Be very careful with ALL the acids,Especially when Combined withh ALLOY parts... Ive used most types and while they all have different effects,they are quite potent when put with alloy.
Mild sulphuric and hydrocloric acid are quite dangerous but very effective if mixed correctly. However they produce a very reactive action and emit Hydrogen gas,So if you use this method make sure its done outside and with respiratory protection. This will clean the rust and react with the alloy,dissolving the piston..BUT again its very dangerous and Id Really NOT recommend its use lighlty.
RECOMMENDED-Phosphoric( usually called alluminium cleaner) Acid is also good,less reaction and a much slower and gentler process. This acid I use in fuel tanks as it cleans the rust and slightly etches at the same time,so it does not promote surface rust as quickly.
Molasses" as Rusty Says is also good,Slower But SAFER.
Another method is an alkaline as it eats through grease/oil and other crap. It doesnt do much for rust but it will dissolve the piston. Again a strong chemical reaction occurs and caution is required.
Ive used all the above chemicals many times,they are effective when used correctly and by experts. Please use extreme caution if you choose this path. My own course of action for your dilema would be heat and re heat to shock,then a press. Just my own preference. And SAFER.:)
Good luck and Safety First".
Where in sydney are you from Scott? And 17....Great to see the younger generation taking an interest,spoke to another recently a little bit older and also very keen. Awesome!
