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The CNC Report Product Review: Dura Fix makes Welding Repairs and Fixture Creation Easy
Welding Aluminum with DurafixTo weld aluminum with a torch using Durafix you must first understand that the oxidized surface of the aluminum is what makes it so difficult to join aluminum. The aluminum oxide on the surface is like the protective coating on anodized aluminum. Many people claim that you must use a high frequency TIG or MIG welding rig to join aluminum. Others claim you need flux to allow a repair rod to bond to the surface of the aluminum. With Durafix all you need is a hand held torch and the included stainless steel brush to remove the oxide. A steel brush will leave deposits that prevent the bonding.
It is difficult to weld thin aluminum with an electric welder. You can easily blow a hole making the area to be filled even larger. Thin, worn through areas such as the ribs on the bottom of an aluminum boat is an ideal application for Durafix. Thin aluminum tubing such as a refrigeration coil can be easily fixed with Durafix and there is no flux to contaminate the inside.
Always wear eye protection, gloves and appropriate safety gear. Practice on scrap pieces of aluminum to
get the feel of the process first.
Even after brushing, the aluminum oxide starts to build up again in reaction to the oxygen in the air. You must heat up the aluminum parts to be welded to the melting temperature of the Durafix rods, 732°F, then apply the rod to the heated surface. . You should not melt the rod with the torch and attempt to flow it onto the colder surface. You must heat the piece to be welded first. When the rod melts from the heat of the area to be joined and flows onto the surface, you must "scrub" the surface of the aluminum under the puddle of melted rod like you would a crayon. This scratching and rubbing removes the remaining thin layer of oxide and allows the Durafix to bond to the surface.
It will not flow into any cracks or holes because of the oxide on the surface that was not removed. This has some advantages because it will not create any restriction inside of a pipe to restrict the flow such as refrigeration gasses flowing through a Durafixed aluminum condensing or evaporating coil, radiator or aluminum oil cooler coil. It is helpful if you preheat your heavier aluminum pieces because the heat of the torch is conducted away so quickly by the aluminum which has high thermal conductivity. For thicker parts the joint or crack should be "veed" out, or beveled so that the oxide can be brushed away in the recessed areas and the Durafix rod can be scrubbed into the joint rather than just bridging over the crack or joint.
If you have two pieces of heavier material to join, sometimes it is advantageous to apply a coating of Durafix to both surfaces before joining them. This is shown in the Durafix video under welding aluminum diamond tread section. You can brush through the molten Durafix to remove the oxide layer underneath and assure through bonding.
You must not use a steel brush. A steel brush will embed particles of steel in the surfaces and Durafix will not bond with them. We supply a higher quality wooden handle stainless steel brush made in the USA instead of the cheaper plastic brushes that melt. [From forums:"Get a stainless wire brush with a wooden handle, trust me I tried the plastic one, it doesn't last long." "It has become difficult to find wooden handled small brushes - most have plastic handles. ... Yeah wood burns but at least it doesn't melt onto your project." "I totally wrecked two cheap plastic brushes because… well, once the stainless wire gets hot, they just sort of melt off. "]
After heating, Brushing and tinning or "wetting" the surfaces and the molten Durafix is flowing, apply a generous fillet of Durafix to both sides if possible.
MAPP gas, in the yellow cylinders, is recommended for bigger jobs. A larger torch might be required for thicker materials and larger joints because of the high heat conductivity of aluminum. If you intend to grind down the repair and possibly polish it to match the surrounding area or paint it, it is necessary to have a recess for the Durafix to flow into and fill the recess.
To restore or repair stripped out threads in an aluminum piece such a a cast aluminum housing, you can either drill out the hole to a larger size. fill it in, drill it and tap it or you can insert the threaded stud or bolt which must be ferrous, magnetic or stainless steel and insert it while the Durafix is still molten as shown in the repairing threads section of the Durafix video.
Durafix will bond to any non-ferrous metal except stainless steel. Because of this you can use a stainless steel or steel rod or even the bolt when repairing stripped threads in a bolt hole using the rod as a form to keep from filling it in completely. Durafix will weld copper or brass to aluminum, zinc such as zinc coated steel or galvanized steel. It is possible to repair parts made from cast aluminum die-cast zinc, white metal, Kirksite, Zamac or pot metal such as carburetor bodies and headlight doors. That makes it ideal for restoring antique autos and parts that are not made anymore.
Farmers use it to repair aluminum irrigation tubing in the field. Fishermen use it to repair leaks in their aluminum boats. Truckers use it to repair their rigs on the side of the road. Rvers use it to restore and repair parts like aluminum window frames. The uses are endless because you can do your repairs at the site. You do not have to take it to a welding shop.
Durafix has been sold on the internet since 1996. It is the original aluminum repair rod. There are many copycat products claiming to be superior. You will see references to Durafix on Ebay and Amazon and elsewhere but Durafix is only sold in the US and Canada by Weeks Distributors. It is sold in Mexico, South America, Europe, Asia and the South Pacific by Durafix distributors in most other countries in the world.
You can read the testimonials here and view the videos demonstrating Durafix above and below. You can go to the ordering page for more information or to purchase Durafix by clicking here. If you have any questions you can call Randy Weeks @ 800-547-weld  for answers.
What is MAPP Gas?MAPP gas burns hotter than Propane gas. It is a mixture of MethylAcetylene gas, Propadine gas and Propane gas, hence the name MAPP gas. Unfortunately manufacure of MAPP gas in North America was suspended on April 30, 2008.
BernzOmatic, maker of the handheld TS4000T / TS4000 Trigger Start Torch makes a Map gas product in a yellow cylinder, MAP//Pro™ gas MG9 - 14.1 oz. MAP-Pro Hand Torch Cylinder that burns at 3,600°F with air.
What is MIG welding?MIG welding is Metal Inert Gas (MIG) welding. It is a type of GMAW [Gas metal arc welding]. The weld is produced by an arc from a wire feed electrode, shielded by an inert gas such as Argon , Helium. As with TIG welding a high frequency AC current is required to break up the oxide layer.
What is TIG welding?TIG welding, similar to GTAW welding [Gas Tungsten Arc Welding] , is Tungsten Inert Gas welding using an arc from tungsten electrode shielded with an inert gas such as Argon or Helium [Heliarc] to make the weld. A filler rod could be used or the two parts can be simply melted and fused together. When TIG welding aluminum, a high frequency [Highfreq] AC arc is usually required to break through the oxide layer.
What is Flux?Flux [Latin for flow] is chemical cleaning agent, usually a paste, that cleans the surface of a metal to be joined so that the joining metal can flow onto the surface and bond. It removes the oxides. However they are made from corrosive chemicals, acids, and give off fumes that can be dangerous and leave corrosive residues that are difficult to remove.
What is Aluminum Oxide?Aluminum Oxide is a very hard material. Sapphires are actually Aluminum Oxide with various trace elements like copper, iron, titanium or chromium that gives them the different colors. Aluminum Oxide is also known as Corundum and they both are used to make sandpaper and other abrasives.
What is thermal conductivity?Thermal conductivity is the ability of a material to conduct heat or it's K value as opposed to the R value as a measurement of a material's ability to resist the conduction of heat, the insulating value.
For the purpose of comparison, at 68 degrees F ,Aluminum has a thermal conductivity of 118 which gets higher as the temperature increases. Steel is 21 to 31, Stainless Steel is 7-26 depending on the alloy. This high thermal conductivity is why aluminum is and excellent material for making heat sinks. It is used by computer "modders" to make heat sinks for "modding" or "overclocking" their processors, modifying their cases, and Durafix is used for the purpose.