Help with cold steel blackening

[choochoo_balooParticipant @choochoo_baloo]

I took off the battered saddle wiper guard from my ML7, sanded back to almost shiny bare steel, and then applied the 4 stage blackening kit (degreaser, conditioner, ferrous blackener, dewatering) sold by Blackgates.

I followed the instructions closely, and was initially happy with the newly blackened article (although in places it did have a very subtle brown-ish shade 'underneath' the black. Didn't think any more of it.)

Now a few weeks later it has developed into some weird wipeable brown surface sludge. As you can see, the inner surface is a lot better, which leads me to deduce that it is an atmospheric reaction, since the inner face is effectively fully coated by the Nutto soaked felt wiper?

Please can someone advise as to what has happened?!

[choochoo_balooParticipant @choochoo_baloo]

[DMRParticipant @dmr]

Posted by choochoo_baloo on 18/08/2017 01:05:50:

almost shiny bare steel,

It has to be absolute bare steel. Did you leave the original Myford black where it still existed? Did you get any rust off? Iv'e never used Blackgates, but did you thin the blacking too much if it specified it? Even your inside surface looks patchy so I have to suspect your cleaning. Never handle it directly at all during or after cleaning it up; use two bits of wire in opposite holes and dunk it with them. The blacking needs to be in one go, over the whole surface, and there is no harm in leaving it in the oil at the end for longer. Hope that gives some clues.

Dennis

Edited By DMR on 18/08/2017 02:17:32

[RobboParticipant @robbo]

I have found when using these blackening kits that the metal to be coated needs to be absolutely bright and shiny clean, preferably with no scratches.

Also temperature is important; at least 20 degrees C.

[MikeParticipant @mike89748]

I agree with DMR and Robbo. I've never used the Blackgates product, but I have used most of the brands sold by gun shops. The surface must be as shiny as possible, and absolutely clean – even a small fingerprint can ruin the result. And, as DMR says, give the item a really long soak in oil – if you don't, rust will start very quickly.

[Mick B1Participant @mickb1]

The gunshop brand I've found best is called (IIRC) G96, and it's a paste, not a fluid.

I made a naval cannon model in 2002 and blued it with this. It's needed only occasional oiling and touchup since.

Wash it in hot fairy liquid suds first, don't touch it with bare fingers when you take it out, and apply the paste while the metal's still hot – a stiff artist's brush is good. When it's taken properly, wash again, dry thoroughly and oil up. 3-in-1 is good, but so is olive oil – I've also had good results on an Opinel knife for camping.

Edited By Mick Burmeister 1 on 18/08/2017 09:47:37

Edited By Mick Burmeister 1 on 18/08/2017 09:48:22

Edited By Mick Burmeister 1 on 18/08/2017 09:56:42

[HillclimberParticipant @hillclimber]

Was the G96, this stuff?

http://www.g96.com/products/gun-blue-creme/

[Nick HulmeParticipant @nickhulme30114]

+1 on the G96 creme, but keep in mind that no cold blue creates the same surface coating as a hot tank immersion process and the corrosion protection when oiled is never as good as the caustic or molten salts system.

– Nick

[HillclimberParticipant @hillclimber]

Has 'elf n safety not hit all that good stuff on the head?

Does anyone still offer a small-scale commercial service accessible to the amateur? I will soon have a bunch of tee-bolts I'd like to treat…

Cheers, Colin

[Mick B1Participant @mickb1]

Posted by Hillclimber on 18/08/2017 12:16:01:

Was the G96, this stuff?

http://www.g96.com/products/gun-blue-creme/

Yes, that's the stuff – unless the elfs have enfeebled or removed all the effective ingredients, that is! 😀

[SillyOldDufferModerator @sillyoldduffer]

Posted by Mick Burmeister 1 on 18/08/2017 09:44:09:

…

Nice cannon MIck. Is it a model of a particular gun? Also, how did you do the flare on the muzzle and the reinforcing rings?

Ta,

Dave

Edited By SillyOldDuffer on 18/08/2017 16:28:04

[Glyn DaviesParticipant @glyndavies49417]

If the item has a fine rust coating, you can put it into boiling water for a few minutes, which will turn the rust black, then rub off the rust with 0000 wire wool and you will get a finish similar to the original black.

[Mick B1Participant @mickb1]

Posted by SillyOldDuffer on 18/08/2017 16:27:43:Posted by Mick Burmeister 1 on 18/08/2017 09:44:09:

…

Nice cannon MIck. Is it a model of a particular gun? Also, how did you do the flare on the muzzle and the reinforcing rings?

Ta,

Dave

Edited By SillyOldDuffer on 18/08/2017 16:28:04

Thanks, Dave. It's a late 18thC 24-pounder, which I think first-raters like Victory carried on the middle gun deck. It was made from a set of drawings by a US engineer, Jerry Howell who used to sell copies for what seemed a reasonable sum at the time. It was supposed to be based on one on USS Constitution, and I anglicised it by changing the cascabel button and a couple of other details I can't remember.

I wish I could think of a neat and simple way to add the rope ring above the cascabel. I made little form tools to shape the reinforcing rings, and did the muzzle swell with 'fingernail' form tools, followed by lotsa work with a half-round file and then lots more with wet-and-dry emery!

[SillyOldDufferModerator @sillyoldduffer]

Thanks Mick,

As a boy I lived in Malta for a couple of years and the place had many old cannon and Victorian bottle guns lying about. I've always wanted to model one but never have. When you look into there are quite a few design features that seem to call for special treatment with form tools etc.. And now you've confirmed my suspicions!

Can't help with the rope ring on the cascabel except to suggest relabelling the display. My memory is awful but I think cascable rope rings are a late 18th century British innovation. So you could claim it's an authentic representation of an earlier gun. And if it's not true you can blame me!

Cheers,

Dave

Edited By SillyOldDuffer on 18/08/2017 18:44:46

[Brian GParticipant @briang]

Looks like the absence of a rope loop is to be expected on cannon made before the introduction of the Blomfield pattern in 1794. **LINK**

Given that ships of the line could spent years laid up in ordinary, I suspect that the earlier Armstrong pattern (typically confusing that two different Armstrongs a century apart gave their names to guns) would have remained in service throughout the Napoleonic wars.

Brian

[Ian S CParticipant @iansc]

For blueing small items I just use heat, I'v not tried cold blacking. This tool holder is quite a good example, and seems quite durable.

Ian S C

Edited By Ian S C on 20/08/2017 10:45:55

[Douglas JohnstonParticipant @douglasjohnston98463]

I too like the heating and quenching in oil method for small items and have tried a few different oils with reasonable results. I tend now to use cheap supermarket rapeseed oil which usually works fine but have often wondered if there is a better oil out there. I seem to remember people advocating used car engine oil but the health and safety people said that was a no no as there were lots of nasty things in that. Has anybody found a safe oil that is better than rapeseed oil?

Doug

[Gordon WParticipant @gordonw]

Don't do this job often, have used heat and quench in oil ,seams to work well. I use old engine oil, pref . diesel . It's very black , I always do it when no-body is watching.

[EmgeeParticipant @emgee]

I use whale oil to quench silver steel in after heating to carrot red and holding for a minute or so, threading tools shown were so treated.

Emgee

[duncan webster 1Participant @duncanwebster1]

Whale oil!!!!!! You'll be giving even me coniptions. Killing whales is outlawed by almost all countries, so where are you getting it from. According to t'interweb the trade in whale products is banned

[Douglas JohnstonParticipant @douglasjohnston98463]

I think whale oil is an even bigger no no than old engine oil ,but there may be a synthetic equivalent out there. Whether it is any good at blackening is another matter.

Doug

Edited By Douglas Johnston on 21/08/2017 08:45:55

[Anthony KnightsParticipant @anthonyknights16741]

Used vegetable oil from the deep fat fryer works for me (and it costs nowt)

[EmgeeParticipant @emgee]

Hi Duncan

Bought a used kiln for hardening metals about 30 years ago, the 1/2 gallon of whale oil was included.

Douglas, is there a safety issue with quenching in whale oil ?

Emgee

[Jon GibbsParticipant @jongibbs59756]

Heat and oil works but probably more faff.

I recently tried Casey Super Blue from these folks… **LINK**

Usual caveats – just a satisfied customer.

Scrupulously clean and degreased (hot water and washing up liquid), and wearing disposable gloves, followed by a couple of wipes over from the bottle – no real need to dip it IMHO. Followed by rinse in hot water and then dried and oiled.

Not the greatest photo but the knurl and dial indicator holder here were done this way.

HTH

Jon

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