Home |
Search |
Today's Posts |
|
Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
|
|||
|
|||
rust removal
can anyone tell me if potassium hydroxide is any good at removing
rust? i am going to boil it(mixed with water) at about 200f and use it to remove rust from a car engine. what do you think? |
#2
|
|||
|
|||
I don't think it will work. KOH is about like NaOH, in other words a
strong base. If you heat it, I'd think it would behave like a hot caustic cleaning solution. Very tough on grease but won't touch rust. The thing about rust is that if you put rusty steel into an acid solution the acid attacks the rust much faster than it attacks the steel. So if you put it in acid for the right length of time then it will dissolve away all the rust but leave just about all the base metal. If I had to clean a car engine I'd certainly start with a grease-removing soak followed by very hot water. Scrub it to make sure it's clean and repeat the hot soak/rinse/scrub cycle until it is. You know the problem with an acid soak on an engine block? How can you guarantee that all the acid gets neutralized and rinsed away? I might use a weak acid and longer soak followed by really serious rinsing. The last rinse cycle should be in water hot enough so the whole block will self-dry within 60 seconds. Grant nattydreadlocks wrote: can anyone tell me if potassium hydroxide is any good at removing rust? i am going to boil it(mixed with water) at about 200f and use it to remove rust from a car engine. what do you think? |
#3
|
|||
|
|||
"Grant Erwin" wrote in message
... I don't think it will work. KOH is about like NaOH, in other words a strong base. Hot caustic baths are what commercial engine rebuilders use to "hot-tank" engine blocks. Local services often offer the same thing, for small-time rebuilders. There are commercial hot-tanking solutions but they are basically lye, if you'll forgive the pun. g They often advertise it as a way to remove rust. But it doesn't strip rust. What it does do is clean out the oil and some other crud trapped in cooling passages, as well as varnish and oil in the oil galleries. Some of the flaky rust in an old engine is trapped there in mungy old oil that got into the cooling system, so some rust does, incidentally, come out when you hot-tank an engine. To remove attached rust you either need to remove it mechanically or with acid, as you say. I'd be wary of using acid in a cast-iron engine because it will be hard to remove. Iron has a lot of pores where graphite flakes out. Maybe someone has experience with it and knows how it works out in practice. I'd just be darned sure to flush it out with a mild alkaline solution if I were going to try it. Ed Huntress |
#4
|
|||
|
|||
On Thu, 09 Sep 2004 14:17:09 -0700, nattydreadlocks wrote:
can anyone tell me if potassium hydroxide is any good at removing rust? i am going to boil it(mixed with water) at about 200f and use it to remove rust from a car engine. what do you think? Oxalic acid would probably do a much better job. That was the principal ingredient in the two-part powdered radiator flush kits and it was really good at cleaning the cooling passages in cast iron blocks. -- The instructions said to use Windows 98 or better, so I installed RedHat. |
#5
|
|||
|
|||
I have used battery acid from old car batteries to clean cast iron BMC A
series engine block water passages. Bolted up an old water pump to seal that apperture and covered the top of the block with vaseline, filled up the water passages to the top and left it for a day, then flushed out the whole thing with lots of water. Left it nice and clean. I can't comment on sodium hydroxide though. nattydreadlocks wrote: can anyone tell me if potassium hydroxide is any good at removing rust? i am going to boil it(mixed with water) at about 200f and use it to remove rust from a car engine. what do you think? |
#6
|
|||
|
|||
|
#8
|
|||
|
|||
I've done this on about 4 blocks and heads and not had any issue with
it. The acid may have been fairly weak but you could see the activity due to the bubbling at the water passages. This eventually died down and I rinsed thoroughly. Considering the water pump and thermostat housing were aluminium alloy they were not noticably damaged by the process as I would have expected, they were however sacrificial. Rex B wrote: On Thu, 09 Sep 2004 23:03:13 +0100, David Billington wrote: ||I have used battery acid from old car batteries to clean cast iron BMC A ||series engine block water passages. Bolted up an old water pump to seal ||that apperture and covered the top of the block with vaseline, filled up ||the water passages to the top and left it for a day, then flushed out ||the whole thing with lots of water. Left it nice and clean. I can't ||comment on sodium hydroxide though. You are a brave soul, or one who has plenty of spare blocks Texas Parts Guy |
#9
|
|||
|
|||
"nattydreadlocks" wrote in message om... can anyone tell me if potassium hydroxide is any good at removing rust? i am going to boil it(mixed with water) at about 200f and use it to remove rust from a car engine. what do you think? Try mollasses, mixed one part mollasses to four parts water. It wont hurt the good metal it you keep it completely submurged, but it is slow. You can get mollasses cheap in bulk at the produce store, they feed it to horses to keep them shiney! regards, John |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Salt and vinegar for rust removal | Woodworking | |||
Electrolytic rust removal question | Metalworking | |||
Which Scotch Brite Pad for rust removal ??? | Woodworking | |||
Electrolytic Rust Removal & Power Supplies | Woodworking | |||
Rust removal... | Metalworking |