what kind of finish ?

[and7barton]

My new barrel is made of EN1a steel. When I take delivery of it, after the engineers have completed their work, I have to decide what kind of finish to apply to it. It will rust pretty quickly if I don't do anything to it........ I suppose it's a choice of painting it black, or having it coated with something else.
I like the idea of having it in its original natural bright steel appearance. I suppose it could be clear lacquered, or coated in some other clear coating, or I could rub it every day with an oily rag !
Any suggestions ? - Is it feasible to keep it oiled ? - or is there a better solution ?
 

[GGaskill]

I have found Break Free to be able to maintain a steel surface rust free for at least a year if it is not disturbed.  Obviously, handling will tend to wipe of the coating and deposit corrosive salts and oils. 

I suppose you could have it nickel plated to have a more corrosion resistant surface.

[dominick]

Top Fuel and Funny Car drag racers seldom paint their chassis and do not have any rust problems [paint weighs too much].  If I remember correctly, I think some of them wipe the tubing with a WD-40 soaked rag. Others use something else that I'm not sure of.  I will ask a fellow chassis builder tomorrow.

[Artilleryman]

What is the barrel style?  If it is patterned after an iron barrel you may want to paint it black.  Be prepared to repaint the muzzle as the paint tend to wear away there.  If it is patterned after a bronze barrel you might want to look into having it plated.

If you leave it bright of course keep it oiled, and from time to time you may have to polish it on a buffer.

[Victor3]

 You might want to blue it. If you leave it bright and oil it, it will still get a bit of visible rust here and there unless you baby it regularly and keep hands off of it. Blueing won't prevent rust, but it does at least camoflage it. In my opinion, even a bad cold blue job looks a hell of a lot better over time than an in-the-white surface left to 'patina.' Varnished steel always yellows in time. I think it looks cheesy, but to each his own.

 Another easy option if you don't want to paint or blue is Parkerize. I do it in my garage.  It looks nice with little maintenance required.

[KABAR2]

Yes depending on the size you may want to blue it or Parkerize it and then paint.

[Double D]

How big a gun is this? 

[and7barton]

How big a gun is this? 

Barrel overall length around 16 inches. Outside diameter at the breech end 5.5 inches, just forward of the vent it starts to taper and at the muzzle end it's 4.5 inches. Bore is GB. Bore length 8.5 inches, no powder chamber. This barrel will have a cascable and ball, turned from a seperate piece of steel 5.5 inches diameter, and turned down in steps. Behind the face of the boring is 4.5 inches of solid steel. The cascable piece will be welded onto the rear face of the barrel (a bevel will be turned around the edge of both faces and filed with weld). I'm not sure what's happening with the trunnions yet; I'm still pondering this part of the build.

[dan610324]

just an sugestion on the trunnions .
use an end mill that you got pockets with an absolutely flat bottom ,
then shrink fit the trunnions into its place and tig weld around the trunnion .
I dont believe there is any other method to secure the trunnions that even come close to this in strength .
ok , maybe to produce barrel and trunnions in one piece 
but thats a bit more difficult .

[Double D]

Pretty big piece of steel for most blueing tanks.  If you could warm it up you could cold blue it.  I really think paint is your best option for a barrel this large.

[Victor3]

Pretty big piece of steel for most blueing tanks.  If you could warm it up you could cold blue it.  I really think paint is your best option for a barrel this large.

 16" x 5.5" diameter is big? I've never encountered a gun shop that does blueing without a tank it could easily fit into. Most any commercial plating shop could do black oxide (same as blueing) on it easily.

 Regardless, painting is the easiest. There are some tough epoxy paints available. It's good to blast it before applying paint so it has a rough surface to adhere to...

[Victor3]

 and7barton, you might find this interesting...

http://www.ukwelder.com/forum/index.php?showtopic=6366

"The problems you encountered when welding En1 or more likely En1a may be due to the fact that it is a low carbon free cutting steel, lead is added to make it more readily machineable. It is often mistaken for 'bright' mild steel but is a royal pain in the ar$e to weld as it undercuts badly and the lead causes weld contamination."

 Note that I believe the poster here may be confusing EN1A with EN1AL (leaded) steel. A near equivalent (as far as I can tell) is 12L14, which is not in my experience easily welded with good results.

 In any event, if you're going to depend mainly on weld to secure your trunnions, it would be a good idea to make sure that the material and welding process used will provide adequate strength. Not really a big safety issue with trunnions, but you wouldn't want them to snap off 

[Double D]

 16" x 5.5" diameter is big? I've never encountered a gun shop that does blueing without a tank it could easily fit into. Most any commercial plating shop could do black oxide (same as blueing) on it easily.

 

Commercial plating shop with black oxide tanks might indeed have a tank big enough.  But most gunsmiths are going have the standard 6" x 6" x 40" tank.  That's what I have.  If I were to put a chunk of steel that big in my tank the displacement would put bluing salts on the floor.

[and7barton]

and7barton, you might find this interesting...

http://www.ukwelder.com/forum/index.php?showtopic=6366

"The problems you encountered when welding En1 or more likely En1a may be due to the fact that it is a low carbon free cutting steel, lead is added to make it more readily machineable. It is often mistaken for 'bright' mild steel but is a royal pain in the ar$e to weld as it undercuts badly and the lead causes weld contamination."

 Note that I believe the poster here may be confusing EN1A with EN1AL (leaded) steel. A near equivalent (as far as I can tell) is 12L14, which is not in my experience easily welded with good results.

 In any event, if you're going to depend mainly on weld to secure your trunnions, it would be a good idea to make sure that the material and welding process used will provide adequate strength. Not really a big safety issue with trunnions, but you wouldn't want them to snap off 

I am considering finding a piece of thick tube that will slide over my barrel tube snugly, then cutting out a piece of it that's almost half of the circumference, and shaping into an oval, then drilling out two holes opposite one another, chamfering the edges of the holes, both inside and outside, sliding the trunnion bar right through both holes, then welding, inside and out. Then cutting off the centre section of the bar and grinding smooth.
I'd then slide the entire assembly onto the barrel, position it and weld all the way around the oval.
The trunnions would be slightly below the centre-line of the barrel.
Not sure I've made myself clear without a diagram !

[KABAR2]

The important thing is if blued to pre-heat the tube before putting it into the bath, if it is put in cold
it will lower the temp. of the tank and give you a poor finish, ask Tracy & Mike from Seacoast
about their experience with bluing barrels with this type of mass. 

[Double D]

The important thing is if blued to pre-heat the tube before putting it into the bath, if it is put in cold
it will lower the temp. of the tank and give you a poor finish, ask Tracy & Mike from Seacoast
about their experience with bluing barrels with this type of mass. 

That's why it's best to have a heated degreasing bath.

[and7barton]

I understand there's something called "Clear-coat", or "Clear-color"....... apparently it's a coating used by the British military on gun barrels.... something like either a blueing, or a powder-coating technology, but it's colorless and transparent, allowing the original colour of the metal to show, but preserves it against corrosion.
Does anyone know about this ?
The technology is also apparently available to the non-military engineering world.

[Cannoneer]

I understand there's something called "Clear-coat", or "Clear-color"....... apparently it's a coating used by the British military on gun barrels.... something like either a blueing, or a powder-coating technology, but it's colorless and transparent, allowing the original colour of the metal to show, but preserves it against corrosion.
Does anyone know about this ?
The technology is also apparently available to the non-military engineering world.

   This product is an epoxy mixture and you'll need an airbrush or spray paint gun.

http://www.houtsenterprises.net/dur_supplies.html

[Victor3]

 You guys still painting your military guns? And here I thought I'd be done with stripping your stuff past the last Ishapore SMLE to come off the line  

 I've had good results with this, but I've never tried the clear version...

http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=1117

[and7barton]

Thanks for the advice - I don't know those products, but there might be an equivalent in the UK. I hope to be taking delivery of the barrel in the next week or so; I'll get some pictures on here !
Unlike my previous builds, the design of this one is deliberately NOT derived from any other barrel that I've seen, therefore it might offend those purists amongst us ! - But it doesn't pretend to look like an old barrel and isn't a "replica" as such. I hope the result is an impressive piece; I'm getting excited about seeing the finished product, but not so excited about trying to lift it off the floor.

[dan610324]

why lift it ??
when you have wheels on the carriage   

[and7barton]

why lift it ??
when you have wheels on the carriage   

I've got to lift it up to put it in my car and bring it home !

[MikeR C]

You might consider looking here regarding leaving it in the white and just protecting it from rust, however, whether or not the same products are available in the UK I don't know.

http://www.gboreloaded.com/forums/index.php/topic,122805.0.html

I have disolved beeswax and parafine (synthetic white wax not kerosene ) in lighter fluid (naptha) and used it on table saw tables and parts of my lathe and mills. It leaves a "dry" finish and seems to last a while, is easy to reapply, and the new coat disolves the old coat so it doesn't build up.

Thx
MikeR C

[and7barton]

Just got this message from a fellow artillerist in the UK about "clear-color" -
Quote - "
What they do is clean it an then use a chemical process, they can use zinc and clear, which is what you see on new car brake servos, they can do it in almost any colour, the black looks nice, it can even be done as a clear,which leaves the surface shiny, its not a paint its a chemical process, zinc and clear or passivate is what they use on nuts and bolts etc, makes them look nice and protects them, one of the treatments they do is japanning, a black chemical etch, I had a small barrell done in zinc and clear looks like new matt chrome, and its hard as hell."
Does this sound like any of the processes you have in the states ?
 

[Victor3]

Just got this message from a fellow artillerist in the UK about "clear-color" -
Quote - "
What they do is clean it an then use a chemical process, they can use zinc and clear, which is what you see on new car brake servos, they can do it in almost any colour, the black looks nice, it can even be done as a clear,which leaves the surface shiny, its not a paint its a chemical process, zinc and clear or passivate is what they use on nuts and bolts etc, makes them look nice and protects them, one of the treatments they do is japanning, a black chemical etch, I had a small barrell done in zinc and clear looks like new matt chrome, and its hard as hell."
Does this sound like any of the processes you have in the states ?
 

 Hmmm...

 You can zinc plate, but I've never seen it in any color other than bright or black (Bright turns dull quickly, black takes on a greenish color if not clear-coated). Not possible to do clear AFAIK.

 Passivation is a process used to remove free iron from a stainless steel surface that leaves a 'passive layer' of chromium oxide to resist corrosion. No good for your barrel material.

 Japanning is a shiney black lacquer coating. I've also seen the term used to describe the flat black (almost a 'crinkle' finish) used for coating some older optical assembly parts. Never heard it described as a "chemical etch."

 Zinc "hard as hell?" Might look like matt chrome, but it isn't any harder than zinc.

 Might be some differing terms between US/UK (?)

[and7barton]

Well, I'll worry about the finish once I've had the thing completed - My "Artillereur" friend tells me that "Clear-color" is cheap to have done.....cheaper than powder-coating.

[dominick]

Top Fuel and Funny Car drag racers seldom paint their chassis and do not have any rust problems [paint weighs too much].  If I remember correctly, I think some of them wipe the tubing with a WD-40 soaked rag. Others use something else that I'm not sure of.  I will ask a fellow chassis builder tomorrow.

I spoke with my friend and he said in the past the fuel racers used a phosphate based dry lubricant to coat the chassis.  He thinks the brand name of the lube is Black Magic.  He said most of them have since switched to WD-40 which works just as well.  Dom

[and7barton]

Top Fuel and Funny Car drag racers seldom paint their chassis and do not have any rust problems [paint weighs too much].  If I remember correctly, I think some of them wipe the tubing with a WD-40 soaked rag. Others use something else that I'm not sure of.  I will ask a fellow chassis builder tomorrow.

I spoke with my friend and he said in the past the fuel racers used a phosphate based dry lubricant to coat the chassis.  He thinks the brand name of the lube is Black Magic.  He said most of them have since switched to WD-40 which works just as well.  Dom

My brother, who is also an old ordnancieur, says that he recommends oiling the surface, far more than any kind of coating. I must say that a dull steel sheen, which shows up the fine pattern of turning does appeal to me.
However, the cylindrical part of the barrel, before it tapers, is the original dirty blackish colour of the billet. I'd like to somehow get that as bright as the turned part. I'm figuring that if I make a set of rollers on a base to support the barrel, I can spin it around and run the surface with fine wet and dry paper, and get it looking the same.
 

[GGaskill]

... is the original dirty blackish colour of the billet.

If that means the original black mill scale found on new hot rolled steel, I think you would be best served be turning it off rather than trying to remove it with abrasive paper/cloth.  The scale is quite hard and will come off in flakes.

I would weld the cascable on, center drill it so you can hold it in a rotating tailstock center, and use the lathe to turn off the scale.  Then weld up the center drill hole and finish the cascable.

[and7barton]

... is the original dirty blackish colour of the billet.

If that means the original black mill scale found on new hot rolled steel, I think you would be best served be turning it off rather than trying to remove it with abrasive paper/cloth.  The scale is quite hard and will come off in flakes.

I would weld the cascable on, center drill it so you can hold it in a rotating tailstock center, and use the lathe to turn off the scale.  Then weld up the center drill hole and finish the cascable.

Thanks for that advice. Trouble is, the muzzle end is tapered and I can't grip it in the chuck securely without marking it.