From: Mike Graham To: dtlc@helios.net Subject: Re: [DTLC] Coolant Heaters Date sent: Fri, 8 Oct 1999 21:43:33 -0400 Send reply to: dtlc@helios.net On Fri, 08 Oct 1999, BJ Cruisers wrote: > Thanks. What about using stainless steel instead? The bolts on the thermostat > housing aren't torqued very tight (13 or 18 ft-lbs IIRC) and aren't under any > stress. Unless you count heat. Or does electrolysis occur anyway with the > stainless, since they are dissimilar metals? No man! No stainless in aluminum! Bad bad BAAAD. Hideous galvanic action. The *worst*. Now, some of those castings are magnesium, too, so don't be getting too quick to dive in there with a torch to try to get them off. If you're worried, file a bit off and see if you can light the filings. Aluminum burns, too, especially in the presence of iron oxide, but luckily there won't be any iron oxide on the 'cruiser, right? 8-) Seriously, aluminum + iron oxide = thermite = what the 'bad guys' used to use to cut into bank vaults. Bad juju there, man. You machine metals and you learn, one way or the other. You try to use stainless in aluminum in a place where the air can get, and the magnesium dissolves and siezes the fastener, and you grab a torch and then your wife is feeding you through a straw for a *long* time. Not worth it. Seriously, man, those two metals are so far apart on the galvanic series you'll be able to watch it rust before your eyes. -- Mike Graham, mikegraham at sprint dot ca Caledon, Ontario, Canada (just NW of Toronto). Raiser of animals. Weldor of metals. Driver of off-road vehicles. Writer of FAQs. Keeper of the faith, and all around okay guy. < homepage currently off-line due to change of ISP; back soon > Date sent: Sat, 09 Oct 1999 09:12:56 -0400 To: dtlc@helios.net From: BJ Cruisers Subject: Re: [DTLC] Coolant Heaters Send reply to: dtlc@helios.net At 21.43 08.10.99 -0400, Mike Graham wrote: > No man! No stainless in aluminum! Bad bad BAAAD. Hideous >galvanic action. The *worst*. I'm confused. If stainless and aluminum are mortal enemies, why does Aqualu supply stainless hardware with its aluminum body parts and tubs? In fact, my new bib just arrived yesterday. Now they don't actually tap the aluminum, but drill it, so there is less contact of stainless to aluminum, and a coat of paint on the aluminum will insulate as well. But on the tubs, you tap lots of wholes and insert stainless directly. And what about stainless in steel - is anti-seize still a good idea? It seems to defeat the purpose of using stainless in the first place (though give me a few years and I'll likely say otherwise, right?). >too, so don't be getting too quick to dive in there with a torch to try to Now you tell me ;-) But is any torch (ie propane too) bad with aluminum and rust? ____________________________________________________________ damian lopes Port Credit Ontario BJ Series Land Cruisers 1982 BJ60, two 1981 BJ42 (1 in parts, 1 for parts) From: Mike Graham To: dtlc@helios.net Subject: Re: [DTLC] Coolant Heaters Date sent: Sat, 9 Oct 1999 09:48:01 -0400 Send reply to: dtlc@helios.net On Sat, 09 Oct 1999, BJ Cruisers wrote: > I'm confused. If stainless and aluminum are mortal enemies, why does Aqualu > supply stainless hardware with its aluminum body parts and tubs? They also supply tons of teflon sleeves and washers and a big tube of 'mystery goo' which seals the aluminum tub from the steel of the truck and fasteners, don't they? Regular steel will rot aluminum, too, just not as fast. Only an issue if you have air/water access, so steel studs in an aluminum head isn't that big a deal because they're sealed in where no galvanic action should be able to occur. > In fact, my new bib just arrived yesterday. Now they don't actually tap the > aluminum, but drill it, so there is less contact of stainless to aluminum, and > a coat of paint on the aluminum will insulate as well. But on the tubs, you > tap lots of wholes and insert stainless directly. Are you *sure* these are stainless bolts and not cad-plated or something? Did you pick up some lard to lube your tap? > And what about stainless in steel - is anti-seize still a good idea? It seems > to defeat the purpose of using stainless in the first place (though give me a > few years and I'll likely say otherwise, right?). Stainless appears twice on the galvanic table; depends on whether it's passive or active. The chrome in stainless reacts with the air to form chromium oxide, which forms a passive 'skin' that protects the steel from further corrosive effects. If you grind this skin off, then you have 'active' stainless. Active stainless is almost exactly the same as regular steel on the galvanic table, so when you grind the skin off and weld stainless to mild steel you don't have a problem because you will always have an active stainless to steel joint - no galvanic action. Passive stainless (stainless that has oxidized) is waaaay down the list with platinum and gold and whatnot. The absolute top end of the chart is magnesium, and aluminum isn't far behind. The point is that stainless *does* rot mild steel, but it takes so long that the steel will rot by itself fast enough that the stainless still helps the equation, if you know what I mean. > Now you tell me ;-) But is any torch (ie propane too) bad with aluminum and > rust? Well, having now read that message which I had written when I was *quite* tired, I now see that maybe I was just the wee-est bit alarmist, there. 8-) Yes, aluminum + rust = a lifetime of burn therapy, but the chance of it actually happening by accident isn't terribly high. If you were going at your block with a big wire wheel then some of the dust of that operation would have the potential to be nasty, but it would probably just be a flash. I've welded aluminum (but you always clean it well, first) and I've even welded magnesium (talk about brown-trousers time) but there's always an inert gas to keep the risk down. -- Mike Graham, mikegraham at sprint dot ca Caledon, Ontario, Canada (just NW of Toronto). Raiser of animals. Weldor of metals. Driver of off-road vehicles. Writer of FAQs. Keeper of the faith, and all around okay guy. < homepage currently off-line due to change of ISP; back soon > Date sent: Sat, 09 Oct 1999 12:54:59 -0400 To: dtlc@helios.net From: BJ Cruisers Subject: Re: [DTLC] Coolant Heaters Send reply to: dtlc@helios.net At 09.48 09.10.99 -0400, Mike Graham wrote: > They also supply tons of teflon sleeves and washers and a big tube of >'mystery goo' which seals the aluminum tub from the steel of the truck >and fasteners, don't they? Nope, at least not with just a bib. The mystery goo is silicone I believe. But with the bib, I got a packing list for the hardware which says stainless for most bolts and washers; instead of nuts they supplied steel nylocs. (Sadly, all the hardware is SAE instead of metric.) >Passive stainless (stainless that has oxidized) is waaaay down the list >with platinum and gold and whatnot. The absolute top end of the chart is >magnesium, and aluminum isn't far behind. The point is that stainless >*does* rot mild steel, but it takes so long that the steel will rot by >itself fast enough that the stainless still helps the equation, if you >know what I mean. So is Aqualu, uhm, mistaken to supply stainless then? What should one use with aluminum, especially aluminum that is going to contact steel? The bib has to bolt to the rest of of the body, though both parts will be painted (ideally anyway). ____________________________________________________________ damian lopes Port Credit Ontario BJ Series Land Cruisers 1982 BJ60, two 1981 BJ42 (1 in parts, 1 for parts) From: Mike Graham To: dtlc@helios.net Subject: Re: [DTLC] Coolant Heaters Date sent: Sat, 9 Oct 1999 13:12:20 -0400 Send reply to: dtlc@helios.net On Sat, 09 Oct 1999, BJ Cruisers wrote: > Nope, at least not with just a bib. The mystery goo is silicone I believe. Probably, or some kind of construction adhesive/sealant. > with the bib, I got a packing list for the hardware which says stainless for > most bolts and washers; instead of nuts they supplied steel nylocs. (Sadly, > all the hardware is SAE instead of metric.) It doesn't specify stainless steel nylocs? Hopefully this is all plated, or it will definately be worth sending them a query and getting the word on what their thinking is. > So is Aqualu, uhm, mistaken to supply stainless then? If it's not plated, and they don't have some other thing going on to stop galvanic corrosion, then yes, they are mistaken. > What should one use with > aluminum, especially aluminum that is going to contact steel? Cadmium plated whatever. Brass, steel, whatever, as long as it's cadmium plated. Cadmium plating isn't expensive - most of the shiny hardware store bolts are cadmium plated. Galvanized is also very good, and in fact better for magnesium parts. -- Mike Graham, mikegraham at sprint dot ca Caledon, Ontario, Canada (just NW of Toronto). Raiser of animals. Weldor of metals. Driver of off-road vehicles. Writer of FAQs. Keeper of the faith, and all around okay guy. < homepage currently off-line due to change of ISP; back soon > Date sent: Sat, 09 Oct 1999 12:07:20 -0700 From: Aarons family <52m37@alaska.net> Organization: mpfc To: dtlc@helios.net Subject: Re: [DTLC] Coolant Heaters Send reply to: dtlc@helios.net Aarons family wrote: > All different metals are enemies. But stainless goes much slower than others. > Charlie No, propane is OK w/aluminum. Irregardless o what Mike syas, look at the 1000 or so aluminum 32' gillnetters in Alaska, what are their props made of: stainless, not brass. What are all the bolts: stainless, not aluminum, brass or regular plated steel. sometimes you just need to make a choice. Of all the choices, stainless, gooped up, is the best choice for aluminum. And over the next 30 or so years, is it going to rot anywhere near as fast as the original body? Of course not. Charlie From: Mike Graham To: dtlc@helios.net Subject: Re: [DTLC] Coolant Heaters Date sent: Sat, 9 Oct 1999 16:31:39 -0400 Send reply to: dtlc@helios.net On Sat, 09 Oct 1999, Aarons family wrote: > All different metals are enemies. But stainless goes much slower than others. Oh, yeah, *it* goes slow because it's a noble metal, but the poor ignoble metals like aluminum and magnesium get eaten alive by it. The fastener causes local destruction of the magnesium or aluminum *around* it. Phone up a marina and ask them about stainless steel fasteners on aluminum boats, and they'll give you chapter and verse about the hideous effects. -- Mike Graham, mikegraham at sprint dot ca Caledon, Ontario, Canada (just NW of Toronto). Raiser of animals. Weldor of metals. Driver of off-road vehicles. Writer of FAQs. Keeper of the faith, and all around okay guy. < homepage currently off-line due to change of ISP; back soon > From: Mike Graham To: dtlc@helios.net Subject: Re: [DTLC] Coolant Heaters Date sent: Sat, 9 Oct 1999 20:09:08 -0400 Send reply to: dtlc@helios.net On Sat, 09 Oct 1999, Aarons family wrote: > No, propane is OK w/aluminum. Irregardless o what Mike syas, look at the 1000 > or so "Irrespective" or "Regardless". Pick one. Sorry, that's a pet peeve of mine. > aluminum 32' gillnetters in Alaska, what are their props made of: > stainless, not brass. Do the props touch aluminum? Is the propshaft aluminum? > What are all the bolts: stainless, not aluminum, brass or regular > plated steel. All the bolts in *what*? I'm talking about stainless screwed into aluminum. -- Mike Graham, mikegraham at sprint dot ca Caledon, Ontario, Canada (just NW of Toronto). Raiser of animals. Weldor of metals. Driver of off-road vehicles. Writer of FAQs. Keeper of the faith, and all around okay guy. < homepage currently off-line due to change of ISP; back soon > Date sent: Sat, 09 Oct 1999 20:22:16 -0800 From: Paul Huber To: dtlc@helios.net Subject: Re: [DTLC] Coolant Heaters Send reply to: dtlc@helios.net Mike Graham wrote: > On Sat, 09 Oct 1999, Aarons family wrote: > > No, propane is OK w/aluminum. Irregardless o what Mike syas, look at the > > 1000 or so > > "Irrespective" or "Regardless". Pick one. > > Sorry, that's a pet peeve of mine. > Sorry Mike, I've got to side with my fellow Alaskan on this one. Irregardless (which is a favorite of mine) is correct (although nonstandard) usage. Websters Dictionary classifies it as a blend of irrespective and regardless. Paul From: Mike Graham To: dtlc@helios.net Subject: [DTLC] Re: "Irregardless" - was Coolant Heaters Date sent: Sun, 10 Oct 1999 08:30:56 -0400 Send reply to: dtlc@helios.net On Sun, 10 Oct 1999, Paul Huber wrote: > Sorry Mike, I've got to side with my fellow Alaskan on this one. Irregardless > (which is a favorite of mine) is correct (although nonstandard) usage. > Websters Dictionary classifies it as a blend of irrespective and regardless. It is a double negative. Incorrect usage, and logically at fault. While I don't doubt that it is listed in Websters as 'slang' or 'colloquial' usage, that doesn't make it *right*. -- Mike Graham, mikegraham at sprint dot ca Caledon, Ontario, Canada (just NW of Toronto). Raiser of animals. Weldor of metals. Driver of off-road vehicles. Writer of FAQs. Keeper of the faith, and all around okay guy. < homepage currently off-line due to change of ISP; back soon > Date sent: Sun, 10 Oct 1999 11:19:59 -0400 To: dtlc@helios.net From: BJ Cruisers Subject: Re: [DTLC] Coolant Heaters Send reply to: dtlc@helios.net At 20.22 09.10.99 -0800, Paul Huber wrote: >Mike Graham wrote: > >> On Sat, 09 Oct 1999, Aarons family wrote: >> > No, propane is OK w/aluminum. Irregardless o what Mike syas, look at >the 1000 or so >> >> "Irrespective" or "Regardless". Pick one. >> >> Sorry, that's a pet peeve of mine. >> > >Sorry Mike, I've got to side with my fellow Alaskan on this one. >Irregardless (which is >a favorite of mine) is correct (although nonstandard) usage. Websters >Dictionary >classifies it as a blend of irrespective and regardless. Oh no, looks like a fight's brewing. And I'm on Mike's side. It may be accepted usage by Webster, and is even listed in the OED (as a NA usage), but it's plain ugly. What's next? Do we accept unthaw too, as in, "I unthawed the frozen fish." It gets used. So Mike, what's the phobia of butchered language? Oh dang, I keep forgetting that phobias are irrational ;-) ____________________________________________________________ damian lopes Port Credit Ontario BJ Series Land Cruisers 1982 BJ60, two 1981 BJ42 (1 in parts, 1 for parts) From: Mike Graham To: dtlc@helios.net Subject: Re: [DTLC] Coolant Heaters Date sent: Sun, 10 Oct 1999 13:53:44 -0400 Send reply to: dtlc@helios.net On Sun, 10 Oct 1999, BJ Cruisers wrote: > So Mike, what's the phobia of butchered language? Oh dang, I keep forgetting > that phobias are irrational ;-) Onomatophobia. A fear of a certain word (or of names). In my case it's less fear than hatred of a certain word. 8-) -- Mike Graham, mikegraham at sprint dot ca Caledon, Ontario, Canada (just NW of Toronto). Raiser of animals. Weldor of metals. Driver of off-road vehicles. Writer of FAQs. Keeper of the faith, and all around okay guy. < homepage currently off-line due to change of ISP; back soon > From: Mike Graham To: dtlc@helios.net Subject: [DTLC] Galvanic corrosion revisited. Date sent: Mon, 18 Oct 1999 16:01:30 -0400 Send reply to: dtlc@helios.net This was posted to rec.crafts.metalworking, and I thought I'd pass it on. Oh, by the way... I found out that the yellow coating on OEM Toyota bolts for mounting aluminum stuff like water pumps is, in fact, cadmium. < --------------------> From: "Barry L. Ornitz" Newsgroups: rec.crafts.metalworking Subject: Galvanic Corrosion, was RE: Stainless/ Aluminum reaction? Several people have touched on the subject of dissimilar metal or galvanic corrosion. The subject can be extremely complicated, but there are several good generalities that can be used as a guide when picking compatible metals. First - you need a chart or table of the galvanic series. You really need one that lists the alloys you are contemplating using. Just saying aluminum or stainless is not enough if you really want good results. Different alloys behave quite differently. Understand how the tables work too (see below) Two of the better tables I have found are listed below. Second - pick compatible metals based on how close they are in the galvanic series. The closer the galvanic potentials are, the less corrosion that will occur. Third - the amount of corrosion is proportional to the ratio of cathode to anode area ratio. This leads to a number of methods to minimize corrosion. Make the anodic metal piece much larger than the cathodic one. The corrosion will be spread out over a larger piece of metal and thus the loss of some atoms from the surface will likely not result in much weakening. If you have to use a different metal as a fastener, use one more cathodic than the metal in which it is to be used. Fourth - remember that sometimes the above rules must be bent a little for other reasons, and that corrosion can be far more complex than just galvanic corrosion. Look at the stainless steels for example. Most can be both cathodic and anodic to themselves! Corrosion while immersed in sea water can be quite different than corrosion from exposure to pollutants in the atmosphere. So before presenting the table, let's look at the original question - stainless fasteners on aluminum. First we need to know what alloy of aluminum and stainless we are talking about. With no other information all we can do is note that aluminum is generally more anodic than any of the stainless steels. This is good from the standpoint of having a small fastener. But note that zinc or cadmium plating is likely better as they are closer to aluminum in the galvanic series. I would probably pick a hot- dip galvanized screw over a cadmium plated one because of the thicker coating, but I would pick a cadmium plated one over a simple zinc plated one (which is likely to be a rather thin plating). But I would certainly not pick brass, copper, or bronze. This brings up the point of why I listed two tables. The shorter one gives a better idea of how far apart the metals tend to be in the series. The longer list gives many alloys, but if you view these with their electromotive potentials (not shown), you will find many alloy series differ little in their actual placement in the series. Thus with aluminum, you might notice little difference between the corrosion with either 304 or 17-7PH stainless steel. Corrosion can be a nearly exact science if everything you work with is exceptionally pure. But in the real world, this is not the case and an experienced metallurgist is a wonderful friend to have. I first learned this in a corrosion class, but it really sank home after I learned it by experience too. [And on one or two occasions, I have seen my metallurgist friend scratch his head in confusion too!] When your choice of materials is limited, sometimes you have to accept that some corrosion is inevitable and design accordingly. Barry L. Ornitz ornitzNOSPAM@NOSPAMdpnet.net Take the NOSPAM out before replying directly. Thanks. ********************************************************* First Table: A Galvanic Series of Certain Metals and Alloys Arranged In Order of Corrosivity ANODIC (Least Noble) End Material Magnesium Magnesium alloys Zinc Aluminum 25 Cadmium Aluminum 17ST Steel or iron Cast iron Chromium-iron (active) Ni-Resist 18-8 Chromium-nickel-iron (active) 18-8-3 Chromium-nickel-molybdenum-iron (active) Lead-tin solders Lead Tin Nickel (active) Inconel (active) Hastelloy C (active) Brasses Copper Bronzes Copper-nickel alloys Monel Silver Solder Nickel (passive) Inconel (passive) Chromium-iron (passive) 18-8 Chromium-nickel iron (passive) 18-8-3 Chromium-nickel-molybdenum-iron (passive) Hastelloy C (passive) Silver Carbon and graphite Platinum Gold CATHODIC (Most Noble) End material Second Table from MIL-STD-889: Active (Anodic) End ------------------------------------ Magnesium Mg alloy AZ-31B Mg alloy HK-31A Zinc (hot-dip, die cast, or plated) Beryllium (hot pressed) Al 7072 clad on 7075 Al 2014-T3 Al 1160-H14 Al 7079-T6 Cadmium (plated) Uranium Al 218 (die cast) Al 5052-0 Al 5052-H12 Al 5456-0, H353 Al 5052-H32 Al 1100-0 Al 3003-H25 Al 6061-T6 Al A360 (die cast) Al 7075-T6 Al 6061-0 Indium Al 2014-0 Al 2024-T4 Al 5052-H16 Tin (plated) Stainless steel 430 (active) Lead Steel 1010 Iron (cast) Copper (plated, cast, or wrought) Nickel (plated) Chromium (Plated) Tantalum AM350 (active) Stainless steel 310 (active) Stainless steel 301 (active) Stainless steel 304 (active) Stainless steel 430 (active) Stainless steel 410 (active) Stainless steel 17-7PH (active) Tungsten Niobium (columbium) 1% Zr Brass, Yellow, 268 Uranium 8% Mo. Brass, Naval, 464 Yellow Brass Muntz Metal 280 Brass (plated) Nickel-silver (18% Ni) Stainless steel 316L (active) Bronze 220 Copper 110 Red Brass Stainless steel 347 (active) Molybdenum, Commercial pure Copper-nickel 715 Admiralty brass Stainless steel 202 (active) Bronze, Phosphor 534 (B-1) Monel 400 Stainless steel 201 (active) Carpenter 20 (active) Stainless steel 321 (active) Stainless steel 316 (active) Stainless steel 309 (active) Stainless steel 17-7PH (passive) Silicone Bronze 655 Stainless steel 304 (passive) Stainless steel 301 (passive) Stainless steel 321 (passive) Stainless steel 201 (passive) Stainless steel 286 (passive) Stainless steel 316L (passive) AM355 (active) Stainless steel 202 (passive) Carpenter 20 (passive) AM355 (passive) A286 (passive) Titanium 5A1, 2.5 Sn Titanium 13V, 11Cr, 3Al (annealed) Titanium 6Al, 4V (solution treated and aged) Titanium 6Al, 4V (anneal) Titanium 8Mn Titanium 13V, 11Cr 3Al (solution heat treated and aged) Titanium 75A AM350 (passive) Silver Gold Graphite ---------------------------------- Passive (Cathodic) End