TIG welding cast aluminum

[ALLstrokedOUT]

Hello everyone,

My question is what the title says...Ive taken a used edelbrock intake manifold and drilled holes out to tig in some injector bungs. My friend and i tried to tig them in yesterday with no luck. I brushed the surface of both the intake and injector bung well with a stainless steel wire brush, but we couldnt get the filler to bond to the casting. Are there any tips or tricks to this? For a bit i tried preheating it with a torch, but didnt know what temperature i got it up to (or what it was supposed to be up to, 300deg?). Should i grind a bit of the surface of the casting down to get below the aluminum pores that have been exposed to the atmosphere?

Even though it is a used intake it is very clean with no carbon deposits or any obvious contamination. We were using a Miller Dialarc HF (i think 40-165amps?) with i believe a 1/8 green tungsten, but we also tried a smaller red as well. For the filler rods we also tried a couple different ones, i dont recall the number on them though...

Thanks for the help, this is the only thing holding my project up and would like to have this done privately and not pay for a shop (more for pride than monetary reasons haha).

[80proZ]

What filler? 4043 or 5056 would be good filler. Sounds like your either not getting a proper puddle or the filler wire could be dirty. Cleaning up around where the bung will be welded in will help. It'll take quite a bit of heat to get the weld started. And don't use the 2%(red) as it will spit tungsten into the weld at the amp levels needed to weld.

[ALLstrokedOUT]

Thanks for the quick reply. I believe we tried both fillers, i know we used the 4043. We'll stick with the green then, the red was just a thought; the welding shop owner said he has had good luck w/ the red and aluminum, but i know green is to be used with aluminum...Would a square wave be easier to weld with than a sine? The only other time i tigged was in a welding class with a dynasty 300, so i dont have much experience to draw from.

[dannyho]

I had to weld a cast aluminum piece recently and i fought with it for a while before tracking down a local guy to do it. the thing is, he only charged by 40 bucks and i had him join a broken convertible top linkage as well as build up material for an ear that had snapped at the bolt hole. he did a really good job on both parts. I'm just saying that a local welder may be worth looking into. to be honest i probably spent more money trying (and failing) to do it myself than he charged me. that cast has so much other junk in it it's so unpredictable in what it's going to do. I wish i knew the guys trick, but at that price I don't mind being in the dark.

[ALLstrokedOUT]

Thanks for the advice. There's a very good welding shop in the same industrial park as us, it would get done quicker and probably look better, but I'd like to say I welded it. At this point it would've been a lot less work and money to have bought an edelbrock efi manifold from the get-go, but with all the pieces to the puzzle it's too late to do that...

[BuzzKillian]

You didn't say what gas you were using, 100% Argon should be what you would use for something like an Intake. I'm not real sure 165 amps is enough to burn the contaminations out of the cast material. We use a 350 amp welder at work.

[ALLstrokedOUT]

...I see, I did have the pedal pegged in our attempts, but in our tests on spare injector bung slugs you could melt right through them at 3/4 pedal I guess that's where the finesse of tig welding comes in...I think that was going to be our next batch of attempts, upping the amps. And yes, sorry I didn't mention, it is 100% argon.

[sccacuda]

Most intakes with the exception on Cup stuff is not great aluminum. Lots of impurities. You will clean it, start to weld, bring more contaminants to the top, stop and clean/grind, and weld it again. Even the best welders won't make it look pretty. That being said, you can use a color stick and try preheating. I set my stuff on wood to insulate it from the table, otherwise it tries to steal your heat. Keep the arc on the runner until you get a puddle and sneak over to the bung and dip the rod. You may have to pulse it with the pedal. I absolutely hate welding cast intakes. They never seem to stop puking out impurities, and the heat management is tough between the runner and bung, but once up to temp, they do okay. I've had the best luck at higher amps (140 or so) and move quick or pulse.

[parsonsj]

I welded an LSx block a couple months ago, and it was hard to get the puddle to start, and that's way better aluminum than a cast intake. You'll need to max your welder to get the puddle to start. Once the puddle starts and you get it on the bung as well, you may be able to reduce heat. It's frustrating... especially when you have to do 8 of them. Good luck!

[ALLstrokedOUT]

thanks guys, I gave it a quick shot today..first off one issue was we didnt have high frequency on constant, it was just on start...but you can definitely tell the impurities in the casting are a factor, I thought the filler rods were to blame at first. I laid like two beads but my friend needs to put a bigger breaker in the fuse panel, it blows pretty easily, with that fixed we'll have more than enough amperage to get it done.

[ccm399]

1/8" Tungsten is way big for those amps.

I would suggest using 3/32. 1/8" will notget up to proper temp on an intake manifold. I used to repair heads and such in a former life and I always used 3/32 green or more recently red tungsten (Miller Syncrowave 250). You will have to sharpen the red more often but it is easier to control the heat with a pointed tungsten.

With a max of 165 amps will be a little tough to get the puddle going, pre-heating as has been mentioned is going to help a bunch. If you run into impurities you can weld up the area without the bungs (run a bead around the hole then make another lap of the area, then grind off the soot and contaminated area and repeat the process until you no longer get impurities. At that point you can grind it off one last time then prep the area for the bung and weld away. This is a long process but if you are having troubles with impurities it could be your only option (ask me about welding up Batten Olds heads some time!). 4043 1/16th or 3/32 filler would be the rod I would use. If your machine has a cleaning cycle turn that up fairly high when welding cast.

Anyway, ditch the 1/8" tungsten and I think you will have much better luck. Even when going over 200 amps in the Sync I would rarely switch to 1/8".

You should be able to get the welds done with 165 amps. I repaired the bell housing that was in multiple pieces using my Diversion 165 and it worked just fine.

Chris

[ccm399]

I thought the filler rods were to blame at first.

Try this, dampen a rag with lacquer thinner, then with the rag in one hand use your other hand to pull the rods through the rag. You will be surprised how much "stuff" you will get off rods that look perfectly clean. Let the rods sit for a minute or two and then weld away. Also, after brushing the manifold and bungs clean them with the lacquer thinner too. I hear denatured alcohol works well too but I have never tried that personally.

The last thing I'll say is this.... be SURE you do not have the rag near you when you are welding!

[ALLstrokedOUT]

Thanks for the tips guys! I'll be sure to try them...I've got more than 165amps at my disposal, the only issue was tripping the breaker- that issue will be resolved tomorrow, and I should have plenty of amperage. I'll be sure to try out the the thi ner as well

[jlcustomz]

Another tip to weld hotter with aluminum is a helium mix will weld much hotter & not require as much amps. Can be mixed with argon or I have heard of some using pure helium to weld heads & blocks. Check into it.
Also with aluminum ,rewire brush the area each time before you restart may help.

[ALLstrokedOUT]

Thanks guys for the advice, we got everything welded up! Some of the welds arent the prettiest,but i was going to dress them up a bit anyways, they just need to be air tight anyways...Im hoping to be trying out and buying a Syncrowave 351 this weekend, so i should be getting a lot more practice in the future.