How much power is required to welder an FB's floorpan? Also does it make a difference if I buy the mig new or used? And finally what's the difference between gas and electric powered? I'm certain all of these questions probably sound very basic, but I'm pretty new to a lot of this. I've searched for the answers already, but couldn't find anything.

 

Are you going to be welding or are you going to have someone weld for you. If you will be welding and this is your first go at it. take the time to read the welding manual and then practice on plate steel, then steel pipe, then sheet metal. the thinner it is the harder it gets.... just about any welder will do sheet metal. question is what quality of weld are you looking for.

Your welding wire also must be in consideration. You cant mix and match with good results.

See here and start reading machine specs. Or take it to a professional welder

http://www.lincolnelectric.com/

If you PM me the setup you plan or can afford to use i'll tell you the best way to weld your peice. and may even show you.

 

Use gas shielding as flux core wire (although cheaper to set up and run) is hotter and you may have issues with it. Flux core can yield solid strong welds but can be more difficult on thinner metals.

 

I preference TIG on thin stuff myself, but you can use MIG on low settings if you practice enough...

 

A LINCOLN ELECTRIC 140 HD MIG will be sufficient for the thickness you want to weld. It can be plugged into any household outlet. No need to add a 220v line.

Gas gives a cleaner weld. Fluxcored wire will work but it's a dirtier weld.

Absolutely most important is to have a perfectly prepared metal surface. That means absolutely NO RUST and NO PAINT on the metal surface to be welded.

And as stated before, the thinner the metal the more skilled the welder needs to be.

Practice on scrap metal before trying the real project. Practice ALOT. Then practice more. Then when you think you're ready, practice some more. Then tackle the project to be welded.

 

Just to add to Mark’s original question: if you’re performing welding on a car using a MIG welder, is it necessary to drain and remove the gas tank from the car first?

I know it’s not a good idea to do any welding on a full gas tank, or even if it’s empty since the gas vapours in the empty tank can ignite, but is it safe to weld on parts of the car that are not near the gas tank; e.g. the front fenders, etc, assuming that you have a gas tank that’s not venting an unusual amount of vapour due to leaks in the filler tube, orventing vapour for any other reason?

Of course, the safest thing to do would be to remove the gas tank, but for a small rust repair; (e.g. on a part of the car not near the gas tank) it seems this would add significantly to the work required.

 

When I was welding on my engine bay, I never undid anything fuel related... Left the fuel lines
intact, even the carb had no filter on it. Then again, I was using MIG with gas, and the garage
door was open.

For thin metal (like the firewall and fenders) I used lower amps and slow wire feed, the higher
amps would literally blow holes in the metal.

 

Sorry to divert, but I'd like to ask if buying a used welder would be a good or bad idea too. Do they have a lifetime?

 

you shouldn't have problem buying used so long as its a good brand

 

All of the above advice is right on. One suggestion is using a piece of brass on the backside of your joint. This will help pull excess heat away and allow the weld to puddle in the joint and not fall/blow though and leave holes. Heavy magnets will hold the brass backer in place.

 

Better to buy a high quality used than a cheap quality new. Shop around.

 

agreed all of the advice seems very correct. and some things i just learned i never used mig until this summer always stick or flux core. mig (wirefeed with shielding gas) is absolutely amazing compared to flux core wirefeed. it is much cleaner. you don't have the slag to chip off when you are done. Ive welded steel, my stainless exhaust (first time and am very happy with), and even aluminum, with my dads little Lincoln pro 100. i converted it to MIG for 125 bucks. Then aluminum looked like **** tho i would say tig for that. I have never tig welded because a decent tig welder is pretty pricy. Like to try someday tho.

And BTW. Most all types of welding take power. Arc and flux core dont use gas they have flux on the rod and in the wire. MIG uses electricity and has gases in place of the flux. TIG uses high voltage through a tungsten tip and then the rod is separate and it also uses gas. The only thing that doesn't require electricity is soldering or brazing/ welding with a torch as far as i know good luck!

 

Wow! That cleared up almost all of my questions. Thanks a lot. Just one more thing -- what how many amps should I need to weld the floorpan of my car and how much should I get for the foreseeable future in restoring my FB?

 

amps to run the welder? alot of the larger ones need 220 or 230. the small one i have (my dad has) can run on 110 its automatically kicks off and if not on a good circuit by itself will trip breakers. if you have 220 that is better.

 

So it's not a big deal? There's no limit if I'm welding on the floor boards? Or are amps even the measurement? Because I'm poor, I'll probably buy the equipment 2nd hand. If at all possible, I'd like to stay under $300

 

im not sure what you are asking? are you talking about the heat setting on the welder itself? that i cant say my dads just has a dial 1-10 and you gotta experiment i usually run about 2-3 on sheetmetal still gotta be careful not to blow through takes lots of practice.... l will definately try the brass backing next time
thanks troc

 

For the amps, you want to keep it on the lower end. Amps will give you the heat and the wire
speed will give you the push (IIRC). When I was welding my fenders, it took low speed feed
and about 30A of juice. Any more and I would end up blowing right through the metal.


When you weld, you want it to hiss and sizzle at you, if you get a lot of fireworks and
POP/POWing, then lower your amps/speed.

No one has pointed this out yet, but we have a hardly used fabrication board:
https://www.rx7club.com/forumdisplay...ysprune=&f=250
It has some people who have "been there done that" and can give you better advice.

 

You can by a 110V powered machine for doing thin metal. It will probably go up to 140amps for welding but its only going to draw 15amps out of the wall. The biggest thing you get with a 220V unit is higher duty cycle on the thicker metals/higher amp settings. A 110V machine might give you a 10% duty cycle when trying to weld 1/4" plate but 95% when you are welding chassis sheet metal. A small 220 machine will probably get you into a 70% duty cycle on 1/4" stuff.

A 110V Mig is a nice first unit for 99% of automotive stuff. Its great to be able to plug in anywhere.

 

yeah i agree my dads lincoln pro 100 110v does about anything we need to unless it thick stuff we have and old arc 220 machine

 

Thanks guys! I think I made my decision. I'm going to still search around for second hand welders, but it's down to one of these two if I buy it new.

http://www.princessauto.com/garage/w...ux-core-welder
http://www.princessauto.com/garage/w...20v-mig-welder

 

like someone stated before i think a used one of better quality is better than a new china cheapo

 

I have a Lincoln 135 Pro welder. It welds with or without gas. This is the first flux core, (gas-less) mig I've ever used and flux core welding sucks. If you buy an inexpensive wire feed, make sure it comes with the parts needed to weld with gas shielding. Mine does but I haven't gotten a tank yet. If your going to be welding thin metals, you need gas shielding. The Pro-135 also has a kit to weld aluminum. I believe the 135 has been replaced with the Pro-140.

The following link is similar to the welder I have.

http://cgi.ebay.com/135-AMP-FLUX-MIG...item255d4dc52f

 

I think you are asking how much heat/electricity to set for the thinner floor. It's generally 1 amp per .001" of metal. It's the same for aluminum or steel.

GD

 

the pro 100 is a totally different welder when converted to MIG from flux core! I love it now! i welded aluminum with it as well just needed pure argon i believe i cant remember it was a different gas for aluminum. it sucks for aluminum... i will never mig weld aluminum again... only tig and have never done that. its too hard to regulate the wire speed as you weld. the aluminum gets hat so fast so starting the weld is totally different than 2 inches down the same bead. steel and stainless are amazing with it tho. although trimex is needed for stainless think that is helium argon and CO2 where as steel is just argon and CO2 i know there are alot of other variations but these worked well for me