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Posted 02 March 2001 - 10:03 AM
Posted 02 March 2001 - 10:10 AM
Two car batteries?
How do you hook up the cables?
Posted 02 March 2001 - 10:37 AM
Posted 02 March 2001 - 11:29 AM
I think bythesea's suggestion to cover the batteries was due to this explosion potential. This would be a real concern in my mind - but maybe only if the battery is on a charger just before you strike an arc?
Posted 02 March 2001 - 12:30 PM
That was part of it. Also just the potential for rapidly heating the batteries with the heavy draw and splitting the cases from the expansion of the electrolyte. I don't really recommend the idea though in general. Also there a few DC welders available on the market meant to run from a vehicle. I wouldn't imagine the batteries giving very consistant penetration. I bet they'd either just scratch the work or if it was light metal they might just vaporize it.
Posted 02 March 2001 - 05:00 PM
Posted 03 March 2001 - 07:19 AM
The old units are AC machines and the newer are DC machines capable of changing the flow of current from the work piece to the torch (gun) or visa versa. This direction of the current flow causes a variety of things one of which is depth of penetration of the weld into the surface - see your welding specialist for more details.
MIG welding (Metal Inert Gas) has a gun that has a trigger for turning on the power( read arc voltage) and at the same time turning on a motor that feeds the welding wire through a hole in the end of the gun's barrel, this is accompanied by a release of a shielding (inert) gas also expelled near the end of the barrel.( Inert gases for the chemically challenged is a substance that will not react with anything, this is due to the outer shell of it's electron cloud being in a "happy state") This shield prevents the build up of oxides and other pollutants that can cause porosity in a weld and make it weak. The inert gas(bottle/regulator/on- off solenoid) can be substituted by using "Flux Core" welding wire which has a core that vaporizes and shields the weld.
TIG ( Tungsten Inert Gas ) Is an entirely different beast. More akin to brazing or gas welding except the heat of the weld is produced by electric current rather than burning gases, this heat is much more intense and controllable by foot pedal or a small figure operated wheel on the torch. The operation goes something like this- Bring the torch close to the grounded work piece- step on the pedal -shielding gas flows out of the torch end and a hi freq. voltage is presented at the torch tip which establishes the arc- once the arc is established the hi freq. shuts off and the current reverts to straight DC( except on AL the hi freq. stays on). This intense arc produces a plasma hot area that melts the work piece- now with practice some work pieces can be fused with no other material needed but in most cases a filler rod ( of the same material being welded) is introduced into the puddle of molten material formed by the arc. Real good TIG welders can weld beer can thickness materials,( I have heard -never seen- that they can weld cig pack al foil- phewie) the weld is VERY clean and professional looking when done right.
WHERE's the TUNGSTEN? it is the very tip of the torch and needs ground to a sharp point or rounded ball ( depending on the work mat.) It can with stand the extremely high temps encountered with out melting. But if "OPPSed" into the puddle must be removed and resharpened to remove mat. and establish a good arc point
May I add to this extremely long diatribe that for novice welders- stick- MIG or TIG the best thing to get to assist you in performing the operation is a good helmet- the glass comes in different levels of "shading" and will let you "see" the puddle formed by the process you choose. Arc flash is a very bad thing to encounter- makes the eyes dry out( you'll lose allot of sleep) and can cause other very serious consequences- do not let it happen to you.
THE BEST thing since sliced bread is the new line of "Speed Glass" helmets these have an electronically dimmed glass that when there is no arc present turn to a pair of sun glasses shading- immediately upon drawing an arc they dim to the level of shading you choose ( This level like a normal helmet is chosen at the time of purchase, but the normal helmet has a replaceable lens and cover glass) Cost for one of these beauties- bout 2 or 3 C-notes.
Please forgive the length of this post and if there are any inaccuracies please point them out.
Posted 03 March 2001 - 06:02 PM
The good stick wleders can even be used to run Tig setups, power wirefeeders, etc. Where as a buzz box is lucky to make a good enough arc to make a decent weld.
Mig is likely the best for Hobby or rapid production where perfect welds are not critical
Tig is Great for high precision, high strength welds. Also many exotic metals are currently only possible with tig.
Gas is great for delicate work, and needed for brazing.
Posted 03 March 2001 - 10:36 PM
BUT, would I be correct, Skip, in saying that your warning about the eyes was way understated? My understanding is that looking at any of the arcs (or even a brazing flame) can/will burn the retina (maybe cause cataracts from lower-level repeated exposure) and possibly cause permanent blindness (even for observers from a distance) in much the same way that looking at the sun can? (I believe it is primarily due to the UV content.) It has always been my practice when walking through an area where welding is going on to *never* have a welding arc (or brazing flame) *anywhere* in my field of vision - I generally put a hand up to my face to act as a shield as I walk through no matter how stupid it looks. Am I being paranoid? This was drummed into my head by my dad when I was a kid working in his mechanical contracting business (or maybe he overstated it knowing that a kid is going to believe only a fraction of what he's told - but this particular thing "stuck").
I would think that the intensity and danger follows a square (or is it 4th power?) law - i.e., the intensity on the retina would be 25 times greater for, say the welder, at 2 feet away as it would be for an observer 10 feet away.
If my information is incorrect, someone speak up.
Posted 03 March 2001 - 11:11 PM
Best idea is no not even look in the direction, and avoid looking at the reflection. The only truely safe way to look at a welding arc is through a camera.
Oh and NEVER use welding goggles unless you like radiation burns. Use a full helmet, decently thick long sleeve shirt, and long pants. Denium is best for both shirt and pants.
Posted 04 March 2001 - 01:39 AM
PS Never carry a Bic type lighter while welding. A piece of hot slag can turn one into a very effective hand grenade. Picture one in your left breast pocket and you'll get the point. It may be Urban Legend but theres a story of a welder at Electric Boat in Groton, CT, blowing a nice hole in his chest with one.
Posted 04 March 2001 - 03:21 AM
Posted 04 March 2001 - 06:22 AM
Just leave it to say NEVER look at a welding op with the naked eye. The dark glasses Witte mentions are for gas powered brazing, silver soldering and cutting and and never should be used for any electrical welding op.
BUT an old wives tale was dismissed by my optometrist- the subject of contacts getting "welded" to an eyeball is false.
When I ask him about this he presented documented proof that the story had been falsified by the person in question. This document was directly from the trial.
And covering body parts when you are welding- a TIG welder at my plant tells tale of one summer when the ambient was around 80 F. He had his shirt open, now TIG welding produces no slag or bits of hot matter flying about, but he got a sunburn like he had never had. I've seen guys arms above their gloves red as beets.
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