Welding Tips and Tricks

Dear folks , I tried yesterday to weld a magnesium piece from a outboard engine . I thought this will be a piece of cake due to this site I'm now good . So I tried and It was hard , heavy reaction form the metal no matter how good i clean it still is was very difficult .It cracked it fumed it burned . Eventually I got anxious because the time was running out and it had to delivered . Eventually after I tried all the bits and tricks I new machine in full cleaning action and the gas in 20cfh I manage to get control and get something called a decent finish . During the pressure my little had dremel rotor burn out . The price it was
prearranged in 10$ it cost me 80$.The worse bit it was when it had an ancontrolable fire that scare me that might explode or something . So does anyone know something that this will not happen again ...

Magnesium is extremely oxidating so you need to make sure you have plenty argon shielding and enough post flow to allow it to cool below ignition temp.
If it catches fire do not use water, that can start a chain reaction and act as fuel instead. There are special extinguishers developed to put out metal fires.
Sand can be used to cover a burning part.

Pick and choose your battles. I am not too proud to tell someone I can't do the job. I look at the cost to benefit ratio and decide accordingly. Let someone
else bleed to death I always say

I think you need to raise your pricing especially on magnesium cases. Considering that these cases usually contain gear oil or other fluids that are hard to remove much less from a porous sand casted part. Then factor filler cost in, I just bought a pound of AZ92 and it was around $80 a pound. I would suggest pouring acetone in case a and letting it puddle in area that needs welding and soaking for awile. Then wire brush it. Clean again with fresh solvent. V grove or grind out what you need to do then clean again with solvent if possible let it soak in area. If dealing with Gear oil since its a pain to get out. suggest using parts cleaner solvent to clean part to help dissolve the oil first then going to lighter weight solvents like acetone.

Biggest thing raise your cost. Charge a dollar a min for prep time. Charge for filler, an alumina cup and gas lens. Then charge what ever you want for actual welding time or per inch.

Listen to dirtmidget!

In a situation like this, if the item to be welded is small enough, would it make sense to wash it in soapy boiling water for a while (say an hour or so) to leach out as much of the oils as possible? I know that when I wash engine parts in solvents, they come out plenty clean for mechanical work, but there is still a film of some sort of petroleum product on the surface, even after being blown dry with compressed air.

some of them hot soap cleaning cabinets are great. yes regular parts washer solvents leave a residue and take forever to dry. acetone breaks that parts cleaner solution down pretty good and evaporates quick. I use a spray solvent from a company called wurth that I spray parts down with that get cleaned in the parts cleaner. That can get expesive using the spray stuff though and since its similar to brake cleaner I dont use it before welding unless it will be awile before it is welded. There was some stuff that ottonobedder suggested at one time for cleaning. I was gonna look into the stuff but cant find the post anymore.

You guys just gave me a brain fart, got a dishwasher that works sitting in the box the new one came in . . . . . . hmmm maybe hook that thing up to clean small parts in out in the shop. wouldn't take much to hook it up to drain and water heater. anyone ever do this Not sure how effective it would be.

Sry about hijacking thread. Will have to search topic on web.

Esenti,
Are you sure it was Magnesium? Sometimes cheap sand casted Aluminum is thought to be Magnesium and is every bit as challenging to weld because of the open pores holding oil. I'm in no way saying it's not Magnesium, just asking.

You can test it with vinegar.

Steam cleaning helps with the oil as well.

Len

dirtmidget33 wrote:anyone ever do this Not sure how effective it would be.

Regular dishwasher is alkalene which is excellent on aluminum. At work we use alkalene cleaning process prior to painting. We have lots of cast aluminum and this removes residual release agents and cutting fluid so it should be good as weld prep too.

Bluegold was likely what Steve was talking about Wallace. That stuff is awesome. It's just really expensive lol

I use gravity to help with oil soaked castings. Do the tinning-cleaning passes in a vertical position working beads from the top down horizontally.
When the crap gets built up I skim it with a fluted carbide, wipe and start again. Thin stuff goes pretty quick this way for me. Thick stuff can benefit-go quicker with a quick quenching on the back side before restarting.

You can buy Blue Gold cleaner from almost any scuba shop but they charge upwards of $100 a gallon for it. I've found it online at thecryoshop.com for about $44 gallon. It's very concentrated so a gallon goes a long way. There's places that sell it in 1 quart containers also, about $20. It's very hard to beat the price that I get it for.

Both Steve and I use it to make metals "Oxygen Clean", meaning no hydrocarbons. It's a very safe product compared to other degreasers. It has an indefinite shelf life as far as I know and you can re-use it if you're just cleaning parts, I put an oil soak pad on the top of the pan when I'm done to pick up what floats in solution.

I can copy this to the product review section.

Len

Damnit.

Len, I thought I was replying here, but I replied on your copy to "product reviews".

My age is showing...

Steve S

So I will answer to all since to talk Individually it will be complicated and some important conclusions will be lost most likely .
Since virtue is my emblem if anyone needs something extra I will be more than happy to assist .
So I was about to weld my piece and when I was about to add filler the paddle was not clear as it should be , I said hops
that's magnesium . So I pick a magnesium rod , and re clean the area , the problem arouse when the back side of it got temp
high and start a nice little strange fire typical to magnesium this should not have happened in the first place , or with buck purge or with a piece of metal to absorb heat . Cleaning is extremely important to any welding application but in this case was not the issue . It was an old aged bit full of porosity .
Usually if you get a porous there is no way to get rid of it by "boiling" extra the paddle you must grind it again and again .
I repeat the problem was the back that caused all the problems and not the cleaning , again and again the biggest ingredient is to keep calm I panic to finish , when you loose control you will panic this is the worse enemy to do the work properly.( do the right moves and enjoy the result do the wrong moves and enjoy the disaster. I you make a short cut might save you a lot of time walking if you do a short cut to welding to save time will end up in catastrophic may be I got a little philosophical but prefer to make an impact to what i did so it will not happen again.I this journey we are bond together thank you for all the
advices given .