I want to share with you my struggles with welding stainless steel for the first time. Most everybody these days uses a tig welder with a foot pedal. The thing I love about the foot pedal is that you have a lot of control over your heat output. However, what most people starting out don't realize is that the foot pedal is just a percentage of what your machine is set at. I used to think that I could control the heat no matter how high I set the amperage. While that may be true to a certain degree, it really makes a big difference when you weld thin guage materials. The thing that you have to keep in mind whenever you weld stainless is that the the properties that make stainless resistant to corrosion can be burned out. What I am talking about here is chromium and nickel. This is what gives stainless steel its corrosion resisting properties. If you overheat stainless when you weld, you can easily burn out the chromium and nickel and it's no longer stainless steel. The way to tell if you have kept your heat right is to look at the color of your weld. The ideal color is a nice yellow. The weld itself will show your heat as it varies. Now the less heat you apply the better, but after all, we are melting metal here. Ok, I'm not going to go into all the technical stuff here so I'll give you guys the quick version. Set your heat low, and I mean low. I would set my amperage between 25 to 40 amps and that was for welding 16 and 18 guage stainless. As soon as you strike your arc you have got to move. You cannot stay in one spot for too long. This will help avoid overheating as well as heat sinks. I would always have different lengths of 3/8''brass to clamp behind weld joints. The other thing that I like to do is turn up my shielding gas. I would do this for a lot of repetative welds. This would allow me to weld a bit faster. Especially if you are just fusing. Remember, what works for me might not work for you and vice versa so always keep an open mind and try different things. If anybody has any specific questions that they would like to ask I will do my best to answer in a timely manner.
Monday, January 3, 2011
Wednesday, September 15, 2010
Fusing vs. Adding Filler
I might make some people mad with this. A lot of guys who fuse do so because they don't know how to weld. Not everyone of course but from my experience I have seen guys who think they can weld and all they know how to do is fuse weld. I am a big believer in adding filler wire!! Especially with stainless. Don't get me wrong, fusing has it's place.
The first thing you learn when you start off TIG welding is how to fuse. This basically is when you melt two pieces of metal together without any filler wire. This is good when you are assembling something and you need to stick it together and you don't want to run over any big tack welds. One of the difficulties of fusing is that if you don't have a tight fit up, you're not going to be able to fuse.
When you have thin gauge sheet metal, it's the preferred method. You might also want to take into consideration if you have to clean up the weld. If you just fuse, you can't grind off too much.
One of the main reasons I don't like to just fuse is because you don't get the strength as you would with filler wire. If you add a little wire in there it will be a lot stronger and you also have something that you can grind.
You must think about what you are welding. For example, if you are making something that is going to be exposed to any vibrations, fusing alone will not be enough. It will hold for a little while but you will be right back welding it again. When I made stainless steel tables for restaurants they wanted us to fuse everything! Yeah, it's faster and there is no clean up but a few years down the road after that table is in a restaurant and it's being abused every which way, welds will break! In this day and age, company's want things done fast. People just don't want to pay for quality work these days. They have the mentality that once it's out the door it's not their problem anymore. I can't stand that!!
I know some company's would fire you if you get caught fusing!! Anything in the aviation field must be welded to be strong. Fusing is a big no no! Then again, when dealing with food or liquid pipes fusing is preferred because germs and bacteria can be trapped in the ripples left by adding filler wire, so each one has it's place. Your job is to figure out what is needed.
The first thing you learn when you start off TIG welding is how to fuse. This basically is when you melt two pieces of metal together without any filler wire. This is good when you are assembling something and you need to stick it together and you don't want to run over any big tack welds. One of the difficulties of fusing is that if you don't have a tight fit up, you're not going to be able to fuse.
When you have thin gauge sheet metal, it's the preferred method. You might also want to take into consideration if you have to clean up the weld. If you just fuse, you can't grind off too much.
One of the main reasons I don't like to just fuse is because you don't get the strength as you would with filler wire. If you add a little wire in there it will be a lot stronger and you also have something that you can grind.
You must think about what you are welding. For example, if you are making something that is going to be exposed to any vibrations, fusing alone will not be enough. It will hold for a little while but you will be right back welding it again. When I made stainless steel tables for restaurants they wanted us to fuse everything! Yeah, it's faster and there is no clean up but a few years down the road after that table is in a restaurant and it's being abused every which way, welds will break! In this day and age, company's want things done fast. People just don't want to pay for quality work these days. They have the mentality that once it's out the door it's not their problem anymore. I can't stand that!!
I know some company's would fire you if you get caught fusing!! Anything in the aviation field must be welded to be strong. Fusing is a big no no! Then again, when dealing with food or liquid pipes fusing is preferred because germs and bacteria can be trapped in the ripples left by adding filler wire, so each one has it's place. Your job is to figure out what is needed.
Friday, June 6, 2008
Aluminum welding tips
A lot of people consider aluminum welding to be the hardest metal to weld. This in my opinion is debatable.
A characteristic of aluminum is that it has a great affinity for oxygen. The atoms of the aluminum combine with the oxygen in the air to form a high melting point oxide that covers the surface of the metal. Pure aluminum melts at 1200 degrees and the oxide that protects the metal melts around 3700 degrees. You have to clean the oxide off before welding. The thermal conductivity of aluminum is very high. In other words, when you apply heat to one area of aluminum the whole thing gets hot. For this reason, you have to apply heat much faster to the area being welded.
Aluminum has to be super clean before welding. You can clean it using a wire brush or using special aluminum cleaners that you spray on and then wipe off. It's important to remember not to use a wire brush after using it on steel or other metals. It picks up contaniments from other metals.
If you are going to be TIG welding aluminum you should use a pure tungsten, although the 2% thoriated tungsten will also work. When welding aluminum you don't sharpen your tungsten to a point. You want to have a rounded end. To get this what you can do is switch your polarity on your machine to DC+ and then hold your torch over a piece of brass and then touch the pedal. You will see the end of your tungsten begin to ball up. After a few seconds of this stop and remember to switch your polarity back to AC. The ball of the tungsten should be nice and shiny.
The amperage required to weld aluminum is a lot higher than that of steel. However, once you get it up to the right temperature you back off. A good rule of thumb to determine the right amperage that I use is this. Lets say that I'm welding 1/4'' thick aluminum. I convert that to a decimal form and this is what I set my machine too. For example in this case it will be 250 amps.
Pure argon is used when welding aluminum. It somewhat cleans the metal as its being welded. Now when welding thicker aluminum I will use a 50-50 mixture of helium and argon. By doing this you can get to your melting temperature a lot faster than with argon alone. However, the cleaning properties are not as good as with pure argon.
Before beginning the weld you switch your polarity to run on AC. Watch for the base metal to become molten before you dip your filler rod into the pool. This is where a lot of guys have trouble. They don't wait long enough to actually melt the base metal before they start applying the filler.
When welding thin aluminum, you have to have good tight fit ups or else you will find that the aluminum wants to run away from you when applying heat. A piece of brass behind the metal will help a little with this. Also, it will prevent burn through.
I think I could write a book on welding aluminum, I will try to incorporate better tips for certain applications in another blog. As I always say, try different methods and techniques because what works for me might not work for you. No two welders will weld the same.Click Here!
A characteristic of aluminum is that it has a great affinity for oxygen. The atoms of the aluminum combine with the oxygen in the air to form a high melting point oxide that covers the surface of the metal. Pure aluminum melts at 1200 degrees and the oxide that protects the metal melts around 3700 degrees. You have to clean the oxide off before welding. The thermal conductivity of aluminum is very high. In other words, when you apply heat to one area of aluminum the whole thing gets hot. For this reason, you have to apply heat much faster to the area being welded.
Aluminum has to be super clean before welding. You can clean it using a wire brush or using special aluminum cleaners that you spray on and then wipe off. It's important to remember not to use a wire brush after using it on steel or other metals. It picks up contaniments from other metals.
If you are going to be TIG welding aluminum you should use a pure tungsten, although the 2% thoriated tungsten will also work. When welding aluminum you don't sharpen your tungsten to a point. You want to have a rounded end. To get this what you can do is switch your polarity on your machine to DC+ and then hold your torch over a piece of brass and then touch the pedal. You will see the end of your tungsten begin to ball up. After a few seconds of this stop and remember to switch your polarity back to AC. The ball of the tungsten should be nice and shiny.
The amperage required to weld aluminum is a lot higher than that of steel. However, once you get it up to the right temperature you back off. A good rule of thumb to determine the right amperage that I use is this. Lets say that I'm welding 1/4'' thick aluminum. I convert that to a decimal form and this is what I set my machine too. For example in this case it will be 250 amps.
Pure argon is used when welding aluminum. It somewhat cleans the metal as its being welded. Now when welding thicker aluminum I will use a 50-50 mixture of helium and argon. By doing this you can get to your melting temperature a lot faster than with argon alone. However, the cleaning properties are not as good as with pure argon.
Before beginning the weld you switch your polarity to run on AC. Watch for the base metal to become molten before you dip your filler rod into the pool. This is where a lot of guys have trouble. They don't wait long enough to actually melt the base metal before they start applying the filler.
When welding thin aluminum, you have to have good tight fit ups or else you will find that the aluminum wants to run away from you when applying heat. A piece of brass behind the metal will help a little with this. Also, it will prevent burn through.
I think I could write a book on welding aluminum, I will try to incorporate better tips for certain applications in another blog. As I always say, try different methods and techniques because what works for me might not work for you. No two welders will weld the same.Click Here!
Wednesday, June 4, 2008
How to fix cracks in cast iron
Cast iron is one of those metals that you don't see too often except when it comes to certain engine components. Cast iron has a higher carbon content than mild steel and it has excellent heat properties. That is why the exhaust manifold on your car is always made of cast iron. Dutch ovens are usually made of cast iron because of their remarkable ability to heat evenly.
The problem with cast iron is that the higher carbon content makes it a brittle metal. If you were to drop a piece and it landed just right it would probably break or crack.
The proper way to fix a crack in cast iron is to first find how far the crack has travelled. You can do this by adding a little heat to it from a torch and it will ususally show the crack a little better. The next step is to keep the crack from getting any bigger. The way to do this is by drilling a hole about a half inch above and below the ends of the crack. It doesn't have to be a big hole. 3/16 to a 1/4 inch should do it. Remember, you will have to fill it with weld after you're done.
Once you have drilled your holes, the next step is to take a right angle grinder or a die grinder with a carbide bit and make a groove in the crack. The objective here is to grind out the crack because you're going to fill it back up with weld. Now you don't want to go all the way through the metal. If the thickness is a 1/4'' then you want to leave yourself at least an 1/8''.
Now lets talk about the proper filler to use. Of course you need to use the same filler rod to match the material. The nickel rods are the best to use. Cast iron rods are expensive, usually around $20 a pound. From my experience the best rods to use are the more expensive ones. The cheaper rods usually don't weld as well and leave a lot of porosity or pin holes.
This is where it gets a little tricky. I find that if you heat the casting a little with a torch and get the temperature up a few hundred degrees it typically welds better. You can not weld the entire crack in one pass. Its best to back step when welding cast iron. Back stepping is basically starting in the middle and laying about an inch of weld and then stopping. Then the next weld you lay will be behind that one and so on. You want to jump around a bit and just weld no more than an inch at a time. The other thing is to peen the weld after you stop. What I mean by this is to hit it lightly with a peening hammer. This relieves the stress that has built up after welding. It is a slow process but if you do this you will have a quality weld that will stand the test of time.
If possible, it's best to wrap the casting in a blanket to let it cool slowly. Too much of a drastic temperature drop could cause it to crack again. I have also brazed cast iron with a silicon bronze rod with good results. In a pinch I have actually used a 6010 rod, but this is only a temporary fix. Any kind of a blow to the piece will cause it to break. I have only used this to attach some broken scrolls on mailboxes. This is not the proper way to do it but it will get you by for the time being.
Click Here!
The problem with cast iron is that the higher carbon content makes it a brittle metal. If you were to drop a piece and it landed just right it would probably break or crack.
The proper way to fix a crack in cast iron is to first find how far the crack has travelled. You can do this by adding a little heat to it from a torch and it will ususally show the crack a little better. The next step is to keep the crack from getting any bigger. The way to do this is by drilling a hole about a half inch above and below the ends of the crack. It doesn't have to be a big hole. 3/16 to a 1/4 inch should do it. Remember, you will have to fill it with weld after you're done.
Once you have drilled your holes, the next step is to take a right angle grinder or a die grinder with a carbide bit and make a groove in the crack. The objective here is to grind out the crack because you're going to fill it back up with weld. Now you don't want to go all the way through the metal. If the thickness is a 1/4'' then you want to leave yourself at least an 1/8''.
Now lets talk about the proper filler to use. Of course you need to use the same filler rod to match the material. The nickel rods are the best to use. Cast iron rods are expensive, usually around $20 a pound. From my experience the best rods to use are the more expensive ones. The cheaper rods usually don't weld as well and leave a lot of porosity or pin holes.
This is where it gets a little tricky. I find that if you heat the casting a little with a torch and get the temperature up a few hundred degrees it typically welds better. You can not weld the entire crack in one pass. Its best to back step when welding cast iron. Back stepping is basically starting in the middle and laying about an inch of weld and then stopping. Then the next weld you lay will be behind that one and so on. You want to jump around a bit and just weld no more than an inch at a time. The other thing is to peen the weld after you stop. What I mean by this is to hit it lightly with a peening hammer. This relieves the stress that has built up after welding. It is a slow process but if you do this you will have a quality weld that will stand the test of time.
If possible, it's best to wrap the casting in a blanket to let it cool slowly. Too much of a drastic temperature drop could cause it to crack again. I have also brazed cast iron with a silicon bronze rod with good results. In a pinch I have actually used a 6010 rod, but this is only a temporary fix. Any kind of a blow to the piece will cause it to break. I have only used this to attach some broken scrolls on mailboxes. This is not the proper way to do it but it will get you by for the time being.
Click Here!
Tuesday, June 3, 2008
How to choose the right welding machine for you
A whole new world opens up when you have the right welding machine. The possibilities are endless to the things you can make or fix when you have the right machine.
The first thing to consider is what kind of welding are you looking to do. If you are looking to do a lot of thin metals than you might consider a MIG welder. This stands for "metal inert gas". A MIG machine is great for thin materials and thick materials as well, provided you have a powerful enough machine. However, ones budget is also another thing to consider.
There are a lot of welding machines on the market these days. The most popular ones are Lincoln, Miller, and Hobart. I seriously would not recommend purchasing anything but one of these name brands. For one, they are a lot more reliable and easier to find new accessories. Now, welding machines hold their resale value quite well and are very easy to sell. You're really taking your chances with any of the other lesser known brands of welders.
If you are looking to purchase a welder for your home then you need to consider your power supply. You will need to add a 50 amp breaker and an outlet for the plug. You can only run single phase machines from your residential house. Three phase machines require some modifications to the pole outside of your house so this is out of the question. This is another factor to consider when shopping around for machines.
Most of the machines that you would find at Home Depot have a 20% duty cycle. What that means is that you can continuously weld for 2 minutes out of 10. This is plenty for the home hobbyist.
If you are going to be doing a lot of welding outside, I would highly recommend a stick welder. The reason being is that you can weld in high wind and it won't affect the welding process. However, a MIG welder will also work outside you just have to be cautious of the wind blowing away your shielding gas. If you are using a flux-cored wire than this is not a problem. For those of you new to welding, A MIG machine requires the use of shielding gas. This is a gas mixture of 75% argon and 25% carbon dioxide. Basically this shields the weld to protect any atmospheric contaminants from affecting the weld.
The advantages of using a stick versus a MIG welder is that it's a lot easier to carry an electrode and your ground wire to any height. This is what is still used on construction sites that are erecting high rise buildings. It's just not practical to use the MIG machine for applications like this. With stick welding there is a flux that floats to the top of the weld and this has to be chipped off before another bead of weld is applied.
Each welding process has its advantages and disadvantages. I haven't even covered TIG welding. This is mainly used for exotic metals such as stainless steel and aluminum. You really have to know what you're doing to use a TIG machine so I'll cover that in another blog.
Let me recap, determine what you are willing to spend and do some research on a few machines to see which one will suit your needs as far as what types of applications you will be using it for. It's best to look at machines that have versatility. It pays to do your homework and shop around before you make a decision. Click Here!
The first thing to consider is what kind of welding are you looking to do. If you are looking to do a lot of thin metals than you might consider a MIG welder. This stands for "metal inert gas". A MIG machine is great for thin materials and thick materials as well, provided you have a powerful enough machine. However, ones budget is also another thing to consider.
There are a lot of welding machines on the market these days. The most popular ones are Lincoln, Miller, and Hobart. I seriously would not recommend purchasing anything but one of these name brands. For one, they are a lot more reliable and easier to find new accessories. Now, welding machines hold their resale value quite well and are very easy to sell. You're really taking your chances with any of the other lesser known brands of welders.
If you are looking to purchase a welder for your home then you need to consider your power supply. You will need to add a 50 amp breaker and an outlet for the plug. You can only run single phase machines from your residential house. Three phase machines require some modifications to the pole outside of your house so this is out of the question. This is another factor to consider when shopping around for machines.
Most of the machines that you would find at Home Depot have a 20% duty cycle. What that means is that you can continuously weld for 2 minutes out of 10. This is plenty for the home hobbyist.
If you are going to be doing a lot of welding outside, I would highly recommend a stick welder. The reason being is that you can weld in high wind and it won't affect the welding process. However, a MIG welder will also work outside you just have to be cautious of the wind blowing away your shielding gas. If you are using a flux-cored wire than this is not a problem. For those of you new to welding, A MIG machine requires the use of shielding gas. This is a gas mixture of 75% argon and 25% carbon dioxide. Basically this shields the weld to protect any atmospheric contaminants from affecting the weld.
The advantages of using a stick versus a MIG welder is that it's a lot easier to carry an electrode and your ground wire to any height. This is what is still used on construction sites that are erecting high rise buildings. It's just not practical to use the MIG machine for applications like this. With stick welding there is a flux that floats to the top of the weld and this has to be chipped off before another bead of weld is applied.
Each welding process has its advantages and disadvantages. I haven't even covered TIG welding. This is mainly used for exotic metals such as stainless steel and aluminum. You really have to know what you're doing to use a TIG machine so I'll cover that in another blog.
Let me recap, determine what you are willing to spend and do some research on a few machines to see which one will suit your needs as far as what types of applications you will be using it for. It's best to look at machines that have versatility. It pays to do your homework and shop around before you make a decision. Click Here!
Wednesday, March 26, 2008
Best welding helmets
What are the best welding helmets out there today? Well, there are quite a few good ones. I am a welder and over the years I have tried several different hoods. My first was a traditional style hood made be Jackson. This is a very reliable hood and I still have it today, however it is somewhat heavy compared to the newer ones out there and the looking glass was approximately 2''x4''. I also had some other Jackson hoods. These were made of a lightweight plastic with a larger viewing screen. This is still one of my favorites and you can get them with auto darkening lenses. I used this one, day in and day out welding 10 hour shifts. Very good helmet. I also purchased a Swiss made helmet called Optrel. This was a blue hood that looks like a space helmet. It was around 300 dollars when it first came out. It had a lot of bells and whistles. And different ranges as this was an auto-darkening hood. What I didn't like about it was that the replacement plastic lenses were a bit pricey. Also the hood itself didn't really want to flick down. Which in some cases that is good because it stayed up even in the oddest position but I guess that is a matter of preference really. After about a year of use the auto-darkening screen went defective. Half of it was changing while the other half didn't. I am sure these things happen but I didn't get any support from the manufacturer and the screen was almost the same price as the hood itself. So I said to myself if I am going to buy a replacement for it I might as well get a new hood. A few years back Jesse James made the hoodlum hoods popular. If you don't know what these hoods are, they are the ones shaped like dogs, skeletons, androids. I decided to buy one. They were around 50 dollars and my first day wearing it the head band snapped. I emailed the company and told them what happened and they made me buy another head strap. After installing the new head strap the same thing happened and it broke in the same place as the first one. The company didn't really seem to care that they had an inferior product so I sent them a nasty email and sent the hood back and asked for my money back. This by far was one of the worst helmets I have ever owned. Very, very unreliable. I then started doing more research and came across a hood that 3m made. Its called Hornell. This helmet is by far the best I have ever used and I am still using it today. Very lightweight durable. Excellent head band and the helmet breaths. What I mean by that is that it doesn't fog up. It has slits where your mouth goes that doesn't draw air in but rather expels it. I got the one with the bigger viewing screen and it has shade 5 lenses on the side for peripheral view. I would recommend this hood to anybody who welds as a profession. I have dropped this hood from 30ft and it still works. It has a variety of options and shade ranges. So there you have it.Click Here!
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