Category Archives: discharge and bleach

Is hydrogen peroxide effective at stopping the damaging effects of chlorine bleach?

Name: Denise
Country or region: United States
Message: Hello Paula –
Hydrogen Peroxide is said to be ineffective as a bleach stop….I have been perusing your website to solve a problem I have with a Pier 1 seat / back cover for a director’s chair. I wanted to remove the color from the fabric, 100% cotton canvas, but chlorine bleach wouldn’t work! Anyway, I was double-checking about a bleach stop to neutralize the bleach I used and I see you still recommend Hydrogen Peroxide. Do you still? I found another resource that says it’s ineffective. It makes reference to a book by Rayna Gillman. Here’s the link: About Bleach Neutralizers, by Natasha Gilani. Let me know what you think ……Thanks. Denise

Thanks for writing, Denise, and thank you in particular for including your reference. I do still recommend the use of hydrogen peroxide for neutralizing chlorine bleach.

Rayna Gillman is mistaken, I think, and I think that Natasha Gilani could use some more authoritative sources. The only mention of peroxide in Gillman’s book reads:

“Anti-Chlor (sodium bisulfite) is the only substance that stops chlorine bleach from destroying fabric. Neither hydrogen peroxide nor vinegar (two old wive’s tales) will do the job. Anti-Chlor is available from ProChem, and a similar product is available from other dyehouses.” (Page 61 of “Create Your Own Hand-Printed Cloth: Stamp, Screen & Stencil with Everyday Objects”, 2008).

There’s no additional supporting evidence, and no reference for her assertion. I think it’s merely an error in which she conflated the effectiveness of hydrogen peroxide with that of vinegar. A larger error is her claim that sodium bisufite is the only substance that can stop damage from chlorine bleach. Dharma Trading Company’s Bleach Stop is a different chemical, sodium thiosulfate; while it is less economical than sodium bisulfite, since a larger quantity of it must be used, nobody (as far as I know) asserts that it is any less effective. I recommend Anti-Chlor over Bleach-Stop only because of the convenience and economy of being able to use a much smaller volume of the chemical; they are equally effective at preventing damage.

In my own experience, hydrogen peroxide, the ordinary 3% strength commonly sold for use as an antiseptic, is highly effective as a bleach stop. Garments on which I’ve used hydrogen peroxide as a bleach stop have survived years of heavy use by my family; when my son eventually wore one of them out, after years of frequent wear (it was a favorite of his), it was the seams that failed, not in the area of the bleached-out designs. This is in spite of the fact that the navy blue dye of that particular shirt was rather resistant to the bleach, so I had left it to bleach for considerably more time than other items. Another shirt even now continues to be worn occasionally by my husband, fourteen years after I neutralized a bleached-out design on it with hydrogen peroxide, and there is still no sign of degradation of the fabric in the bleached-out areas! (Unfortunately I don’t have any unneutralized bleached shirts for comparison.)

Now, hydrogen peroxide might not work if it has been sitting on the shelf for a long time. Hydrogen peroxide is quite reactive and will eventually go bad. If a bottle is still sealed, it may be good for up to three years after purchase, but once the seal has been broken, expect it to last no more than a year. In fact, its full effectiveness starts to decline within a month or two after the bottle has been opened, so it’s best to use a recently opened bottle for critical uses like neutralizing chlorine bleach. I don’t know how fresh my bottle was, but obviously it was fresh enough. I rinsed the bleached fabric with water, and then poured the peroxide over it.

Hydrogen peroxide is less economical than Anti-Chlor or Bleach-Stop, but it’s not unreasonable in cost. It has a real advantage, moreover; unlike either sodium bisulfite or sodium thiosulfate, it doesn’t present any risk to asthmatics. Five or ten percent of people with asthma are sensitive to sodium bisufite and are better off if they avoid exposure to it (though I imagine that using it as a bleach neutralizer would probably be safe even for people with sulfite-sensitive asthma, if they wear a respirator with an acid gas cartridge).

To compare the effectiveness of hydrogen peroxide with vinegar, for neutralizing the hypochlorite in chlorine bleach, it’s worth taking a look at the chemical reactions involved. The chemical reaction between hypochlorite (the active ingredient in chlorine bleach) and hydrogen peroxide is as follows:

OCl- + H2O2 -> Cl- + H2O + O2

It produces chloride ion, which makes sodium chloride, i.e. ordinary table salt, plus bubbles of gaseous oxygen. In contrast, the acetic acid in vinegar reacts with the hypochlorite to produce sodium acetate plus hypochlorous acid:

NaOCl + HOAc <-> NaOAc + HOCl

In the presence of acid, hypochlorous acid degrades to form chlorine gas. It is quite unlikely that a home dyer will use a large enough quantity of acid to produce lethal accumulations of chlorine gas, but the fact (as I’ve heard it) is that hypochlorous acid is even more damaging to fabric than hypochlorite, so it’s hardly an improvement. Deaths and serious injuries caused by mixing chlorine bleach with acids have all involved a much stronger acid than vinegar (a strong phosphoric acid solution used for cleaning toilets has sometimes been mixed disastrously with chlorine bleach). Chlorine bleach as supplied for home use is supplied as a mixture with extra sodium hydroxide in order to help prevent the reaction of chlorine bleach that occurs with acid.

For more information on neutralizing chlorine bleach, please see my page, “How can I neutralize the damaging effects of chlorine bleach?”.

For your canvas director’s chair seat and back, after you have washed out the chlorine bleach and used either peroxide or Anti-chlor to prevent damage from the bleach….although bleach did not work to remove the color, it is possible, though far from guaranteed, that a reducing type of color remover might work. Bleach and color removers work in a different way, so sometimes one works when the other does not. Howveer, some dyes simply cannot be removed, and it is impossible to know what dyes were used in your covers. See my page, “What chemicals can be used to remove dye?”. Alternatively, you might use the old seat and back as patterns to sew new covers from undyed cotton canvas. If a beige color will do, Pier One currently has new director’s chair covers, in “sand”, on sale on their website.

(Please help support this web site. Thank you.)

Paula

Bleaching a black t-shirt is producing orange – How can I get white?

Hi Paula,

I have a project that I am trying to achieve a certain garment treatment. I am attaching an image of the design. I have tried using bleach on a black garment but end up with an orange under-color and my client is looking to get it as close to white as possible – see picture. Do you have any other treatment suggestions on how to achieve this look?

Best regards,

Tim

Hi Tim,

t-shirt print with white sections

Your picture of the desired results [shown to the right] appears to show the use of an opaque white screen-printing ink. The white is so bright and so devoid of variation that it doesn’t have the look of bleached-out dye, to me.

Discharging black garments is a perennial problem. Most commercially-available black garments are dyed with unidentified dyes that will discharge unpredictably.

The spider-web pattern on this navy blue shirt discharged with bleach to a pink color.

Unless a shirt is sold with specific claims as to dischargeability, you never know whether it will discharge to white, or to an aged-looking orange or brown, or even refuse to discharge at all, remaining black. Some dyes cannot be discharged at all. Black garments may have been originally intended to be black, or they may have been overdyed with black dye after dyeing with another color produced undesirable results; if the other colors are non-dischargeable, you could get an entirely unpredictable color. A supply of black blanks may discharge well and then suddenly, after many successful uses, be replaced, with absolutely no notice from the manufacturer, by black shirts that do not discharge acceptably!

To complicate matters, while results will be pretty much the same with one reducing-type discharge as another, the results may be very different from those obtained by discharging with an oxidative discharge such as chlorine bleach or dichloroisocyanurate. Bleach may produce an entirely different color than a reductive discharge. For more information on this, see my page, “What chemicals can be used to remove dye?”. If you ever use Procion dyes yourself before discharging, also check out my page “Which Procion MX dyes discharge the best? Which are good at resisting chlorine bleach?”.

I recommend that you search specifically for a dischargeable black blank t-shirt for dyeing. There are some on the market. Ask your current suppliers if they can supply you with some, or do a search including the word “dischargeable” to locate another supplier. Alternatively, consider the use of an opaque white screenprinting ink. For example, Jacquard Professional Screenprinting Ink in the color “Super Opaque White” gets good reviews for being very opaque, though I don’t have personal experience with it.

(Please help support this web site. Thank you.)

Paula

Is it possible to bleach this black jacket and dye it yellow?

Name: Sierra
Country or region: USA
Message: Hello!

I’ve been scouring your blog and I don’t see my particular situation being represented. I hope I’m not asking a repetitive question. (I apologize if it is and I just don’t know enough about dyeing to know better)

Hot Topic Black Sweetheart Double-Breasted Tiered Ruffle JacketI’m making a cosplay for this character, Yellow Diamond [shown to the left]. My plan is to buy this jacket, which is 72% polyester; 23% rayon & 5% spandex [shown to the right].

Is it possible to bleach it and then dye it yellow and if so, which method of doing so would you suggest for the best result? Regular bleach or a color remover?

Thank you so much for your time!

No, sorry, you can’t bleach that! Chlorine-based bleach will damage the polyester (turning it an ugly yellow that can’t be removed) and break up the spandex. Non-chlorine color removers require heat which will damage the spandex. Besides that, there is never any guarantee that a commercially-dyed black even can be removed by either means. Many black dyes cannot be removed. When bleached, or treated with other color removers, they may stay black, or they may turn an ugly brown, not suitable for dyeing yellow. It’s rare for a commercially-dyed black garment to bleach out to nearly white.

Maybe you could build something suitable starting from pieces such as, say, a dyeable rayon jacket and a skirt that you cut up the front (and fold over the edges and sew so that it doesn’t ravel), from Dharma Trading Company, which is an excellent source for dyes and dyeables. Look at the skirts on the Dharma site and the jackets there, for example, their waterfall jacket. Since they are white, and made of dyeable materials, these clothing items will dye a beautiful yellow. Don’t forget to check out the accessories section to see if they have dyeable gloves, etc. They also have dyeable cotton/spandex leggings.

If you buy a yellow Procion fiber-reactive dye and dye several white dyeable clothing black garments at once in the washing machine, it will all match beautifully, which is a great aid in designing a costume.

(Please help support this web site. Thank you.)

Paula