Black protective oil coating

[Omnimill]

Good idea on the dishwasher tablets Norman, I would not have thought of that! They are caustic and must contain sufficants as well. Will be a safer and less smelly alternative to sulphuric acid drain cleaner or caustic soda that I normally use.

 

[macmarch]

Hi all,

For 'ordinary' steel, ie non hardened then I still have steel devices that I made when an apprentice, (50yrs ago), stillnot gone rusty. " methods were used.
1) Clean and then heat part up to 200/300 degrees then drop into USED engine oil for 24 hrs. Its the old carbon that does the trick.

2) Send the part to the platers and have it phosphated then bichromated and passivated.

HTH

 

[Swifty]

Great idea Norman, I forgot about the dishwasher tablets or powder. Even though we use tablets in our dishwasher, I keep some powder on hand to mix with hot water and clean the BBQ, certainly gets rid of grease and oil.

Of course, there are commercial business's around that do hot blackening, the only problem is the minimum charge, if you were making something large like a locomotive with side frames and running gear, it would be worthwhile considering. But with the small pieces, it's still a home job.

Paul.

 

[goldstar31]

Nice to be able to pass on a comment! It gets a bit sillier-or more sensible( choose which).
Actually, Swifty you made the ash in the BBQ is lye which is the basis of many soaps. Abrasives or many of the finer ones come from something called fly ash from power stations. So you are probably cleaning your teeth with coal ash! And paying for it!

On the subject( or not, so choose) my mad family of heart surgeons, dentists , children's doctors and the village *****( me) were having a sort of laugh over the remains of the dead turkey( as one does)

We lost a member of the family- we really did, in the past and he was blown up with collected urine.
Urine was the most important product of Tyneside. No, not coal, not ships or guns or lots of things but good old fashioned pee. Unknown to most, it makes explosives, stuff for whitening teeth, for removing stains and stuff to make nitre to do steel.

Our departed cousin, bless him, got involved with a load of urine ready for export and it exploded.

Afraid it is all quite true.

Happy New Year- if you don't try to do it at home.

 

[Swifty]

Norman, I recall reading a novel by Wilbur Smith where they collected urine to add together with other ingredients to make gunpowder. I wonder how they collected the urine in Tyneside, did all the population contribute. Maybe that's what all the pathology labs do with the urine once they are finished with their various tests.

Anyway, happy new year.

Paul.

 

[goldstar31]

We are moving away from the main topic but others do!

Recall the expression 'Piss Poor' when people were actually too poor to own a container.
There's an expression about a pot to piss in.

Recently the TV in the UK has been running a series on a Monastery Farm and there has been a wonderful set of clips on how people lived and how they made lead and how they made gunpowder fireworks. It was all very jolly about how they made 'booze' and I just wonder what really went on- behind the scenes.

However, urine was used to tan leather as well as clean stains. Again, I recall Bob Hope( ah?) singing about 'We are Morocco Bound' and recalling that Moroccan leather was tanned with collected dog poo.

On another forum there is a sort of happy romp of old farts like me talking about steel making and iron railings and whatever is remotely printable. I had a British WW1 tank in the furnace and we had a lark on how to sink battleships. I then recalled my dear old Dad tempering steel and obviously there was no such amenity as a toilet so he and the rest of the gang kept topping up the water tank beside the forge.

Another of my collection of nut cases always wanted to do Roman iron work. he wanted to know how the Centurions or whoever they were built the Roman Wall just North of here and it was built with mortar reinforced with --blood. No, sir, I never found out! Then I 'did' Herman Melville's Moby **** again and the harpoon was tempered in blood donated by the harpooners. It got quite exciting to find that in steel or iron smelting that one authority recommended the urine from a ginger headed boy.

From an engineering point of view it is worth looking up this urine thing.

Happy New Year, keep well

Norman

 

[Gedeon Spilett]

just a note about post 23 (Swifty) on dishwasher powder : the degreasing power comes from the enzymes (from bacterial origin) included in those powders in addition to detergents, lipase that digests lipids and protease for proteins. This is Biotech, not chemistry.
It is not recommanded to use the tablets with bare hands, they would dissolve your fingers at the end, but not the bones for now, I guess.
Many receipes generally suggest that there is not one really superior to the other, at least in the home workshop, you have to experiment to find the most convenient way to blacken your steel parts i'm afraid...
Cheers & happy new year

 

[Lindo]

Lots of good replies on this topic from Chemistry to bodily functions.
A local Spanish gent told me to clean the steel with white vinegar,dip in olive oil,
dip in chimney soot and bake in a fire 250 dec C,resting the parts on a shovel
to keep away from the ash.
Also he has used Black boot polish and baked.
I have sulphuric acid and will dilute to 15% Add ACID to WATER ( I remember from A&W root beer).Then try out various suggestions and see what happens.

John
Spain

 

[gus]

Chemical Blacking.
Just found this article from Model Engineer's Workshop December 2013 No.210.
Covers Chemical Blacking/Chemical Browning/Hot Oil Blacking etc.3 1/2 pages to read.
Hot Oil Blacking.
Veggie Oil gave best results.

Happy New Year .
(and happy blacking)

 

[Lindo]

Happy new year to all.
I have made some extension arms for my circular table,need in the future for
holding the wheels of the minnie traction engine I am building.
Have posted attachments of my first time blacking process using the old boys
recipe
1 dipped in diluted sulphuric acid.
2 dipped in olive oil
3 painted on warm black KIWI boot polish
4 oven baked at 240 deg C +/- a few degrees.
Seems to have done the trick.
As a previous post,here in Spain most older houses have "Rejas" grills,
these were not to keep the thieves out,mainly to keep the young girls
in,they were only allowed out with chaperones.many rejas were fashioned with scrolls and blacksmith's handy work,and used the soot from chimneys for the blacking compound.
After the treatment bolted on to the table and flycut the faces flat and parallel.
Photos also show the tee slot cutter I made,possibly will never need to use again.
I have the clamps I made to blacken,will treat with the same process

Regards
John
Spain

 

[Wizard69]

Talk about timing!

I just picked up my copy of Model Engineers Workshop and wouldn't you know it but there is an article on blackening steel! Haven't read the article yet but I'm letting you guys know to enhance the discussion.

 

[abby]

I have two Pultra lathes , these are very high quality instrument makers lathes . I have one as a standard centre lathe and the other as a capstan for production runs of small parts.
Why have I posted here ? well one of the accessories I thought would be useful is a QCTP so over the holiday I made some. I made the tool post from close grained cast iron and the tool holders from a good quality steel although not hardenable.
I always "black" my tools where possible , ok it doesn't totally prevent rust but the tools can be left on the bench for months without showing signs of rust.
The black colour is in fact black iron oxide and it is formed by heating the parts to a very dull red and dunking in oil. The oil doesn't do anything to the colour, it simply soaks into the oxide layer and helps to prolong the finish. I use old cooking oil but anything will do.
For an even coat the parts should be degreased , I simply boil for 10 minutes or so in water with some washing detergent , rinse off with hot water and allow to air dry.
Try to avoid touching the parts after cleaning , I thread them onto a piece of welding wire first.

The tools are 3/16" square which will give a scale reference.
Dan.

 

[modeng2000]

That looks a nice finish Abby.

John

 

[gus]

Hi Abby,

Will monkey see monkey do now that I bought l Mapp Gas Torch with three burners. Camping Gas Torch can't do the job.
Sick and tired of having to remove rust. Foto shows a newly mint DIY QCTP. Will post picture
of blackened QCTP.

 

[barnesrickw]

Is that acrylic scrap in the background?

 

[abby]

Gus I use a self blowing torch (25mm nozzle) hooked up to a 47 kg propane cylinder , very convenient but there is a lot to be said for a petrol or paraffin blowlamp.
You won't easily silver solder a large boiler with one , although before bottled gas that's mainly what was used.
I have a couple which I haven't used for years but will not scrap because .... well you never know !

 

[BaronJ]

Hi Abby,

Very nice finish. I'm most impressed. I hope my pieces come out looking that good when I try blacking.

 

[Walltoddj]

If you are looking to Blacken as most tools are it's very simple with no heating of the tools. I've been using a couple different ones to do gun parts as well as my tools and it has a sealer to. The first one I tried was from Eastwood at http://www.eastwood.com/metal-blackening-system-set.html this is a fairly cheap investment if you want to start. The second type was from EPI at http://www.epi.com/c/black-oxide/steel/room-temperature-black-oxide this works a little faster but cost more. Both have a sealer or coat it with oil works well.

Todd

 

[abby]

Todd I am sure most of us have come across chemical colouring kits and solutions especially for gun "blueing" , but you have to buy them , the whole point of the heating process is that it is free and anyone can do it.

 

[barnesrickw]

Intentional oxidation is always so much prettier.