VC bung welding troubles
 

So I have welded a few -10 fittings on some B-VTEC cover and they came out somewhat decent. But this last one I tried to do, I couldn't get a clean puddle to form if my life depended on it. It would start popping and cracking, all while developing this black soot that would only spread like a wild fire. and I would end p with something that looked like a dried up lava rock, fll of pin holes and black in color. I thought I had done a decent prep job on it by stripping the paint to at least 2 inches away from all sides of the fittings, sanding down to what appeared to be clean aluminum, and giving a good once over with my dedicated SS wire brush.

Oh by the way I'm using a Diversion 180, 3/32 2% ceriated sharpened to a point, and 3/32 5356... Hopefully it something I have done wrong, and correctable. Thanks Guys!

Re: VC bung welding troubles
 

did you clean the inside? sounds like argon isn't covering also.
also might want to add more cleaning to the AC balance cycle.

Re: VC bung welding troubles
 

yea, I cleaned the inside as well. I used my die grinder with a red scotch brite pad and followed with my SS wire brush. These welds were doomed from the get go, they never made a clean puddle. To me it looks like the aluminum is actually saturated with oil and its coming through as soon I try and melt it.

Re: VC bung welding troubles
 

That's exactly what happens. I like to sand blast both sides. Take the torch, and dont even weld at first, just go over it with the torch on very low heat. You'll see all hte oil start to burn up. Wire wheel it clean. Heat it very slowly with the torch. Clean again. Once you dont smell oil anymore you're good and it'll weld just like normal.

Re: VC bung welding troubles
 

Seeing how much extra work it took me to cut that bung off and make the surface flat again... I'm definitely going the extra 3 miles on prep next time.

Does anyone know of any chemical i can use to help out? I read somewhere that some people use some chem. let it sit for a few minutes then burn it off with a propane torch. does this sound familiar to any of the pro's?

Re: VC bung welding troubles
 

I think acetone and torching it first is probably ok. I used to just clean well and use high cleaning on the AC balance. Perfect welds every time.

Re: VC bung welding troubles
 

I got my valve cover acid dipped first, Then mig spot welded the 4 bungs all around to the valve cover then tig welded it to make it look clean.

Re: VC bung welding troubles
 

Sounds more like gas coverage issues than issues with the metal. Bad argon coverage will make it turn dead black and pit really bad. If you have some clean scrap laying around try welding on that and see if you continue to have the issue.

Re: VC bung welding troubles
 

IMO This is the best way to get nice clean aluminum welds. The surface does need to be cleaned/prepped well though. Use that AC cleaning action and slowly heat the metal till a nice shiny puddle forms.

Also i would try using Zirconium it has better arc stability and Reduced weld-metal contamination compared to 2% Cerium

Re: VC bung welding troubles
 

I'm using a diversion machine so I can't change any balance or any of that good stuff. I'm also using a gas lens with a 7 cup, pure argon at about 15cfh. I'll try the acetone and some really low amperage passes to see if I can get some of the saturated oil to burn off. I'll see if my LWS has Zirc tungsten's in stock on Monday and try that out too

One thing that just cam to mind is that these issues are most likely magnified because I'm welding the bungs onto the rear of the VC where it has always been fully exposed to oil

Thanks for all the input guys, this is def. the most productive sub forum on this entire site :thumbup:

Oh and I almost forgot, i was getting so frustrated that I did try a bead on a piece of scrap and it came out perfect

Re: VC bung welding troubles
 

Since you have an inverter machine, I would say go with Thoriated red tungsten with a sharp point. Dont know much about diversion but just looked it up and it's too bad you cant change the balance. That will be a let down eventually.

So now you just need to clean well, torch, clean again, use red tungsten and keep good gas coverage (even get a lens if needed)

Re: VC bung welding troubles
 

Someday after i can make some purrdy, strong pieces Ill end up getting a dynasty. I just couldn't afford that extra 1,200 right off the bat... thanks again for all the help guys

Re: VC bung welding troubles
 

Well in that case you don't need anything but cleaner basemetal on your valve cover. That should be encouraging...Use a torch to burn anything out.

Re: VC bung welding troubles
 

all the above methods help, but, I have also learned that turning argon flow DOWN to around 9-13 on the flow meter helped GREATLY. It was an instant improvement on the same weld I was fighting with.

Re: VC bung welding troubles
 

we use to keep an old dishwasher around just for cleaning parts like this, what you are experiencing is deff all of the above. sometimes the valvecovers can just be tricky. I had a company with some great fittings and cheap too and I notices the more i concentrated my arc on the fitting and just briefly dipped to the VC it was perfect, very tiny and very clean welds.

Re: VC bung welding troubles
 

Was this with Aluminum or what? Just curious

Re: VC bung welding troubles
 

I tried concentrating the arc on the fitting but I almost couldn't keep it from melting away. when you guys keep saying to clean with a torch, are you talking about a low amp pass with the tig torch, or hit with a propane torch? just wanted to clear that up

Re: VC bung welding troubles
 

Probably talking about hitting it with a propane torch to burn the excess oil that is coated in the metal, heating it until it comes out of the metal. ( Kinda like it does when you attempt to weld it)

Re: VC bung welding troubles
 

Yeah propane torch to just burn any contaminants away. Oil is really hard to get rid of sometimes..

Re: VC bung welding troubles
 

Use acetone and when your getting holes such as you are and black soot...usually the black soot is gas and even flakes into the air...clean the surface with acetone..this will break down oil or anything in its way and be sure the weld is free of porosity or pin holes as for using the tig to make it look good is a great idea but if the existing weld is bad then you can hit that weld all day and the tig will draw anything in that mig weld to the surface and keep doing the same thing...remember tig is getting more penetration than mig and is directing more heat in a smaller location..so if the mig is contaminated with oil holes etc...then the tig will just keep bringing it to the surface....what I would do is grind or file away the surface of the mig make sure its a clean weld..if you see holes then its no good..if not file or grind it evenly and then acetone it and make sure its acetone..other things used to clean such as degreasers have oils in which will do this to your tig pass..acetone will break all that down and dries very quickly and cleans all the contaminates out..so make sure your first weld pass is good clean with acetone and your ready...with tig make sure your tungsten is clean and free of spattered junk that may have got on it and gas on tig 30-35 for steel 22-26 for stainless...but remember!! The first weld must be good clean and no holes or the tig will just keep bringing it to the surface...hope this helps buddy...so to sum that up focus on your first weld make sure it was good clean weld..then use acetone only and set machine to dc clean surface and tig it up..just make sure tig is getting gas...because black soot usually is a sign of no gas and that gives you the lava look also...sorry to make so long but I wanna help and explain everything as much as possible to help you get a good result..two sentences aren't helpful when it comes to this!! Need anything or make out well let me know hope this helps buddy..
U

Re: VC bung welding troubles
 

Sorry if I said dc if aluminium I meant ac plus use the red tungsten its harder and you can keep your point much easier...also if aluminium then that's even more of a must for acetone!! Aluminium mist be very clean and make sure you use a small cup!! Sorry I read above wrong!!

Re: VC bung welding troubles
 

^^^ this is most likely what's happening. If anybody above has welded aluminum pieces that have cycled oil, then they know what is happening. It's not poor gas coverage from your collet body. But not preheating, or preburning the oil in aluminum will have the op's problems.

Re: VC bung welding troubles
 

this problem sucks!! I have spent alot of time today heating, cleaning, heating cleaning, re shaping, heating , cleaning, burning, filling, etc... making progress but I will most definitely be taking extra time in prep next time...

I also may just try welding the bung from the inside first next time too

Re: VC bung welding troubles
 

Those are some super high gas glow ratings if your gauge is in LPH. should be about 15 for most anything with about a normal 3/8"-1/2" cup nozzle size. higher if a bigger cup is used and lower if a smaller is.


To the OP. You can also run your TIG torch over the weld area after you use the propane torch. This will have the effect of cleaning the weld area too. No filler and leave the bung out of the hole. Just run the TIG torch around the hole with lower amperage and it'll clean it.

Re: VC bung welding troubles
 

I've tried to burn it out with propane. Propane is not hot enough IMO, you really need an oxy torch if you're not trying to go over it with the tig torch first. that is unless the piece you're welding is so small that the propane will heat it up, but if its a sizable piece at all propane will just take FOREVER.