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post #61 of 106 (permalink) Old 09-23-2008, 05:26 AM
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I have an auto darkening helmet that I bought from a local "cheap" tool place very similar to Harbor Freight for I think $55. It has made welding MUCH easier, when I first took a class I bought the regular type helmet with the flip up shade, now that I've used the auto darkening a few times I'll never go back! They really do darken quickly. One thing that can be annoying is if you have a light source close by and look in its direction the shade will darken so you can't have the light source right up close to the work.

One thing you do need to remember is to hit the on button before you start welding though, don't ask me how I know...

Kevin

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post #62 of 106 (permalink) Old 09-23-2008, 10:02 AM
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post #63 of 106 (permalink) Old 12-07-2008, 09:42 PM
 
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This post is years behind the initial question but for what it may be worth I started my project with very little welding experience and learnt as I went along.

The 1972 Spider 2000 I aquired was from a seaside area and was a very sick puppy heading to the wreckers until it landed in my lap. The previous owner had intended doing a chequebook restoration but got cold feed when the estimate climbed well above $40,000 Aus.

I've almost finished a lot of welding repairs having used most of an 8x4 foot sheet of 0.9 mm mild steel, learning the hard way. I didn't but any fastory panels but cut and shaped over 50 patches of various size using common hand tools.

In my view the welding courses I did at TAFE night school were almost useless when it came to welding thin body metal. They taught welding the thick stuff and completely left the thin (1mm and less) stuff out, so one has to learn technique by trial and error. That's why I started with the floor panels.

Heat distortion and rust scale underneath are the enemies of a good weld and smooth finish so I strongly endorse previous advice to tack weld and progressively fill in between tacks, little by little.
I started out doing the floor areas with a small cheap MIG and used lap joints. Butt joints I found to be impossible. The MIG left raised beads but this didn't matter on the floor. When I started on the body panels I used an Essetti TIG (about $1000 Aus) and it was fantastic once I gained some skill.

Auto darkening welding helmets are great but get a good fully adjustable one (about $250-350 Aus) and if your eyesight is not 20/20 anymore like mine, I strongly advise fitting a 2 to 2.5 power magnifying lens inside the helmet. This makes it much easier to recognise the instant you get a molten pool and thus avoid burning holes in the thin metal.

What else? I almost completely stripped the body and made simple, hight adjustable front and rear tripods for a rotisserie. This has been fantastic allowing complete 360 degree rotation and I doubt if I could've done the project without it.

Clean shiny metal gives the best weld but it can be impossible sometimes to clean the inside surface and you need to make do with some contamination. Speed is vital here to judge the formation of the molten pool as soon as possible.

I fitted a small aperture tip to my TIG ( about 10mm dia) to concentrate gas shielding and I got a cheap gas flow metre to more accurately measure flow rate, saving quite a bit of Argon gas.

I've used rust converter in many areas where required and the rotisserie has made this treatment much more effective.
The body now in the final stages of prep for priming and painting.

My advice to anyone taking on such a project is to have a dedicated workshop, tackle one small part at a time rather than get discouraged by the whole shambles and possibly wait until you retire from full time work.

What colour??? MMmmm? It'll be hard not to go for Rosso but it was white originally and I like a deep, lustrous metallic silver which would look good with the black hood and interior.

For an 105 Alfa Romeo, I say give it a go!
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post #64 of 106 (permalink) Old 11-22-2009, 08:08 PM
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This thread is obviously fairly old, and I haven't read all of it, but I thought I'd add something to it.

Arc welding has no place with sheet metal. I've watched experianced Boilermakers struggle when using 1 portable $1200+Aus welder to weld thinner than 2mm sheet metal. Even the $12000+ welders at work aren't used for welding thin material with Arc welding.

MIG welding is, in my opinion, very over rated. Weld spatter, distortion and a chunky/fat and hard beed of weld make it less than ideal for pannel work. Useless if there is a breaze as it blows awy the sheiding gas. Flux cored filler wire just seams to add more spatter.

TIG welding is excellent if you have the skills and the tools. You get what you pay for with TIG welders. Having 20 dials to set the thing up just makes it difficult and annoying. Digital type 1s like what I'm fortunate enough to have access to at work, make set up so much more simple. Practice is good, but experianced advice is much much better.
Not all TIG welders can weld aluminium. It's only those that can be set up with AC current (typicaly 3 phase) that can.

Oxy/Acetelene is as old as the hills, and so are most of the torch's.
I have a Henrob 2000 (called soething else these days) torch and it is the king of oxy welding. A low flame velocity prevents the parant metal from being blown away when it becomes molten. Small heat affected zone (HAZ) reduces panel distorsion. A soft, ductile weld that is easy to hammer flat or grind smooth. Low regulator pressure (4psi) means you get to drain your bottles dry befor you take them back for replacement. Weld penetration is brilliant. It can weld upto 1/2 inch thick, but wear thick gloves for that . Fusion welding (no filler wire) is so easy, you'd think you were a proffesional after your 1st attempt.
I've welded everthing from a hollow copper bus bar (copper obviously being an excellent conductor of heat) that had a hole blown thru it, thin(!!) muffler bodies, turbo exaust manifolds and chromolly frame work on a (propper racing but extended to take a motor bike engine) gokart with mine.

Slowly Progressing Vortech Supercharged 1990 Alfa Romeo 75 Potenziata. Out of Action Twin-Charged 1988 AW11 MR2. Current Daily Driver, The Glorified Taxi 2006 BF FPV F6 Typhoon.

Last edited by Duk; 02-03-2011 at 10:17 PM.
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post #65 of 106 (permalink) Old 11-23-2009, 01:13 AM
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I`ve got a Henrob too but I tend to use my mig for panels where I can`t get to the back of to use the hammer and dolly. Where I can get to both sides I quite agree with you and you eliminate that mig weld bead plus you have a lot more control- my best repair with the Henrob was the repair of a petrol flap after removing an aftermarket lock and welding a patch in. Having both gas and mig gives the best of both worlds as you can heat & expand, cut and weld & braze with gas, plus shrink. Mig is quick and I don`t get quite as much heat into say a butt weld on a body panel than I would with my Henrob but perhaps I should practise a bit more.

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post #66 of 106 (permalink) Old 02-11-2010, 03:37 AM
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What about the flux ?

Hi all,
We've only used a MIG for body repair (my dad being the welder, me being the mechanical guy...), but I've always wanted to investigate gas welding.

But the basic problem of removing the flux left over after welding seems to defeat gas welding right from the start ? (And brazing for that matter)

i.e. If you're not able to guarantee 100% flux removal, you'll get rust starting on the seam sooner or later from the acidic flux remnants ?

Is this right ? If not what's wrong with the description ?
Or how do you avoid the flux problem, especially if you're trying to attach panels with no or difficult rear access.

Cheers
Neil
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post #67 of 106 (permalink) Old 02-11-2010, 05:46 AM
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I think you have some mis-conceptions about Oxy-Acetylene gas welding ... generally speaking, when welding steel, there is no flux used nor left to remove. The same cannot be said for Brazing with Oxy-Acetylene.

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post #68 of 106 (permalink) Old 02-11-2010, 06:11 AM
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forget arc it's between Mig and Tig , and Tig wins cause you can do better more detail welding and also u can do tubes exhausts and alloy more easily and better.
Now if what u gonna weld needs only one hand in order to reach go MIG.
My repair NEEDED a Mig cause it was practically unreachable with two hands
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post #69 of 106 (permalink) Old 06-08-2010, 01:47 PM
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My 82 GTV6 has several rust spots, thankfully none structural. I got several quotes from welders to cut out and replace the panels, ranging from $1,200 to $2,500.

Being a DIY'er at heart, I just picked up a LIncoln 110v unit for a couple hundred bucks on Craigslist. I haven't touched a torch in about 20 years, but was pretty handy with both gas and arc. I do plan to spend as much time as is necessary to get my skills up to snuff.

What gauge sheet metal should I be working with to practice? The welder came with .35" wire, which I assume is too heavy for bodywork (the previous owner was using it to replace floor pans in his old Challenger). Suggestions?

It also doesn't have the shield gas attachment (which I can buy from just about any tool supply store). I read Bill's restoration story and noted he didn't use shield gas, at least at first. Given that I'm going to be grinding the area prior to paint, is it even a requirement?

As for cutting, in the past I used a specialized sheet metal cutter. These are pretty cheap at Harbor Freight, but a friend said he was able to use his Fein oscillating tool with a sheet metal blade with MUCH more precise results. I have the Craftsman cordless version (really cool little tool, by the way), but none of my blades seem to be made for cutting sheet metal. Hmmm...

I'm not gunning for the concourse, or even a full restoration - just a solid, clean job.

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post #70 of 106 (permalink) Old 06-08-2010, 07:04 PM
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Please go to the first post of this thread and read ... also use the SEARCH feature.
The questions you ask have been answered previously.

Get yourself a shielding gas arrangement as flux-core wire is no way to start out. The welds look like crap until you wire brush them ... then they look like wire brushed crap.
Seriously, practice inside a building (gas shielded is useless outdoors) on some junk body panels. Any body shop has a pile of these out back.
Use thin wire (.020 - .024) for thin metal. Learn to tack - skip - tack ; that's how body work is done. If you can find Silicon-Bronze wire it will make you look like a pro!

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post #71 of 106 (permalink) Old 08-10-2010, 02:02 PM
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post #72 of 106 (permalink) Old 10-12-2010, 07:50 AM
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...I have a question which i could not find an answer to in this thread. I have an Arc Welding machine. I have just tried to weld a thin plate onto a panel which i cut out (practicing on old Alfa). It worked perfectly the first time, but then i missed a small section and welded over again. It burnt a perfect round hole right through....SO my question is: Can you get a welding rod which does not burn so hot?? I am not sure what thickness I used, i have seen thinner rods. I just want to know if they burn cooler, or do they all burn at the same temp.?? Or do you set the machine according to the use or to the rod thickness??

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post #73 of 106 (permalink) Old 10-12-2010, 08:10 AM
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FYI - Harbor Freight auto darkening helmets are 50% right now with their Super Coupon. About $35 I think...
Harbor Freight Tools

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post #74 of 106 (permalink) Old 10-12-2010, 06:45 PM
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The thinner the welding rod, the less amperes needed to strike an arc. All rods burn at the same (general) temperature ... you're melting steel with electricity. You control the rate of that melting with the current setting. Less current (amperes) produces a shorter arc which is more controllable ... but the current must be high enough to maintain an arc.

You match the size of the electrode (rod) to the thickness and purpose of the material being welded.
I use rods as thin as 1/16" to as thick as 3/8" ... but not on an ALFA.
With experience, you can use a 1/8" rod to tack - skip - tack body panels.

Find yourself a copper plate to back up thin metal while welding ... you'll be surprised at your results.
Or ... contact me about getting one of these from Harbor Freight tools, item # 66785:
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Last edited by GTD; 06-06-2011 at 05:17 AM.
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post #75 of 106 (permalink) Old 10-12-2010, 09:51 PM
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Excellent GTD. I will purchase the thinner rods today. I will then test them out and let you know what the results are. I will post photos on my thread: http://www.alfabb.com/bb/forums/car-...-thinking.html

1 x Alfa Romeo Giulia GT 1600 1966 Stepnose Project.
1 x Alfa Romeo GT Junior 1600 1973 Non-stepnose Project. Ford F100 1977 Sold.
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