Sheet metal

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I saw a show on tv a while back and a guy was talking about how he did the body work on his car using sheet metal from old refrigerator doors that people were tossing out. Has anyone here done any projects using sheet metal scraps from anything like a refrigerator before?I would think the metal used for refrigerators would be galvenized. Does anyone know for sure if it's just regular mild steel or something? We just got a new fridge so I'm about to cut up the old one if I can use it. lol
Reply:Sort of...I made lower cab corners for a 1989 F150 from the sheet metal cover from an old furnace.    I had gone to the salvage yard to get rid of a drum of scrap steel shorts and saw this old furnace off to the side.   The radiused corners already on the cover were almost the perfect dimension to what was on the truck cab.     The metal measured out to .080" thick and was easy to cut, fab and MIG.The only issue was scraping off the wrinkled paint finish.   It was tough stuff.There are no small projects
Reply:I think you will find that the sheet metal of refrigerators is not galvanized, but painted.  At least the little apartment size units I have scrapped were.  It may also have a lot of adhesive residue or foam insulation stuck to it, which can be a PITA to deal with.Remember that you must have the refrigerant recovered using a professional recovery system with a vacuum pump and reservoir, rather than venting it to the atmosphere.I don't know about the metallurgy, but it's probably pretty ordinary stuff, considering the job it has to do.awright
Reply:@awrightYea, I'm pretty sure they're powder coated, but I wasn't sure if the metal was galvanized underneath. Is it even possible to powder coat galvanized metal?I'm not sure what you mean about the refrigerant being recovered. Can you explain that a little more?@imagineerGood idea using the old furnace.
Reply:If you are scrapping a refrigerator that has not already had its refrigerant recovered in compliance with EPA (I think) regulations, you must not cut into or otherwise compromize the refrigerant plumbing circuit.  Unless the refrigerator was quite recently manufactured (and if it was, why are you salvaging it?), it is charged with R-13 refrigerant, which is a virulant scavenger of ozone in the upper atmosphere.  The R-13 is not consumed in the reaction with ozone, since it simply catalyzes the ozone into oxygen (I think).  Thus, one R-13 molecule can scavange thousands of ozone molecules before it is finally broken down.  The resulting oxygen does not block ultraviolet rays from the sun.  The naturally formed ozone layer is what filters the ultraviolet light out of the raw sunlight impinging on the upper atmosphere, thus protecting life forms on the earth's surface from a myriad of severe deleterious affects of UV exposure, including blindness, cancer, and death in addition to starvation from expiration of lower life forms.Ok, that's a little dramatic, but that doesn't make it untrue.  Anyway, it is illegal (not to speak of highly irresponsible) to vent R-13 to the atmosphere in salvaging or disposing of refrigerators or air conditioners.  Since it is now prohibited to manufacture R-13 (in the US, at least), the only continuing source for applications that cannot use safer, modern refrigerants is recovery of the stock that remains in various refrigeration systems as they go out of service.Recovery basically consists of attaching a vacuum pump to the system at a tap or with a piercing valve and pumping the refrigerant into a storage pressure vessel.  Don't try this at home, as you will probably lose most of it and used refrigerant is of no use to you anyway.  Appliance repair services and many auto shops are equipped to properly recover R-13 under prescribed procedures.The "ozone hole" in the southern hemisphere is primarily a result of this process, along with the effects of many other ozone-killing chemicals that have been released into the atmospheric garbage can.I'm not aware of a good reason to galvanize metal that is going to be properly painted in a factory setting, anyway.  Galvanizing is a poor base for paint.  I think galvanized metal can be powder coated, since the powder coat fusing temperature is around 500 degrees (I think, again), and I think galvanizing can tolerate that temperature.  But that's a guess.awrightLast edited by awright; 06-13-2006 at 03:49 AM.
Reply:I would also say that you don't want to vent any refrigerant to the atmosphere period.  The newer types are less harmful, not ozone safe.
Reply:There are some sheet metals that are galvanized before painting or powder coating- but there are two types of galvanizing- hot dip, and electrogalvanizing, which is more similar to plating.The hot dip stuff is almost never painted, as it takes a good etching primer to even begin to stick.But the electrogalvanized sheet, sometimes sold under the trade name Galv-anneal, is made to be painted. Sign makers use it for big outdoor signs, and companies like BMW have been using it for car bodies for years.So its quite possible that some higher end appliances, or some sheet metal boxes that are meant to be outside, like say, a swimming pool heater, might be galvanized and then painted.In general, most reefers, stoves, and cars, are made from sheet metal that is pretty hard- they dont want it to dent. So it doesnt hand hammer very well. Some very old cars were made of more ductile stuff, but anything in the last 30 years or so is gonna be pretty crummy for hand forming. In fact, a lot of it even needs special processes to weld.Most auto body shapers, the guys who make custom new parts for 30 Packards and Ferrari's and stuff, use an Aluminum Killed, deep drawing alloy of steel- it moves a lot easier, and is much better for making compound curves with. You can special order it from Hot Rod type suppliers.I have used it, and the difference between it and regular cold rolled from the steelyard is noticeable- I can raise a 12" diameter 3" deep bowl by hand with it in a few minutes, while a normal cold rolled, or even worse an appliance skin, would take much longer, and need to be annealed a few times because of work hardening.So to answer the original question- yeah, you can make car parts from old fridges- but anybody who does it professionaly, and charges for their time, is gonna buy a better grade of steel sheet instead, because it will be so much easier.
Reply:Well my question wasn't really about cars, I had just got the idea of recycling my fridge from the car show I saw on tv. I just want to be able to use the metal instead of tossing it at the dump. I'm building a custom bicycle and I plan on using the metal for that if I can. There probably won't be a whole lot of hammering and shaping going on, just want to weld the sheet to the frame.As for the refrigerant, I'm not going to be tearing the whole fridge apart and venting anything, I just want to remove the outer metal shell.
Reply:But then you have the skeleton of the refrigerator to dispose of or put out behind the trailer.  Either way, someone has to take responsibility to recover the refrigerant.  Once it has sat out in the weather without it's skin for a few years, someone will cut out the copper to to take to the salvage yard and you're back to square one.I fully agree with onefastduc about recycling any refrigerant, but didn't want to sound too extreme on my first post on the topic.  Thanks, onefastduc.awright
Reply:What do you think I am, some trailer park hick who leaves a bunch of trash and hazardous materials sitting around in the yard? lol The insides of the fridge would be taken to the landfill to be desposed of properly, all I want is the metal. I don't see why I would have to go through some big production. Thanks for the help though.