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NATURAL RUST BLUE?

epanzella

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I'm a big fan of rust blueing and have done a few rifles that way. I just finished a spare tire mount and need to press it into service immediately. The mount is all painted surfaces except for the 3/4 inch threaded shaft that holds the tire on. If it rusts naturally outdoors can I then boil it and card it or is rust blueing a different chemical process than naturally occurring rust?
 

kev74

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It should work the same.

I rust blued some tools by using supermarket grade peroxide and salt to stimulate the rusting. It works fast, but can leave pitting if not careful.
 

seanb

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Heat it up and dunk in some used motor oil (outside) burn off rest with propane torch.

Rust bluing is one of the weakest rust preventatives around. First time it rains you will have rust next day.
 

epanzella

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Heat it up and dunk in some used motor oil (outside) burn off rest with propane torch.
Rust bluing is one of the weakest rust preventatives around. First time it rains you will have rust next day.
Thanks for the tip on the motor oil. I forgot about that. I do beg to differ on the protective quality of rust blueing. I rust rust blued two rifles that I built and the finish seems to be impervious to rusting despite some all day hunts in the rain. I keep repeating the application until the surface refuses to rust anymore even when treated with the chemical designed to cause rusting. I have to figure if the surface is completely rusted already, how can it rust any more?
 

epanzella

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It should work the same.

I rust blued some tools by using supermarket grade peroxide and salt to stimulate the rusting. It works fast, but can leave pitting if not careful.
Salt for the rusting and peroxide for the oxygen! Great idea! I'm gonna try that. The solution I use is for guns. It produces a beautiful finish but takes all day. The part I' trying to protect doesn't need a good finish but it will be outdoors all the time and i don't want it to rust all to hell. Thx for the tip.
 

wrmiller

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Salt for the rusting and peroxide for the oxygen! Great idea! I'm gonna try that. The solution I use is for guns. It produces a beautiful finish but takes all day. The part I' trying to protect doesn't need a good finish but it will be outdoors all the time and i don't want it to rust all to hell. Thx for the tip.
I'd really be interested in how you rust blue a firearm. I've been wanting to try this on a pistol but am not sure what method/chemicals would give the best results. :)
 

epanzella

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I'd really be interested in how you rust blue a firearm. I've been wanting to try this on a pistol but am not sure what method/chemicals would give the best results. :)
Easy, great finish, great durability, but sloooow. The part should be prepped using progressively finer grits but don't go finer than 300. 1. degrease part 2. cover with rustblue chemical available on internet. 3. Leave in damp environment until it gets a fine coat of rust. ( 2 to 8 hrs depending on humidity) 3. boil in distilled water for 30 minutes until it turns blue/black. 4. card with carding brush (super fine wire brush available on internet). Using FRESH distilled water every time, repeat as required (it will get progressively darker with each cycle) until it will no longer rust with the chemical. I've done 2 rifles and both times it refused to rust any further on the fourth cycle. Both rifles have been out in all day rain without a spec of rust. This system is almost foolproof and is the way custom rifles costing many thousands of dollars were finished back in the day. The only thing that will spoil the finish is oil or grease on the parts or in the water tank. I made a sheet steel tank that looks like a 3 ft piece of rain gutter. Good Luck!
 

whimsnag

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The following Youtube video shows an accelerated rust blueing process using vinegar and hydrogen peroxide. I haven't tried myself, yet, but I plan to!


Craig
Thank you for the video. I'm eager to test this out on some steel test pieces.

Here are another two videos on rust bluing.

In the first one, they recommend steaming the red rust to convert to black oxide. This avoids any need for distilled/RO/DI water, but I think there is a risk of streaking and spotting if a cold part is introduced into the steam.

In the second one, Mark conserves a shotgun by converting the patina into blue. It's like magic, but better.
 

seanb

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Rust or hot water bluing does produce a beautiful finish but its too time consuming for me.

I have started doing caustic salt bluing, recipe is pretty forgiving 2 to 1 ratio of sodium hydroxide to sodium nitrate.

So 5 lbs sodium hydroxide 2.5 lbs Sodium nitrate per 1 gallon of water. get temp to 285deg F and insert part for about 20 minutes

Since sodium hydroxide (lye) is a degreaser if you have a missed a spot of oil on your part, no need to worry.

Surface prep is key as always, use fresh sand paper, true up your grinding wheel etc. using sand products that have been used on other metals will cause streaks/bare spots in the bluing.

I use graniteware pots/ pans for small pieces with a 1500 watt hotplate. I have a plain steel tub for things like barrels. which i use propane to heat.

If the mixture gets over heated you will get a thick coating of soft rust on the part, Just scrub lightly under running water with steel wool and underneath you will see the bluing.

I order my chemicals from Duda Diesel they are the cheapest i have found so far.
 

Jubil

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Easy, great finish, great durability, but sloooow. The part should be prepped using progressively finer grits but don't go finer than 300. 1. degrease part 2. cover with rustblue chemical available on internet. 3. Leave in damp environment until it gets a fine coat of rust. ( 2 to 8 hrs depending on humidity) 3. boil in distilled water for 30 minutes until it turns blue/black. 4. card with carding brush (super fine wire brush available on internet). Using FRESH distilled water every time, repeat as required (it will get progressively darker with each cycle) until it will no longer rust with the chemical. I've done 2 rifles and both times it refused to rust any further on the fourth cycle. Both rifles have been out in all day rain without a spec of rust. This system is almost foolproof and is the way custom rifles costing many thousands of dollars were finished back in the day. The only thing that will spoil the finish is oil or grease on the parts or in the water tank. I made a sheet steel tank that looks like a 3 ft piece of rain gutter. Good Luck!
This process works very well, but you can also use degreased 0000 steel wool to card with. Also you can make a steam pipe instead of boiling, (easier, cheaper, faster). Google rust blue and rust blue steam pipe.

Chuck
PS Sorry, I didn't see Whimsnag's post above.
 
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john.k

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I suppose a bit like the towball on my trailer hitch ......polished in places when the trailer is hooked up,rest of the time it rusts a bit,some grease here and there too.............In my experience ,rust starts to progress rapidly when the flaky form develops,and holds moisture,scabs of rust will then eat thru the whole piece.......this is the theory with ships.......keep chipping away any loose rust,and serious damage is averted......Some steel is very rust prone too,Caterpillar makes its earthmoving bolts and nuts from a very resistant steel,Chinese black finish bolts in the same place rust away,Cat bolts are good with just surface rust.
 
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