Page 7 of 7 FirstFirst ... 234567
Results 91 to 100 of 100
  1. #91
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,182

    Default

    I had a go with the rusting solution (salt+H2O2) and steam this morning.

    This is what it looks like after applying the rust soln with the rod held vertically.
    Longrod.jpg
    Unevenrusting.jpg
    Because the rusting was not very even the bluing/blackening did not come out even. That's a major benefit of the fume bluing(as compared to the salt/H2O2 method) is the fume method really does come out very even,

    On the second pass I lay the rod down on a strip of plastic film and applied the rusting solution that way.
    This made the rusting a bit more even but it will take several passes to mask the unevenness of the first application.
    Should be OK after a few more passes.

  2. #92
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,182

    Default

    OK a direct comparison between the Fume and salt/H2O2 bluing.

    Top & bottom rods are fume/boiling water blued, middle one is salt/H2O2/steam blue
    This is after 4 time through the bluing cycle.

    Looks reasonable comparable on this scale
    Comparison0.jpg

    But not as good on this scale.
    The H2O2/salt steam seems to etch the surface more and the finish is patchier - these could be related,
    Comparison.jpg

  3. #93
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,182

    Default

    OK found a simple way to fume blue the 820mm long rod.

    I added a 400mm long x 32 mm diameter Black HDPE irrigation pipe (Snorkel) to the fuming tank lid.
    The rod is suspended from the top of the snorkel.
    Fortunately I already had these parts - including the 32mm/1" BSP die to cut a longer thread on the pipe so I could make better/lomnger seal

    Snorkle.jpg

    It probably won't be exposed to many fumes inside the snorkel but I can always invert the rod for subsequent passes.

  4. #94
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,182

    Default

    All done, 4 passes of fume bluing, except for the long rod which had 2 passes of salt/H2O2 and two passes of fumes,. This seemed to fix the unevenness of the salt/H202 rusting.

    It seems to work quicker if the first pass through the fume tank is using an exposure time of ~30 hours instead of 20.
    Subsequent passes were 20 hours.

    Apart form the hand vice the remainder form part of the articulated arms that hold the dust extraction system hoods for my sliding compound mitre saw.
    Finished.jpg
    Finished2.jpg

  5. #95
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,182

    Default

    Carding wheel turned up today (3.5 weeks from Florida) so I turned up a bit of a hub with a 12mm shaft so I can use it on a few different machines with chucks.

    For removing black oxide soot produced during the bluing process (carding) I'm going to use it on my WW lathe like this.
    Cardingwheel.jpg
    This lathe has a built in sucker that will reduce the carding mess.

    This lathe also has a VFD so I can control the speed.
    The wheel wires are very fine/soft and even at 2000 rpm I can hold my fingers on them for about 10s without any problems.
    This means I can card small objects like knurled wheels etc and hold them right up to the wheel and if I slip it wont matter.

    Normally I handle the sooty objects while wearing latex gloves.

  6. #96
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,182

    Default

    Started doing some more bluing - this time it's parts from a Radial arm saw that I'm doing up together with a mate.

    The parts i'm doing at the moment are the saw blade flanges, the main stop bracket, and the M10 levelling bolts and M8 screws for the table which was made of MDF but it got wet so needs to be replaced.
    These metal parts were pretty rusty so firstly an ON bath in citric acid.
    OASB7678.jpg

    Handling all these small parts is a right PITA to handle thru the bluing process and as far as the screws and washers were concerned it was tempting to just buy new ones.

    This is how I usually handle things like bolts and screws so they can be suspended in the acid fuming tank.
    The white material is scrap HDPE and just drill and tapped some M10 and M8 holes in the HDPE so that only one suspension point is needed to hand many items inside the tank..
    Nuts can be mounted on the bolts themselves and provided their positions on the bolt are varied after each cycle , enough bluing will take place.
    Bolts.jpg

    Washers are suspended as shown below - sorry about the poor photo.
    Either like nuts on on bolts themselves
    OR
    A piece of HDPE has holes drilled in it at an angle and short pieces of SS TIG rod are hammered into the holes and small items are suspended from the rods.
    Washers.jpg

    The carding wheel is proving the "ducks nuts" especially for small items like screws/bolts etc where it can easily get into threads.
    The one issue (when applying them to the turning wheel) is holding onto the items tightly enough to prevent them being thrown across the shed.
    The faster the wheel spins the quick it moreover the loose soot but it's also more likely to grab the item.

    I admit I spent more than a few minutes on the floor looking for such items until I worked out a way of minimising this.
    A screw or bolt can be held firstly at one end and slowly rotated in the opposite direction to the wheel and then the other end of the screw/bolt can be held.
    If there are just a few items involved then a cordless drill can be used to hold them but its faster to just hold them by hand as the fine wires don't hurt if they make intermittent contact with skin.


    Bolthold.jpgBolt2.jpg

    Washers can be held on a steel rod and poked into the wheel like this.
    Washers2.jpg

    I worked out that about 2000 rpm is about the fastest to be easily able to hold onto small items and given the wheel only has a wooden hub that is probably enough anyway.

    The wheel quickly and easily removes the black oxide soot but doesn't remove the hard black oxide coating. Of course wheel can't get into deep recesses or holes she some manual carding is still needed but overall it has speeded up the process considerably. Trouble is this then drives then taking on more and fiddler items.

  7. #97
    Join Date
    Nov 2008
    Location
    Perth WA
    Age
    71
    Posts
    6,458

    Default

    Bob,

    I've only used steel wool for soot removal. How would a brass bristled brush go like one you get in a pack of three brushes, steel, brass and nylon, from the likes of Bunnings?

    Bob.

  8. #98
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,182

    Default

    Quote Originally Posted by Anorak Bob View Post
    Bob,

    I've only used steel wool for soot removal. How would a brass bristled brush go like one you get in a pack of three brushes, steel, brass and nylon, from the likes of Bunnings?

    Bob.
    The pundits don't recommend brass as it may rub off onto the steel and "may" affect the uptake of the black oxide - probably one for the purists.

    The SS brushes from those 3 packs are what I was using - the best type I've used are the Kingcromes that looks like this.

    Screen Shot 2020-11-24 at 9.57.37 am.png
    The "tuft" of wire poking out the top comes in very handy for getting into places the straight brush side can't get into. However it does get pretty ragged fairly quickly.

    These brushes are really useful for things like screw threads and knurled surfaces but unless carefully handled all of these wire brushes can scratch the black oxide surface so I tend not to use these on flat surfaces during the final couple of passes, and just use steel wool.

    The carding wheel wire uses wires that are much softer than any wire brushes i've tried and it appears it is not possible to scratch the black oxide surface while using it.

  9. #99
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,182

    Default

    A few things that went through the bluing process this week.
    These have only had 4 passes through the fuming tank.
    Though the black is not as "deep" as for 7-8 passes it seems to be enough to prevent corrosion so it will do for these.

    Tp - Tool post support for a WW lathe that enables it to be used along with rod (R) as a lightweight metal spinning tool..
    TN are custom T-nuts for a mates large Table saw
    S - more nuts and screws from the Radial arm saw table I'm doing up with a mate
    IDec2020S.jpg

    Close up of tool post

    The moveable stub/rod is zinc plated but only a very small amount of Zn appears to have been removed by exposure in the fuming tank.
    This enables the exposed/cut ends of the rod to be blued with without losing the Zn.
    Dec2020.jpg

  10. #100
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,182

    Default

    Somewhere amongst my bluing posts I referred to how difficult it was for a DIyer to buy concentrated nitric acid for use in the bluing process which is understandable as concentrated nitric acid will oxidise pretty much anything flammable and eventually set fire to them.

    Well, I just managed to buy 500 mL of Analytical grade concentrated nitric acid direct from a supplier.

    https://www.anpros.com.au/laboratory...-70-a-r-grade/

    You can see the details/price and conditions for purchase on their web pages but you have to order it by phone or email.

    It's not cheap - 500ml cost $80, the acid costs $48 the rest is packaging and postages. Part of the cost is that being Analytical Grade reagent it is relatively pure acid but they didn't seem to have any other.
    This much should last me for the rest of my bluing days.

    It arrived yesterday but the packing was nothing special, glass bottle packed in a double wrapped plastic bag which was inside a strong (double layered) cardboard box filled with packing foam pieces.
    The box was marked fragile but not "oxidant" which surprised me.

Page 7 of 7 FirstFirst ... 234567

Similar Threads

  1. My second attempt at steel bluing
    By BobL in forum METALWORK GENERAL
    Replies: 20
    Last Post: 4th Dec 2018, 02:25 PM
  2. Blacking As An Alternative to Bluing
    By Anorak Bob in forum METALWORK GENERAL
    Replies: 7
    Last Post: 6th Jan 2014, 08:32 AM
  3. Bluing a tapered shaft
    By jack620 in forum METALWORK GENERAL
    Replies: 20
    Last Post: 9th Apr 2013, 07:02 PM
  4. Bluing
    By bollie7 in forum METALWORK GENERAL
    Replies: 1
    Last Post: 28th Apr 2009, 10:37 PM
  5. Metal bluing solution
    By ohno in forum METALWORK GENERAL
    Replies: 28
    Last Post: 16th Dec 2006, 08:00 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •