Converting sodium percarbonate to hydrogen peroxide

[Muddy37]

I noticed a previous thread on the above subject in this forum.

For several years now, I have used 30% concentration hydrogen peroxide mixed with a few drops of ammonia to very great effect* for dealing with blood stains on cotton fabrics (on sheets—a recurring problem for me) by soaking the stains for a minute or two in the above solution. With this new age of terrorism, it is unfortunately becoming increasingly difficult (and very expensive) to get hold of H2O2 (at least where I live in Belgium). My question: I have recently bought a bottle of Sodium Percarbonate powder which I think is 100% pure. What ratio of water to powder would be necessary to obtain a similar H2O2 concentration to the H2O2 concentration I have been using up until now? And, if you know the answer, is there a possibility that the presence of soda ash (present in sodium percarbonate) could compromise the efficacity of this proposed method in relation to my method up until now?

Please note that I am an ignoramus regarding all things related to physics so answers will necessarily need to be formulated with this in mind.

Thanks!

*and previously an even stronger concentration (50%? I can't remember) to even greater effect

 

[rootone]

Hmm, I thought H2O2 is regularly available from hairdresser suppliers as a non corrosive bleaching agent, things may have changed though.

 

[DrDu]

Hmm, I thought H2O2 is regularly available from hairdresser suppliers as a non corrosive bleaching agent, things may have changed though.

But not 30%