Needs Pictures: 0
Results 16 to 30 of 100
Thread: More metal bluing
-
29th Jul 2015, 06:40 PM #16Member: Blue and white apron brigade
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 7,182
Great.
How about this for isopropyl alcohol? - http://shop.coles.com.au/online/nati...ubbing-alcohol
What you need is 100% IPA like this http://www.isocol.com.au/products/isopropyl-alcohol also available in a Diggers brand at bunny
-
29th Jul 2015, 06:49 PM #17Member: Blue and white apron brigade
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 7,182
Yeah the first couple of things I tried were quite patchy. Then I started using gloves and double rinsing and things improved. I should have know better as I worked for many years in an ultra clean laboratory where we went to extremes to minimise contamination.
When I actually blow with compressed air it is usually when I'm doing a rifle barrel and I do it mainly to clear water from the rifle bore as that is my biggest concern with rust and I dont want that rusting at all. A lot of people plug the ends of the barrel with wooden dowels to keep the water out, but I'm nervous to leave it locked up for the week it takes to blue. You can coat the bore with lacquer and then use lacquer thinner to clean it out at the end too. This of course relates mainly to firearms.
I do plan to set up a hot bluing set up, but this is another level of danger with boiling hot sodium hydroxide and potassium nitrate just for added fun. But the process is much quicker and easier, but the consequences a lot nastier.
I don't mind the process being slow as I have many other projects on the go and things to do in between the steps of the fuming cycles.
-
29th Jul 2015, 09:57 PM #18Most Valued Member
- Join Date
- Jul 2006
- Location
- Athelstone, SA 5076
- Posts
- 4,255
Bobl and Hornetb
Why do you your methods over the manganese phosphate ie Parkerising method
-
29th Jul 2015, 10:44 PM #19Member: Blue and white apron brigade
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 7,182
My understanding of Parkerising is that it is quicker and provides a stronger more robust coating than the oxides, but the process (especially the manganese version) is trickier.
There are many recipes with many variations and additives and getting it right is not as straight forward as it seems. Nevertheless, as evident in various firearms forums etc, there are many DIYers having a go with it - just how effective these DIT coatings are I have no idea.
My main worry with Parkerising is that it involves heating and disposing of large containers of phosphoric acid which I don't find appealing, especially the getting rid of bulk phosphoric acid afterwards makes it a bit of an environmental problem. In the bluing processes the only thing that gets heated and disposed of down the sink is distilled water with a wisp of acid fumes in it. The fuming process uses very little hydrochloric and nitric acid (20 mll of each will do many batches of parts) and there is no disposal required unless you want close up shop and never do any ever again. Bluing acids are also easily disposed of by neutralizing with caustic. The nitrate in nitric acid could be a nuisance but the amounts are so low as to not be a problem.
It's interesting to see that Parkerising processing services are now being set up in third world countries because gaining environmental approval for large scale Parkerising is getting harder to get in first world countries.
There are better Parkerizing processes than the Manganese Phosphate method now available using hydrofluoric acid (i.e. nasty stuff) and zirconium, The best recipes are patented and the methods are probably outside most DIY user . If I had access to a decent chemistry lab including a way of disposing of the acids afterwards I would give it a go.
[EDIT] I had a bit of a read of a couple of Patents for the Fluoro Zirconic Acid method and here is a typical list of ingredients
Chromic Acid Flake CrF3—4H2O CrOHSO4 35% Phosphoric Acid 75% Thickener Surfactant Fluorozirconic Acid, Liquid Caustic Potash
DIstilled water
-
30th Jul 2015, 01:52 PM #20Most Valued Member
- Join Date
- Jul 2010
- Location
- Melbourne
- Posts
- 9,088
-
30th Jul 2015, 03:34 PM #21Member: Blue and white apron brigade
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 7,182
Correct
Would there be a best before or use by date on a bottle of this once mixed?
Hi Bob,
Whats the Aluminium foil for in your vapour transfer setup?
The arrangement below is better as it concentrates the warmth on the ammonia feed.
We controlled the ammonia transfer using a light dimmer on the light globe.
No heat required a week or so to get a reasonable amount of ammonia into the water - with heat the time it took depended on how much heat was used.
We used clear teflon PFA 500 ml bottles and back then they cost about $50 each and a teflon connection.
Because the bottles were teflon we could crank the light globe up and we even used a 150W infra red lamp but this is not possible with PE or it would melt.
It is possible to purify small amounts of acid like this as well - no water is needed in the receiver
-
30th Jul 2015, 05:50 PM #22Senior Member
- Join Date
- Jun 2013
- Location
- Tasmania
- Posts
- 257
-
30th Jul 2015, 05:54 PM #23Most Valued Member
- Join Date
- Jul 2010
- Location
- Melbourne
- Posts
- 9,088
-
30th Jul 2015, 05:57 PM #24Most Valued Member
- Join Date
- Jul 2010
- Location
- Melbourne
- Posts
- 9,088
-
30th Jul 2015, 06:52 PM #25Member: Blue and white apron brigade
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 7,182
-
30th Jul 2015, 06:56 PM #26
-
31st Jul 2015, 01:13 PM #27
Thank you for the write up ... I do find this subject very interesting, although I've only ever done Parkerizing (with mixed success).
One question I have is why does the rust go black when boiled in distilled water? Is it actually changing from "rust" into something else?Cheers.
Vernon.
__________________________________________________
Bite off more than you can chew and then chew like crazy.
-
31st Jul 2015, 02:21 PM #28Member: Blue and white apron brigade
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 7,182
Rust is a mixture of red ferric oxide (Fe2O3) and water.
The boiling distilled water converts some the red oxide to the ferrous (black) oxide or FeO.
The final combination of FeO and Fe2O3 is called black rust or magnetite (Fe3O4)
Magnetite is moderately more protective against rust than plain iron and especially but it wear off and will still eventually convert to rust.
-
31st Jul 2015, 06:24 PM #29Most Valued Member
- Join Date
- Jul 2010
- Location
- Melbourne
- Posts
- 9,088
-
31st Jul 2015, 08:48 PM #30Member: Blue and white apron brigade
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 7,182
Similar Threads
-
My second attempt at steel bluing
By BobL in forum METALWORK GENERALReplies: 20Last Post: 4th Dec 2018, 02:25 PM -
Blacking As An Alternative to Bluing
By Anorak Bob in forum METALWORK GENERALReplies: 7Last Post: 6th Jan 2014, 08:32 AM -
Bluing a tapered shaft
By jack620 in forum METALWORK GENERALReplies: 20Last Post: 9th Apr 2013, 07:02 PM -
Bluing
By bollie7 in forum METALWORK GENERALReplies: 1Last Post: 28th Apr 2009, 10:37 PM -
Metal bluing solution
By ohno in forum METALWORK GENERALReplies: 28Last Post: 16th Dec 2006, 08:00 PM