Cylinder blueing (bluing)

For me the key info was that the colour won't affect cooling. It was also good to find out that high temperature enamel would peel off, so that I did not go out and buy a whole spray can for just that, and that it would not last. I like the balloon idea very much.

Restorations are admirable but I am lazy and a bit afraid i might botch it. So long as the engine will run happily, that is good enough for me. I think that I can keep the cylinder corrosion-free by paying attention, so will not be trying to restore the blueing. Hope I don't seem ungrateful. Please let me know if there is something wrong with this.

If the model became lost in the woods, blueing might keep the engine safe from corrosion longer. I don't know how it became corroded in the first place, but evidently the conditions were worse than even the factory blueing, which is better than anything I could do at home, could resist.

Hey Doug I would still encourage you do it. It only takes a small bottle if gunblue, some nail polish remover (acetone) to degrease the surface and 1 or 2 ear cleaning buds to apply the fluid. The results pay back the effort, believe me.

The gun bluing Walmart sells works fine, use a Q-tip or soft toothbrush and rub it in.

While I respect Doug's decision not to blue his cylinder, I don't agree with it.  Besides the aesthetic value, bluing protects against future deterioration.

For everyone else, Birchwood Casey will work, but the best gun blue by far is Brownell's Oxpho blue.  Cost's a bit more but the results are well worth it.  I used to buy it by the quart.  But it is available in smaller sizes.

Don't worry about getting it inside the cylinder.  I just dump cylinders on a string into the solution (I keep a small bottle for that) for 30/40 seconds remove it, rinse with cold water and burnish with a cloth or soft tooth brush with Remoil which neutralizes the blue.  Some advocate baking soda, but I find that an unnecessary step.  When your through use a .45 caliber brass brush through the cylinder to remove the blue which in my humble opinion isn't going to hurt a cylinder requiring a reblue anyway.  

I have done about 10 Cox cylinders this way with no ill effects. Many firearms too along with car parts.

By the way any member has experience with Cox International cylinder brush?

https://coxengines.ca/cylinder-devarnishing-brush-for-cox-.049-.051-engines.html

I sure have Levent. If used with caution, it is very useful. I did not have to use it too many times though. I do not mind if my piston is a very lil bit tight in the cylinder due to some varnish that helps retain compression.

Always screw it in and out only once at a time of devarnishing. Never push/pull it coaxial with the cylinder because that may kill compression.

Andras, how do you decide where to stop devarnishing? A little colorization left inside of cylinder?

After the removal of the brush from a screw in screw out cycle, I drench a Q-tip or ear bud in nail polish remover acetone and scrub the cylinder wall to remove the loose varnish. It normally suffices, and the piston will move easier in the cylinder. Your eventual sign that devarnishing was sufficient is the lighter friction of piston than before. But again, I like a very little tight fit there because that also means good sealing.

I am contemplating to also try kitchen cold grease remover fluid used for cleaning ovens etc., by spraying it into the cylinder and rinsing it after some resident time. In principle that should also work without scratching the cylinder.

balogh wrote:After the removal of the brush from a screw in screw out cycle, I drench a Q-tip or ear bud in nail polish remover acetone and scrub the cylinder wall to remove the loose varnish. It normally suffices, and the piston will move easier in the cylinder. Your eventual sign that devarnishing was sufficient is the lighter friction of piston than before. But again, I like a very little tight fit there because that also means good sealing.

I am contemplating to also try kitchen cold grease remover fluid used for cleaning ovens etc., by spraying it into the cylinder and rinsing it after some resident time. In principle that should also work without scratching the cylinder.

Hi Balogh. My only concern about using an oven cleaner is its effect on the cylinder bluing.
I guess we've gone full circle in a short time.

Bob! I just ordered the Brownell's and a brush. I've been mulling doing this for a while.
Bob

I've had pretty good luck with the Birchwood Casey kit on a TD Special .15 Mk II cylinder. Definately increased its value. Link to the before and after pics are part way down the thread.

https://www.coxengineforum.com/t9266-cox-td-haul

Question for those that have been rebluing cylinders. Unless I have missed something. What do you use, or are you using to remove the bluing before rebluing, or are you just going over top of what is there? I mean if there is rust / surface rust, what are you using to remove it? I know in the past, I have used plain white vinegar to remove rust with very good success, just that on some things, it turns black. When you do use something to remove the rust / bluing, do you also plug or 'fill' the cylinder with something to stop it from any sort of coating inside? I have a cylinder here that I may try this on. Thanks.

I chuck the cylinder in my lathe and use fine sandpaper to remove rust and fine scratches prior to bluing. Must be ultra clean prior to bluing.

I blued several parts, such as needle valve body, screws. I used Zippo lighter fluid or ethyl alcohol to clean. Filled a plastic cup with Zippo lighter fluid and immersed part in it. I also wear gloves to avoid finger marks.

I just use gun blue and immerse the whole cylinder. I've never worried about the effect on the cylinder bore nor have I noticed any problems in running cylinders done in this way.

I think the nitric acid or similar in the gun blue creates a chemically modified layer on the cylinder wall. This wears off sooner or later. Whether this material loss matters for compression I am not sure. AFAIAC I try to keep the cylinder interior intact, anyway..

Chancey , the white vinegar is what i have used and a brass bristle brush , fine sandpaper on edge works for fins . Personal i don't plug the ends ( what's another coat in the cly. going to hurt ?) You may bee leaving the cly. in too long if it's turning black? I had this happen and think that is what happened . DougW i would suggest doing it you will bee proud of the results !

NEW222 wrote:Question for those that have been rebluing cylinders. Unless I have missed something. What do you use, or are you using to remove the bluing before rebluing, or are you just going over top of what is there? I mean if there is rust / surface rust, what are you using to remove it? I know in the past, I have used plain white vinegar to remove rust with very good success, just that on some things, it turns black. When you do use something to remove the rust / bluing, do you also plug or 'fill' the cylinder with something to stop it from any sort of coating inside? I have a cylinder here that I may try this on. Thanks.

Forgot to address that.

Vinegar works over time, but if you want to remove all the blue and quickly use muriatic acid as used in swimming pools.  I had 3 foot sections of PVC pipe in 2 and 4 inch width's capped on one end to do my rifle barrels.  I plugged each barrel end with tapered dowels first.  Removes all the blue right now.

If you do immerse the cylinder in bluing, slosh it around a bit or bubbles will form in the fins.

Edit add:

This guy is the king of the juiced up anodized Cox engines. Forgot his name something like Juenne. He has posted here before but the member list doesn't show it.



A couple of the engines that I have done, both rescued from the trash heap. Chucked up the stepped muffler equipped engine in the drill press and using 400 grit paper (notice the bluing in the exhaust ports) and sanded off the blue. Painted the backplates with gold Krylon. They won't see fuel. Hangar queens.

Love the contrast between the two backplates. One manhandled by a gorilla with a screwdriver, the other not.

Thanks all for the great tips and suggestions!

NEW222 wrote:Thanks all for the great tips and suggestions!

I'll second that. Lots of good information in this thread.
I'm going to give it a go.
Thanks all,
Bob

Jenuine Motor, see his gallery photos and eBay listings

coxaddict wrote: Jenuine Motor,  see his gallery photos and eBay listings

Thanks CA, I knew if I blundered around with his name someone would come up with the correct spelling. He sure leaves no stone unturned with his auctions. Professional all the way.