Skip the normal AC and run DC, mix some He in with the Ar shielding gas to put more heat in the weld and run any good size tungsten in a water cooled torch and it’s a piece of cake.

Why? It’s not like any of this has to be all that precise, zap some 5356 in there and then you have to cut/grind it to the right shape anyway. If you’re a serious monkey with them MIG you can always take the tops off your welds with an angle grinder before doing any precise work. For that matter, if you have the head preheated enough before you start going there won’t be much of an issue with cold starts so you can literally get away with spot welding the individual pock marks

Stress relieving and controlling warping are not the same thing. The only way that you’re going to do anything about a warped head with stress relieving is if you managed to stress relieve the head while it was bolted to something much stiffer and straighter then it is while doing it. The is the reason that I suggested preheating is to prevent as much warping as possible and to prevent as much of that stress from forming in the part to start with (it also lets you get away with much wimpier welding equipment). The reason to cool it slowly is to make the newly welded areas as consistent (mostly wrt hardness) as possible with the base, which will ease machining, that is if you tried to machine it right after having it welded.

 

Do you even have a MIG or TIG welder? What is the special coated tungsten you talk about cause I have never heard of it??

 

True but it's easier to yank out a 5356 stick and go to town with the TIG rather than setup the MIG for it if it's not already. The point being if you are going to be there a long time the MIG would work better since you don't have to keep grabbing for sticks.

Good points, stress relieving is relatively easy to do so just do it when you are done anyways. Most guys don't use the larger stuff so preheating the head makes sense. I'm coming from the point of putting 100cc of material in a chamber, even after you finish one chamber, go away from it for an hour and comeback the head still has enough heat in it.

Ziconium Tungsten, they put up with a ton of heat. Most welders you talk to never have heard of this.

Bret

 

HA HA Zirconiated Tungsten. The tungsten isn't coated, it has the element mixed with it. I have 2 boxes of it. If you are talking to a TIG weldor that has never heard of it, let me give you some advice, don't leave your aluminum with him because if he has never heard of Zirconiated tungsten then there is a 99.9% chance he doesn't know what the hell he is doing.

 

Yeah I have that tungsten, as well as ceriated, thorated, and trimix. I agree with ChiTown all good weldors will know what zirconated tungsten is, because it give the best performance on AC TIG.

 

Bring it over to my garage, it’ll take me about 10 min to swap the reg from one bottle to the other, and swap the wire and tip out. Well, it will only take that long if I’m some combination of pissed off, tired and don’t want to do it… less otherwise.

No 350A TIG here… honestly I’ve never seen much of a point to own one. If I REALLY need it I’ll take it down to Bill about 2 miles up the road, he has a 600A TIG the size of a refrige/freezer and has welded up some big/thick brackets and other stuff for me, for cheap.

Something like this… no problem… my little MIG or my little TIG is fine. Hell, the only way that I would do something like this without preheating was if it was an emergency repair and I didn’t have time, and if I was in that position regularly then I would have a reason for owning one of the BIG TIGs.

Again, if I was doing this, I’d consider it an all day/overnight deal. Get it preheated, weld it and then let it cool overnight, at least.

Zirconiated or Lantanlated is OK for the application… with those on the market there really isn’t a good reason for pure tungsten to exist at all. Really, for this kind of application I’ve had good luck with 1% thoriated (not the normal 2%), DC and some He in the shielding gas. Any of the alloyed tungstens will work OK, but the 2% thoriated might be prone to blooming if you try to use it with a more traditional AC or Square wave process for aluminum. Pure tungsten will only work with a big, water cooled torch, and really, I don’t like it for anything, but it is the traditional way of getting aluminum welded.

Huh, actually… just looked to see what was actually in my tig torch right now… 2% Zirconiated (brown)… huh… (I got a big pile of half used tungsten for free, so I have a tendency to use whatever is around and works OK for the application)

 

:scratching head: Are we looking at the same pics? Why add any (more) weld/material? Take it (back) out. It appears to have weld added already, to what was originally, the oem .040-.045" shelf, cast into the deck. Machine it out to the original depth/contour, to match other chambers, and be done with it.

http://img184.exs.cx/img184/9872/hpim03287xd.jpg