[diydude]

i am looking to purchase a tig welding machine with a built in plasma cutter hopefully...i am looking to spend about maybe $1200-$1500 so does anyone know where to start looking for a good machine for a reasonable price.....i appreciate the help guys

 

[PThompson509]

Heck, even *I* know the answer to this one - ebay. Harbor Fright has some cheap ones, but the emphasis there is cheap.

As always with ebay, be careful about the seller.

 

[JRoque]

Hi. A tad more than what you want to pay but as I understand it, this is a good machine:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=390060365662#vi-content

There are also a number of Chinese knock offs at lower price/quality.

I'm not sure what application you have in mind but I'm going the low-tech route and will be cutting my car up with a Porter-Cable 9750 saw and cutting wheels and welding with a Lincoln MIG welder.

JR

 

[diydude]

thanks for the suggestions guys but i also wanted to try an get a warranty along with it

 

[Woodsmith]

Hi and welcome.

I presume the welding is related to an electric car project? Plenty of advice on that here.
For welding though you might find more information on a welding specific forum. Also some vehicle or project specific forums have sections on welding that might be helpful too.
I use a number of forums to the same ends but asking different but relevent questions on each.

Good luck on finding a good TIG set. I am also on the look out for one but I am looking for cheap used industrial set up. In the mean time I have bought a small industrial MIG set to go with my MMA set.

 

[JRoque]

Hi. If you decide on MIG or are curious as to what you can do with MIG, I highly recommend this site: http://www.mig-welding.co.uk. Lots of good people there and their tutorials are simply fantastic.

JR

 

[DavidDymaxion]

I poked around the web, and for hobbyist welders there seemed to be consensus for getting a Miller for MIG and a Lincoln for TIG (the Miller TIG is good, too, but the Lincoln was a bit cheaper). I bought a Lincoln 180 TIG and have been very happy with it. The arc is easy to start and very stable, even if your spacing to the work varies a bit. I can weld 1/4 inch steel with about a 1/3 duty cycle (you need that to cool off your hands anyways!), 1/8 inch or thinner is continuous. I'm not a great welder, but you can see some of my welding projects, for my gas and electric cars, on my web page http://ExplodingDinosaurs.com .

Safety Caution: You need a special helmet for TIG. TIG is much brighter, so you need a darker eye piece. TIG also sunburns you very quickly. You need to wear a leather jacket and gloves (the light will shoot right through cloth). My sleeve pulled up once. In 2 minutes of welding I got a sunburn -- the pain took a week to go away.

There are special gloves for TIG -- they are thinner, so you can feel what you are doing better.

One caution is the really cheap TIGs are not computer controlled. The arc would be hard to start and maintain. I was also warned more than once you get what you pay for and to avoid the cheapy, no-name TIGs. Another trick they'll pull is to quote specs for a really low duty cycle (something like 180 amps, but only at a 10% duty cycle).

Final suggestion is to get around 10 of each size of electrodes. They are pretty cheap. When you contaminate one by touching the puddle, it's nice to just grab the next one rather than stop everything to regrind the tip. Also be sure to get a big enough tank so it fits safely in the machine. My first tank was too small and I had to be careful it didn't fall out below the retention chain. Don't get too big a tank, either, it'll be hard to pick up and put in a small car. My tank is about a meter high but lasts for several projects, I only refill it about once a year.

 

[Duncan]

Hi Diy

This may be completely off topic but I am using Oxy-Acetylene and Bronze Welding,

I decided to do this as the process is much more forgiving - a poor bronze weld is much stronger than a poor weld
A good well designed bronze welded joint is stronger than a welded joint

(in both cases the joint is stronger than the parent parts but the welded parts have bigger heat effected zones and tend to have localised section reduction at the edge of the weld)

It is a lot slower and more expensive in materials,

Just my tuppence worth!

 

[karlos]

One caution is the really cheap TIGs are not computer controlled. The arc would be hard to start and maintain. I was also warned more than once you get what you pay for and to avoid the cheapy, no-name TIGs. Another trick they'll pull is to quote specs for a really low duty cycle (something like 180 amps, but only at a 10% duty cycle).

All good advice, I can tell you have done a lot of TIG welding! What you call computer control is what we call a HF start (high frequency) which as far as I'm concerned is essential, well I have done a lot of stainless steel welding and scratch start can drive you nuts plus leave impurities in the weld.
Duncan, I have done a little Copper Nickel plate welding with TIG, how about TIG brazing with the rods you use?

 

[Duncan]

Hi Karlos,

I don't know about TIG bronze welding - sounds like a good idea but I don't know enough to recomend

I am using bronze welding because of my limited skills - it used to be a common automotive practice - Original Lotus 7,s

BUT it is a lot slower - so commercial use is now limited

 

[karlos]

I am using bronze welding because of my limited skills - it used to be a common automotive practice

You are in good company as I think it's the Atom Exo car that brazes or it may be the RCR Superlite (comes in on topic EV version too ). I think I read somewhere they TIG braze and it gives a real nice looking joint. Maybe distortion is less too...

 

[DavidDymaxion]

karlos: I was lucky to have some very experienced welding mentors help me get started!

Duncan: I did look at brazing for my project, but it looked like parts needed to be a very precise fit for that to work -- TIG can do some gap filling if you need. Also, racing specs say you must weld a roll bar, so no real choice there. On the plus side, brazing is less heat and I have read stronger if done right.

All good advice, I can tell you have done a lot of TIG welding! What you call computer control is what we call a HF start (high frequency) which as far as I'm concerned is essential, well I have done a lot of stainless steel welding and scratch start can drive you nuts plus leave impurities in the weld.
Duncan, I have done a little Copper Nickel plate welding with TIG, how about TIG brazing with the rods you use?

 

[Duncan]

Hi David

Can't do much about the racing specs!

Bronze welding and Brazing are two different processes,

Brazing uses close fitting overlapping joints that the braze metal flows into

Bronze welding uses a filler metal to build up the joint, it can cope with small gaps

Fusion welding can cope with larger gaps - but any joint that you had a gap and then filled with weld is not as nice as a good joint to start with

 

[EVfun]

I bought a Lincoln Weld Pak 100 a number of years ago. It is a basic 120 vac flux core wire feed welder that works quite well on up to 1/8 inch steel. I've worked down to about 20 gauge sheet metal. Lincoln does make a kit to convert it to MIG. Though the 100 is still available it seems that the Weld Pak 140 is the newer model.

 

[DavidDymaxion]

Interesting, I didn't know about bronze welding. Thanks for the education!

Hi David

Can't do much about the racing specs!

Bronze welding and Brazing are two different processes,

Brazing uses close fitting overlapping joints that the braze metal flows into

Bronze welding uses a filler metal to build up the joint, it can cope with small gaps

Fusion welding can cope with larger gaps - but any joint that you had a gap and then filled with weld is not as nice as a good joint to start with

 

[david85]

I realize this isn't a very affordable welder but its the only tig machine I've ever used:

http://www.millerwelds.com/products/tig/dynasty_200_series/

After several years we had zero problems with it and its used several times a week when the shop is busy.

At 200 amps, its rated for up to 1/4" material, but the comfortable limit is half that. Extrusions will eat up heat much more so than the edge of a piece of sheet so it's ideal for 1/8 thick aluminum and not much more unless you preheat the parts (which can be tricky with aluminum). Something like 1/2" rod can be more easily welded even though its thick due to a smaller heat capacity of the part.

Also bear in mind that even if you are to find a machine that can push more than 200 amps, you will need to start looking at a water cooled torch and it gets more complicated.

I learned with a foot control then switched to a thumb control. At first I didn't want to switch over but its a much better setup once you get used to it.

I would almost suggest looking for an older brand name used welder locally rather than take a chance at an off shore knock off that is brand new. Brands like Miller, Lincoln, and Hobart (now bought out) usually make solid products that can last for years even in commercial duty. Our old Hobart Mig welder is probably close to 15 years old and it still works just fine. Bought a Miller plasma cutter used a couple years ago and that works like new as well.

What sort of thickness of material are you planning to weld? 1/8"? 1/4'? half inch??

 

[karlos]

I realize this isn't a very affordable welder but its the only tig machine I've ever used:

http://www.millerwelds.com/products/tig/dynasty_200_series/

That looks a real beauty David, AC (Aluminium) and DC (ferrous metals, SS etc) I have a similar model but not AC capable and totally agree with you about needing water cooling for bigger Alu jobs.

 

[Duncan]

Hi DavidD

I was probably being a bit too picky when I was talking about Brazing v Bronze welding

True brazing is only used where you get overlapping joints - old push bikes where the tubes are pushed into fittings and then brazed,
This gives superb results but needs very good fits

90% of "brazing" is actually Bronze welding - "brazing rods" are actually the higher viscosity Bronze welding rods

True brazing rods have very low viscosity when melted to flow into small gaps

Sorry I was too picky

 

[karlos]

Hi DavidD
I was probably being a bit too picky when I was talking about Brazing v Bronze welding

Yes there is quite a difference between brazing and what I know in the trade as soldering. We actually in NZ called filling say a mitre joint brazing and what you call brazing we called silver soldering in which often one tube slips into another like in the bicycle example you gave and silver soldering rods are very pricey for obvious reasons. Plumbers use a lower silver content version we called silfos and it has a low melting temp and does not wick as well as the silver solder or is not as strong but mostly it is used on copper so that's OK.
Of course different terms are used in different parts of the world

 

[samborambo]

If anyone's interested (and I'm sure there's a few, considering this is a DIY site), someone's documented building a TIG welder attachment to a cheap DC arc welder.

http://www3.telus.net/public/a5a26316/TIG_Welder.html

It has pretty much everything that a fully featured TIG welder has. He designed it with standard 4000 series logic. If you used a microcontroller instead of 4000 series logic, you'd reduce the logic board down to a single chip. Plus you could have an LCD screen, store different TIG settings, etc.

Also he built an HF Start using a neon sign trafo and a spark gap. You could acheive the same thing simply using a flyback trafo from a TV driven by an HF signal from the microcontroller.

Always dreamed of doing this project myself but the car conversion is more of a priority right now.

Sam.