Slow rust blueing

[johnj]

Hi all,

Prob a bit pointless this but when I was at school or college, once we had made a project piece from mild steel, we would clean the item up and then heat the steel up until it was red hot with a gas torch before quenching it in a bath of sump oil.

This would be done several times and each time the sump oil would coat the steel darker and darker until it was almost black.

This provided a rust resistant coating on the steel that look very nice.

Never done this on a large area like a air rifle cylinder and you would have to be very careful not to warp the cylinder or barrel but with the right knowledge I think it could be applied.

It would be a lot safer than home hot bluing providing you used the right personal safety equipment and had the correct fire extinguisher and blanket to hand.

Has anyone else very used this technique?

Just thought someone might like to know about it anyway.

Johnj.

[Mike95]

Described in the Q Cobham book as well as blacking by noxious chemicals.

The heat process seems reserved for smaller items such as pins and bolts.
The blackening salts are described as 15-20% sodium nitrate and 75-80% sodium hydroxide. Ikg salts mixed with 1 litre of water, heated to 140C, immerse parts for 15mins. Quite detailed instructions given. Full radiation suit needed!

Mike95

[spartan]

mike

that formular would probably work, you just need lots to practice to get everything right, and believe me i know, i still make mistakes and i have been refinishing guns for over 20 years. be carefull when useing molten salts at 140 degrees, it will take your skin off in seconds ive got the scars to prove it

[Morningstar]

I would just like to thank everyone who have and are contributing to this thread.

I have tried the caustic soda and potassium nitrate method and it works very well on small items ( triggers , screws etc.) , the problem with larger pieces seems to be a matter of heat,
When you put a cylinder or barrel of a rifle in the solution its to cold to start with and quickly forms a layer of reddish brown which does not allow the rest of the chemical to penetrate properly.
I have some more potassium coming soon and I intend heating the larger items up to the required heat before immersing them in the solution. Will let you know the results in a couple of weeks hopefully.
ATB Graham

[T 20]

I would just like to thank everyone who have and are contributing to this thread.

I have tried the caustic soda and potassium nitrate method and it works very well on small items ( triggers , screws etc.) , the problem with larger pieces seems to be a matter of heat,
When you put a cylinder or barrel of a rifle in the solution its to cold to start with and quickly forms a layer of reddish brown which does not allow the rest of the chemical to penetrate properly.
I have some more potassium coming soon and I intend heating the larger items up to the required heat before immersing them in the solution. Will let you know the results in a couple of weeks hopefully.
ATB Graham

Hi Graham
What volume of salts are you using?
I was working on the idea of using 5 gallons of salts in a 10 gallon tank so that the work didn't lower the temp when immersed.
A ten gallon tank would also allow me to have more than one gun in the salts if I staggered their entry.

All the best Mick

[Morningstar]

Hi Mick
Use protective goggles and gloves, It burns holes in leather shoes( I found that out)

I used the ratio of 25% nitrate to 75% sodium Hydroxide or 20% - 80%

Mix Ratio- 1kg of salts mixture to 1litre of water =ca. 1.25kg solution

Put the salt in suitable shaped iron or steel container, Other container materials will be attacked.

Add water and stir. At this point the solution will heat it self but will need additional heat is needed.

Heat the solution slowly until all the salts have dissolved and a working temperature of 135-145 degrees C has been reached (as the parts are added the solution will cool and need more heat) I used a Jam making thermometer) Cheap enough.

if the solution needs topping up , carefully add hot/boiling water and avoid the strong spitting.

Polish the parts and remove pitting- remove any grease or oil from parts

Dip the parts in boiling solution for about 15 minutes us tongs to turn parts over so all surfaces are treated.

After 15 minutes lift parts from solution and dip them in a bucket of cold water or hose them off. Becareful of steam and spitting boiling water.

Make sure all solution removed. dry parts with clean rag and immediatley apply coating of oil and rub this into blackened surfaces .

How you get rid of the solution? this stuff sets hard as it reforms into a wet crystaline mess, Its good for cleaning drains out though but i would not recommend it go down any streams. I would wait for it to cool down and rinse the stuff down a drain with copious amounts of running water.

.
Hope this helps? any questions just ask
ATB Graham

[paw8826]

Hi guys! theres a company called 'sporting antiques of ashbourne' who are based in ashbourne , derbyshire. Ive just had a quote from them for slow bluing my 30'' barrels 12bore. nearly dropped through the floor! only £35 + £10 for p&p 4to6 wks process. is it worth the hassle o diy??:

[uk litehammer]

If you scroll down this page, you will find Klever Quick Browning solution. This is reputed to be really good stuff. Demoed somewhere on youtube.

http://www.ballistoluk.co.uk/acatalo..._Products.html

[mickikirk@talkt]

Hi all SPIT and POLISH with cherry blossom brown boot polish (the way a soldier cleans his boots ) works and looks well on damascus barrels etc ,needs a few coats , gives a lovely old patination effect but its only for display indoors for a collector of old guns. rgds Mick

[Oldandshaky]

Hi, just noticed this thread, here's a link to a very interesting site with all you need to know about hot Bluing and also Parkerising just click on the refinishing tab. Lots of other good stuff on the site too..

http://www.blindhogg.com/

Dave...