PLEASE READ: Chemicals suggested for drain cleaning in this article are very dangerous and all cautions most be read on the bottle before using. It is best to wear chemical resistant gloves, safety goggles and protective clothing.
About Sulfuric Acid used as a Drain Cleaner
I have found sulfuric acid to be the best drain cleaner. Sulfuric acid quickly eats through paper, rags, sanitary napkins, food scraps and all organic matter.It will melt ice and liquefy grease. Do not use sulfuric acid with stainless steel, aluminum chrome or galvanized steel pipes. it is safe to use with plastic piping.
Sulfuric acid is very simple to use and will unclog a drain within an hour, usually within seconds if it’s not completely plugged up. Sulfuric acid is naturally occurring and is sewer and septic safe as it is diluted in its journey down your pipes.
Our sulfuric acid is 98%, the most powerful available. Higher concentrations are unstable and will break down to 98% on their own, with the remaining 2% being water. 98% sulfuric acid is very corrosive, so use extreme caution when using it. It is best to wear chemical resistant gloves when handling it, and preferably safety goggles and a lab coat.
Using Sulfuric Acid as a Drain Cleaner
Open all windows in the room where the drain is to be unclogged to allow for proper ventilation. Wear your PPE (Proper protection equipment) when handling the sulfuric acid. Read and understand the MSDS (Material Safety Data Sheet) before using it.
For mild clogs (where water still passes through, but slowly) slowly pour about 200 ml worth of sulfuric acid into the drain. After about 10 seconds, apply a slow flow of water. If the clog has not gone away yet, you can turn off the water and let it sit for a longer period of time or add some more sulfuric acid to speed up the process. Usually 200 ml will handle any slow flowing drain. Once unclogged, flush piping with plenty of water to remove left over sulfuric acid.
For severe clogs, slowly apply 500 ml (half of a Liter bottle) of sulfuric acid to the clog. Let sit for an hour, and then test for drain opening by applying water. If the clog has not been cleaned out, apply another 250ml or 500 ml of sulfuric acid and allow to sit for another hour. Continue adding sulfuric acid if clog persists. Even with severe clogs, sulfuric acid should be able to eliminate them within 15 minutes. Flush with water once clog has been eliminated.
General notes and cautions when using sulfuric acid
It is not advisable to add sulfuric acid directly to water since it can cause spitting or splattering in the neutralizing process. However, the good news is that adding acid to water is safer than adding water to acid, so if this is for use in a toilet bowl or a sink full of water, it is reasonably safe. Usually, only a bit of smoke and very light splattering will occur when the acid is added slowly. Should any acid get onto your skin, flush with water immediately. Always have a source of running water nearby when handling this acid.
The combination of water and sulfuric acid produces an exothermic reaction. The fluids will heat up significantly, so be sure not to add too much at a time or it could potentially cause melting of the pipes.
About Sodium Hydroxide used as a Drain Cleaner
Sodium Hydroxide was once sold as Red Devil Lye in stores, but is no longer being marketed by that company. Red Hot Devil Lye distributed by Duda Diesel is now the red Devil Lye replacement.
Sodium hydroxide lye reacts with fats and greases when combined with water to make soap. It is a strong base and effective when attacking clogged drains. Sodium Hydroxide is naturally occurring and is sewer and septic safe as it is diluted in its journey down your pipes. Though not as effective as sulfuric acid, it is safer and easier to use. If you get dry sodium hydroxide on your skin, it will not burn unless a small amount of moisture is present. Just wash it off immediately and burns will be minimal.
Potassium hydroxide may also be used in drain opening. It is a bit more expensive but dissolves into water faster and usually clears the drain quicker. It is best when drains are very clogged.
Do not use sodium hydroxide with aluminum chrome, brass or galvanized steel pipes.
Using Sodium Hydroxide as a Drain Cleaner
Wear your PPE (Proper protection equipment) when handling the sodium hydroxide. Read and understand the MSDS (Material Safety Data Sheet) before using it.
The amount of lye needed depends on the severity of the clog. It is best to add a little bit of sodium hydroxide at a time to the clog, using water to dissolve it into the piping. If the clog is not severe, it should unclog the drain within a few seconds of applying it to the drain with running water. If the clog is severe, sodium hydroxide will need to be dissolved into the backed up pool of water and left for at least an hour, with a little more added if the clog is not cleared fast enough. Sometimes it can take overnight or a few days to pass the clog if not enough sodium hydroxide is used or the clog is extremely severe.
The amount of lye to use is difficult to quantify. Usually, with drains not too clogged, about 1/2 lb will be sufficient. Severely clogged drains may require up to 2 lb or more.
General notes and cautions when using lye as a drain cleaner
Sodium hydroxide produces an exothermic reaction when mixed with water. Do not add too much lye at once or the excessive heat can cause the water to boil or it can melt plastic pipes. Do not touch any water which has lye in it, as it becomes severely corrosive to the skin.