I remember a few posts of yours where you were describing welding cast iron(i.e. to make intake ports larger) I have a few hunks of iron I'd like to put bigger holes in, and I was wondering if you could share any advice.

Thanks,

Q

 

I didn't think you could weld cast iron. It's called brazing.

 

nono....you *can* weld cast iron....but you will never find a bigger pain in the ***! You fist have to heat it with a torch...(or something hot ) Then weld, try to finish fast, or do small sections at a time. Keep the torch on it, you will want to VERY SLOOOOOOOOOOLY cool off the piece of cast iron. It would be good practice to then heat realativily slowly, and heat it realativly slowly, for a few weeks, re-machine it since it will by now be far out of spec, by .01's of an inch or more! (depending on the amount of internal stress you added by welding it) ...In other words, welding cast iron is NOT FUN! I tried it once....and failed...but some pro welder friends of mine say it's not really that big of a problem....assuming you have everything you need... If you are just trying to make some holes bigger, I'd seriously reccomend a dremel, it might take longer, but if you aren't experienced in cast iron welding, you'll probably do what I did, crack the work in half.

 

The material to be welded in is of a high-nickel content and its supposed to mate to cast iron very well.

Holes = ports. I'm wanting to enlarge them but it looks as though the metal may be extremely thin by the time I'm finished.......

 

Kind oif a lost art in this day and age, welding heads was common practice 30+ years ago, not so any more.

It's a total crapshoot on a thermally cycled piece like a head if tried to be done via torch..the oldtimers used a furnace, heated up the head, welded, the put it back in the furnace and slowly brought down the heat.

There may be new methods these days, not sure, but I'd advise that since you're asking about it, that you talk to a shop and see if they can help you out first, before trying it on your own.

I've had good luck splittling 6 cyl exhaust manifolds to run dual... using certainium rod and preheating/post heating...but not 100% great..I'd hate to have to pull heads because of a leak/seperation in the weld.

Adding Al. is a much easier process, using Al heads kinda affords you the ability to make a mistake and recover...and the recovery is life long..not just a few months.

I think when you weigh the price of "filling" a cast iron head vs. a new head, you'll opt for new.

 

Thanks for the advice guys, but what I really need is some advice as to HOW to do this. Stock Casting heads are what this engine is going to run, and second, I have more time than I do money. The heads I'm going to finally do this to are a pair of old heavyweight "370" castings, and I have a stack of junk heads to practice on before I work on those.

I am also aware of the distortion caused by welding- which is why all machining is getting done after I weld these.

Q

 

Hey '8Mike9' It's not that much different than what you said when I was considering having a Quad Four head crack repaired.
So it's not to much of lost art untill you find out how much it cost, vs a replacment head. Needless to say I traded in the car

Hell, I think they did it with AL as well, just used a lower temp. I can't remember, but I was doing some research on repairing cracks between valve seats. Anywho....


Ron

 

cast iron can be welded relatively easily with stainless steel. (arc welding)
It bonds to cast very well and the need to preheat and slow cool is not nessesary.
a good prep of your iron and you shouldn't have any probs.
I forget which rod number we use, I can find out tommorow.
It's a kickass rod too. starts up like a dream and flows nice.

expensive though.

 

rod numbers would be some good info

 

I'd be interested in the rod info as well,

What kind of applications do you guys use it for?

 

lets see Mr. Vader is an eletrical engineer so he ought to know a lot oabout this right? not really but he does. now i'm a CWI, NDT level II certified, degree in IE, and have over 25 years experience with welding and weldments. damn shame you never ask for me i could of helped.

 

This is why the questions should not really be addressed to named individuals....IE: it puts some people "off" so to say.....

Anyway.....Mr. ede I would for one like to know since I have some welding experience (not anything like yours) and I have recently had this cast welding in mind for a project. Actually closing heat risers on the two middle ports.



Just a thought...

 

I'm sorry Ed. I directed this post towards vader simply because I recall him describing the process- which I would like described to me in more detail. If you could help me out, I would really appreciate it

 

Q,

This is not necessarily directed at you personally, but just another generic reminder.

<h1>O.K. One more time...</h1>

#1. I normally try to avoid posts that are directed at a specific member (especially ME). I usually read them, but seldom reply. This site is a community, with a lot of experience across the board. No one knows everything - especially me. I can show you how little I know if you really want. Posts are for the whole community. Private messages and email are available for specific individuals. It hasn't been easy to train everyone in this, but I keep trying;

#2. I've never preheated any casting as small as a SBC head for arc welding with nickel filler. The entire casting will get plenty warm eventually anyway - just don't quench it (except an air quench). A DC TIG with H/F start is the easiest way for me to do this, but I suppose a torch would work if you could avoid an oxydizing or carburizing flame (¿somehow?). If I have been instructed correctly, aluminum castings should be preheated and slowly cooled for welding - extrusions and forgings are supposedly less sensitive, but I'll yield to Ede's judgement on that one. Instead of an oven, I've used a rosebud tip on a torch set to slowly heat the area evenly. I've also preheated larger iron castings (John Deere clyinder cases) for nickel welding to a show-quality "cast-look" finish without failure;

#3. If you're really as bright as I think you are, you'll listen to Ede about metallurgicial matters. I've probably done it the wrong way in the past, but at least it worked out. I'm sure he could instruct you a lot better, or write volumes on the topic. If you're lucky, he might even reply with some advice. If you've offended him more than that, then you're not so lucky.

#4. Ede is correct. Welding isn't my specialty. I can slag things together usually well enough to get them to stick, but electrons are my game.

 

LOL! Maybe titles should be changed to "Experts, please help" or "I'll pay $100 to someone that helps me fix this problem"? There's so many guys on here that know so much, but sometimes it's hard to know if they've seen the message- and the more this stuff keeps up, the less we'll see of guys like Ede & Vader & GMTech (does he come around anymore?) & etc!

 

hmmm....I musta done something horribly wrong the one time I tried...it was a cast iron "drill mill" vice...I cracked it tightening a piece too much. (I have a bad habin of over tightening screws...keep me away from those headers!) So I said well I have done some welding....I know about the problems w/ cast iron...heated it up using a torch (just a standard propane torch...probably not a good idea...) proceeded to start the stick...about 1/4 of the way into the crack, the piece split again. Disheartened, I began to preheat just a small area, figuring the area I heated was cooling too fast so I should concentrate on small areas, slowly heat, weld, heat/cool....etc....I eneded up splitting it again....so I quenched it and tosssed it, and said I'll leave the cast iron welding to the pro's, I know several of the principals, I just have almost no experience....

 

Oh please....


like I said, stainless rods work great.
the rods we use are 309's

can only flat weld with em, we use them when repairing cast parts and also for certain steel fab work.

 

If I may say one thing for myself:

I directed this towards Mr. Vader for a reason. That reason being that I was interested in a very specific operation: an operation that I have seen only described by Mr. Vader and no one else during my visits to thirdgen.org. Finding out how to weld cast iron was only 1/2 of what I needed. I also needed to know where to add the metal. With that in mind, I aimed my question to the individual who described what I wanted to do exactly .

If there was anyone offended by mo post I am sorry, but then again, if you get offended so easily I have to wonder about you.


Note to self: Pick up some 309 rods and start practicing- thanks Jer82Z28