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You have hit on one of my favorite subjects. I have enjoyed every minute I have spent over the last 28 years introducing people to powder welding and also to metallising with exothermic powders and solid or cored wires. After I give you a procedure for hardfacing those blades, allow me to provide some insights regarding powder torch choices. OK, when it comes to hardfacing mower or chipper blades, placement of the deposit is key. Put a thin smooth deposit under the sharpened edge. This will slow the wear along the bottom and cause the top side to wear sharp. Put a smooth thin deposit along the outer edge. This will prevent rounding off of the blades edge. Lastly, if there is a suction wing on the back of the blade, coat the entire front surface of that area with a thin, smooth, coating. This of course will promote long life in that area and provide maximum lift. There is a bit of a simple technique to prep and initial procedure. Don't spray anything you haven't previously ground, blasted, or sanded clean. By clean, I mean absolutely no foriegn material left. No low spot left unclean either. Before you spray the clean surface, preheat to about 500�F to 800�F. At around 800� you will notice a small shadow following the flame. The metal will have turned blue and then back to its natural color. At this point and no later, apply a thin but uniform layer of unmelted powder. It should be thick enough that you can't see any of the base metal showing through. Next, pick a spot near an edge that will heat up quickly and hold the flame about 1/2" off the metal. Concentrate the heat until the powder begins to fuse. This fusing powder will appear to be orange and slick. Sort of shiny looking. When the power "slicks up", it's time to add more or move on. If you want to add more, you can develope a travel speed that is appropriate in time. You will also find that it is beneficial to pump the feed lever as opposed to holding it down. A powder welded deposit can be machined, drilled, milled, tapped, and left as is. The welding powder creates a metallurgical bond with a 78,000 PSI tensile strength. The hardface powder is the same matrix with the addition of chrome and can also contain a percentage of WC. Last August, I started a private venture. I have my own small manufacturing and supply business dealing primarily in welding and metallising for repair. When it comes to powder welding torches, $300.00 or thereabout is cheap. Those torches will range upwards of 1200.00 in price. The approach I'm taking is.....it's not the razor it's the blades. The torch has to be sold to market the powder. There are basically three models of them: 1. The 300.00 torch will no longer be manufactured for sale through direct distributors. It will be only sold to distributors through the manufacturers sister company. Replacement parts aren't going to be made available for the center section because the center section is outsourced. This in my view will be a big mistake. When the center section needs a feed valve or mixer, you will have to buy the entire set-up to get it. I am currently in the process of arguing this point with them as I have that torch in my inventory and would like to continue to do so. I will not sell a torch I can't get parts for. Makes no sense. 2. The other model is one that sells in the 800.00 range. I have sold those for years as well and they are considerably more robust than the less expensive torch. The quality of the more expensive unit is uniform. With the less expensive one, if you get a good one you're OK, if not..... .you will need those parts that may not be made available. In any case, either one will eventually need a feed valve. 3. The most expensive torch of all is the one made in Europe. It will run as high as 1200.00 or more. It is a durable appliance with some nice features but IMPO is not worth the price. It is also designed for heavier mesh sized powders and will not shut off properly if the powder you are using conatins too many fines. Not a big deal for hardacing chisel plow points but a very big deal if you are rebuilding glass bottle molds. There is not enough space in this forum to go much farther. Applications for this torch are only limited to the imagination. In all these years I am still finding new ones and each day is a new learning experience.
HTH,
Steve
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