Welding magnets, or, magnets for welding

in real world fabrication ive found them to be a real pain to work with.

They have their uses, but it isn't very often, plus they end up very furry with iron particles.

MSC sells some with an ON/OFF switch that turns off the magnets. I plan on buying a few of those soon.

I have one and don't bother using it other than to hold my tape when doing long jobs or circumferences. Don't throw away any old speakers because they are handy as a source of magnets to hold tapes. The big problem with holding something exactly ninety degrees while you tack weld it is that the tack always pulls the pieces. If you say " But my ninety degree magnet/clamp will hold it!!" that's true, until you release the device to put another tack on it or to weld it. I tack and hinge on the first tack. I use a one foot square for small stuff, a framing square for slightly larger stuff, and then 3-4-5 Different folks .... Randy

"SteveB" wrote in message news:Kk%Ob.11109$AA6.1570@fed1read03...

None of my stuff is really critical. I have done a zillion fence and gate spindles without them. Was just considering some after I saw a few at Harbor Freight at cheap prices.

Steve

Hi, If you weld too close to them, the magnet pulls the arc out of the weld puddle. I though I was seeing things, but it makes sense.

regards,

I've got a couple, hate'em. The last thing you want around a welding arc is a magnet. It makes the arc unpredictable. However, I do use the things when tacking up something I can't easily clamp in position otherwise.

*Sometimes* they save me time, especially when I'm working alone.

Gary

heh.....first time i saw that happen i spent half an hour moving my ground clamp around. :-)

They're handy occasionally. Cheap ones work fine. HF has one with a hinge. Easiest way to clean the furr off them is with compressed air.

Wayne

I don't always have the air hoses strung out so I use an old tooth brush with a quick wipe motion. Works good.

--I'm a beginner and I've found them to be damn handy in my shop. Most of the stuff I make consists of square tube. Trouble with the on/off switch magnets is that they're too thick to use on small tube; i.e. anything less than about 1-1/4" square and you can't position them correctly. The old fashioned kind are quite handy; cheap, too. Don't plan on depending on magnets alone for squareness though; a good Mitutoyo square is the essential ingredient for square welds.

Has anybody besides me set one of these on fire? I don't know if all such magnets will burn, but the ones I have gotten from Harbor Freight will.

I don't use the magnets nearly as often as I had thought I would, but once in a while they do come in handy when there is no other good way to hold a couple of small parts in just the right relationship. They certainly will not ensure squareness (and in fact, sometimes can be a hindrance to squareness, due to the rivets on the sides), but can hold parts in place long enough to tack.

Usually just tacking does not set the magnets on fire :)

Yes! I just burned one! Bought it cheap. Went home and set a couple of pieces at 90 degrees vertical. Great, as it's hard to do with clamps and alone. Started welding (OA torch) and seconds later I smell noxious smoke. When looking at the magnet I discovered that the magnetic material is actually plastic. Now I wonder If I can cut a triangle from 1/4 plate and magnetize it somehow. Else one need to put the flame away from the magnets.

regards,

Mongke

Not me.

But I did once torch the plastic non-scratch base on a magnetic nut & bolt tray, when I didn't realise I'd had it jump up off the bench and stick itself to the workpiece.

Magnets are handy and cheap. You should get some - no-one is forcing you to use them, and they do have their limits. I hardly ever use them as 90° clamps - usually as a flat surfaced clamp for light tacking, or to hold two ends of something together and stop them flapping about. If you're welding up right-angle in two long bars, then it's handy to magnet a diagonal strip between their ends. Takes much of the force off the accurate clamp you've placed in the corner.

The clamps I _really_ hate are cheap copies of Vise-Grips or Moles. They don;t keep the jaws square to each other, and they'll ping off if you look at them.

-- Die Gotterspammerung - Junkmail of the Gods

"Andy Dingley" wrote

Ditto there. I bought 12 ViseGrip 11R clamps for $16 each, and didn't think twice. You get what you pay for.

Steve

A great idea; I'll have to try that -- thanks!

I think you've put your finger on the key to using these magnets -- don't position them such that the flame or arc makes contact with the magnet. Unfortunately, sometimes that's hard to achieve -- where I've run into trouble is when I've needed to weld a bolt to the side of a short piece of round bar (the bolt becomes the handle of a cam-action clamping mechanism). The magnets work really well holding the pieces in just the right relationship, but it's pretty hard not to overheat the magnet in the process, even when just tacking.

The less expensive ones are a magnetic powder bonded in a plastic binder. Easy to cut and form, so cheap. You can make up your own using better magnets, or just cut disks of thin (maybe 26 gauge? I did it out of the scrap bucket for a totally different reason) sheet and fit them to the magnet. They need to be a little smaller than the inside of the cup so as not to short the magnetic path.

Other problem is if the magnets get too hot, they lose their ferromagnetics properties and demagnetize (at the Curie tempperature)-- temp is materia dependant, but most magnet materials are over 500F, so unless you REALLY overheat your work, not a worry. Had a magnetic work lead overheat (yes, they really mean 150A, not

300) and drop off, never to be magnetic again. Lft one heck of a burn at the contat point, too..

Another useful tip is a simple framing square - but welded up from 2" x 1" square tube, with legs a couple of feet long and a diagonal brace of 1" L. The inside and outside faces are smooth, so that you can clamp fabrication parts to them.

-- Die Gotterspammerung - Junkmail of the Gods