Heat control

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Yesterday I tig welded 4 caster wheels to a frame I made out of an old bed frame. The reason I elected to weld instead of drill and use nuts bolts is that I heard it's a bear to drill through hardened bed frame steel. Well there was so much heat generated that the plastic to keep the ball bearings melted. Luckily, the caster still work.So here is the question: How can I control the heat so that casters (or other temperature sensitive) will not melt? Or should I forget about it and drill and use nuts and bolts?Thank you.Last edited by qdn; 02-01-2010 at 01:18 PM.
Reply:You can drill it. Just be sure the bits are sharp.                           MikeOl' Stonebreaker  "Experience is the name everyone gives to their mistakes"Hobart G-213 portableMiller 175 migMiller thunderbolt ac/dc stick Victor O/A setupMakita chop saw
Reply:I didn't have any luck drilling that stuff.You'll have to Weld it slowly- I mean just a short bead on one caster and then move on to  another caster and so on so you don't put too much heat in the Casters at one time.Ed Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:Originally Posted by qdnYesterday I tig welded 4 caster wheels to a frame I made out of an old bed frame. The reason I elected to weld instead of drill and use nuts bolts is that I heard it's a bear to drill through hardened bed frame steel. Well there was so much heat generated that the plastic to keep the ball bearings melted. Luckily, the caster still work.So here is the question: How can I control the heat so that casters (or other temperature sensitive) will not melt? Or should I forget about it and drill and use nuts and bolts?Thank you.
Reply:The suggestion to weld a little on one caster and move to the other is good.  You could also use a spray bottle of water to cool down the caster after welding on it.TIG (or O/A) is not the best choice in this situation because it tends to be slow, allowing more time for the heat to build up.   MIG or stick would tend to reduce the heat build up.  As far as I know, virtually any TIG welder can be used for stick. RichardSculptures in copper and other metalshttp://www.fergusonsculpture.comSyncrowave 200 Millermatic 211Readywelder spoolgunHypertherm 600 plasma cutterThermal Arc GMS300 Victor OA torchHomemade Blacksmith propane forge
Reply:Sorry, I forgot to mention. I welded the first one and it melted so for the next three, I spot welded one spot (about 1/16inc long bead) and move to the next caster and keep rotating until I get 8 spots per caster (2 per side) and it still melted! This bring me to the next question, since I'm still very new at welding, I think I staying too long for my spot weld or I'm not depressing the pedal all the way down. Basically, I'm just staying there heating up the metal instead of give it more current to make a puddle. Should I gun the pedal and get the bead as quickly as possible?
Reply:For tacking, yes, gun it, get the puddles, control them to where the two puddles "snap together" then back off quickly, but keep the torch there so the shielding gas can do its job."SOUTHPAW" A wise person learns from another persons mistakes;A smart person learns from their own mistakes;But, a stupid person.............never learns.
Reply:Originally Posted by qdnSorry, I forgot to mention. I welded the first one and it melted so for the next three, I spot welded one spot (about 1/16inc long bead) and move to the next caster and keep rotating until I get 8 spots per caster (2 per side) and it still melted! This bring me to the next question, since I'm still very new at welding, I think I staying too long for my spot weld or I'm not depressing the pedal all the way down. Basically, I'm just staying there heating up the metal instead of give it more current to make a puddle. Should I gun the pedal and get the bead as quickly as possible?
Reply:Wet rags wrapped around heat sensitive parts will help keep them cool. I've also welded with items sitting in a pan of water so that the sensitive parts are submerged. You want to floor the machine get the puddle going fast and then back off. If you sit and wait you are just pouring heat in that the steel is wicking away from the weld point. When you mash down, you throw in so much heat at once, that the puddle forms faster than the heat can disipate. Short small welds with time to cool between them..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:For sensitive parts we would use a copper or aluminum backing bar, then go the wet rags route.  Remember though if you go the wet rag or water route that your essentially creating a huge difference in temperature and that can create a lot of warpage. In fact that's the exact technique you use for heat bending metal, you heat up an area and keep the other area cool with a water spray or rags.in terms of heat, it seems counter intuitive but if you increase the temp and just travel faster you'll actually put in less heat. It's also true that MIG is a little better for this than GTAW.
Reply:gun it.UA Local 598