all about welding

[Phil Waterman]

Over weekend I hosted our MV Club welding seminar on the 23rd of April came off well despite steady snow in the morning with 14 people attending. This year we had something a little different from previous years in that different members of the group brought their own welders with them and we had the chance to compare 5 welding machines. (for simplicity I have used the term Mig for Wire Feed, Flux Core or Shield Gas ) and a plasma cutting torch. Link to time lapse video of the event http://www.canadianmilitarypattern.c...%20Seminar.wmv

• HTP 140 Argon/CO2 Mig http://www.htpweld.com/ 110 Volt machine http://www.htpweld.com/products/mig_...s/mig_140.html machine is about 20 years old, but is still on the market. (Current on-line price $850)
• Hobart Handler 210 Mig running Flux Cored wire (also can run gas shield) http://www.hobartwelders.com/ 230 Volt machine machine is 1-2 years old . This has been replaced in the model line by the Handler 210 MVP. http://www.hobartwelders.com/product...ed/handler210/ new machine is a dual voltage 115 or 230 with auto change over (Current on-line price $1,874)
• Hobart Handler 120/150 Mig running straight CO2 110 Volt machine http://www.hobartwelders.com/product...ed/handler140/ machine was an older one with many years of use and is no longer listed by Hobart,
• Century Welder Mig 125 volt machine, running Flux Core wire (also can run gas shield) typical of hardware/auto part store welder (side note this one was purchased used for $100)
• Montgomery Ward 230 Stick welder 230 Volt machine that is 30+ years old typical of the home, farm utility stick welder.

To begin with, all these machines can and did weld steel with good structural welds so they all meet the primary shop purpose of welding. They all demonstrated that they could be used by experienced welders as well as first time welders. The purpose of the welding seminar was to try different machines to compare the ease of welding, ability to weld 1/8 wall box tubing and heavier gage steel, with a little playing with thin sheet metal.

Following are observations:

• Flux Core wire is simple to use without the necessity of gas bottle and regulators. Leaves more residue on the weld to be cleaned up with a rougher appearance to the weld.
• Argon/CO2 or Straight CO2 share a cleaner smoother weld with no residue to clean from the weld. Argon/CO2 appears to have a slight edge in smoothness of weld but Straight CO2 is less expensive.
• For straight structure welding any of the four machines can get the job done. The voltage 120 vs 230 was not apparent in the welding we did that day, but from (my) experience only starts showing up as you weld heavier steel 3/8 to 1/2 as you use heavier wire or sticks.
• Both of the people with welders running Flux-core wire have the gas regulators and their machines are equipped for shield gas, both agree that before they start doing any real finish type welding they’ll have to go out and get a gas bottle.
• Everyone seemed to agree that wire feed machines with just flux-core wire are probably not worth the small cost savings.

Also discussed and demonstrated were various welding accessories:

• Most important of these was auto darkening welding helmets, those in the group who had not used one of these helmets were surprised what a difference these welding helmets make in the ease of welding. These helmets have a huge range in price from $50-300 with various options as to sensitivity, max shade density, delay. Before you buy go on line and read the spec sheets to get a better idea of what you need or can get http://www.hobartwelders.com/products/welding-helmets/ or http://www.htpweld.com/products/weld.../overview.html
• Carbon arc attachments
• Sheet metal clamps and alignment tools
• Wire brush tools to cleanup before and after welding, including steel brush vs brass brush.
• Online welding forums http://www.mig-welding.co.uk/forum/index.php , http://weldingweb.com/ offer a great deal of information as does YouTube (search phrase - welding tips and tricks)

One of the things we discussed but obviously didn’t test was duty cycle of the various machines and this is a critical issue in price range of machines, the higher the duty cycle rating the more expensive the machine. For the average home shop duty cycle will probably not be an issue unless you are doing a lot of heavy welding. The HTP 140 for example has a listed Duty Cycle 20%@140 amps. – 100%@62 amps the only time this machine has gone off on thermo overload was welding 1/8-3/16 steel on a cargo body running a 12’ continuous weld at full power got through about 10’ before saying it wanted to rest.

A point in passing for those of you who use Oxy Acetylene torches or cutting torches, there is a major shortage of Acetylene developing in the US as a result of fire and explosion at larger of the two plants in the US that produce carbide from which Acetylene is made. Most if not all gas suppliers have already instituted restrictions on who they will sell to so that they can meet their contracts with commercial users. If you use Oxy Acetylene you will have trouble getting refills and should probably start looking at alternative gases. This shortage may be of lengthy duration.

Writers Note-I have had very good luck with HTP welding products, having a Plasma Cutter, Mig Welder, and Pinch or Spot welder, they have an excellent web site, and catalog http://www.htpweld.com/index.htm I will warn you about one thing they don’t have, prices on their website but if you go to http://www.usaweld.com/ they have prices, if you are looking buy in the future get a catalog from http://www.htpweld.com/index.htm as they have sales which from time to time that offer some real savings. The other thing is that I have been pleased with their service when I have needed parts or consumables.

[Mike Kelly]

Thanks Phil

Very informative article

You will laugh at this: I have read about carbon arc welding recently. It is a alternative to oxy acetylene welding . You have two carbon rods and a arc that creates the heat . You can braze and solder and even weld steel .

The rods are available on EBAY in various sizes . You use a standard arc welder as the power source .

Are these welders viable ? Have you ever tried the process ?

http://en.wikipedia.org/wiki/Twin_carbon_arc_welding

MIKE

[hrpearce]

Mike I did the oxy welding course at night teck over 30 years ago and as part of the course we some carbon arc and tig welding. I'd take tig over carbon arc any day, my humble opinion.

[Robin Craig]

Noah was a master of carbon arc welding.

TIG is more modern way to go.

All the welding processes have their uses mind you, I still braze items, especially cast repairs, not to be sniffed at. Silver solder has its place also.

Learning to understand the processes and what they can do and why is key to being able to effect a good solid repair.

Am happy to answer questions where I can on welding.

Robin

[Phil Waterman]

I've used both the twin carbon and single carbon torch methods. Used them a lot more before I got the mig welder. Now I use the twin carbon torch primarily for heating steel. Depending on the carbon size and amp setting the heat it can generate is impressive.

Prior to getting a mig welder I did a lot of single carbon brazing of sheet metal seams. I'd just put a carbon rod in the stinger of the stick welder ground the work with the clamp, put the tip of the brazing rod (no flux) on the seam and then stroke the arc on the tip of the brazing rod and puddle and flow the bronze. I could braze better than I could weld sheet metal with the stick welder.

Interestingly there is a carbon rod attachment for the mig welder so that you can spot heat for shrinking dents.

This weekend was first time I got to try and compare different welders side by side. I think everybody walked away at the end of the day knowing more about their own machine and how to get more out of it. The guys who didn't have welders who are thinking about get one got the most out it.

This type of event would be a good idea for any MV (antique car) club to host.

Cheers Phil

[Mike Kelly]

Originally Posted by Phil Waterman

I've used both the twin carbon and single carbon torch methods. Used them a lot more before I got the mig welder. Now I use the twin carbon torch primarily for heating steel. Depending on the carbon size and amp setting the heat it can generate is impressive.



Cheers Phil

Interesting . I have read that it's a very handy process for brazing broken cast iron bits together . The twin rod setup is best with a AC source they say . With DC, one rod tends to burn away faster than the other .

Mike

[Robin Craig]

Not wishing to teach Grandma how to suck eggs you understand . . . .

Briefly some cast snippets for you guys.

The basic problem with cast ferrous objects is that when welded the weld material deposited shrinks, as all metals do as they cool, the shrinking speed is faster than the cast and hence the weld cracks.

That is the simplified basic problem.

Basic remedies are to pre-heat the subject, keeping heat on if you can during welding. If it is just a crack then stop holes must be drilled at the end of the cracks. If it is two or more lumps / pieces then making a bevel from both sides helps in preparing the joint.

Also in preparation drilling either side of the break and installing knurled pins into holes making an interference fit helps alignment and strength also.

Preparing a cooling bath of fine material such as sand and post heat should be considered.

When using MIG welding I have had great experiences with a very slow jive of pre heat, weld a 1/4 inch, heat and peen simultaneously, heat and weld and peen weld and repeat and nauseum. The peening stretches the deposited material and stops the cracking. Once the joint is closed, backgrind the weld and weld over again. Failure to peen at any time is direct path to a cracked weld.

If you have no patience dont start.

I have used mild steel MIG wire, high nickel stick rods, done it with TIG and bared stick nickel rods, done it with stainless wire or rods.

Brazing is much easier.

Understanding why the part broke in the first place is the critical step most fail to understand. Often it is just abuse or the same spelled differently ie too much power.

If it is a classic flaw in the design of the casting you will have to remedy that first.

Brazing is brilliant for making a new surface for machining and bearing installation when the old one has worn out the cast as it thrashed around.

Because brazing is softer, home made mills in the drill press and dremel tool fondling has been known to make things work. Brazing is so kind on the restoration as it can easily be worked and blended in and after paint is hard to spot.

Silver solder is remarkably strong and is great for small item repair.

Cleanliness is a vital ingredient in any of the above, welding detests hydro carbons be they paint, grease, oil or fuel.

If you want a cheap and easy workshop dye penetrant for cracks my preferred route is finely shaved soap stone and dyed diesel fuel.

Clean and dry the suspected area. Using Q tip or larger dab dyed diesel alog or around the crack. Dry by wiping surface clean thoroughly, do not apply heat.

Gently lightly dust crack area with soap stone dust. Watch dust turn pink as fuel gets drawn out of crack into the dust. You will be amazed at the results.

Have fun

Glad to pass on what others have taught me.

R

[RHClarke]

As a new "welder" I am amazed at how much I need to learn about this "art".

[Phil Waterman]

All I can say is Practice, practice, practice, I have to force myself every time I have welding to do on a project to stop and practice before I try to do the welding on the "finished" part. I've found that if I take the time to get some scrap steel out of the same thickness of what I want to weld and practice until I can produce a good smooth weld it actually takes less time than grinding off the crappy first weld.

For me I need to run 1-2 feet of seam weld as practice or someplace where it won't show before I can produce a weld that I want other people to see.

But then again on CMPs they didn't clean off the splatter,the underside of my HUP looks like they held a welding class while they were fabricating it, there are some really crude welds. But remember this was mostly done with stick welders, none auto darkening helmets and somebody screaming hurry up we have another 50 to get done on this shift.

We have some guys in the club who are real well trained experience welders for them it doesn't matter if they haven't touched a torch in a year they pick it up and produce perfect welds.

Cheers Phil

[Phil Waterman]

To produce a crack free weld in cast iron is an art. And is really all about pre-heating from my limited experience. The question is how much pre-heating and to what temperature.

Once watch and old timer weld up a Model A Fords head that had cracks in the water jacket from freezing. He cleaned it up, dumped 20-25 lbs of charcoal in the barbecue grill put the head on the grill and lit the charcoal. He let the whole thing sit their until the coals were all nice a hot then with the thing still on the grill he took a stick welder, with what I suppose were the correct rods for cast iron, and started to weld up all the cracks. As he weld a few new ones showed up and he welded those as well. Then he said just leave it on the grill until its cold. My brother had that Model A for about 20 years after that no leaks, people would ask about the funny looking welds on the head.

Cheers

[Alex Blair (RIP)]

Originally Posted by Phil Waterman

To produce a crack free weld in cast iron is an art. And is really all about pre-heating from my limited experience. The question is how much pre-heating and to what temperature.

Once watch and old timer weld up a Model A Fords head that had cracks in the water jacket from freezing. He cleaned it up, dumped 20-25 lbs of charcoal in the barbecue grill put the head on the grill and lit the charcoal. He let the whole thing sit their until the coals were all nice a hot then with the thing still on the grill he took a stick welder, with what I suppose were the correct rods for cast iron, and started to weld up all the cracks. As he weld a few new ones showed up and he welded those as well. Then he said just leave it on the grill until its cold. My brother had that Model A for about 20 years after that no leaks, people would ask about the funny looking welds on the head.

Cheers

Phil..
The old lad had it right..I used 2 hibachi BBQ's as a forge with a pilot line of oxygen out of the oxy-acetlyne into the bottom of it..Get that head red hot and stick weld it with a cast iron rod..then let it cool off to cold and then re-machine IT..I THOUGHT YOU WOULD TRY IT WITH THE CRACKED HEAD WHEN YOU GET YOUR NEW ONE..CLEAN UP THE CRACK WITH A DREMEL AND
give it a go..

[Mike Kelly]

Can I ask Phil or Robin or anyone:

I am making new outer fender or wing panels for my 1950 land rover . In order to get the correct radius on the top corner I have to weld in a section, rather than make the panel in one big lump.

The metal is 18 gauge aluminium . I read that its possible and easy to mig weld thin alum. with ER 4043 wire , but it has to be .3 size wire. After googling , I found some suppliers in the USA , but none here . I can only get .9 wire here .

And, dont know how .3 wire will work in my machine , its rather thin wire , will it feed ok ?

BTW they recommend pure Argon for shielding , not CO2 mix with Argon
Mike

[Alex Blair (RIP)]

Originally Posted by Mike Kelly

Can I ask Phil or Robin or anyone:

I am making new outer fender or wing panels for my 1950 land rover . In order to get the correct radius on the top corner I have to weld in a section, rather than make the panel in one big lump.

The metal is 18 gauge aluminium . I read that its possible and easy to mig weld thin alum. with ER 4043 wire , but it has to be .3 size wire. After googling , I found some suppliers in the USA , but none here . I can only get .9 wire here .

And, dont know how .3 wire will work in my machine , its rather thin wire , will it feed ok ?

BTW they recommend pure Argon for shielding , not CO2 mix with Argon
Mike

Mike

When welding aluminum you use a heli-arc machine..with a foot pedal volt/amp control..
Auto wire feed and you can butt weld two pieces of aircraft aluminum skin as fast as you can move your hand with the stinger..
And look like you have been welding for years..
I used to go to the metal shop on the hanger line and play with the heli-arc welder with scrap aluminum..with a few minutes instruction you would look like a pro..Helium is the shielding gas..
Check out your local air craft repair facilities..
Of course I had the whole RCAF aircraft metal shop to play in...
Heli-arc was the old timers terminology..TIG welding is what it is called now..
Here is a good video of the TIG foot pedal operation..the more you press the hotter it gets..You can by lightly pressing on the foot pedal butt weld your thin aluminum sheet with out filler rod with a little practice.
Enjoy your welding..]
http://www.youtube.com/watch?v=QpPQNq7Y-WY&NR=1
http://www.youtube.com/watch?v=R8B3q...feature=relmfu
http://www.youtube.com/watch?v=Gvk8r...eature=related
http://www.youtube.com/watch?v=VEEpi...eature=related

[Mike Kelly]

Ok Alex

Yes the aeroplane guys have some neat gear . I tried to get a airframe fitters apprenteship in the early 1970's but they ( TAA and Ansett ) said it's nigh on impossible , every dog and his uncle was trying for the same job .

I made a error with my metric /imperial wire sizes.. I looked again and they are talking about .03" which is .8mm wire

QUOTE
from the Miller site
Successfully Welding Sheet Metal With MIG And TIG

For fabricators and others with bottom line goals, welding sheet metal often means a constant battle between productivity and equipment investment vs. burn-through, warping, excessive heat affected zones (HAZ) and weld appearance. For the individual occasionally welding sheet metal, success can be as simple as learning the proper techniques.

Process Selection

When welding thin metal, the main objective is to avoid warping, burn-through and excessive heat affected zones while still ensuring the weld has sufficient mechanical strength for the application. The welding processes that provide the most control over heat are short circuit transfer GMAW ("short arc"), pulsed GMAW, GTAW and pulsed GTAW.

Process-Specific Advice

GMAW Electrode and Shielding Gas Selection
Use the smallest wire diameter feasible. A smaller wire takes less heat to melt, which in turn heats the metal less. A smaller wire also gives you more control over the weld bead and a better chance of recovering from mistakes because it has a lower deposition rate. That's why professional groups like I-CAR, the Inter-industry Conference on Auto Repair, recommend using .023 in. diameter wire for most collision repair work. For welding material 18 ga. and thicker, you may be able to use a .030 in. wire for higher deposition rates.

For welding mild steel, choose an AWS E70 wire in S-2, S-3 or S-6 classification. For shielding a shielding gas, always use a high argon-based gas, such as 75 percent argon/25 percent CO2 gas (commonly called 75/25 or C25). Argon carries less heat than pure CO2, and you'll get less spatter.

The two most popular wires for aluminum are ER4043 and ER5356. While the latter feeds more easily, choose ER4043 in .030 in. diameter to solve heat-related problems. ER4043 melts at a lower temperature and uses slower wire feed speed, often making it the superior choice in sheet metal applications. Always use 100 percent argon shielding gas.

For welding 304 stainless steel, ER308, ER308L and ER308LSI wires are compatible. For welding 316L stainless, you need a 316L wire. Use a "tri-mix" shielding gas consisting of 90 percent helium/8 percent argon/2 percent CO2. Note: Do not attempt to weld thin metal with flux cored wires. These wires use more heat because they require globular transfer. Unlike short arc, where the weld puddle cools every time the wire touches the base metal, the arc remains "on" constantly with globular transfer.

Electrode Polarity
For welding with solid wires, use electrode positive or "reverse" polarity. While EP directs more heat into the base metal than electrode negative (EN or "straight" polarity), you will obtain the best results with EP and following the guidelines provided here. If you've been using flux cored wire, be sure to change your machine's polarity from EN to EP.

GTAW Electrode Selection & Preparation
Forget the ubiquitous 1/8-in. diameter tungsten electrode and use a smaller one. They come in diameters down to .020 in. Smaller electrodes carry less heat and enable you to better focus the arc in a smaller area. For steel and stainless steel applications, keep the tungsten pointed, and be sure to grind parallel with the length.

For best results on thin aluminum, use an inverter-based power source (see GTAW power source recommendations) and forget another popular practice: welding with a pure tungsten and balling the end. Instead, select a 3/32-in. diameter tungsten with 2 percent cerium (2 percent thorium as a second choice), grind it to a point and put a small land on the end. Compared to the balled tungsten used with conventional GTAW machines, a pointed electrode provides greater arc control and enables you to direct the arc precisely at the joint, minimizing distortion.

Aluminum Preparation
Clean all metals before welding, but especially aluminum. Remove oil and dirt with a degreaser/solvent. Just prior to welding, remove oxide with a stainless steel wire brush, grinder or chemical oxide cleaner. When exposed to air, an oxide layer forms on aluminum - and aluminum oxide melts at a temperature 2,000 degrees Fahrenheit higher than plain aluminum! Any slacking in weld preparation degrades weld quality and integrity, so be diligent.

If you store aluminum in cold places (outside, unheated warehouses), bring it up to room temperature and eliminate condensation. Do not heat cold metal with an oxy-fuel torch (which is a common practice, but not a good idea). This can drive carbon into the oxide coating.

Universal Advice

Weld Technique
Direct the arc at the middle of the weld puddle. Normally, you would keep the arc on the leading edge, where the weld puddle is thinnest, to drive the arc into the work for more penetration. However, staying back enables the puddle to insulate the base metal from the arc's full force.

To prevent burn-through and warping, do not whip or weave the torch, as the more time you keep the arc in an area, the hotter it becomes. Always travel in a straight line and use the fastest travel speed possible that maintains a good bead profile.

Skip Welding
Unevenly distributed heat causes distortion and warping, which in turn wreaks havoc on parts that theoretically fit together. To minimize warping, distribute the heat as evenly as possible. You can accomplish this by using a skip welding technique.

For example, let's weld a 2 x 2 ft. piece of 18 ga. stainless steel to repair the side of a tank. Start by making a 1-in. long weld. Skip 6 in. and make another 1-in. long weld. Continue to work your way around the plate's circumference, welding 1 in. out of every 6 in. You may have heard of this as a 1" on 6" weld. After you've traveled around once, make your next 1-in. long weld 3 in. from the first weld. Continue to place the second set of welds between the ones you made on the first pass, and so on until you achieve the integrity desired.

The same technique holds true for welding linear parts. If the metal starts to warp or pull to one side, solve this by: increasing the distance skipped between welds; welding at the beginning, middle and end of the piece, then repeating the sequence; or welding on alternate sides of the joint.

Backing Bars
To dissipate heat from the weld area faster than atmospheric cooling alone, place the heat affected zone (HAZ) in contact with a "backing bar" or "chill bar." A backing bar can be as simple as a metal bar (usually copper or aluminum because they dissipate heat best) clamped to back of the weldment. This simple technique enabled one fabricator to use an all-in-one pulsed MIG power source to weld a continuous seam on .040 in. aluminum.

In higher-duty cycle applications, you may need to consider a water-cooled backing bar. Elaborate versions feature a water cooler that circulates chilled water or special coolant through holes drilled in the bar. Simple, homemade versions feature a water cooler circulating coolant through PVC pipe touching the back of the bar.

Fit-up and Joint Design
Welding thin metal demands tight fit-up. Imagine a butt weld on 20 ga. metal. If the parts fail to touch for even 1/16 in., you have just created a hole that begs for burn-through and left a gap that cannot absorb the heat. On thicker metal, the edges of the metal can support the arc, but not here. Gaps cause nothing but trouble. To avoid rework caused by burn-through, adhere to the old saying "measure twice, cut once."

If you can redesign the part with joints that can withstand more heat, do so. For example, instead of a butt weld, can you make a lap joint? If you can, you double the amount of metal available to absorb heat.

Don't Overweld
Most people, especially those without formal training, feel compelled to overweld a joint to obtain greater strength. Assuming you have sufficient heat, the leg of the joint (the long side of the triangle) does not need to be any longer than the thinnest plate. For example, when welding a 1/16-in. plate to a 1/8-in. plate in a T or lap joint, the weld only needs to be 1/16-in wide. Excessively wide welds reduce travel speed, waste time, waste filler metal and gas, may lead to unnecessary post-weld grinding, and may affect the temper of the metal.

GMAW Power Sources

When selecting a power source for short circuit GMAW, use one with good voltage control at the low end for good arc starts and arc stability.

If you plan to buy an all-in-one power source that uses 115V household current, go with one from a major manufacturer of industrial welding equipment. Machines with low-ball prices simply do not have the slope and inductance necessary for good control over the short circuit. Be sure the unit comes with a contactor and gas solenoid valve; some units designed only for flux cored welding do not.

If you plan to weld with an all-in-one power source in the 200 to 250 amp range, look for one with a spool gun that connects directly to the front panel. This eliminates a lot of hook-up headaches by letting you switch instantly between two different wires, such as .023 hard wire in the "regular" gun and .030 aluminum wire in the spool gun. To weld aluminum down to .040 in., Miller's Millermatic® Pulser provides the best value for moderate-volume fabricators because it features built-in pulsing capabilities.

For high volume work, both 200 to 300 amp all-in-one units and industrial, production type machines can weld sheet without exceeding their duty cycle. While several all-in-one units provide excellent results, they cannot compete with industrial machines for controlling spatter. If you currently spend a lot of time on post-weld cleaning and grinding spatter, you may be able to increase productivity and lower overhead costs by upgrading your power source technology. Remember that gas, wire and the power source account for less than 15 percent of a weld's total cost; 85 percent comes from labor. Far too many companies try to save pennies by cutting welding costs while obliviously wasting dollars on grinding time.

For metals in the 1/16-in. to 3/32 range, consider investing in a pulsed GMAW system when bead appearance and no spatter are factors. Pulsed GMAW is almost spatter free and provides faster travel speeds than short arc, so it can pay for itself very quickly. Pulsed GMAW may be able to replace GTAW in some applications to improve travel speeds. Again, industrial power sources with built-in pulsing controls, such as Miller's Invision™ 354MP, provide the best value.

GTAW Power Sources

GTAW power sources come in two basic categories: those with a DC output for ferrous metals and those with an AC/DC output for non-ferrous metals as well. For welding thin steel or stainless steel (and no aluminum), invest in one of the new GTAW inverters that feature pulsing controls and HF arc starts, such as Miller's Maxstar® 200 DX or Maxstar 150 STH. Pulsed GTAW, which allows the weld puddle to cool between pulses, is one of the easiest methods to prevent warping and burn-through.

For welding thin aluminum, use a GTAW machine with an adjustable squarewave output. By fine tuning its "balance control," or adjusting the EN to EP ratio, you can narrow the weld bead and take heat off the base plate.

For unbeatable results on thin aluminum, use an inverter with advanced squarewave technology, such as Miller's Dynasty™ 200 DX. These machines feature extended balance control (up to 90 percent EN, versus 68 percent EN for convention technology) and an adjustable output frequency (typically from 20 to 250 Hz). Inverters create the narrowest arc cone possible and let you weld in the AC mode with a pointed tungsten. You can precisely direct the arc, establish the weld puddle faster and place the filler wire right where you want it. People who weld with these inverters consistently state that they make aluminum weld almost like steel.
Technical/Informational
Products

* DYNASTY 200 SERIES
* MAXSTAR 150 S
* MAXSTAR 150 STH
* MAXSTAR 150 STL
* MAXSTAR 200
* MAXSTAR 200 STR

Welding Categories

* TIG
* Pulsed TIG
* MIG
* Flux Cored/Metal Cored
* Pulsed MIG

Welding Applications

* Aluminum Welding
* Stainless Steel Welding
* Motorsports (car, truck, bike, etc.)
* Fabrication
* In-plant Maintenance/Repair

Key Business Issues

* Reducing Downtime
* Improving Weld Quality
* Increasing Productivity
* Reducing Weld Costs

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file:///C:/welding-alumin/sheet-metal-MIG-TIG-GMAW-GTAW.htm

Mike

[Cameron Reed]

Hi Mike, welding of the outer fender should be reasonably straight forward, as long as where you are trying to put the patch in, is tying in with good sound metal. It has to be super clean both inside and out as when you weld it tends to draw any impurities from the backside through. If you have a mig and wish to try it you have to use pure argon as sheilding gas(as stated) buying wire shouldn't be to bad .035" (.9mm) 4043 is available in small spools (I've got some if you wish to try). Make sure that you keep the gun lead as straight as possible, give the liner a good blow out(generally best if you take the liner out of the cable and blow compressed air through whilst trying to rap it lightly on the ground). I would generally go for the next size up tip to help the wire to feed freely (all helps to avoid birdsnests when you get burnback). Probably another thing to check is that the feed rolls line up with each other in the vee, if they are offset a little they tend to shave the wire which then builds up in the liner and then makes nice birdsnests. The feed roll pressure should only be enough to feed the wire smoothly(my simple test is to pinch the wire between your thumb and finger and adjust feed roll pressure until you can't stop the wire with reasonable pressure) When you buy material to make patch ask for 5052 grade if available it is a marine grade 5% magnesium, it is a little stronger than 5005 so it will help hold it's shape a little better. Not sure where in Vic you are but if your sorta close to s/e burbs I could do it with the Tig (dynasty 200). please feel free to sing out if you have any questions or want any help just pm me, or from anyone for that matter
regards

[ozm29c]

Further to the constructive comments by other forum members. Here are some other thoughts to consider.
1. Always check what lies behind your proposed patch panel ie will it burn!!!!! Is there a fuel line or electrical wiring looms.
2. Prepare the joints to ensure that you are welding clean metal, Any contaminants in the weld pool will either weaken the join or blow out while you are welding like a mini volcano!
3. Keep the joint width between 0.5 to 1mm to allow for expansion of the donor patch and to ensure good joint penetration.
4. Use 0.6/0.8mm dia wire with your smaller Mig welders. Having said that my thoughts on MIG welders are the bigger the better. Small MIG welders are fine but the bigger welders have more OOMPH! In Australia 0.9mm welding wire for the bigger welders is cheaper to purchase as it is made locally where as 0.8mm wire is imported.
5. If possible try to avoid using flux cored wire.
6. With patch panels don't try and weld in continuous seams, spot here then move away and place a spot there. Continue staggering your spotting until the join is filled-This takes more time but will help dissipate the heat and minimise your patch panel and parent metal from heat distortion. Remember HEAT is your enemy. A good cup of Tea or Coffee can be enjoyed many times
7. Use heavier gauge metal ie 1.2mm or at a pinch 1.6mm (than your parent metal)to make your patch from. This will help you to start and maintain your weld without blowing a hole in the joint. Looks no different on the outside.
8. Use sunscreen on exposed parts of your skin as MIG welders have a tendency to burn your skin with excellent results. Better still try to cover all exposed parts of your body.
9. I know it is hard but try to weld with elbow length gauntlets (Leather gloves). I am sure experienced welders at some time in the past have grabbed a hot bit of metal with their bare hands by mistake. OUCH!
10. If you can borrow or purchase an auto darkening helmet, do so. Good for tak welding.
11. Buy yourself a cheap Chinese angle grinder but always use good quality cutting and grinding discs. Use the very thin section cutting discs. As always use PPE ('FULL' Eye protection and hearing defenders)
12. When grinding off the finished welds try not to use excessive force to speed up the removal of excess weld. All you will do is create heat with the end result being metal distortion. Once you have levelled the ground surface, get hold of a flapper disc to further smooth the surface. After all due care to minimise distortion you still might have to delve into the lost art of heat shrinking metal. The technique is for another post.
13. Paint/prime the exposed metal as soon as possible to prevent corrosion.
14. BTW The point of a screw driver is a very good tool for probing around the affected area to try and determine the extent of rust damage. Once you have cut the rust out of a particular area, then and only then is when you will know where to start your repairs.
Anyway I hope this will give you something to work with.
Don't rush the job
Good luck
Cheers
John Wilson

[maple_leaf_eh]

Originally Posted by Robin Craig

Not wishing to teach Grandma how to suck eggs you understand . . . .

Brazing is much easier.

Understanding why the part broke in the first place is the critical step most fail to understand. Often it is just abuse or the same spelled differently ie too much power.

If it is a classic flaw in the design of the casting you will have to remedy that first.

Brazing is brilliant for making a new surface for machining and bearing installation when the old one has worn out the cast as it thrashed around.

Because brazing is softer, home made mills in the drill press and dremel tool fondling has been known to make things work. Brazing is so kind on the restoration as it can easily be worked and blended in and after paint is hard to spot. ...

Glad to pass on what others have taught me.

R

Hmmm? I have a Spanish FR7 rifle with a $hit trigger pull. A nub on the top of the trigger rotates on the bottom of the receiver. The Spanish gendarme must have dry fired 25,000 times, because there is depression worn in the steel. I've often wondered what I could do about that problem. Now I see an option.