DTSFab.com (Desert, Trail and Sand)
The Machine Shop => Welding/Cutting/Bending/Forming => Topic started by: Reidy02 on December 26, 2010, 10:01:44 PM
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Hey guys I've just been trying to weld a bellhousing off an old VW beetle and I'm doing it in square wave with a 2% thoriated tungsten and it seems to weld after pre heating but when it cools down you can hear it crack sometimes when I'm a bit slow with the torch to warm it down. Oh and when it's cool you move the thing and it breaks, and you can see the porosity on the gearbox side I think I shoulda cleaned it more!! eyes Any thoughts greatly appreciated! ;D I just went and had a look it seems to me maybe it has magnesium in it?? Cause the aluminum filler rod doesn't seem to stick to the parent metal, it's all sorta crystalised where the weld came off the bellhousing, but as I weld it seems to flow together OK, but I was welding outside and I think also the wind was blowing the argon away. eyes I did bump the flow up to over 20cfh
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might want to check with Bill at AZ transaxle see if this can be done - he would know and is a member / sponsor here.
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Yeah thanks Yummi I couldn't remember the guys name! ;D Bill OK Thanks again.. ;)
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The porous casting is full of oils.
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Hey guys I've just been trying to weld a bellhousing off an old VW beetle and I'm doing it in square wave with a 2% thoriated tungsten and it seems to weld after pre heating but when it cools down you can hear it crack sometimes when I'm a bit slow with the torch to warm it down. Oh and when it's cool you move the thing and it breaks, and you can see the porosity on the gearbox side I think I shoulda cleaned it more!! eyes Any thoughts greatly appreciated! ;D I just went and had a look it seems to me maybe it has magnesium in it?? Cause the aluminum filler rod doesn't seem to stick to the parent metal, it's all sorta crystalised where the weld came off the bellhousing, but as I weld it seems to flow together OK, but I was welding outside and I think also the wind was blowing the argon away. eyes I did bump the flow up to over 20cfh
Reidy
Them VW trans's are all magnesium. You will need a magnesium rod to weld it. And yes you will need a way to keep it warm for the cool down. I used a old blanket wrapped in a welding cover to put over it when I was welding a lot of them. just weld and inch or two and then put the blanket on it for a time and let it cool real slow. On small stuff I built a Lime box. Put Lime in it and when I was done welding I would put the part in the box and cover it with lime to let it cool.
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Yeah Thanks very much guys! ;D I had a feeling it was Magnesium, Fast you're right man I asked Bill as Yummi said to and he sent me a PM telling me it's Mag Feeeeeew I looked at it where I tried to weld it with the ali filler rod and it was like crystallised and I thought man that don't look like any aluminum I've seen! Ah that makes me feel a bit better. Thanks again! Now I just gotta try and find the filler rod for the Magnesium. :o
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Just dont let that sucker catch fire!!!
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Yeah well yesterday we tried those rods where ya use a propane torch to heat up the parent metals and rub the rod on it to see if the rod would melt to weld it. A little bit flew off and burnt up so from that I think we may have been luck it didn't burn.. :o :o
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The shielding gas is what keeps it from burning during welding. I would keep open flame away if you can.
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The shielding gas is what keeps it from burning during welding. I would keep open flame away if you can.
I hate to say this..... BUT, do you know what the hell your talking about Boost?
Unless you get it to a powdered form, you won't have to worry about it starting to combust.
Reidy, it's important to keep it clean, and preheat to about 300 F. We weld mag all the time. I prefer to preheat with a rose bud, and AC TIG weld it using a really short arc, large gas cup, 30 cfm Argon, 12-14 sec post flow. I'd clean between passes, and keep your weld bead small.
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I know that once mag starts, it ain't going out. I'd prefer to not take the chance.
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keep a door open and a clear path out of the shed! Just sayin! Never welded it and have no desire to ever.
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Yeah honestly I'm not too keen on the idea! Thanks for the input guys I appreciate it! Thanks Adam I was very consious of blowing away the dust after sanding! That's very helpful all the info you put up! I was pre heating and I got one of those laser thermo guns they are handy gadgets! What's the best tungsten to use?
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I may be wrong but I am of the understanding that the cases are mag ALLOY. The alloy won't burn.
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Apparently the dust from grinding or sanding will catch fire or so I was told..
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Hell ya
Yave you ever seen the survival blocks..one side is magnesium and the other is a flint...
It's used for starting fires in the wilderness ;D
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here's a link
http://www.amazon.com/Genuine-Magnesium-Survival-Fire-Starter/dp/B0002X1IOM (http://www.amazon.com/Genuine-Magnesium-Survival-Fire-Starter/dp/B0002X1IOM)
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Apparently the dust from grinding or sanding will catch fire or so I was told..
Hell,IRON dust and steel wool will burn. Try it.Mag alloys will not burn while welding tho. Pure,or near pure,mag is a totally different animal.
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here's a link
http://www.amazon.com/Genuine-Magnesium-Survival-Fire-Starter/dp/B0002X1IOM (http://www.amazon.com/Genuine-Magnesium-Survival-Fire-Starter/dp/B0002X1IOM)
Spec,you're comparing apples to oranges. A VW case is nothing like that fire starter. WHen I was young and dumb (as compared to old and stupid,LOL!) I melted down a few cases with an oxy/acet torch directly on the case pieces into a pot to do some very small castings. Melting the case is no issue.
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I honestly don't know the exact volitillity of it but I have seen the shit burn and I know ya don't wanna be near it when it goes! But you'd have to be sorta right because they wouldn't have made engine cases outa the stuff if it were prone yo going up just like that!
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Not sorta right,my friend. ;D But,YES,be careful of ANY kind of dust near a combustion source.
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Yeah OK Fabr ;D thanks I'll keep it in mind ;)
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Yeah honestly I'm not too keen on the idea! Thanks for the input guys I appreciate it! Thanks Adam I was very consious of blowing away the dust after sanding! That's very helpful all the info you put up! I was pre heating and I got one of those laser thermo guns they are handy gadgets! What's the best tungsten to use?
Reidy, These are the types you can use with Mag and Mag alloys Ceriated, Thoriated & Lanthanated. I prefer to use 2% Thoriated on castings because they are generally thicker. If you are welding really thin areas of either Mag, Mag alloy, or Alum, then I switch to Ceriated, and grind a point on it, just like you would to weld steel. You'll still use AC, but the Ceriated Tungsten will carry more current and be more stable than the pure Tungsten.
I hope this helps Reidy. As for what filler rod, I'd start with AZ101 because you have a Mag alloy.
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Powdered mag is one of main ingred in BIG fireworks. Hell we had a sugar factory here blew to crap and back, sugar dust.
I had a mag piece welded, the guy said biggest prob was cleaning all the oil that soaked into it from the years of use.
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A lil off topic but even common household baking flour will make AWESOME flames when you aerate it into a fine powder over a flame!
Put some in a tube. Point the tube at a fire big enough to not go out with the air and hit the other end of the tube with an air hose. Pyrotechnics baby!
It takes a little to get it just right but when you do you will be surprised at the amount of flames certain flours will make.
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When I worked for Flashing Thunder Fireworks Display, we used to use coffee creamer. Try it at home, is fookin fun. I use a 1 gal ice cream bucket. Pour about .125" of flash powder in the bottom, fill the rest with coffee creamer till about 4 inches from the top and ignite the powder. The powder not only acts as the propellant for lifting the coffee creamer sky wards, but it also starts the ignition of the creamer as well. It will barley make a noise when you get the mixture perfect, but it makes one hell of a mushroom cloud and ball of fire and inferno. Check this video out.
http://www.youtube.com/watch?v=GKmyQtpvhB8&feature=related (http://www.youtube.com/watch?v=GKmyQtpvhB8&feature=related)
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mythbusters
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Reidy, These are the types you can use with Mag and Mag alloys Ceriated, Thoriated & Lanthanated. I prefer to use 2% Thoriated on castings because they are generally thicker. If you are welding really thin areas of either Mag, Mag alloy, or Alum, then I switch to Ceriated, and grind a point on it, just like you would to weld steel. You'll still use AC, but the Ceriated Tungsten will carry more current and be more stable than the pure Tungsten.
I hope this helps Reidy. As for what filler rod, I'd start with AZ101 because you have a Mag alloy.
Thanks agian for all the good info guys! I knew I could get the low down on here 8) Yeah Thanks Adam I was using 2% thoriated tungsten but it's good to know I should swap on the thinner stuff. I am getting some AZ92 filler rod and I'm gonna use helium argon mix. Is the helium mix a good idea? Oh and yeah Carl I've degreased it a few times I'm gonna wipe it down with acetone and put a smaller diameter tungsten in the torch and do a few cleaning runs over the areas to weld.
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Throw the part in an oven and burn out the oils. You can surface clean till you're dead and still have oil in "pores" of the casting.
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Thanks agian for all the good info guys! I knew I could get the low down on here 8) Yeah Thanks Adam I was using 2% thoriated tungsten but it's good to know I should swap on the thinner stuff. I am getting some AZ92 filler rod and I'm gonna use helium argon mix. Is the helium mix a good idea? Oh and yeah Carl I've degreased it a few times I'm gonna wipe it down with acetone and put a smaller diameter tungsten in the torch and do a few cleaning runs over the areas to weld.
The Helium is going to allow you to punch a lot deeper than just straight argon. Which reminds me, if you ever break thick aluminum, you can use a helium / argon mix, and DC reverse to get a lot of punch. That's the same setting you would use to put a ball on the end of your tunsten for welding aluminum. With the helium gas, your tungsten won't dance around like it does when you are running straight argon.
Getting back to the magnesium, I'd probably try running straight argon as it will likely be easier to keep your weld puddle small / narrow, which is what you want when welding that stuff.
Fabr's idea of throwing it in an oven is a great idea. ;) I've never tried it with mag, because I've never had a piece small enough to put into an oven, or an oven large enough.
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Yeah that'd be my problem too, I don't have an oven at all to put it in let alone one big enough! But thanks for all ya help guys. 8)