I have to weld a mild steel stud to a cast iron exhaust manifold.
I'm no professional welder, but I can weld most mild steel with no
problems. I know that cast iron needs a special rod, which I was told
is a nickle rod. My question is how to weld this since it's both cast
iron AND mild steel. Will this special nickle rod weld both? This is
an AC stick welder. The weld itself is pretty small, just to make the
stud stay in the stripped manifold hole.
Are there any special things I need to know about welding with these
nickle rods? I have never use one?
Bite the bullet and take it to a shop. The process of welding cast Iron
is quite difficult and involves specific temp that need to be reached
before the weld and durring the cool down. If you try to weld this stud
with out preheating the piece there is a stron chance that the iron
will crack durring cool down. This is best left to a professional. The
other option I guess would be to re thred the hole and put a larger
stud with some kind of adapter if possiable..
I'm not the OP, but I have a tendency to think anything I've never
bought before will be very expensive. I needed two small pieces of
lucite 25 years ago. Turned out to cost only a dollar a piece.
Needed foam rubber. I forget but it seemed cheap when I bought it.
(3rd replacement last year seemed expensive. :) )
And welding when I needed some, was cheap too. although my needs were
less demaning than the OP describes.
I wonder if I'll ever get over the feeling that all new things are
I'd think it would be easier and better to Heilacoil it. Say it is a
or other sizes;
Hi. It is quite correct that the preheat is important. Here is a www
page that tells how to do it:
Your particular job is about the same level of difficulty. It looks
like the jigging requirements are less, but it is very likely that the
manifold is contaiminated with carbon from the engine by-products.
This is much more critical than preheat requirements. Try to
mechanically clean it, then follow the above procedure. If it fails,
which is quite possible, you will have to chemically clean it. This
will be hard to find info for on the web. Get a good welding book or
the advice of a pro. BTW, a lot of pros will not want to do the job at
this point. I have had very good luck with welding *uncontaminated*
cast iron. Remember, the peening is important.
It's like this ...........
It will work or it won't.
You say it is a simple thing just to hold a stud in a stripped hole. You
may get lucky, and have enough fusion to hold it, or it might not fuse
correctly and pop out the first time you torque it or it heats up. It's a
crapshoot. If you want to just try it, zap it with a 7018 rod with stinger
positive at a high amperage, making sure to get a puddle and fuse base and
adjoining metal. If you want to be more sure, take it to a shop. Doing it
right according to the book entails preheating, welding with a special rod,
And even then, there are on guarantees.
On Mon, 07 Aug 2006 11:02:09 GMT, email@example.com (Doug Miller)
1. No one has them in this rural area.
2. The hole only goes in about 5/8" deep and will require a special
tap, which is also not available, and probably very costly.
A one dollar welding rod sounds much easier and cheaper, but if it's
this risky, it looks like I am back to square one.
A elderly guy who used to be a mechanic said he had one like mine, and
he could not tap it either because the hole is so shallow and does not
exit on the top of the manifold. He's a Ford guy, and he went on for
15 minutes how GM really f**ked up on these manifolds. I am not
"sold" on either Ford or Gm because they both have their faults, but I
will agree with him about this manifold being a poor design. He told
me he once had the exact same problem, and he tried everything. He
even tried some furnace cement but found it would not stick, He
finally went and just drilled at an angle right thru the side of the
manifold and put a bolt right thru the side of it at an angle. He
said he pushed the bolt in the hole and bent it somewhat straight at
the tip. This might be my only option aside from replacing the
manifold, which I wont even consider as an option with all the AC
pieces and other junk that would have to be removed to get it out, if
not pulling the engine entirely. I'd take it to a welding shop in a
second, but once again, I'd have to remove the damn thing. I'm
beginning to think it's Maybe time for a different car because this is
getting real tiring.....
If only someone made an extremely hi-temp epoxy. Don't NASA have such
Thats what I originally wanted to use, but it appears the manifold is
too hot. JB Weld says up to 600 deg. I dont know how hot a manifold
gets and no one has given me an figures. JB Weld would be real easy
to do too.
Yes, they do seem to have everything.
Question: Is a "bottoming tap" what I need for a hole that only goes
in about 5/8 inch? and stops? It needs to thread most of this,
without leaving the useless tapered threads.
You haven't been looking very hard. Got an Ace Hardware anywhere near you, or
a NAPA Auto Parts store? If not... try other hardware or auto parts stores --
there must be some nearby -- or search on-line.
The taps are available anywhere the inserts are. Any decent hardware store
(and that does *not* include Lowe's, Home Depot, etc) will stock Helicoil
inserts and taps, or surely be able to order one for you.
A tap and insert together won't cost you as much as having the stud
professionally welded... and you may even be able to rent the tap.
Spend some time with the Yellow Pages in one hand, and a phone in the other.
No, you're back to using a Helicoil.
Doug Miller (alphageek at milmac dot com)
On Mon, 07 Aug 2006 18:52:02 GMT, firstname.lastname@example.org (Doug Miller)
No Ace hardware stores, the local small hardware store did not even
know what I was talking about. There is a NAPA, I will ask them. I
generally use Car Quest, but I'll ask NAPA. If not, I'll check online
sources. However, will this tap work on a shallow hole? I dont mind
buying the stuff, but it's got to work for my situation.
I wouldn't be caught dead living in a city, but the disadvantage of
rural life is the lack of hardware and construction supplies. We have
one mom&pop hardware. Napa and Car Quest, 2 mom&pop lumber yards that
charge twice the price of a place like Menards or Home Depot. The
nearest larger city is 55 miles away and at todays gas prices I dont
get there very often, and of course when I need car parts, I got no
way to get there since my farm truck is not valid to drive in the
city. Our small local town just got a big improvement. Another
grocery store. Like we really needed that !!!
I betcha you talked to some of the teenage help. Go back to the hardware store
and find an employee with gray hair, and ask him.
Or check with whoever fixes cars in your area. Anybody who's been doing
mechanic work for any length of time will know where to get Helicoils.
CarQuest is a decent bet too. Ask them both.
If you go to www.helicoil.com, you can find addresses and phone numbers that
will enable you to ask that question directly of the manufacturer.
Doug Miller (alphageek at milmac dot com)
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