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  #1  
Old Sat 19 January 2008, 14:57
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Welding equipment & techniques

This thread started from this post on another thread,

Mig is easy and will do all of the work necessary....but you could get by with a stick welder if your careful.
The welding requirements really are minimal!
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  #2  
Old Sat 19 January 2008, 16:48
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
I used both stick and MIG. Stick on the table and MIG on the gantry and car. If your welder is large enough, you could MIG the entire thing.
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  #3  
Old Sat 19 January 2008, 20:26
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
The idea is that you could use any type of welding. There is no critical welding.
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  #4  
Old Sun 20 January 2008, 07:47
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Craig,

I used a wire feed MIG welder. Very inexpensive and easy to use. Not easy to get good looking welds Allot of "splatter", so extra time required to remove splatter marks.
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  #5  
Old Sun 20 January 2008, 08:28
Robert M
Just call me: Robert
 
Lac-Brome, Qc
Canada
Send a message via Yahoo to Robert M Send a message via Skype™ to Robert M
Greg,

I will say I’m the last one to pretend knowing how to make a nice weld cord/joint. Actually, I’ll debate with many on & about wood & woodworking since it’s my trade, but never the less I have/do my share of some welding with a nice little LINCOLN Power MIG 140 (http://www.lincolnelectric.com/produ...ig_140_180.asp ) welder enough to understand some basics, not all of them, but some.
One of them is a little about splatter. Many reasons why it occurs, but top of my head for now is that you are welding to “cold”. Feed rate not good, wire size wrong, wrong gas, impurities from corrosion or protective oil on steel…. and the list goes on & on.
But I’ll stand on one thing as far as I’ve experience ( not that much after all, just hobbyist welder ) with various type of steel combination I’ve weld together, if splatter occurs it is defiantly not because of the machine type ( MIG for this discussion ) it is most likely a code 18 !!! ( most likely the real cause is 18’’ from the cause ) !!
Again… Please this is not in any form some type of personal attack here, au contraire, just exposing my experience and from what I was guided by some reel pro’s, witch defiantly for my part of the experience may be questioned since remember, I make a living as a studio furniture maker, but on the other side, defiantly not just an average tree hugger guy !!

One thing I’ll say, the Power MIG 140 will do for most of the needs for the big blue beast, it Can weld up to ¼’’ no problemo, but 5/16’’ is pushing it !! ) but if you can afford it, go for the 180, just a tab more powerful for less than +/- 175$ more. !!
With any of those, lots of fun waiting with out major splatter, if any !!


Amicalement, Robert
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  #6  
Old Sun 20 January 2008, 08:29
J.R. Hatcher
Just call me: J.R. #4
 
Wilmington, North Carolina
United States of America
Send a message via Skype™ to J.R. Hatcher
I was using my mig welder with flux core wire and getting the same results as you. I talked to the instructor at the local community college and he told me to invest in a bottle of gas, switch to solid wire and it would make all the difference in the world .... and it did.
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  #7  
Old Sun 20 January 2008, 09:18
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Investigate some anti-spatter sprays or paints before welding. The good ones really do help a lot. The bad ones don't help at all, plus they contain silicon which makes subsequent painting nearly impossible.

In my shop;
- all anti-spatter spray is totally non-silicon.
- grinding off spatter is forbidden. It must be chiseled or scraped off. If spatter is so severe that a chisel doesn't break the blob off cleanly, then the job goes to the scrap and the welder goes for re-training.
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  #8  
Old Sun 20 January 2008, 09:23
revved_up
Just call me: Craig
 
Hartland, MI
United States of America
I see I have much to learn and alot of practice ahead of me. I will try to keep all my future questions in the appropriate threads. I look forward to the challange.

as a side note: Sean I sent you a pm about the laser cut parts.
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  #9  
Old Sun 20 January 2008, 10:40
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Robert,

I agree totally. As usual, I didn't give enough detail. Like J.R., I am using flux core. People have told me to use gas and solid wire and the issues would go away. Another advantage is the welding is easier to make nice beads. My next MM will be much cleaner.
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  #10  
Old Sun 20 January 2008, 10:56
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
I have a small Lincoln welder too. Gas and solid wire eliminates the splatter but, at least on my welder, you are limited to welding thinner metal. Flux core allows you to weld the thicker stuff. However, I'm betting the larger (250 amp) welders can weld thicker material with gas and solid wire.
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  #11  
Old Sun 20 January 2008, 11:12
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
MIG vs. Flux-Cored: Which Welding Process Is Right for You?
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  #12  
Old Sun 20 January 2008, 14:57
firebrick43
Just call me: Jay
 
Indiana
United States of America
I would like to make a few comments on welding.

Now as Gerald put it there is no critical welding on this machine so some of the following is moot. Most of the following is just therory and does not neccessarly apply to the mechmate.

I have welded tig, mig, arc, and gas(oxy/fuel). I have certifications in several different types. I see people all the time pushing mig welding to beginners and it makes me cringe. You can teach a monkey to make nice looking mig welds in a matter of an hour or two and that is the problem. Mig welds can look absolutely beautiful and have no penetration or have porosity and you wouldn't even know it unless you cut the weld in to sample strip and bend it for analysis. I don't know how many times when I was working on certs and the weld would not pass inspection even though the instructor though it looked great. They would fail dye penetration test or show porosity when ground and bent in a test rig. Ended up being the machine that was giving the fits but it showed no outward appearances. With arc, tig, and gas welding, if the weld looks pretty with no outward defects, 99 percent of the time the weld is a sound one.

I am of the personal opinion that a beginner would be better off buy a nice DC stick welder and learning to use 7018 for most work. The skills take a little more time to pick up but rarely does it take some one more than 8 hours to learn the skill. Heck I was 7 or 8 when I learned and was doing a decent job. Plus a stick can do very heavy work and very light as well (I prefer gas or tig for light work however)

I don't have the aversion to grinding welds as Gerald does, although I agree with him on using a chisel to cleaning spatter and a grinder should not be used as a crutch for poor welding. In thick heavy pieces, a good penetration weld should be preformed first(6011), one side built up(7018), and the Root ground mostly ground out from the oppisite side and 7018 bead put in its place.

In the production eviroment, the mig has earned its place because of its speed and therefore reduced labor cost. A nice DC (or AC/DC) arc welder will cost about the same as a small mig(I won't include the no name harbor freight and similar jobies) and will have much more capacity/power.
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  #13  
Old Sun 20 January 2008, 22:35
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Even with our production MIG welders, we revert to stick arc when a weld gets critical. Yes, a beginner should be using stick.

Jay, I have no experience with flux-core mig - does that give any more penetration than the typically poor penetration from gas-shield mig? Do beginners have better strength with the flux core mig? If this is the case, then it might be a serious thing to watch for the guys who are aiming for cleaner welds and want to switch from flux core to gas shield. (The only good thing I can say about spatter is that it indicates better penetration )
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  #14  
Old Sun 20 January 2008, 23:01
firebrick43
Just call me: Jay
 
Indiana
United States of America
Yes and no Gerald on the flux core migs. It has been my observation that it is an increasing trend that heavy industry is actually going to flux core wire welders. These welders are very large, computer controlled, with inverters and a lot of other technology built in(also expensive). With advances in the flux in the wire they are a lot better in controlling contamination than gas shielded mig and amazingly leave little to no spatter but you do have to chip of the slag(it comes of very easily). The smaller mig (<250 amps)welders just don't cut it and while I am not certain, I belive part of it is due to wire size(ie amount of flux that is in the center of the wire). Also remember that one of the reasons that mig is hard to get good welds is that it is very hard to see the puddle straight on because of the large diameter of the gun. Other welding process, especially stick does not limit your view of the puddle. This is one reason that most critical pipe applications (Gas, oil, chemicals, ect) are not certified to use mig and are typically welded with tig on the root pass and 7018DC on the following passes. MIG welders are starting to be used in these applications but it is normally again the very large, computer controlled and modulated models, some even are automatic or robot welded.

For beginners wanting good looking welds, a 7018 ***DC*** rod used in a good ***DC*** welder will do a beautiful job. A little anti splatter spray will keep it from sticking. A 225 amp dc stick welder will cost about the same as a 125-140 mig welder when you consider the gas. And those little 140 amp migs are marginal for any thing bigger than sheet metal.
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  #15  
Old Mon 21 January 2008, 06:07
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Jay,

Excellent points. I'm already thinking about the next MM and a stick welder will be in the plans.

Not so much for the MM (not as critical) , but when I welded up (using flux core MIG) my gantry crane, all welds were in the flat, horizontal position. No vertical or overhead welds. Not that I could weld them anyways.

I was very concerned about penetration (strength of weld) and went overboard on length of welds. More length equals more area equals more penetration. I also make up for my poor welding skill thru design. The gantry structure is rated for 3,000 lbs [1,360.7 kg] but I only attached a 2,000 lbs [907.1 kg] chain hoist. Raises the factor of safety from the original 3 to 4.5.
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  #16  
Old Mon 21 January 2008, 07:57
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
This is the inside cover of my Lincoln 135 MIG welder. It shows the settings that are required depending on whether you are using gas and solid core wire or flux core. As you can see, the solid wire and gas is limited to thinner material. I've had excellent results with it and the flux core splatter scrapes off fairly easily with a chisel.
Attached Images
File Type: jpg Welder.jpg (78.1 KB, 2499 views)
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  #17  
Old Mon 28 January 2008, 07:48
GregA
Just call me: Greg
 
Dundee MI
United States of America
I just considered another angle here.

If you are a total noob to welding, like me for instance... Going to a fabrication shop to have the mechmate welded and painted, will only cost a few hundred dollars more than purchasing everything you need to weld the mechmate.

For example, I am looking at $1500 fabrication and painting cost beyond materials. Looking around at welding kit I think it would be easy to spend that if you were a total welding noob...
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  #18  
Old Mon 28 January 2008, 08:33
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
GregA,

Another aspect that's an advantage. Purchasing the equipment and learning to weld is self reliance. There are so many "small" items on this project that need welding. It would be a time savings to do it yourself, rather than wait on a shop.

I don't think one needs to be an "expert" welder for this project. The design is very forgiving.
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  #19  
Old Mon 28 January 2008, 08:36
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Greg and Greg,
I also like the opportunity to buy a new tool and learn a new skill. I bought a mig welder about 5 years ago and find all kinds of stuff to do with it. I wonder how I got by without one for so many years berfore! Now it will help me build my Mechmate!
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  #20  
Old Tue 29 January 2008, 09:22
DMS
Just call me: Sharma #9 India
 
Rajasthan
India
Guidelines for Shielded Metal Arc Welding (SMAW)

Gentlemen,

I have also got Ac Stick Welder (150 A) and learning Welding process. This Manual helps me.
If anyone interested here it is -
Attached Files
File Type: pdf guidelines_smaw.pdf (463.8 KB, 314 views)
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  #21  
Old Wed 30 January 2008, 01:06
m_leblanc
Just call me: MARS
 
SHAWINIGAN
Canada
Quote:
Originally Posted by GregA View Post
I just considered another angle here.

If you are a total noob to welding, like me for instance... Going to a fabrication shop to have the mechmate welded and painted, will only cost a few hundred dollars more than purchasing everything you need to weld the mechmate.

For example, I am looking at $1500 fabrication and painting cost beyond materials. Looking around at welding kit I think it would be easy to spend that if you were a total welding noob...
Do yourself a favor or more likely a gift, buy a welding machine and learn how to use it, that's what I did not so long ago and I am asking myself how I made to do without one before, always have the odd thing to weld. Best of all you will have it the way you want and when
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  #22  
Old Wed 30 January 2008, 06:36
IN-WondeR
Just call me: Kim
 
Randers
Denmark
I'm using a 250 Amp Co2 welder for my welds, and I'm no pro at this either, but I seem to be getting better at adjusting Power and feed of the wire so I get much nicer welds than I startet out with...
It's all int setting up, so try on some scrap bpieces of metal and just try to weld it together and get a smooth weld then you slowly learn both how much wire to feed and how much power to pull.

It should sound something lilke frying bacon on a pan when you weld... So just think FOOD....
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  #23  
Old Wed 30 January 2008, 07:12
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Kim,
Have you ever tried using argon/CO2 mix instead of straight CO2? I find it makes better welds on clean steel. CO2 I believe will give a little better penetration but not as nice a weld and a little more splatter. Gerald do you have any comments cause I am not the expert here, just some personal observations over the years in hobby welding.
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  #24  
Old Wed 30 January 2008, 07:21
cobra427mnsi
Just call me: Paul
 
Leamington, Ontario
Canada
Another question re: welding, for the guys with experience. Do you clean off that bluish/grey scale coating on new steel before you weld or does it matter if it is left on? It seems to me that there is a little more splatter from a flux core mig welder if I don't remove the scale, but removing the scale is a PITA for each weld.

Paul
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  #25  
Old Wed 30 January 2008, 07:33
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Paul,
I generally clean any surface I am going to weld. This included NEW steel as well. If it is new steel, I generally use just a grinder with a knotted wire wheel and get the metal nice and shiny. If it is rusted I use a grinder and then clean it with the wire wheel well too. I have found that it takes less time to properly prepare my surfaces than to grind out bad welds due to surface impurities and then clean and re weld. With really clean surfaces, my welds go easier and I know they will hold. I have done a lot of welding on old rusty cars and every time I cut corners on the grinding I regretted it later.
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  #26  
Old Wed 30 January 2008, 08:00
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Mixed gas (CO2 plus Argon and some others) cost more, but people pay for it because it makes for better welds. Mixed gas helps the under-powered welders to get better results.

A powerful welder will burn through the "scale" and make a good weld. If your welder is not that powerful, best is to clean the scale off first.

In volume production, we don't clean the scale, nor use mixed gas because our 300-400 amp welders have a lot of punch.
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  #27  
Old Wed 30 January 2008, 08:39
cobra427mnsi
Just call me: Paul
 
Leamington, Ontario
Canada
Thanks for the info

Paul
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  #28  
Old Wed 30 January 2008, 10:07
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Correction to my last post; after checking with my welders, we are using a mixed gas for production. Havn't personally held a mig torch for many years and my memory is going rusty.
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  #29  
Old Wed 30 January 2008, 12:58
IN-WondeR
Just call me: Kim
 
Randers
Denmark
I bought my welder used, with a full bottle of gas, so right now it's straight forward Co2, but when I'm going to have it replaced, then I'm going for the mixed version.... I have also heard the splatter would improve. And as for thread, I'm getting full rolls from work, so this is high grade mig thread...
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  #30  
Old Sat 23 February 2008, 17:44
ekdenton
Just call me: Ed #8
 
Alamogordo, NM
United States of America
I have been a welder for 35yrs now. Done pretty much all kinds. I haven't got my gantry parts yet but the table has some pretty hefty metal to be joined.
The strongest most reliable welds will be with a stick welder using 7018 or comperable tinsel strength rod.

Problem is unless you want to invest $$ in a good welder, the smaller "crackerbox" type welders have what is termed "drooping voltage". Which causes the arc to drop out just after you strike an arc. For a beginner this can make learning to weld very frustrating. A larger welder that does not do this is not really a hobby type welder it is one that you would use for business. Kinda like the difference in a MechMate and a hobbie cnc

If you decide to use a mig, you will need a 220v size mig perferably using the 75/25 co2 argon mix with bare wire. Which will give you the most heat and therefore penetration. This will be the smoothest combination also. Straight Co2 works but is not near as smooth and makes a colder weld at the same settings. If you have everything set correctly there will be very little splatter to clean and it should scrape of easily, however I don't see anything wrong with using a grinder or flap disk for cleaning, as long as you don't get real aggressive and gouge into the base materials. Small scratches will be covered with the heavy equipment enamel type paint.

Note: if you use mig you do not drag like stick welding, the weld puddle will actually be behind the cup and you will need to get used to just seeing the front and sides of the puddle. You have to get used to knowing how wide the puddle needs to be and adjust your travel speed to maintain the same puddle width. Dragging a mig will give little penetration, and ugly welds IMO

The blue bark on the channel iron and angle iron I normally leave without any cleaning or grinding the flux or gas in the case of mig welding will flow the impurites out of the weld. The only time I seriously clean and degrease is for tests.

Last edited by ekdenton; Sat 23 February 2008 at 17:58.. Reason: thought of another entry
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