Our kitchen sink drain is blocked and only draining slowly. I have a
bottle of One Shot acid - is it Ok to use on plastic pipes and what's
the best procedure?
Instructions say remove as much water as possible first and then add
water once you have put in 125ml acid - obviously I can get rid of the
all the water in the trap but I was taught never to add water to acid...
Is it best to slowly add to the water in the trap and then wait and
then flush some cold water from the tap?
Personally I've found the Mr Muscle foaming drain cleaner extremely good
for situations like this as it coats all the gunk in the pipe. I've
cleared a slow draining shower - took 3 goes but now the water just runs
away rather than filling the tray to 3" deep.
To answer your question, we'd need to know the make of the cleaner - or
Your teaching only applies to adding water to concentrated acids where
the mixing releases a lot of heat - notable conc. sulphuric acid. Conc.
HCl is no problem mixing with water. Also applies to sodium hydroxide
To be honest, it does not seem the best. Bleach is sufficient to take
out the living scunge and to a degree attacks grease - the problem is it
doesn't get to the upper parts of the pipe, which is where the foaming
stuff comes in handy. I've only ever used acid on limescale.
As with acetone that depends on the type of plastic
According to this chart both 75-100% and hot and cold concentrated
sulphuric acid have a severe effect on PVC and are not
recommended for any use.
And its PVC which I believe, many drainpipes are made of.
Indeed. Plastic's plastic, it's all the same stuff really.
Just the same as wood.
Which must come in handy when explining to the punters
why you're knocking up decking from piles of old pallets.
As regards acid resistance it pretty much is, One Shot has been used for
donkey's years. If it damaged plastic pipes it would be well known & the
bottle would have a warning on it.
Do you have any evidence that sulphuric acid attacks any kind of plastic???
Pretty sure that it does, from A level chemistry.
Its a very strong reducing agent IIRC. So any plastic with oxygen
molecules in it is prone to attack
looks like the PVC/polythene classes are OK, but acetal which is a sort
of nylon, is not.
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
Not according to numerous websites. The fact it may not damage
plastic drainpipes is only because its diluted with so much
water. Maybe you're suggesting there's no problem either
in storing it in old plastic milk bottles or plastic
You're right. It would have been far better to suggest that
the body of your Makita or whatever it is drill, is made from
exactly the same stuff as are plastic milk or lemonade bottles
'Plastic' is an imprecise and generic term. 'Plastic' embraces a large
range of chemical compositions. Basically, anything that becomes
moldable at moderate temperatures can be and is described as 'a
This, from http://tinyurl.com/huycaad
"Corrosivity to Non-Metals:
Sulfuric acid attacks plastics, such as nylon (all concentrations),
polyvinylidene chloride (50-100%), acrylonitrile-butadiene-styrene
(ABS) (60-100%), styrene acrylonitrile (SAN) (90-100%), polyurethane
(rigid) (40-100%), polyetherether ketone (PEEK) (50-100%), olyethylene
terephthalate (PET) (40-100%), high-density polyethylene (80-100%)
(HDPE), thermoset polyester bisphenol A fumarate (80-100%), thermoset
polyester isophathalic acid (70-100%), polystyrene (80-100%) and
ethylene vinyl acetate (EVA)(75-100%); elastomers, such as butyl
rubber (isobutylene isoprene) (80-100%), nitrile buna N (nitrile
rubber) (90-100%), chloroprene (neoprene) (75-100%), isoprene
(60-100%), natural rubber (60-100%), hard rubber (60-100%), soft
rubber (30-100%), chlorosulfonated polyethylene (CSM) (90-100%),
styrene-butadiene (SBR) (10-100%), polyacrylate (10-100%),
polyurethane (10-100%), chlorinated polyethylene (all concentrations),
nylon 11 and 12 (20-100%), silicone rubbers (120-100%), flexible
polyvinyl chloride (PVC) (95-100%), low density polyethylene (LDPE)
(90-100%) and ethylene vinyl acetate (50-100%); and coatings, such as
coal tar epoxy (10-100%), general purpose epoxy (30-100%),
chemical resistant epoxy (60-100%) and vinyls (90-100%). Sulfuric acid
does not attack plastics, such as Teflon and other fluorocarbons, like
ethylene tetrafluoroethylene (ETFE; Tefzel), ethylene
chlorotrifluoroethylene (ECTFE; Halar) and chlorotrifluoroethylene
(Kel-F) (all concentrations), polyvinyl chloride (PVC) (up to 96%),
chlorinated polyvinyl chloride (CPVC) (up to 96%), polypropylene (up
to 98%), acrylonitrile-butadiene-styrene (ABS) (up to 50%),
high-density polyethylene (up to 75%) (HDPE),ultrahigh molecular
weight polyethylene (UHMWPE) (up to 100%), cross-linked polyethylene
(XLPE) (up to 96%), polyetherether ketone (PEEK) (up to 50%) and
polystyrene (up to 70%); elastomers, such as Viton A and other
fluorocarbons, like Teflon, Chemraz Kalrez and Fluoraz, ethylene
propylene(EP) (up to 100%), butyl rubber (isobutylene isoprene) (up to
80%), nitrile buna N (nitrile rubber) (up to 80%), chloroprene
(neoprene) (up to 70%, flexible polyvinyl chloride (PVC) (up to 50%)
and , low density polyethylene (LDPE) (up to 80%); and coatings, such
as polyester (up to 80%), urethanes (up to 80%) and vinyls (up to
The figures in brackets refer to the strengths of acid to which the
particular plastic is vulnerable. Note that there are some plastics
that are attacked by moderately dilute sulphuric acid, but not by
concentrated sulphuric acid.
So yes, sulphuric acid attacks 'plastic'. The fact that it's sold in a
'plastic' bottle, merely shows that the mfrs have carefully selected a
suitable plastic for that purpose.
And the fact that it has been used for years without a problem shows
that the mfrs have carefully selected a suitable plastic for waste pipes.
Do you really think that B&Q, Wickes, Screwfix, Homebase, Amazon, Asda,
Plumbase, Robert Dyas, Tesco, Wilkinsons and every independent plumbers
merchant in the UK have been selling a product that damages waste pipes
for the last 20 years?
ABS solvent weld is commonly used in domestic waste pipes. This, from
"ABS polymers are resistant to aqueous acids, alkalis, concentrated
hydrochloric and phosphoric acids, alcohols and animal, vegetable and
mineral oils, but they are swollen by glacial acetic acid, carbon
tetrachloride and aromatic hydrocarbons and are attacked by
concentrated sulfuric and nitric acids"
So there's little doubt that One Shot is capable of attacking a great
many plastics, including one commonly used in domestic waste
situations. That is undeniable. But you make a reasonable point. I
note that One Shot is described as a 'drain cleaner'. Perhaps the mfrs
don't expect people to use it in domestic waste pipes, only drains,
which may be less susceptible to attack than domestic waste pipes,
especially if made of stoneware (not that much is, these days). If
that's the case, it should be made clear. It's also possible that when
the One Shot is poured into a domestic sink, for example, there's
enough water in the trap to dilute it down to a safe concentration.
But there's still the case reported in the DM, for which the most
obvious explanation is that the One Shot attacked and ate through the
Indeed. On the B&Q web page
they don't actually say it can be used on waste pipes. And given that
they claim it can dissolve "grease , rags, soap, paper towels in minutes"
it's rather surprising that the bottle itself, or the web page isn't
plasterd with hazard warnings; maybe other websites are more
informative. It's the "rags" bit there that seems a bit scary.
As most people will only discover they have a blocked waste pipe
as a result of the pipe filling with water maybe the product
is sufficiently diluted during those minutes when its dissolving
the grease , rags, soap, paper towels so as to not to effect
the plastic, or any joints.
From the One Shot website;
DO NOT USE ON ALUMINIUM, GALVANISED METAL, STAINLESS STEEL OR WASTE
MAY ETCH ACID SENSITIVE PORCELAIN, ACRYLIC AND ENAMEL FIXTURES.
WILL NOT HARM IRON, STEEL, CLAY, LEAD, COPPER, PLASTIC PIPES OR HARM
SEPTIC TANKS WHEN USED AS DIRECTED.
I don't think we can entirely trust the DM to report things accurately.
We simply don't know what happened. The DM reported "But the liquid
was so strong that it melted the pipes, floor and ceiling".
How much did he use? Did he follow the instructions & flush?
The manufacturer clearly states that it will not harm plastic pipes.
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