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Thread: Testarossa replica build

  1. #131
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    Why did you choose galvanized steel? I was told by a few different pro welders that you never want to use galv tubing or sheet for fabrication/welding. They say it is not possible to remove all of the gasses and can not provide a good weld. The slag it produces is a white soot and will almost always produce a cold weld because the escaping gasses are considerable more than your sheilding gas.

  2. #132
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    Quote Originally Posted by FerrariXXXman View Post
    The slag it produces is a white soot and will almost always produce a cold weld because the escaping gasses are considerable more than your sheilding gas.
    Not to mention welding galvanized steel releases zinc oxide fumes which are poisonous.
    Last edited by Bloozberry; 10-10-2018 at 06:29 PM.

  3. #133
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    I’m a MiG welder. And was always informed of the above post to be true. Please consider thank you
    Last edited by Minihawn; 10-22-2018 at 06:43 PM.

  4. #134
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    hey there dominic, sorry for the lapse of updates. I have several builds going at the moment. along with the Testarossa I am building a monster 5 ton international, a 88 porsche 928 s4 restoration, a 1986 chevy 4x4 full build and last but not least I am also in the process of refinishing my Custom dually van. on the Testarossa I have the quarter glass frame work installed and im working on trim panels for the interior to finish the quarter glass on the inside. Ill post some pics in the next couple days.

  5. #135
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    The process of welding zinc/galvanized coated steel.

    The sheet metal I use has a very thin coating of the zinc galvanizing.But I have used this stuff for years to give an added protection agains rust in places where the otherwise bare metal could be exposed to the elements. If I do weld I simply use a angle grinder with 36 grit disc to grind the zinc off. I have also welded straight through the galvanizing you have to run a hotter weld to burn through and provide a good weld. as with all my paint work I always wear a chemical compliant Respirator. If you want a good read this is produced my Sperko Engineering.
    Welding Galvanized Steel -- Safely
    © Sperko Engineering Services, Inc.,1999, Page 1 of 6
    Background
    Galvanizing has been used to protect iron and steel from rusting for over a hundred years in places as diverse as the wire rope
    used for the suspension cables on the Brooklyn Bridge to gutters on houses.
    Galvanizing is simply coating of zinc over steel. Like paint, galvanizing protects steel from rusting by forming a barrier
    between the steel and the environment, but galvanizing goes one giant step further than paint -- it also provides
    electrochemical protection of the steel. Since zinc is electrochemically more reactive than steel, it oxidizes to protect the steel
    near it; as a result, even if a galvanized steel surface is scratched down to the bare steel, the galvanizing coating will prevent
    the steel from rusting. Galvanized steel is, therefore, a superior product to steel with any other type of coating on it since it
    protects the steel even when the coating is damaged in handling or in service.
    Welding of Galvanized Products
    Welding of galvanized steel is done almost exactly the same way as welding of the bare steel of the same composition; the
    same welding processes, volts, amps, travel speed, etc. can be used with little modification when the switch is made from
    uncoated steel to galvanized steel -- unless the zinc coating is unusually thick.
    The difference between welding galvanized steel and welding uncoated steel is a result of the low vaporization temperature of
    the zinc coating. Zinc melts at about 900˚F and vaporizes at about 1650˚F. Since steel melts at approximately 2,750˚F and
    the welding arc temperature is 15,000 to 20,000˚F, the zinc that is near the weld does not stand a chance -- it's vaporized!
    By the time the weld pool freezes, the zinc is gone. This has two immediate consequences:
    • The vaporized zinc increases the volume of welding smoke and fumes.
    • The zinc at and near any welds is actually burned off by the heat of the arc, removing the protective zinc coating.
    Zinc Fumes -- A Safety Hazard?
    When zinc vapor mixes with the oxygen in the air, it reacts instantly to become zinc oxide. This is the same white powder
    that you see on some noses at the beach and the slopes. Zinc oxide is non-toxic and non carcinogenic. Extensive research1
    into the effects of zinc oxide fumes has been done, and although breathing those fumes will cause welders to think that they
    have the flu in a bad way, there are no long-term health effects. Zinc oxide that is inhaled is simply absorbed and eliminated
    by the body without complications or chronic effects. Current research on zinc oxide fumes is concentrated in establishing
    the mechanism by which zinc oxide causes "metal fume fever," how its effects are self-limiting and why zinc oxide fume
    effects ameliorate after the first day of exposure even though the welder may continue to be exposed to zinc during subsequent
    days ("Monday-morning fever"). Other research is being done using zinc oxide fumes together with various drugs which
    results in a synergetic effect for treatment of cancer and AIDS. Another area of research is use of zinc compounds as the active
    ingredients in throat lozengers that are recognized as significantly effective in reducing the duration and intensity of the
    common cold.
    Typical “metal fume fever” begins about 4 hours after exposure, and full recovery occurs within 48 hours. The symptoms
    include fever, chills, thirst, headache and nausea. All of these symptoms, pain and suffering, as well as lost work (and play)
    time, can be avoided entirely by simply not inhaling the zinc oxide fumes. This can easily be done using any of the
    methods described later.

  6. #136
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    Unlike other heavy metals, such as copper, lead and mercury, zinc is an essential micro nutrient. Zinc is essential to the
    proper growth of plants and animals. Zinc forms part of the enzyme system that regulates biological processes throughout the
    body. As shown on any multi-vitamin/mineral bottle, the recommended minimum adult intake is 15 mg/day.

    1Walsh, Sandstead, Prasad, Newberne and Fraker, Environmental Health Perspectives, Volume 102, Supplement 2,
    June 1994, 5-46. Provides summary plus 471 references.
    2 Kuschner,D'Alessandro, et. al., Pulmonary Responses to Purified Zinc Oxide Fumes, Journal of Investigative
    Medicine, 1995:43:371-378.
    3Robert Sabin, Zinc Activated Profile, COPE, March/April 1995: 16,17
    Welding Galvanized Steel -- Safely
    © Sperko Engineering Services, Inc.,1999, Page 2 of 6
    The zinc that is generally used for hot dipped galvanized coating has a naturally occurring lead content around 1/2%. Since
    lead is not soluble in zinc over 0.9%, it cannot exceed 0.9% concentration. This lead may be vaporized along with zinc
    during welding. Since lead does not vaporize until it gets over 3000˚F, and since some of it is soluble in steel,
    proportionately less lead is vaporized than zinc; lead oxide fumes, however, should not be inhaled, and the practices
    recommended below for avoiding inhaling zinc oxide fumes will also prevent inhalation of lead oxides. There is also some
    concern about residual lead where galvanized products will be in contact with children, such as when it is used on
    playground equipment without a high-qualify top coating.
    Some galvanized product manufacturers use zinc that is 99.99% pure zinc, so the presence of lead is of no concern when
    welding these products or due to contact. Similarly, galvanized products that have very thin organic coatings or have been
    chemically treated to improve the adherence of top coatings are welded safely when the practices recommended below for
    avoiding inhaling zinc oxide fumes are observed.
    Properties of Galvanized Steel Welds
    The successful welding of galvanized steel is so widely accepted that there is very little recently-published mechanical
    property data comparing uncoated versus galvanized weld properties. The welding industry recognized fifty years ago that
    welds on galvanized steel and welds on uncoated steel are of comparable strength if the quality of the welds is comparable.
    Recent publications on welding galvanized steels deal with weld toughness, porosity control, weld appearance, restoring
    corrosion resistance and other issues that are much more complex than the strength of the weld.
    When using SMAW ("stick") welding, galvanized steel can be welded in the same manner as uncoated steel. When using
    MIG or flux cored welding, one may have to adjust the voltage slightly to control spatter, and one may have to clean the
    welding gun of spatter and zinc oxide deposits more frequently that when welding uncoated steel. Hobart makes a flux cored
    wire called “Galvacore” that some users have had good success with when welding galvanized steel.
    When difficulty is encountered welding galvanized steel that was not encountered during welding uncoated steel, it is usually
    because the Welding Engineer has not accounted for the volume of gas that is evolved by the vaporization of zinc during
    welding. The thicker the zinc coating, the more fumes are generated, and those fumes have to be able to escape easily into
    the atmosphere and not be forced through the liquid weld metal.
    For example, welding galvanized plates to form a T-joint is a commonly troublesome situation. Since the galvanized edge
    of one plate is butted against another galvanized surface, the zinc vapors that are formed at the abutting surfaces will not be
    able to escape to atmosphere easily as the zinc is vaporized. Instead, they will blow into the weld pool, creating porosity or
    a poor weld surface. This is aggravated when welding conventionally hot-dipped products, since the edges frequently have
    excessively heavy zinc coatings. One solution is to separate the parts by 1/16 inch using wire spacers or fixtures which will
    leave a gap for the zinc vapors to escape easily. Other approaches are to use a slight (15˚) bevel on one member (Figure 1), to
    remove the zinc from the faying surfaces by shearing or mechanically cuting the plate where the faying surfaces will meet, and
    to abrasively remove most of the zinc from one or both of the faying surfaces (Figure 2). Any of these methods will
    significantly reduce the amount of zinc between the parts, and this will reduce the volume of gas evolved, improving weld
    quality.

    Slight
    Bevel Abrasively
    remove
    zinc

    Weld this
    side first

    The welding engineer should also check the welding electrodes which are being used for high silicon levels. Excessive
    silicon can cause zinc to penetrate the weld metal, leading to cracking, especially when the zinc coating is thick. The silicon
    in welding electrodes should not exceed 0.85%; this means that commonly used ER70S-6 filler metals should not be used
    when welding galvanized steel.
    Welding Galvanized Steel -- Safely
    © Sperko Engineering Services, Inc.,1999, Page 3 of 6
    Avoiding and Filtering Fumes
    The first line of defense in dealing with zinc oxide fumes is welder training. Welders should be taught -- even when welding
    uncoated materials -- to keep their heads out of the fume plume and to position themselves relative to the air flow around
    themselves so fumes and dust do not collect inside their welding shields. If a welder finds white dust inside his welding
    shield when welding galvanized products, he is not positioning himself properly. When welding galvanized products that
    have thin, uniform coatings and the process is gas-shielded MIG or flux core, the fumes generated are sparse and the
    shielding gas blows them away from the welder; this is frequently sufficient to avoid metal fume fever without further action.
    To complement proper positioning, a fully effective method to preventing inhaling zinc fumes is to wear a suitable respirator
    (mask). Some of the commercial products which are suitable are:
    Manufacturer Product Description C
    3M (800-328-1667) 9920 Half-Mask, Disposable
    3M 9925 Half-Mask, Disposable
    3M 9970 Half-Mask, Disposable 6
    Moldex 3400 Half-Mask, Disposable
    The prices shown are list prices for purchase of 40 or more; these items are usually available with some discount.
    These masks are similar to a painter’s mask; although there are other larger and more complicated masks, these work, while
    providing minimal interference and discomfort to the welder. The higher priced masks contain activated charcoal which
    removes some odors as well as the zinc oxide; welders who use these masks frequently wear them even when they are not
    welding on galvanized steel, since they make the air smell better and they filter out other particulate matter in the welding
    fume plume.
    Masks that are not properly fitted will not be effective in protecting the welder since the zinc oxide can be pulled through any
    openings between the mask and the welder's face. Welders who are given masks or any other kind of personal protection
    equipment have to be trained how to adjust them so that they work correctly. In addition, OSHA regulations (29CFR Part
    1910.134(b) requires that fabricators have a written procedure for use of personal protective equipment such as respirators and
    masks; that the equipment be selected from that approved by the Mine Safety and Health Administration and the National
    Institute for Occupational Safety and Health; that the equipment selection be based on the hazard to which the welder is
    exposed; that only employees who are physically capable of doing the job and know how to use the safety equipment are
    assigined to perform work; that respirators are cleaned and disinfected regularly, stored in a convenient, sanitary location and
    kept in good repair; that the work area be monitored for changes in exposure; that the medical status of employees is
    reviewed regularly; and that the program be reviewed on a regular basis to appraise its effectiveness. OSHA does not
    currently require periodic medical evaluation of employees, but that is under consideration. Disposable masks eliminate
    some of the hassle associated with meeting these OSHA regulations.
    More complex and expensive than masks are the “personal environment systems” in which the welder has air supplied to a
    loose-fitting helmet and outer shroud which drapes over the his shoulders. Portable fans or compressed air supply filtered air
    to each welder under positive pressure, keeping any welding fumes out of his breathing area.
    Supplier Product System Cost ( Approx)
    3M Whitecap W-8200B $600 (CA)
    Racal Airstream AH-17 $550 (BP)
    Racal Airstream AH31, 33 or 39 $425 to 615 (CA)
    Neoterik CB14-77 $227 (CA)
    Neoterik MB14-77 $472 (BP)
    Hornell Speedglas Fresh-Air™ $880 (BP)
    (CA indicates compressed air supplied, BP means battery powered)
    It should be noted that any compressed air supply has to be "oil-free" air; normal shop air contains oil which, if inhaled, will
    coat the lungs in a short period of time, causing irreversable death.
    Welding Galvanized Steel -- Safely
    © Sperko Engineering Services, Inc.,1999, Page 4 of 6

  7. #137
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    The other approach to removing the air from the welder’s breathing space is to capture it so that the fumes never rise into the
    welder’s face. Source capture devices are usually flexible ducts attached to an exhaust or filter system. Suppliers of fixed
    single welding station fume extraction systems are:
    Supplier Phone Product System Cost ($) (est)
    Nederman, Inc 313-729-3344 FilterBox 3500 to 7000
    Nederman, Inc 313-729-3344 Electrostatic Filter 4,200
    Torit (Donaldson Co.) 612-887-3900 Trunkline 4,000 to 7,000
    Morris Mobile Clean 800-541-0817 MC-2000 3,000
    Morris Mobile Clean 800-541-0817 MobileVac 2,200
    One difficulty with “source capture” devices is that their range is limited to less than a foot from the end of the flexible duct;
    this means that the welder has to move the duct if he moves outside its capture range.
    Another type of “source capture” device that can be used when “MIG” welding is a welding gun that has a vacuum nozzle
    attached directly to the welding gun. All “MIG” welding gun manufacturers, including Tweco, Lincoln, Hobart and Binzel
    make these modified guns and filter units. The primary disadvantage is that they are slightly bulkier than guns without
    vacuum attachments. This can make welding more difficult for the welder.
    The optimum method for capturing welding fumes over a large area is a downdraft work table. This is because the fumes are
    drawn downward away from the welder’s breathing zone. Interestingly, the effective capture distance of a downdraft table can
    be easily extended to over a foot simply by addition of a small overhead fan directed downward. Downdraft tables are
    available from:
    Supplier Phone Number
    Weldsale Company 215-739-7474
    Aercology 203-399-7941
    Eutectic Corporation 800-323-4845
    Downdraft work table will cost approximately $1,200 for a small (30" by 36") table to $5,000 for a large (4’ by 8’) work
    station plus the cost of fan, duct and, if necessary, filter system. Downdraft work stations for assembly line work, where
    welding is done in isolated areas, is much less costly. Downdraft ventilation is not only better than overhead ventilation,
    but it is usually less expensive, since many of the components are off-the-shelf items, and the ventilation system is integrated
    into a convenient work table.
    Welding fumes and zinc oxide dust can be removed by general ventilation; however, American National Standards Institute
    (ANSI) Z49.1 limits zinc to 5mg/cubic meter. General ventilation or tall ceilings (over 16 feet) are needed for all welding
    operation to ensure adequate dilution of smoke and other pollutants associated with welding. This is true whether or not
    zinc is involved.
    Overhead exhaust systems can be designed and engineered to remove welding-related pollutants as well as zinc oxide dust
    from the air. These systems can exhaust to the outside atmosphere or they can be recirculating systems. Recirculating
    systems can be supplied by:
    Supplier Phone
    Torit (Donaldson Co.) 612-887-3900
    Nederman, Inc 313-729-3344
    Airomax 609-933-1780
    Overhead exhaust or filtering systems will cost between $50,000 and $100,000 for four large welding stations, such as would
    be used for fabrication of scaffold components or playground equipment.
    One of the primary considerations for engineered exhaust systems is that the flow of the air must be controlled properly. The
    general flow rate of the air should be 150 to 200 feet per minute, and the flow pattern should be such that the air flows from
    Welding Galvanized Steel -- Safely
    © Sperko Engineering Services, Inc.,1999, Page 5 of 6
    the welders left to right or right to left. Air flow should not come from behind the welder, since this creates a “smokestack”
    effect which brings fumes directly into the welder’s breathing zone.
    Restoring Corrosion Resistance
    The heat from welding vaporizes the protective zinc coating near the weld. Even though the remaining zinc continues to
    provide some protection to the zinc-free areas, the appearance is poor, and the zinc-free areas will rust when exposed to the
    environment. Paints which are high in elemental zinc (i.e., "Zinc-rich"), properly applied, will effectively restore full
    corrosion protection to the weld areas. These paints are available in either spray cans or in containers suitable for brush or
    spray application. This paint can be applied to the weld after sand blasting or wire brushing to remove all welding slag
    followed by wiping the weld clean with a rag. Thermal- sprayed zinc is also effective in restoring corrosion resistance, but
    the surface has to be sufficiently roughened, usually by sand blasting or coarse abrasive conditioning to enable thermalsprayed
    zinc to stick properly.
    Alternative Filler Metals
    Is it possible to avoid the corrosion problems resulting from vaporizing the zinc by using, for example, stainless steel
    welding electrodes?
    Carbon steel, whether galvanized or uncoated, can be readily welded using stainless steel electrodes. Stainless steel,
    however, is electropositive (cathodic) to zinc and also to carbon steel. This means that, in the presence of moisture, both the
    zinc and the expsoed carbon steel immediately next to the weld metal will corrode to protect the stainless steel - not a happy
    situation!
    Another possible filler metal is aluminum bronze (Copper with 7 to 15% aluminum). This alloy has a melting point lower
    than the steel, bonds well to the steel, flows nicely against the galvanize, and is more like brazing than welding. However,
    aluminum bronze is electropositive (cathodic) to zinc and also to carbon steel (more electropositive than stainless steel, in
    fact.). This means that both the zinc and the expsoed carbon steel immediately next to the weld metal will corrode to protect
    the aluminum bronze - again, not a happy situation!
    Why not galvanize after welding?
    Why not avoid the entire problem of dealing with welding over galvanized steel by galvanizing after fabrication? Steel
    products, after all, were always galvanized after fabrication because there used to be no practical way to restore the effectiveness
    of galvanizing after welding.
    Galvanizing after fabrication is still done routinely, but it has to be done very carefully. The fabrication has to be cleaned in
    acid, the acid has to be neutralized, and then the fabrication had to be immersed in a pot of liquid zinc at over 900°F. One
    has to be very careful that the fabrication is dry when it is lowered into the zinc, since any trapped water will flash to steam,
    exploding zinc everywhere. One also has to be careful that the zinc can flow easily into and out of any nooks and crannies to
    achieve complete coverage; this is especially difficult if the fabrication is made of tubes, since the tube has to be open at both
    ends to allow the zinc to flow properly. Achieving uniform coverage on any but the simplest fabrication can be very difficult.
    Finally, the fabricated product has to be able to fit into the pot of molten zinc -- a difficult challenge with large structures.
    Plates, sheets, wires, structural shapes and especially tubes are very easy to galvanize before being made into products, since
    their shapes are simple - no nooks or crannies, no hidden cavities, no place for water to get trapped.
    Products which are ordinary hot dipped galvanized as opposed to being galvanized "in line" exhibit special problems when
    welding, mostly due to the uneveness of the coating. Edges and corners -- typically right where welding is being done --
    frequently have very thick, heavy zinc deposits which may interfere with welding much more than where the zinc has been
    applied evenly. In addtion, hot dipped products typically have rough finshes which do not top coat very well, and top
    coating, especially with powder topcoats, has to be done within 48 hours to avoid difficulty with white rust formations.
    Summary
    In short, it’s usually a lot easier and less expensive to galvanize steel before it is welded into useful products than it is to
    galvanize it afterwards.
    Welding Galvanized Steel -- Safely
    © Sperko Engineering Services, Inc.,1999, Page 6 of 6
    1) Galvanized steel can be welded using the same arc welding processes that are being used for fabrication today.
    2) Galvanized steel can be arc welded safely with little increase in cost or welder discomfort.
    3) Corrosion resistance at welds can be effectively restored by application of paint coatings which are high in elemental
    zinc or by thermal spraying zinc over the weld areas.
    4) Galvanizing simple shapes can be controlled better than psot-fabrication galvanizing, resulting in smoother surfaces and
    a more uniform top coating appearance.
    Portions of this article appeared as an article in The Fabricator, March, 1997. Reprints of that article are available form
    Sperko Engineering.

  8. #138
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    I saw that same video Drewbdo. It got a lot of pictures of my car under construction, But my car is still under construction. those finished cars are some that I have seen for sale. I didnt know anything about the video so they hacked pictures off the net. My car was built in Hollywood as one of the replica fill ins for the movie Glass House.
    Last edited by bodyman; 11-07-2018 at 03:20 PM.

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