Archive for the ‘Arc Welding’ Category

Carbon Arc cutting/gouging

Tuesday, February 7th, 2012

From time to time, mistakes are made in a weld seam, or a repair to a weld will be needed. It can be quite time consuming grinding and cutting the affected area to get down to good metal. Especially in a field repair situation, something may need to be rapidly cut or gouged away. The best solution is the Air-Carbon Arc Cutting torch. It’s a relatively simple process. Though it’s not as neat as a plasma or even an oxyacetylene torch, the Air-Arc process is rapid. It can remove a lot of metal in a very short amount of time. The Air-Arc process however, needs plenty of amperage to do the job properly. A simple high amp output Constant Current power source such as a stick welder is used. The usual minimum amperage required is 300 amps, though smaller electrodes will demand less amperage. The carbon arc torch is very similar in appearance to the standard tong type electrode holder. However, it also has a starting button and an air hose that provides a “jet” of air from the torch. Instead of a wire electrode, a carbon electrode is used, which provides a super hot arc. It is fairly slowly consumed, but it does wear. The arc is struck and held short while the air is turned on. The air pressure starts to wash away the metal, as the torch is held at a relatively flat angle. This is technically referred to as “gouging”. Carbon electrodes can be a little expensive, particularly the copper clad ones which last longer, and provide a little more uniformity in the cut. The torch oscillated gently around directing the arc and the air to spread out the cut. If a deep cutting action is need the torch should be rotated to a steeper angle. Slag and sparks come with the job, so extreme caution must be used to prevent the wash of slag being directed toward any flammable surface. Also good personal protective equipment is a must to prevent accidental back splash.

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Selecting the right filler metal – Miscellaneous rods

Friday, January 6th, 2012

Without going into too many details there are other classifications of welding rods for TIG, Stick and MIG welding other than basic steel, aluminum, and stainless categories. In these instances, you may be joining dissimilar metals, essentially bronze welding. Or you may be trying to improve wear resistance or hardness of a material surface. There are exotic metals of course that will require a special rod or filler to join. High nickel content rods may be used for repairing cast iron. In some circumstances these rods may be literally hundreds of dollars per pound. There’s really no use in keeping a lot, if any of these rods around. You have to have a big budget to keep them all in stock and ready to use at a moment’s notice. Keep it practical by asking around at local welding suppliers what their most common moving rods are. To be sure, rods designed to repair cast iron are likely to be their number one rod that is sold out of all the miscellaneous rods sold. Some may consider bronze or brass filler rods that are used for bronze welding or brazing in the top. But still, the sales of these rods are a small portion of the annual sales of filler metals within the company. Most likely you’ll want to reserve purchase until you actually need it. Having it around on hand to decay or to oxidize isn’t worth the added money you could make if you had them in stock right when you needed them. It isn’t necessary to be an all around welder unless you have the money to waste on product that may never be used.

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Selecting the right filler metal – Stainless

Thursday, January 5th, 2012

One of the biggest joys and frustrations in TIG welding is welding stainless steel. It can go great or it can go awful. Welds can look smooth as silk or look like burnt sugar. But one of the things that can help ease the process some is having the right filler rod to start with. ER 308 is a common stainless steel filler rod that can be used to join many Stainless metals that are common to restaurants, chemical storage and application equipment and all sorts of tanks and industrial equipment where high quality metal is used. It is used to join many other metals as well. Using the ER 308L will improve the final corrosion resistance as it designates a lower carbon content filler rod. The 308and 308-L are used on 308 stainless steels. In fact it can be used to weld all metals considered an 18-8 steel such as 301, 302, 302B, 303, 304, 305, 308, 302 and 202. As you can see the range is quite large for the 308 series. If budget is a concern, consider just using the 308L. It blends well, and flows easily into the base metals of the metals listed above. When using this one, consider your average potential for use that you may have in restaurant equipment repair or in chemical or certain food grade storage tanks. Also think of the diameter that you will need. Ordinarily, a 3/32 welding rod will get the job done in many other steels, and in aluminum, but with stainless, having a correctly matched diameter filler rod is critical due to the heat conducting properties that make it difficult to wet the rod into the puddle.

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Selecting the right filler metal – GTAW ER316L

Tuesday, December 27th, 2011

One of the biggest joys and frustrations in TIG welding is welding stainless steel. It can go great or it can go awful. Welds can look smooth as silk or look like burnt sugar. But one of the things that can help ease the process some is having the right filler rod to start with. ER 308 is a common stainless steel filler rod that can be used to join many Stainless metals that are common to restaurants, chemical storage and application equipment and all sorts of tanks and industrial equipment where high quality metal is used. It is used to join many other metals as well. Using the ER 308L will improve the final corrosion resistance as it designates a lower carbon content filler rod. The 308and 308-L are used on 308 stainless steels. In fact it can be used to weld all metals considered an 18-8 steel such as 301,302,302B, 303, 304, 305,308, 302, and 202. As you can see the range is quite large for the 308 series. If budget is a concern, consider just using the 308L. It blends well, and flows easily into the base metals of the metals listed above. When using this one, consider your average potential for use that you may have in restaurant equipment repair or in chemical or certain food grade storage tanks. Also think of the diameter that you will need. Ordinarily, a 3/32 welding rod will get the job done in many other steels, and in aluminum, but with stainless, having a correctly matched diameter filler rod is critical due to the heat conducting properties that make it difficult to wet the rod into the puddle.

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Selecting the right filler metal – GTAW ER 5356

Monday, December 26th, 2011

If you have got room for it in your budget, and want to complete your line of “necessary” welding rods you’re going to need for welding most grades of Aluminum, the ER 5356 is right next to the ER 4043. Most TIG welders find the 5356 relatively easy to lay a nice bead. Comparatively, the strength of the 5356 is fairly high. Comparatively, the strength of the 5356 is fairly high. It doesn’t mean that it would replace the 4043 in many cases as the 4043 is a good match for strength and ductility of many parent aluminum alloy metals, but when a weld will be subjected to more than average shear stresses, the 5356 is worth considering. The addition of magnesium helps to increase the overall tensile strength. Conversely, the 5356 is more susceptible to post weld cracking. Thick plates will need to be preheated to at least 300 degrees Fahrenheit to get the best fusion. It is also a desirable choice for any weld that will be anodized after welding or for welding on anodized metal. The color is a good match after it cools and when anodized does not get a dull gray cast as 4043 does. Of course, this is a summary of its strengths. If you think you need to use a stronger filler metal, just as you would with 4043, try to determine the parent material before using. Then cross reference it with the manufacturer’s summary list of weldable aluminum alloys that is usually available before purchase online or attached to the box to make sure the 5356 is a good match for your application.

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Selecting the right filler Metal – GTAW ER 4043

Friday, December 23rd, 2011

So you want to TIG weld aluminum but don’t know where to start or what classification metal you are dealing with? After making sure that your TIG welder has AC capabilities with HF start, the next thing is to find a welding rod (filler metal) that will best suits your needs The ER 4043 filler metal is considered the “general purpose” rod for aluminum TIG welding. In most circumstances, the soft ER 4043 is a dream to weld with. The rod flows easily and quickly so forward speed is fast and dipping motion is rapid. It’s a great choice for someone wanting to keep one rod around. No, it won’t weld all aluminum, as some aluminum alloys just aren’t all that weldable. But chances are if you have a repair or some fabrication to do, this is the rod of choice. The color can be a little off with some aluminum alloys and may not match well when it will be anodized afterwards, but with its resistance to cracking, it does offer an advantage where fit up or shrinkage is a challenge. Again, Silicon is a primary deoxidizing agent used in this rod, so the welds are relatively clean and free of soot and the Silicon reduces the melting point, preventing overheating of the base metal. It’s very stable and resists cracking well if the weld is properly filled. However, the puddle can grow quite large if travel speed is slow and be difficult to manage because of its ability to wet in and the ease of which it melts into the base metal. Overall the 4043 is probably the number one most used aluminum filler rod in the industry. Because of the expense of filler metal, the average hobbyist or a small shop may only have the budget to stock one aluminum rod. The ER4043 will typically work well in that situation. It’s definitely a utility player when it comes to welding Aluminum.

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Selecting the right filler metal – GTAW ER70S-3

Wednesday, December 21st, 2011

If you are looking for a disappointing first welding experience, buy the ER70S-3 for filler metal. The ER70S-3 wire is often referred to as having a “moderate” deoxidizer content. In reality by comparison, this is really little or none. The question of course comes immediately to mind, “Why use it?” The answer is that it is really economical to use, especially if you have exceptionally clean metal. ER70S-3 is among the cheapest wires to buy. Its primary use is in the fabrication industry where there is time taken to fully clean the steel. The low deoxidizer content also means that little slag will be formed on top of the weld, so more than likely a second pass can be made without so much as brushing the weld before the next one is made. However, if rust or other contamination is present, the weld will result in a dark, dull weld that may have porosity or a “burned” look to it. And as far as wetting in, good luck trying to force that blob of metal on the end of the rod to cooperate. For the beginner, it will be hard to achieve a satisfactory looking weld. For the experienced TIG welder, the welds will still occasionally have a less than perfect appearance to them. If you have the time to thoroughly clean and prep the metal and want to save money, then the 70S-6 may be something worth considering. But, most people would rather skip this rod and go for either a 70S-2, or a 70S-6 and lightly brush the weld afterwards. Yes, it’s economical, and widely available, but beware, you may bite of more than you can weld with this welding rod.

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Selecting the right filler – GTAW ER70S-6

Monday, December 19th, 2011

A good choice for almost any mild steel TIG application is the ER 70S-6 filler rod. It’s reputation is well deserved thanks to the high deoxidizer content of the filler metal. The overall melting and wetting characteristics are unparalleled, especially on less than ideal metal, where rust or other contamination may be a concern. The first thing you’ll notice is how easily the metal “wicks” to the sides of the puddle and joins itself to the parent metal. As the rod moves along the ripple pattern or “stack of dimes” look is very easy to achieve, whether you are free-handing or walking the cup. Unless chrome moly is being welded, most people never deviate from using the 70S-6. It is also resistant to undercutting because of its filling and wetting characteristics. This makes welding out of position much easier even though the puddle may seem to be more fluid. When compared directly to the ER 70S-2, results are very similar. However, the surface of the weld may have a slightly glazed look at points where the deoxidizers have done their job and floated the contaminants out on top to form a spotty glass like slag. The primary component of this slag is silicone, so it removes easy. Upon wire brushing, the metal will be shiny as a new nickel. However, if left untouched and another pass is made, the slag can be trapped under the metal and an defective weld can result. Whenever working with the ER 70S-2, make sure all traces of the glass like slag have been removed. It’s simple enough to do, and takes very little time to make a perfect weld.

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Selecting the right filler metal – Part 7 GTAW ER70S-2

Friday, December 16th, 2011

Ever want to build a race car or a roll cage? If so, become familiar with the ER 70S-2 steel filler rod. The 70S-2 enjoys a reputation for being a good rod to use for high strength 4130 chrome moly steel. It is the primary structural component of nearly every motorsport vehicle custom built, from motorcycles to Baja race vehicles. The strength and ductility of the 70S-2 makes it a favorite choice for people in the fabrication and racing industry. The 70S-2 is a practical all around rod however and works well with less critical welds as well. The flow and wetting in properties of the filler metal are clear from the first bead. It’s a consistent filler material that works well on pipe or body panels. The higher amounts of deoxidizers make it fine for every day mild steel with a bit of rust or paint as well. Very little clean-up is required, though it is always strongly suggested. The result is usually a bright weld, with very little clean up or brushing. The 70S-2 may be all the rod you’ll ever need in regards to welding most steels. It’s a real world welding rod. It’s versatile and well liked. But in some circumstances, particularly the most dirty and rusted applications, you may find that a little better rod is needed, something that will provide enough deoxidation to make a sound weld.

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Selecting the right filler metal – Part 6 SMAW AWS 309L

Wednesday, December 14th, 2011

When welding stainless steel one of the finest rods to use is the AWS E 309L. The 309 is a versatile welding rod. Its capacity to join stainless to stainless, stainless to steel, or steel to steel makes the 309L a favorite rod the job site. The corrosion and wear resistance of the 309L is quite high. It’s often used in the pipe industry to join fittings and valves where corrosive or abrasive material might cause fast wear and damage to the joint. The 309L has considerable slag so it’s a little difficult to use. Attention must be paid to the rod angle or slag will tend to run ahead of the weld. The slide component that makes it difficult control is primarily lime and iron powder. When using a 309L, less amperage is required than other rods. Use approximately 20% less heat than you would with a rod like 7018. Too too much heat will result in a lot of problems, particularly an uncontrollable weld puddle. Many weldors use a stringer bead when welding with the 309L, because of the difficulty and problems the 309 presents. However, the 309L can make some of the most beautiful and aesthetically appealing welds you could possibly make because of the flow qualities of the stainless. Too much heat though will leave you with a molten mess. The tendency of the welding rod to get hotter as the weld progresses is another problem, even if you start within the right amp range. A lot of inexperienced welders will find that the rod gets too hot to weld after it burns about half way down. Stainless heats up rapidly because it has a higher resistance to the flow of heat than regular steel. It also has a habit of drawing the metal up around the weld seam. Prepositioning and restraining the parts is critical. A weld that is started between two pieces of metal that are laying flat on a table will usually result in a “V” shape. By beginning the weld with the two pieces of metal fitted so they make an inverterted “V”, will often offset the draw so that the two pieces of metal or perfectly in line with each other when the weld is finished. Though it is difficult to learn, after a while, the 309L becomes a favorite when toughness, and corrosion resistance is required.

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