Guys,

I am working on Cessna and Boeing 737 model.  I am using HD thermacol for building it. But there is bug problem as after carving and sanding thermacol there are still rough patches on it. Any one has idea how make it smooth and which material is available locally. I am in Mumbai.

Thanks,

Shantanu

Nice sanding. 
cover it with brown paper.

See below link for chiffon covering.

http://www.rcindia.org/electric-planes/pusher-trainer-for-beginners-bgnr/

Mix 1 part white glue in 3 parts of water. To this add talcum powder and make a paste. This works well as a filler. It is a little difficult to sand due to the texture of white glue but if you apply it well enough, it seldom requires sanding. Great job on building the air frame by the way. Keep us posted.

Thanks!

Another observation. The tail feathers, especially the horizontal fin/elevator, seem to be a little small when compared to the size of the aircraft.

Thanks, I will correct that

Please help on putty whih can be applied on HD thermocol and then sanded off.   

If you are going to fly it.... put masking tape... (brown tape) over it and it will cover up all the rough patches and also give stiffness to your model...
If you are not going to fly it.... apply a coat of distemper paste (Berger white distemper past cast Rs 80 or so per Kg and comes as a paste).  Allow it to dry and then sand it off..... if you have issues of the distemper not sticking properly.... add some distemper glue to it.. (fevicol has a distemper glue as for it at a home paint shop).
Happy making your model...

Thanks, I will try this. My only concern is it should not develop cracks after few months.

Good morning guys,

Here are first pics of my Boeing 737 model. Lot of work to be completed. Currently working on Main Wings. I have used Sunboard for wings, horizontal stabilizer and vertical stabilizer .... toooooo heavy . HD thermocol just can't hold it properly. Anyways it is not going to fly so no worries.

I will be working soon on main wing assembly.

Any suggestion for improvements are welcome...

Thanks..