Waste oil means black oil bcz it is easily available n also cheapest everWhich oil should we use for shuttering? ( black oil, mustered oil or any )
Black oilWhich oil should we use for shuttering? ( black oil, mustered oil or any )
Sir,Contractors have tendency to use burnt oil which is available cheaper in the market which works as a form release agent.
However, as Engineers, we overlook the disastrous effects it can have over the set concrete as well as the reinforcement which is coated with this oil and is generally not washed with detergent etc to remove the oil.
As a rule, I have been enforcing the use of " form release agents " like Fosroc -Reebol Wb / or Sika -Separol " and so on.... These form release agents dry out in about 15 min of application and hence create a film on the shutters and are easy to de-shutter. However, due to the cost contractors do not use it.
If we consider the effective use then these release agents work out cheaper as the shutters are protected at the same time giving you more repetition in turn becoming cost-effective to both the contractors as well as the client in case shuttering is in his scope.
It can be used on following type of shuttering:
Steel formwork - coverage @ 40-50 sqm/lit
Plastic formwork - coverage similar to steel
Timber formwork - coverage @ 20sqm/lit
Aluminium formwork - coverage similar to steel
Off late cost at site per litre is about Rs 140/lit and comes in 200 lit capacity, 50 lit so actual cost for timber shuttering works out to Rs 7.5/sqm and steel/alln/plastic shuttering works out to Rs 3.75/sqm.
Use of rollers makes it easy to apply at the same time giving good coverage as compared to the burnt oil which is generally applied thick with katha, goni , cotton waste and what not......
So take your call sensibly
Sir,
Please tell burnt oil is good to use or not for concrete surface ???
Sir, Sometime we can see some some black sticky patches on RC wall after deshuttering. Is it due to excessive black oil coating with gunny bag?Contractors have tendency to use burnt oil which is available cheaper in the market which works as a form release agent.
However, as Engineers, we overlook the disastrous effects it can have over the set concrete as well as the reinforcement which is coated with this oil and is generally not washed with detergent etc to remove the oil.
As a rule, I have been enforcing the use of " form release agents " like Fosroc -Reebol Wb / or Sika -Separol " and so on.... These form release agents dry out in about 15 min of application and hence create a film on the shutters and are easy to de-shutter. However, due to the cost contractors do not use it.
If we consider the effective use then these release agents work out cheaper as the shutters are protected at the same time giving you more repetition in turn becoming cost-effective to both the contractors as well as the client in case shuttering is in his scope.
It can be used on following type of shuttering:
Steel formwork - coverage @ 40-50 sqm/lit
Plastic formwork - coverage similar to steel
Timber formwork - coverage @ 20sqm/lit
Aluminium formwork - coverage similar to steel
Off late cost at site per litre is about Rs 140/lit and comes in 200 lit capacity, 50 lit so actual cost for timber shuttering works out to Rs 7.5/sqm and steel/alln/plastic shuttering works out to Rs 3.75/sqm.
Use of rollers makes it easy to apply at the same time giving good coverage as compared to the burnt oil which is generally applied thick with katha, goni , cotton waste and what not......
So take your call sensibly
It depends on what you want to do with structure.
If you want to make structure non stick - use any kind of above stated oil - you will ensure no bonding of any kind of material with surface of concrete, your plaster will get de-bonded.
Purpose of shuttering oil - to facilitate the de-shuttering by making non stick layer on shutter face.
Water base non stick shutter oils are best for it, for doing eye wash you can use any kind of oil in thickness which can be seen on shutter.
If you do not use oil on shutter - it wont harm concrete but it will lead to damages of shutter at earliest, which increases the cost of material and contractor get heavy losses due to it.
Do not worry if you don't see oil on shutter - it wont hurt structure (may be shutter get its life lowered)
Application of oil
It should form a layer on form surface, when you walk on it, it should not stuck to your shoes and reinforcement.
If reinforcement get coated with shutter oil due to heavy application, consider cleaning of reinforcement bars with detergent (coating of shuttering oil is most dangerous and can cause failures as it wont allow rebar to get bond with concrete)
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