[powerrodsmike]

We were referred to this place while trying to find the best way to fix those firetruck cylinders. crack is bad, M'kay.

http://www.locknstitch.com/

They can repair castings as well as sell you the materials and training videos to do it yourself.
There were some really good explanations about why certain repairs in cast iron are bad ideas. They explain expansion and some of the reasons why iron cracks after a repair. Good stuff on how to avoid messing up your iron parts.

http://www.locknstitch.com/ExpansionContraction.htm

Advice about preheat/postheat/slow cooling cast iron

http://www.locknstitch.com/CriticalTemperature.htm

And welding advice for different types of cast iron welding/brazing procedures..

http://www.locknstitch.com/PreheatWeld.htm

I found much of it very interesting, they do try to sell thier product, which is several types of pins and locks, but it seemed like they explained the other processes without bias.

What do you guys think?

Later, mikey

[weirdbeard]

Thats good stuff. Now how do you slow cool your parts over a 24 hour period?

[powerrodsmike]

Originally Posted by weirdbeard

Thats good stuff. Now how do you slow cool your parts over a 24 hour period?

I had one welder guy tell me to pack the part in sand or vermiculite.(some of that stuff has asbestos. be careful) I think a box lined with refractory blocks would work also. Probably the best way would be to put it in an oven and gradually decrease the temp over a 24 hr period.

Mikey

[home brew]

Great link!!! Good info and tech. Never know when you will need this kind of info. I think I will now be able to save a couple of exhaust manifolds by myself without sending them out. Guess it is time to look for an old oven for the garage.

[BOBCRMAN@aol.com]

I've been using their stitch process for over ten years. It works well and combined with the new cross-link sealers the repairs are bulletproof.

In this area, ore of the best places for major "Hot" cast iron repair/reconstruction is Sperry Welding, in Capac, Mi. He literally builds his furnace over the part and does the welding/repair at red hot temps.

In my own shop. I have been using the "oven" from the bake and blast system. I set it up to max heat. Weld/repair the block while hot in the oven, turn it back on max for a time. Then transfer the hot block to the shot blaster and let it blast for about 45 min. Then let the block naturally cool for the duration. I have had no cracking problems with this method.

Recent repairs were a Bowtie BBC that was cracked three places in the lifter valley. Several 400's with valley cracks. A tall deck BBC that was almost sawed in half by a bad piston pin and an Eagle "H"beam rod. This took a lot of reconstruction in the lower cylinders and pan rails. Plus two sleeves. Also a couple of "Bad starter boss" SBC's. Next is a 454 BBC that was dropped from a fork lift and took out the last five inches of the starter/block corner.

[powerrodsmike]

BOBCRMAN, what are the welding or brazing processes that you use on your repairs in your shop? I'd imagine that different types cracks require different approaches.

I wonder if the blasting process you do after the repair does any stress relieveing to the iron.

Did you look at that pic of the firetruck cylinder I put a link to? There are some more pics of that nasty thing in my gallery.

Later, mikey

[oldred]

Again Mickey an excellent find I would like to point out however that as detailed as they are they have omitted (at least as far as I have read) the fact there are so many different types of cast iron and they seem to want to lump them all together in one all-inclusive category. This is a serious and all too common mistake as the procedure for some types is completely different than for others and some simply can't be satisfactory welded by normal means. The very common Malleable irons are a good example since the heat from the welding will destroy the integrity of the base metal itself by converting it into brittle Grey iron even though the weld itself may be acceptable. They do however point out something I, and many others, have argued for years and that is arc welding should be used only as a last resort but again they leave one with the impression that it should never be used when in often cases it will work ok depending on the end use. They also say that even a Nickel rod will leave the transition area from the weld to the base hard and brittle and too hard too machine but this is only half true If you use the common much cheaper 55Ni rods for cast iron then even though the weld is machinable the surrounding metal is not. The 99% and higher Nickel rods do not have this problem when used properly and can be used to repair holes that will need rethreading and other parts that may require machining. I think they should have explained that better because this is a very common procedure that we have used in mining machinery repair for years very successfully but they plainly say it can not be done, after doing it successfully for over thirty years I find this to be news to me.

[BOBCRMAN@aol.com]

Just quick looked at crack. Where is this crack? Yes, I use several different methods of welding. Depending on location, material etc.

In the oven I use braze welding techniques or high nickle electric rod. Depending on if it has to be machined afterwards. Some cast iron rod is not machinable. I have also hot welded with what used to be called "easy grind" wire in my old MIG welder. Not machinable.

The purpose of the shot blast is to peen and stress relieve the weld/repair.

Just looked at gallery.. That should not be that hard to repair. Is this a sleeved or sleevable cylinder?

[powerrodsmike]

Oldred, I do agree that they seemed to lump all types into one category. I think their focus was on engine parts,, and I don't know how many types of cast iron are typically found being used for those applications.

One of the sections in the preheat weld section did actually say that they used the high nickel rod in certain applications.

I thought it was neat that they described the process of oxy/acetelene fusion repairs using cast iron rod. I never heard of that one.

Half of my reason for posting this here is entirely selfish. I would like to get input from guys like you and bobcrman, experienced in actually successfully doing these types of repairs in cast iron.

I would like to see that firetruck run again, and taking advice from those who have only done a few repairs seems unwise., (like the welder at the sheetmetal shop who wanted to heat the casting to cherry red and bend it back out of the way to clean the inside of the water jacket )

I really appreciate this type of reply. Pointing out the flaws in a process helps to get steered in the right direction.

Thanks for reading this,
Mikey

[powerrodsmike]

Originally Posted by BOBCRMAN@aol.com

Just quick looked at crack. Where is this crack? Yes, I use several different methods of welding. Depending on location, material etc.

In the oven I use braze welding techniques or high nickle electric rod. Depending on if it has to be machined afterwards. Some cast iron rod is not machinable. I have also hot welded with what used to be called "easy grind" wire in my old MIG welder. Not machinable.

The purpose of the shot blast is to peen and stress relieve the weld/repair.

Just looked at gallery.. That should not be that hard to repair. Is this a sleeved or sleevable cylinder?

I'm not sure if it can be sleeved, but another crack also runs around the cylinder, where the water jacket casting intersects the cylinder . It has to run at least 1/4 of the way around. That is why I was scared to let someone inexperienced weld a big bead across it. The shrinkage and distortion that would come from that much heat couldn't be good.

Here is a link to a big pic. http://hotrodders.com/gallery/data/500/big_crack.jpg

And another
http://hotrodders.com/gallery/data/5...nder_crack.jpg

The truck in question is a 1923 Seagrave fire truck. The pic of the 1014 cubic inch motor is in my gallery.

Again, thanks for the input
Mikey

[oldred]

My comments are aimed more at welding cast iron in general and more toward the weekend welder and it would seem that Bobcrman has far more experience than me in the repair of engine blocks. This whole subject has become very interesting and I am really interested in how this repair is finally done, keep us posted

[ChevyTruckGuy]

Originally Posted by oldred

My comments are aimed more at welding cast iron in general and more toward the weekend welder and it would seem that Bobcrman has far more experience than me in the repair of engine blocks. This whole subject has become very interesting and I am really interested in how this repair is finally done, keep us posted

Now were getting in to metallurgy don't you think trying to determine what its made of which would determine the welding material needed. Also most cast iron has a preheating spec and a cooling process. My friend uses a heatreating oven and a Metallurgy charts. I used the old timer method hot sticks and damp burlap for slow cooling.
The welding supply I used had great people with metallurgy backgrounds to serve the many needs. We would come in tell them what we were doing they would pull out charts and we got what we need. Maybe a little research in to material used in that time frame would help to determine the materials needed to repair it.

Craig

[oldred]

Chevy, Those temp sticks work really well and I have used them for years but now the IR thermometer has about made them obsolete but still they are handy, cheap and accurate. The guides you mention can also be a great asset both in identifying the type and the temp/process to be used however something like an engine block or head should be left to the pros. Bobc's post gives some idea of what is needed both in equipment and know-how to properly repair engine castings and a great many engine blocks/heads have been destroyed by "good" welders using the wrong methods and equipment. The guy at the sheet metal shop Mickey mentioned is one example, he wanted to heat and bend part of the water jacket? it most likely would have broken off and the break would have been anything but clean the "bend" almost certainly would have had numerous cracks over a fairly large distorted and stretched area making it extremely difficult or impossible to repair. I have had quite a number of cast iron items brought to my shop that had broken in an attempt to heat and bend them and most were beyond practical repair. Cast iron is a different animal than steel and has some major characteristic differences that MUST be considered when attempting any welding process, in most cases it is not as simple as just heating before welding and then cooling slowly.

I think Mickey is talking to the right man(Bobc) because someone with his background who can look at those pics and say "that should not be that hard to repair" has got my vote, they sure look intimidating to me

[ChevyTruckGuy]

Hey Oldred,
Yeah I took a look at mikey links, I learned this stuff in Millwright trade School. Like I said I never used it much Like my friend did. Anyway He was in to the metallurgy end of welding which is what were talking about what process and materials is needed to do the repair.

I'm all for taking it to someone that does it for a living when you got a lot of hard to do or multiple cracks where you really need to know what your doing. I guess I looking at this as I could repair this maybe because I've done minor crack repairs before I've never had any thing fail so that being said I may be a little full of my self in my old age.

Oldred you don't need all the fancy stuff to do a repair if you follow the process required to do a repair. Again maybe the old millwright and field repair think kicking in or I just hate to take my stuff to a welding shop when in fact I'm a welder there's the kicker when one welder look at the other guy's work.
Yeah you want how much for this work. Hmmm
l'm really enjoying the conversation on cast iron its been a while hang out with welder talking repairs.

Craig