Best way to fix small hole?

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Below are photos of a problem that I have with a rear lamp housing from my '72 El Camino.  I've ground through the casting and need to fix it.  It appears to be 'pot metal' but I'm not sure what to use or how to go about a repair.  I have  polished these and was not planning to chrome them.  I'd like to have something with a fairly close color match to the surrounding metal.Any ideas?Thanks,Bill
Reply:For that size hole, it's going to be tough to "fill" it with something then not have it chromed. You might get away with some stainless filler and then grind the extra away and polish. Hit it a few times around the edges with heat and filler and work your way around and in. I'm sure others will post and will give you different and/or better ideas.John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:You may find it impossible to add anything to it without just melting more away.  It all depend on what was in the pot when they made the pot metal.  You might get lucky, though, especially with the older stuff.  Any scraps to test on by any chance?  Of course, that would make the best TIG filler, too, if you had scraps.Is it magnetic?  What resources are available to you for this repair?
Reply:Although I think the stuff is pure crap, you might try "Alum-alloy" or some other low temp aluminum brazing rod.   I fixed an old cap gun made from cast pot metal using the stuff.    Basically, the barrel was cracked and a small jagged piece was missing.   First I found a piece of steel bar that was close to the correct diameter and inserted it into the barrel.     Using MAPP gas, I melted the alum-alloy in a steel can and dripped it onto the cracked section.    I also heated the cap gun barrel at the same time and cleaned it with a stainless steel brush.  Once ground smooth and buffed, it didn't look too bad.   In fact, the alum-alloy patch polished better than the original metal.There are no small projects
Reply:Yes, I've heard that "alum-alloy" is some decent stuff. I'd give that a shot!John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:I worked in the ZINC die cast industry years ago so have a little experience with pot metal.First there are a number of ZINC alloys used in those pots.   It will be very difficult to know what the part was made of if it is ZINC based.    If it is ZINC based I'd have to say you are out of luck with wedling approaches.   You may have some success with a solder approach, but off the top of my head I can't even reccomend a flux and aloy to use.If you get lucky and find that the part is aluminum then your options expand.   If the metal is taking a polish and holding it then you might have aluminum.    Generally "polished" pot metal turns dull prety quickly.The reality is that I think a trip to the auto recyclers is in order.Dave
Reply:I think that stuff is stainless steel.  All of the trim on my '76 GMC is stainless.  You could weld it up with some 309L wire.
Reply:Thanks for the replies, guys!As for the material, it is not magnetic and seems too heavy for aluminum, so I'm thinking a zinc alloy of some sort.  I do have a good supply of similar metal that could be used for filler if need be.I posed this same question some time ago to the Chevelles.com forum, didn't get too much response.  Someone said silver solder.  Is that an option?  Also, I've had this polished about 4 months now and seems to be holding up - but the car is always garaged and sees no rain.I might try the Chevelle forum again (I have better photos this time) and see what happens.-Bill
Reply:if it is     POT metal then it may be tuff ,,try solder--what they use with a propane torch -map gas.  (wonder rod)??  it takes low heat an is a strong solder---works on the botom of beer cans. but pot metal is hard to repair with-out some kind of epoxy((grrr glue)))  it s  a trash metal
Reply:My best guess by looking at the picture is that it is a "pot" metal. any attempt to repair this by welding will most likely result in more problems than you have now. My fix would be to use Alvin Lab-metal. It has many uses. It has aluminum in it and should match closely to your weathered chrome. A 12 oz. can is about $23.00 and the thinner is 16 oz. for about $15.00. If you  wear latex type gloves and use the thinner, you should be able to feather the inside corner as near original as the others. I know Fastenal sells it, probably Grainger, and a real good hardware store as well. We could almost open up a section on how everybody uses this stuff, it won't be your last can.Just my  opinion, not from a book, just from the road.Howes Welding Inc.www.howesweldinginc.com
Reply:an other epoxy is  (devcon) some good stuff in the right place
Reply:I would lean toward believing this is a stamped part rather than a casting, and if as 76GMC said its stainless it should be an easy fix. If it is indeed stainless I would remove material from inside the hole untill the feathered edge was gone.[Appears to be feathered.] I would then cut,grind, file, a piece of matching material [scrap] to fit the hole and tig it in. Unless you have some .015-.025 stainless tig rod you will need to grind down some larger tig rod or use some hand shears to cut very thin slivers of scrap for filler. Once the part is welded you can grind and buff the part to shape. Unless you have some experence in low amp tig work it might be best to seek advise from a good tig welder who can actually hold the part in his hand. This is may be the only way to get a true assessment of your needs.
Reply:IT'S STAINLESS!!!!I've repaired headlight rings with a more standard 1/16th inch rod, they're much thinner.  You're going to have to do a lot of grinding no matter what size rod you use, so it doesn't matter if your beads are kind of big.
Reply:Hello Doc, I also agree with Allan, first identify the material it could be stainless, if it is follow his great advice.However if you are correct in your material identifaction it's anybodys guess what elements make up the "melt de jour" of that day for pot metal. Generally the pots are not the most maintained item in the foundry, when the parts being poured are considered "junk metal material". I've fixed hundreds of these items like you are describing made of pot metal with a propane torch if that is all thats available or I use a Hen Rob (Cobra Mfg.) torch and get the MIRACLE rod from Dura Fix @ Durafix.com Ph.# 1-800-547-WELD (9353) it melts @ 700-750deg. and polishes quite nicely. You can obtain a similar product from Muggyweld.com or contact Eastwood Restoration they are a mail order house for the restoration crowd. The product you are looking for is the type of thing you see at a County Fair being demonstrated with a propanne torch fixing holes in beer cans, the product we all walk away from wondering who has a leaking beer can? I hope this info helps you. Have a great week,Ric HavelLast edited by Ric Havel; 06-16-2006 at 11:24 AM.Reason: addition
Reply:The best way I found is to use a heavy piece of copper as a backing and then use light heat.... just enough to melt the stainless tig wire I perfer .035 wire. I've done this many times it works for me.
Reply:Originally Posted by DDalke8The best way I found is to use a heavy piece of copper as a backing and then use light heat.... just enough to melt the stainless tig wire I perfer .035 wire. I've done this many times it works for me.
Reply:BTW the Alumaweld, rod is on sale at eastwood for $4.00 for 10 9" rods.  I fixed a small hole in a 68 911 tail-light assembly with it.  Worked really well (potmetal)
Reply:i'd use a piece of aluminum for backing...tig straight argon..go around in circles untill the hole is filled......zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.