I would like to know if it is possible to recycle plastic at home by melting and molding.
Yes it is possible.
One guy makes chairs out of melted plastic .
There are several guides on melting plastic that show up when you search google for it.
This one, on ehow shows how to melt plastic in a toaster oven.
Basically, wash the bottles, cut 'em into small manageable chunks and pop them in a metal container and into the oven at 350F.
It should take a few minutes for the plastic to melt.
As for molding them, I found a few guides - Molding plastics at home
How to produce small plastic parts at home A list of molding projects on a crafts site But remember, melting plastics will produce fumes which can be harmful if inhaled.
Make sure to melt them in a well ventilated area.
And if you're doing it in a room, it would be nice to have an exhaust fan in there.
Also, check out this guide on what the different rating numbers on the bottom of plastic bottles mean, specifically, what kinds of plastic a number refers to and whether or not it is safe to melt that plastic.
sustainability.stackexchange.com/users/83/elssar
To contribute to the options offered by Elssar's answer, here is an interesting thing I read about just a few days ago: Filabot is a project of compact 3D printer that directly recycles plastic objects at home to create new shapes.
It was launched for funding on the 19th of December 2011 on Kickstarter and tripled its goal by the 23rd of January 2012.
Here is the homepage of the project: http://filabot.com/
They apparently shipped the devices to at least some of the project backers during 2013.
sustainability.stackexchange.com/users/80/stragu
Even when melted/burned in a place with lots of ventilation, plastics can produce many toxic chemicals.
These are then breathed in or attach themselves to soil, where they can stay for years and years.
Therefore, I really wouldn't suggest trying to reuse plastics at home by melting or heating them, as the health implications can be really dangerous and damaging in the long run.
sustainability.stackexchange.com/users/680/Beth
It depends on the plastic you're using.
Plastics often come in the thermoplastic and thermosetting categories.
If the plastic is a thermosetting plastic then it is not able to melted (Most, if not all thermosetting plastics burn rather than melt).
However, a thermoplastic plastic can be melted and remoulded as much as you want (quality of plastic is likely to degrade after each phase melting and remoulding however).
sustainability.stackexchange.com/users/1161/user1161
Depending on the type of reshaping you are interested in, you can do basic crafts with the right kind of plastic by simply using a hairblower to heat them up and bending them into shape.
sustainability.stackexchange.com/users/4159/Jennifer Rae Pierce
I would like to know if it is possible to recycle plastic at home by melting and molding.  Is it at all possible? What technique or technology do I need? Can it be done with any plastic? Are there health hazards associated to this activity?
Can I recycle plastics at home by melting and molding?
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<recycling><diy><plastic>
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sustainability.stackexchange.com/users/144/Benjamin
This is possible but it depends on the plastics. There may be health implications to melting or heating plastics. Basic crafts can involve heating the right kind of plastic with a hairdryer and bending the plastic into shape. Much depends on the type of plastic and reshaping, though this may or may not be possible due to safety reasons.
It is possible to do this. This is not recommended for safety reasons. The feasibility depends on the type of plastic and reshaping.