RADBMX.CO.UK

Technical & Reference Section => Tech and Restoration => Topic started by: 20to26 on April 30, 2009, 07:10 PM

Title: anyone used 'Oxalic Acid' bath?
Post by: 20to26 on April 30, 2009, 07:10 PM
...for removing rust from chromey bits?
The results over on bmxmuseum look impressive. Can we get this stuff here in the UK?
I've done the coke(zero)/foil thing which is great but sometimes doesn't get all the rust or black stain off.
Title: Re: anyone used 'Oxalic Acid' bath?
Post by: stidds on May 01, 2009, 12:41 AM
Used it loads of times, it really is as good as they say.

On ebay type....... Oxalic Acid

Disolve said OA in water, immerse rusted part for 24 hours and they wash off.  All the rust has gone.
Title: Re: anyone used 'Oxalic Acid' bath?
Post by: 20to26 on May 01, 2009, 09:07 AM
Thanks Sean, does OA effect aluminium or anodizing at all?
Title: Re: anyone used 'Oxalic Acid' bath?
Post by: Juju on May 01, 2009, 05:16 PM
Oxalic acid works by attracting the positively charged ions in the iron oxide (rust).

I dont think its going to harm aluminium, as aliminium oxide is a different chemical compound.

Its safe, but apparently its not great for the environment to pour your bath straight down the plug hole when finished - I've seen suggestions that you should at least neutralise the acid by adding an alkali to make the bath at least ph neutral.

A small qualtity of caustic soda might do it.
 
Title: Re: anyone used 'Oxalic Acid' bath?
Post by: stidds on May 01, 2009, 06:28 PM
Thanks Sean, does OA effect aluminium or anodizing at all?

Doesn't harm aluminium or decals at all, only the rust is affected.
Title: Re: anyone used 'Oxalic Acid' bath?
Post by: rhino_mac on May 01, 2009, 06:37 PM
Don't for Gawds sake add Caustic to Oxalic. It will boil vigourously instantly and "explode" (it doesn't explode as such but the reaction is so vigourous it looks like it).

And always dilute Caustic Soda by adding Caustic to water, not the other way round or you get the same effect!
Title: Re: anyone used 'Oxalic Acid' bath?
Post by: rhino_mac on May 01, 2009, 06:41 PM
Sorry, meant to add to neutralise an acid such as Oxalic, dilute the comncentrated solution you've used to treat the frame, then add as much water as you possibly can to make it as dilute as possible.

Then add "Soda Ash" (Sodium Carbonate or Soda Crystals) to the bath. Best to dilute these in water first too.

Basically, always use as much of the dilute chemicals to each other, as slowly as possible. Acid + Alkali = mucho heat if they are concentrated
Title: Re: anyone used 'Oxalic Acid' bath?
Post by: hunterdubber on May 02, 2009, 12:43 AM
I've tried OXY 10 in a bird bath





Got rid of my budgie's acne a treat !  :4_17_5:
Title: Re: anyone used 'Oxalic Acid' bath?
Post by: 20to26 on May 02, 2009, 03:59 PM
LOL...

ok, so I should be able to put complete wheels into an OA bath to clean up the spokes & axles without any effect to the hubs & rims?
I presume the grease (or what's left of it) will also dissolve.

Then I can toss the diluted OA water onto all the weeds in my garden...
Title: Re: anyone used 'Oxalic Acid' bath?
Post by: Juju on May 02, 2009, 06:48 PM
Quote
I've tried OXY 10 in a bird bath





Got rid of my budgie's acne a treat !

I've heard some of your birds could do with a good bath...........

SimplePortal 2.3.5 © 2008-2012, SimplePortal