welding a cylinder head!

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hey guys im new to this forum, and i am looking for some advice on welding a aluminium cylinder, like what filler rod to use (as its a cast aluminiun head i assume), and any other tip like preparation cleaning ect... many thanks!
Reply:There are a couple threads that talk about welding aluminum heads, you would have to search for them to find them. Zap is one that has done it I think.
Reply:If it's cast then I would use 5356 for filler..Is it possible to post a pic of the problem??...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:I will be much easier if you preheat the weldment to about 350º THEN weld.AWS certified welding inspectorAWS certified welder
Reply:If this is just an experiment thats cool. If your new to welding with a stick and or welding Aluminum  plus want to use this head again you may want to break down and have it done for you, at least until you have some more experience. Aluminum can be tricky and heads are a few bucks. DrivesectorDrivesector Hobart Handler 140Hobart Handler 180Ready Welder 2Hobart Air Force 400Airco Stinger 225Of all the things I've lost, I miss my mind the most."OZZY"
Reply:This is how we do it in m y end of the world:If it is cracked grind the crack out completely ,(if you dont it will recrack or come out again during cool down)Preheat head in an oven of some kind to between 400&450 degrees(be careful not to go over500 degrees cast aluminum anneals at that point)We use 4043 rod with straight argon( some use argon helium mix for more penetration,but with good preheat you dont have a problem)After welding put back in oven and let cool down.After all that heat from welding the head might bend with the center raised up on top,And thats another hole process to straighten it...I wonder if I will be spanked for this one too!?!
Reply:Originally Posted by zapsterIf it's cast then I would use 5356 for filler..Is it possible to post a pic of the problem??...zap!
Reply:Originally Posted by zapsterIf it's cast then I would use 5356 for filler..
Reply:Originally Posted by HephaestusCrack the books Zap. Last I checked 5356 filler is discouraged on anything to be used in an "elevated temperature service" application. (extended periods over 150 deg F).Cylinder heads are a high temperature application. 5356 would be considered a no-go for anything bolted to an engine regardless of the casting alloy being repaired.
Reply:thanks for the advice guys, ill use a 4043 silicon rod, i was aware of the fact that a 5356 rod might crack at high tempatures, i use the 5356 filler rod for marine grade aluminium welding so i am familiar with the rod!! Thanks again!
Reply:Originally Posted by makoman1860Its even more basic then that, the metalurgy of the interface would be not acceptable....I mean thats BASIC.....for about...I dunno....98 years now we have used the same filler metals for most aluminum work. Either that Zap guy is just pulling a joke....or seriously needs to become educated on aluminum welding.
Reply:Originally Posted by zapster 5356 if the head is cast....zap!
Reply:The main problem with welding cast aluminium / silicon heads, eg: 4000 or 6000 series, is the 4043 filler is well undermatching in strength. If large cracks are repaired, the soft weld repairs often don't last, leaky head gaskets are inevitable.Small minor repairs can be successful. Baking at 150°C for some time will assist is "drying out" the casting, oil impregnation is murder when trying to perform repairs of this type.For welding - 100°C preheat via oven to ensure even heat throughout, 4043 filler, clean out prepared excavation again immediately prior to welding, cool slowly in vermiculite, machine, then hope for the best when back in service.A lot of effort, and usually a replacement head can cost less with less headaches and longer service.Cheers
Reply:Originally Posted by BurnitCare to explain why?
Reply:ZapsterShould not be a problem for small repairs, GTAW AC aluminium is very high dilution, so < 50% of your weldmetal is BM anyway. Al / Si alloys can only be hardened by "cold work" therefore 4043 weldmetal is low strength. Both the 4000 and 5000 series are non heatreatable to improve properties, however Mg additions will increase the hardness / strength of Al.Someone stated before 5000 series, Al, Mg alloys are not suited for service above 65°C, however this is base material related, and stress corrosion may be a problem where stresses are present at temperatures above 65°C, ( 150°F for you lot ).I suspect your weld chemistry when welding 4000 series with 5356 may produce a heat treatable alloy, not unlike the 6000 series - Al, Mg, Si. - This could be a good thing !Welding is a casting process really, and BM dilution always should be considered.Nuff sed !!!Cheers.
Reply:Originally Posted by zapsterNo joke at all..I have repaired dozens of heads from lawnmowers to 7 sec dragsters with 5356 if the head is cast.No failures..4043 is what I use in billett heads..Here is where I agree to disagree and I should have known by now "not to get involved"I have a pic somewhere in my other computer of a 351C head that lost a valve @8000 and was torn up pretty bad..All done with 5356..It still runs mid 9'S today..I'll look for the pic later.So just agree to disagree and we'll all live happily everafter......zap!
Reply:Originally Posted by zapsterNo joke at all..I have repaired dozens of heads from lawnmowers to 7 sec dragsters with 5356 if the head is cast.No failures [...YET]..So just agree to disagree and we'll all live happily everafter......zap!
Reply:Dont get too offended Zap I was also told the way we repair heads for over 15 years,Yamhato motors(who builds motors for Jasper),every automotive machine shop I have talked too,and every article in automotive machining mag. is wrong...If the head gasket fails or the head cracks again, it is from being over heated again,proof is from what we use in the biz called a heat tab...If the head cracks again its not on the weld or the edge...So I guess I will keep repairing them using the industry standard...And Zap if it works for you,KEEP DOING IT YOUR WAY!!!!But I guess Im too stupid to know better...I wonder if I will be spanked for this one too!?!
Reply:Originally Posted by ELCO1And Zap if it works for you,KEEP DOING IT YOUR WAY!!!!
Reply:Originally Posted by zapsterI plan on it..Funny though..This thread had no answers untill I chimed in..Now suddenly there are experts from all over saying it's all wrong..And I'll bet the experts have never sat down with a blown up P.O.S. and worked for hours on it to get it back min service..I have done dozens of heads..How about the rest of you?How many between all of ya?...zap!
Reply:To answer your question Zap, we weld 1 to 4 cyl. head a week.Ranging from 1 scorch mark were the gasket blew to total destruction of the combustion chambers... I didnt reply till after you because I didnt read it till then, and no Im not saying your wrong I just said this is how we do it...I wonder if I will be spanked for this one too!?!
Reply:Let  me tell you our expeirence...We take alu. cylinder head to be made of A356 alloy or something very close (it means AlSi12... or AlSi10... or AlSi7... families of alloys) and proceed accordingly...We preheat to around 250C and use 4047 rod (AlSi12). In very rare occassion we fail.If we failed we believe the problem is in sealing compounds. A lot of heads (castngs) were dip in some penetrating sealing fluid in order to seal microporosity.While weld, such compunds are great problems...
Reply:Have a close look at the various markings cast into the part, sometimes the manufacturer makes things easier for you...The bottom line on the pic is the alloy the part was cast from. You can use that to get filler recommendations/the parts weldability from all the usual suspects- sticking 'welding alsi9cu3' into google for example will produce hits like THISAs (almost) everyone said, 9 times out of 10 the casting will be primarily Si based
Reply:Yeah its nice when they cast the actual alloy in the part, Europeans are pretty good for that, but then I think they tend to not be as wasteful as the US and keep vehicles around longer....or at least are willing to do more to repair them. That and as with any alumunum casting....it only has so long to live...so sometimes as the vehicle gets older, constant welding repairs (more constant if incorrectly welded) are a common method of keeping it running. Certain aircraft cylinders are known to crack in non-critical locations, so welding at overhaul is a common business....again using the CORRECT methods and materials.Research the repair yourself, read technical books, understand what your doing, and if what your doing contradicts science and engineering.....maybe think twice about it.
Reply:Actually Mako I lived in Germany for 3 1/2 years (early 1998 to late 1991) and you didn't really see all that many old (as in 20 years or so) cars on the road like you do over here. Their annual inspection is much tougher than any I have seen over here and they are very specific as to how repairs have to be made. A good example is rusted out body panels. Here if we did anything at all fiberglass is acceptable. Over there all of the rusty material must be cut out and a replacement panel welded in. I did a few fenders and floor boards when they could catch me on post and off duty and no I was not an army welder. It's a whole different world over there. I didn't say anything about how to go about this repair because I have no expertise or even experience with aluminum heads. Now cast iron is a different story.Last edited by Jolly Roger; 08-23-2008 at 08:29 PM.Reason: added toThe difference between art and craft is the quality of the workmanship. I am an artist.Priceless-Not one Slagger involvedEd Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:Originally Posted by Broccoli1Priceless-Not one Slagger involved
Reply:Originally Posted by Jolly RogerActually Mako I lived in Germany for 3 1/2 years (early 1998 to late 1991) and you didn't really see all that many old (as in 20 years or so) cars on the road like you do over here. Their annual inspection is much tougher than any I have seen over here and they are very specific as to how repairs have to be made. A good example is rusted out body panels. Here if we did anything at all fiberglass is acceptable. Over there all of the rusty material must be cut out and a replacement panel welded in. I did a few fenders and floor boards when they could catch me on post and off duty and no I was not an army welder. It's a whole different world over there. I didn't say anything about how to go about this repair because I have no expertise or even experience with aluminum heads. Now cast iron is a different story.