Hi,
rc people .i wanted to know about the use of diluted fevicol and tissue coating on thermocol. will it give me a
nice sandable surface ,will it give strenght to my frame .my plane has been crashed a lot of times so wanted
to hide those repairing cracks does it work.

I wrap my hot-wired Thermocol wing cores with Fevicol and newspaper, they turn out pretty neat if done correctly.
And yes, it does some strength to it, although, not enough strength to render a carbon rod useless in such a case.

put tissue neatly with 50-50% water and Fevicol.

if u see wrinkles sand it and coat with Fevicol again. As sanding will loosen some strength.

I use normal brown paper cover ... although this makes it slightly heavy but good strength.

regds
Saurabh

will it be sandable .the main concern i have is finishing  .if i sand it tisse should not tear apart
will this work for that

It will Be sandable ..to be sure do a sample test on waste Thermacol

these are the photos on which i have to work i need to hide those ugly cracks and bends.kindly give me suggestion that what would best to that
1. cover it with fevicol and tissue and then put coloured tape to make designs on it
2.cover it with white tape and then use coloured tape to make design
3. use directly some coloured paper(glase paper to cover those cracks by making some design
iwant a nice beutiful plane pleae give some ideas

Man thats taken a lot of beating!  
cover it with fevicol and tissue and then paint it with enamel paint(looks good,cheap and long lasting! ) shouldn't react with thermacol as your coating it with tissue(experts please correct me if i am wrong)

I would personally recommend a light weight glass cloth with thinned foam safe epoxy... that will be best solution..

from where i will get those material(glass cloth and epoxy)

Quote from: Himadri Roy on April 30, 2015, 10:19:22 PM
Man thats taken a lot of beating! 
cover it with fevicol and tissue and then paint it with enamel paint(looks good,cheap and long lasting! ) shouldn't react with thermacol as your coating it with tissue(experts please correct me if i am wrong)

yes bro you are right it has taken a lot of beating but still its my favourit plane its my first scratchbuild

Cut all the chatter here dear..... What I use is this...

1.   Cut the piece of butter paper or computer paper (80 column or 120 comumn... even news paper can be used) to the size required to cover the area of thermocole on the wing or what ever surface you have...  Dip that paper in water in a tub.
2.   Use 60:40 fevicol:water ratio mix for brushing over the thermocole structure....
3.   Take out the paper and hold it in the air gently.... let the water run down....
4.   Before the thinned fevicol dries on the wing... gently with the help of a friend... stretch the paper over the area where fevicol has been applied..
5.   once it has been placed on the thermocol surface.... brush the paper again with thinned fevicol..... the complete surface...
6.   Allow it to dry completely.

The surface will now be stiff enough and without any wrinkles.... even if you have some wrinkles use a sanding block to rub the wrinkles off.... If you happen to sand of some extra bit... paste the paper again as done before over the small area....

The paper can now be painted with Acrilyc colours.... aka... FEVICRYL colours...... remember to paint your models well... not only it looks good but it also becomes water proof as acrylic colours are water proof.  In case you want more strength it can be covered with transparent masking tape for additional strength....

Here is a picture of my model covered in a similar process.... for wing strength I have given a vertical balsa spar of 12 x 6 mm all along the length of the wing....  In face all my foam wings are made in a similar manner and all have taken a lot of beating and flown well all through.

The model shown here is a VT Speedster flying on a motor from EMax and nylon propeller 7 x 4 made by Sharma Models of Jodhpur..... in fact I generally use Nylon propellers of Sharma motors for all my models...

thanku very much shobhit for you complete explanation i wnted to ask that can i use toilet paper in place of computer paper etc as it is very light and soft so easily sandable
2.by how the weight will be incresed by this process aproximatel on 3 feet long ang 4 feet brod wing span plane i i put 2to 3 layet of paper

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Unnecessary Quotes removed

Well.... its your choice... what paper you use for what purpose...... you will only end up increasing the weight... You may use the typing paper or the Rice paper which was available earlier. I am not sure if it is available today.

Quote from: harshit batra on April 30, 2015, 10:25:24 PM
from where i will get those material(glass cloth and epoxy)

Get help from the people who are into selling fiber glass products at your place, since you stay in Delhi I have no idea about it, best is to call just dial in your area n get their numbers, for the epoxy please use araldite epoxy resin "slow cure", this works the best...  do not use other epoxies use by fiber glass manufacturers as it can melt your foam... be careful.

Well... if you do not find fiber glass cloth and you are getting delayed because of it.... Use cloth of any old nylon saree or any thin nylon cloth and paste it with epoxy... (araldite slow cure is best as stated by Sharlok)...... it will suffice your requirements....... Fiber Glass cloth is available in many grades and we need the lightest of them for our general aeromodelling use.....

What I usually do is, coat the surface with a thin layer of 30min epoxy, fill all the cracks then cut and stick small pieces of gauze over the coated area, let it dry, another coat and then sand the surface..works well..

Look at thr image below..its a stock RC aerodyne Bell fuselage modified to a Bell 412 Griffon..the top cowl is made from foam and hardened using the above method and sanded smooth..

Wow that's great work. Thumps up

@shobhit is fiberglass method is sandable
@controlflyer really great work man . what is a gauze where do i will get it ?

Unless you have protective face masks and a place outside the home never sand fiberglass. There are old links that show step-by-step the paper covering method. Gives a good strong wing with more weight though.

Normal gauze available at pharmacies!

Harshit... you read coltrol fliers post... it does he says.... and yes it does

@shobhit icant see where did control flyer said that in his post he is describing his method of doing that
anyway thanks to all you guys for your great support  thanku

the post just after my earlier one wherein he has put a picture of the helicopter which he is making.  Controlflyer's post