patch up and seal the hole.
Also your flame is not adjusted properly because you're leaving soot on the parts.

 

[Tarmy]

Been watching this thread from the get go. Love the hard work and effort of OP.

My only suggestion to OP would be to go on Welding Web and post this repair with questions about how to do it. I would also ask those guys if one of them is nearby and could help out or do it. Much like this place, there are some VERY skilled people and helpful as well. I have welding/brazed enough to know that this is not a first timers repair job To try.

Good luck OP and I hope this work out.