I know RC doesnt really recommend arc welding, but i just cannot afford to buy a good MIG welder, as ive never known an SIP one to have a good wire feed mechanism. ESAB welders are the business, but about 700 quid! Hence, i would much rather buy a cheapy arc welder (you cant really build a crap one, cos its just a BIG adjustable transformer).

Anyone use arc??

Ed.
P.S. I have arc welded before, but until the electrode was down to about 6 inches i used to keep sticking it to the bloody work. Sod's law makes me much better at MIG.

I disagree with your comment about how difficult it is to build a bad arc welder! I've used both good and bad ones, and the difference is amazing.

Use one of the cheap ones, and you're continuously fighting to stop the rod sticking, maintaining a good arc, and so on. On the other hand, my model engineering society has a little 1940's Oxford welding transformer, and that's the easiest thing I've ever used!

I think the difference is how the transformer copes with the sudden increase in current as the arc is struck - i.e. regulation - the cheapies allow the voltage to drop sharply, while the decent boxes keep it pretty near to the voltage just before the arc starts.

I now have a TIG that can also be used as a stick welder - DC arc welding, with an electronically regulated power supply - luxury! It is SO EASY to keep a good arc going, with the added advantage of a foot pedal to cut power if the rod sticks.

David

P.S. Have you looked at buying a second-hand MIG? With care and luck you can buy a near-professional grade box for the price of an indifferent new one.

[Edited on 15/12/03 by David Jenkins]

ive got an arc that is 30 years old,works fine on heavier stuff and an "inverter" from screwfix,that will weld down to very thin stuff and arcs up no probs at all.

The cheap sip and machine mart arc welders are no match for an oil cooled transformer plant. They grab and snatch and you have to fight them all the time on thin stuff. Frost do a small dc welder which is reasonably priced or you can buy the cheaper tig box from clark and use that as a dc arc welder. It should cope with the thickness needed to build a locost chassis.

yours, Pete.

Ed,

In my opinion (only! ) you're looking at a build cost (depending on engine choice) of getting on for £4000 anyway. What's an extra £100 on that when you get something you can sell on anyway.

I bought a new SIP 150 Turbo from a show (Donnington 2002) for £130. With it I've done welds good enough to get a basic (very basic some might say!) welding qualtification and build my chassis to a strength I'm pretty happy with.

Look around e-bay and the like I'd have thought you could pick up something similar for similar money.

Good Luck!

James

I have to agree about the SIP welders, I've used three now, and every one has had the worst wire-feed ever. your forever cleaning out the thing.

When I first started I had the horrible "whining-blob" type welding where you just get a hot blob of weld forming that bounces off the work. I tried everything to fix it; different gas, different gas rate, less power, more power etc, turned out to be the wire feed slipping.

I'd have to recommend buying something else, there seem to be quite a few people who find the SIP machines a bit pants. Their "support" sucks as well, they have a very "well its not my problem, speak to your supplier" attitude.

The reason why the air cooled arc welders stick so easily is the open circuit voltage is only 48v, whereas most oil cooled (oxford etc) have an OCV of about 70-90v which makes things a bit easier. The cheap inverters available from screwfix/clarke/machine mart have high OCV''s and weld like a dream.

If you are going to use an arc (aircooled) for the chassis, use 2mm satinex rods and preheat them by striking up on a piece of scrap first and then straight onto the chassis, keep the arc VERY close to the workpiece and adjust the electrode angle if the arc starts to 'fizz'

It can be done but will take some practice, flux slag should not be a problem as it should curl off if you have laid the pass down correctly.

I totally agree about the Oxford welders,
And as for tigging anything never mind just the chassis - bring it on.!! Olerikon 175 invertor = £525 all in with the best torch I have ever seen and all the flow meters,regulators...sooo smooth,takes a bit of getting used to in arc mode how good it is compared to my old unit....and before anyone says it, I do not work for the company...!!!

i have done mine with a arc welder
dont even think about it
james is right
in the overal cost it is nothing
i have found it has made the welding very hard work with arc and i have had to have a lot of help from my farther in law who is a welder
i dont know if he comes to help or laugh at my welding but without his help i would of given up on arc a long time ago
cheers dave

Im with Malcolm, stuff the Mig buy a middle of the road Inverter (mines a wee fronius) Fan cooled, welds all day brilliant torch and a skoosh case to use, slower than Mig but a far superior looking weld
Shug.

I started mine with TIG and, again, I have a basic qualification in it- I'm very glad I moved to MIG.
Yes, TIG gives lovely looking welds but you just can't beat the speed and ease of MIG for something like this chassis.

Grinding that Tungsten filament down, everytime you put it a little too close to the weld pool, to the correct angle is a pain in the ass! Whilst MIG'ing is about as hard as using a marker pen.

Cheers,

James

When I mentioned my TIG machine I was talking about using it for arc welding - makes it really easy, as long as you remember to reverse the polarity!

David

were just about ready to start the chassis and will be using an arc welder i dont see the point in spending big money on a mig set if you have a good arc welder stood there. cal me set in my ways but i know which welder i would prefer to use between arc and mig.

I rekon you should stick wi MIGs, i picked up one from screwfix for jus over 100 quid and it suits me fine. Its a well easy to use and u can weld at any angle. If you have access to gas then go for that, but its really hard, but its easier to control once you set up the flow.
Trust Me Though, what you pay extra for a mig set, you will save in time.

if you want to maintain the locost spirit you might want to check out

http://www.turbomustangs.com/forums/showthread.php?s=&threadid=8872

homemade tig welder made from auto alternator.

I am going to try it, but, as with everything else, it may be weeks (months) before results are known.

dave

his picture has been downloaded 16000 times!

[Edited on 19/12/03 by JoelP]

I whipped out the old ARC today and had a crack at welding. I got some old rusted 1" square with 1.6mm (i think) walls, cranked up the beast to 120A and started burning my retinas . I surprised myself with my welding, the first 3 weds broke witha few strokes of a hammer, but the fourth was well penetrated and was as tough as old boots. Lots of hammer-whacking and i still couldnt break it. But still, i dont really trust my welding with a ARC when i start building the chassis, and it takes so much longer to do coplete seam welds on a Loco chassis. However what i AM doing, it building my chassis by tacking it together with my ARC, then either borrowing a MIG or taking it to a welding place to get it all seam welded up.

Regards, Glenn.