COMO DESMANCHAR PLASTICO AMARILLENTO:

SE NECESITA:1.- Peróxido de hidrogeno ( agua oxigenada) en farmacias solo se consigue al 3% ( 10 volumenes). Lo recomendado es que sea entre 6% y 12% (20 volumenes), aunque hay hasta de 40 volúmenes.2.- Maizena ( solo para darle consistencia al peróxido.(hacer una crema)3.- Glicerina líquida4.- Oxi vanisch. Cree en el poder rosa.Detergente activado por O2.5.- Guantes de latex, mascarilla y lentes protectores.

Estamos trabajando con químicos.

Lo primero es lavar la pieza que vamos a tratar, con agua tibia, no caliente y jabón antigrasa.

PREPARACIÓN DEL DESMANCHADOR DE PLÁSTICO: En un recipiente de plástico mezclamos 500 ml. De agua oxigenada y una cucharada de maizena, lo revolvemos bien y dejamos reposar 5 minutos. Nuevamente lo revolvemos y agregamos glicerina l/2 cucharada.

Cuando tenemos la mezcla, colocamos la pieza en una bandeja con tapa transparente.Todo listo.- Ahora agregamos a la mezcla una cucharada de detergente y revolvemos muy bien.No agregar el detergente a la mezcla hasta que ya se vaya a aplicar directamente a la pieza.Se cubre la pieza con el gel/crema que se ha formado, sin miedo, no importa que se forme una pasta gruesa.

Se cubre la pieza y se pone al sol unas 5 horas.Se lava con agua tibia y se procede a su secado.

Pero cuando te pones a buscar un poco más, te das cuenta que utilizan esta técnica de blanqueo, para mucho más que los bloques LEGO, echad un vistazo a Retr0Bright, y veréis que lo utiliza para viejos ordenadores, teclados, etc... En general se puede utilizar para quitar el color amarillento que va apareciendo en los objetos hechos de plástico ABS a causa del tiempo.

OTRA PÁGINA CON CASI LO MISMO.

Aunque para ser sincero en ocasiones, este amarillo viejo, es lo que les da identidad propia.

El método consiste en hacer un gel a partir de:

200 ml de Peróxido de hidrógeno (Agua oxigenada o H2O2) 1/4 de cucharadita  Percarbonato de sodio (como el vanish) 1 cucharadita de Glicerina 2 cucharaditas Goma de Xantano (Xanthar Gum, no sé donde se compra,

ni si en España ahí alguna marca conocida)

Mezclamos por un lado el Vanish con una cucharada de agua caliente, pero sin hervir e intentamos disolver.

Por otro lado, mezclamos el agua oxigenada con la goma durante 5 segundos y entonces añadimos la glicerina y meneamos durante otros 5 segundos, para luego dejar reposar.

Justo antes de ponerlo en la pieza es cuando lo mezclamos todo.

Este gel lo aplicamos a la pieza y le aplicamos rayos ultravioleta, bien con alguna lámpara o a la luz del sol. Y veremos como va blanqueando

OTRA PERO EN INGLÉS…

Making the Retr0bright Gel

SAFETY WARNING!!!You are warned that hydrogen peroxide is very nasty stuff and can cause severe chemical burns to skin and can also cause blindness if splashed into the eyes, if handled incorrectly. Usually, you can’t buy stronger than 12% over the counter, as this is the maximum strength sold to the public and is used to bleach hair. If you want to try this, I would strongly suggest that you wear goggles and gloves to protect yourself.

Merlin's Original Recipe

The original magical "Retr0bright" gel mixture that was found to work is:-

1 pint (500ml) Hydrogen Peroxide, 10 to 15% strength (40 vol) (available from hairdressers' supplies, e.g. the 'Sally Beauty' franchise in the UK)2 heaped tablespoonfuls of Xanthan Gum (available from health food shops or online)1 level teaspoonful of Glycerine (available from pharmacies)1/4 teaspoonful of "Oxy" laundry booster

Add the Hydrogen Peroxide and Xanthan Gum to the blender or liquidiser. Mix on high speed for 5 seconds. Add the Glycerine and mix for a further 5 seconds. Let the mixture rest for a minute then mix again for 5 seconds. A smooth, non-drip gel should have formed. This gel can be put into a dark coloured jar or tub (e.g. a coffee jar covered in tape) and stored, as long as you DON’T add the “Oxy” until you are ready to use it.

Lorne's Variant Recipe

Lorne at Vintage Computer Forums prefers to use stronger Hydrogen Peroxide and his variant recipe is below.

1/2 pint (200ml) Hydrogen Peroxide, 30% strength2 level teaspoons of Xanthan Gum1 level teaspoon of Glycerine1/4 teaspoonful of Oxy laundry booster1 teaspoonful hot (not boiling) water

In a very small ceramic or plastic bowl/dish, dissolve the Oxy in the hot water. Lorne found that the Oxy doesn’t want to dissolve in the paste/gel very well – this premixture of the Oxy fixed that problem. While the Oxy is dissolving, mix the Hydrogen Peroxide and Xanthan gum in the blender for five seconds. Add the Glycerine to that mixture and blend for another five seconds.Let this mixture sit for five minutes.Blend for another five seconds.

Just before you apply the gel, thoroughly stir in by hand, the dissolved Oxy/water mix.

Tezza's Arrowroot Variant Recipe

Tezza at Vintage Computer Forums came up with a variation of the original recipe, based on another starchy food thickener called Arrowroot. Also, Tezza's recipe doesn't use glycerine. Trials have found the arrowroot-based paste dries out more quickly than the Xanthan gum/glycerine mixture in the recipes above and requires more frequent re-application. However, Arrowroot tends to be easier to find than Xanthan gum and is a workable alternative where this is the case.

The addition of glycerine may held to slow the drying processes but Tezza has not tried this at the time of writing.

Tezza's recipe is listed below. Note that Oxy-Magic could probably be replaced by any "oxy-type" laundry activator.

1/2 pint (200 ml) Hydrogen Peroxide, 6% strength (available from most Pharmacies as a hair bleach or antiseptic)2 heaped tablespoonfuls of "White Crest" Arrowroot1/5 teaspoonful of "Oxi-Magic" laundry booster (to be added to the gel just before use, like the original recipe)

If you use Arrowroot, you will need to heat the mixture. Don't worry, this is safe to do. Tezza suggests warming the mixture up in a microwave oven for about 45 seconds, based on a 750 Watt microwave oven, you may need to adjust the timings based on the wattage of your microwave. He strongly suggests that you do this in 15 second bursts and check the consistency after each burst. It's ready when is appears as a gel. Sprinkle in the Oxi-magic and stir vigorously with a spoon. This will also help thin the mixture so it can be brushed on.

Foaming when adding Oxi-Magic is related to how hot the mixture is and the concentration of peroxide. Usually the foaming is mild but if ithe mixture is hot and higher concentrations of peroxide have been used, the reaction can be vigourous. It would pay to let it cool first.

Other Gelling Agents

Other starchy thickeners such as corn starch, guar gum or even wallpaper paste may work. If you find another thickening agent that gives good results for you, let us know via the discussions tab and we will add your recipe to the Wiki.

Other Ingredients

If you decide to try other ingredients which have not been mentioned here, please be aware that you are out on your own and we cannot be held accountable for the results. Hydrogen Peroxide can react violently with some materials and you are strongly advised to do some reading around and research first. The recipes stated above have been thoroughly tested and are safe to prepare as long as the instructions are carefully followed.

If buying hydrogen peroxide from a pharmacy or hairdressers, check to make sure it has no other additives. All you want is diluted hydrogen peroxide (typically 3% to 12%). Additives may lead to unpredicable results. Lorne has tried a hair bleach product and he found that a solvent called terpene was present in the list of ingredients; when this was tried there was some evidence of the product attacking the surface which was particularly visible on dark coloured parts. A picture of the problem is posted in the Problems and pitfalls section