Green oxide in Kato unitrack

[Khaul]

I have found a suspicious green spot in my track. That's in a point already glued in the module. Is there anything I should do about it?

[kvp]

That might be caused by the glue used fit the tracks or scenery down or some other chemical. I would first try to wipe it off and see if it shows up again.

[Khaul]

It may well be the glue... the spot is behind the guard rail, a place hard to reach.

[HantuBlauLOL]

corrosion of copper and its alloys..

[nah00]

A q-tip and rubbing alcohol is my go-to for this. Always get a spot or two after I do any scenery even with taping over the track. 

[cteno4]

Nickel silver is a copper/nickel/zinc alloy so in therory it can corrode and most nickel oxides are green and some copper oxides are green/tourquoise in color.

 

I've never seen it on unitrack, but some have reported getting a lot of it at times. I left a piece of unitrak in water for a few weeks and saw no corrosion and also in a baggie with a wet paper towel (to give 100% humidity) and could not make the green ever show up, so I have figured it was a unique combination of chemicals that were applied to the track with cleaning, scenery and such that causes an oxidative reaction to occur.

 

Is it ballasted track? I've wondered if some ballasts have some salts in them that comes out when fixed with flooding and salts can be the need tip to get oxidation like this to occur.

 

I would hit the spot with some brasso or other metal cleaner that's good at taking off oxides and buff it out well. Dremel or cheap rototool would work great to do this.

 

Jeff

[Khaul]

Thanks everyone.

 

Jeff, this is the regular unitrack with plastic ballast. I will add some ballast to make it look better soon.

[cteno4]

Khaul,

 

Sorry I meant have you added ballast to the plastic ballast and soaked it in glue that might have added something to the rail.

 

Jeff

[kvp]

What i did see cause green spots were acidic flux for soldering and cheap white glue with non water based solvents. Some highly acidic household cleaning fuids could also discolor the rails. For normal water i only got some grey spots that could be wiped off.

[Khaul]

It says "acid free" in my PVA bottle. I hope they are not lying. I have wiped off most of the stain with alcohol. The plan now is to wipe it off completely, then apply a sealer to the rails and paint with acrylics. The idea is to do that in tracks that are already glued to the modules. My experiments indicate that one can paint joined tracks and they will not lose electrical connectivity. I have also tried painting first, scratching the paint at the joint and the connect the tracks. That also worked well. I am slightly apprehensive about the metal sealant. Hopefully it will not insulate the joints. Does anyone have any experience with it? I am using Derivan Matissse Clear Sealer as I would like the paint to stick to the rail without having to apply n coats.

[cteno4]

Khaul,

 

I don't think you need to seal the rails at all. I've had unitrak laying around for 20 years with lots of humidity w/o any corrosion like this. Sounds like something got on the track to cause your corrosion and getting rid of it should have stopped it. I would also use swab with water to hit the areas well to clean them as it will work better to clean it off than alcohol.

 

The unijoiners can alsways be suseptable to any liquid getting in there with paint, ballast glue, etc. it's a problem folks have had on and off a lot with Ttrak and ballasting. So try to get as little as possible around the joints.

 

Jeff

[stevenh]

My coffee-table layout did this to me. I plastered my scenery and (stupidly) let it dry inside with very little ventilation.

Have you recently done any plastering work?

 

http://modelrail.otenko.com/my-layout/kato-unitrack-vs-moisturehumidity-from-setting-plaster

 

http://www.jnsforum.com/community/topic/7972-moisture-destroys-unitrack/

Edited April 5, 2017 by stevenh

[velotrain]

I am using Derivan Matissse Clear Sealer as I would like the paint to stick to the rail without having to apply n coats.

But wouldn't n coats be appropriate here?

[cteno4]

yeah its basically tarnish, that a little cleanup should remove it after you do the scenery and before coloring the rails. its basically some of the salts in the plaster or glue causing the oxidation. once removed and washed away with damp cloth and dried it should not come back.

 

jeff

[Khaul]

No, I haven't done any plastering. Everything looks ok now. Thanks everyone.

[Ochanomizu]

Hello,

 

It is likely to be the humidity in the room.  I use an electric dehumidifier to keep the humidity below 50% for my layout.

[cteno4]

Ochanomizu,

 

I kept a piec of unitrak in tap water and also in a sealed tub with tap water but track out of water (to have high humidity) for like a month and could not get the green corrosion to form. Really think it's some other chemical added to the equation to facilitate the oxidation/reduction. Also we store our club layout here in D.C. In my garage and most of the summer it's really high humidity in there and not seen any green corrosion in 10+ years of this storage.

 

Jeff