It's a pitty that I can't putty

I like the Tamiya putty a lot, but have used Squadron White as well with success. I don' t think the Tamiya shrinks as much, and has a finer grain to it, but that's just me. Check out Swanny's website, he's got a great article on filling gaps exactly like this. His technique makes it much much simpler, and you don't loose very much surface detail either.

Also, welcome to the forum Lilmodeler, glad to have you aboard.

is that good for small cracks

Lil Modeller, Hello and Welcome.

I use Swanny's fencing method for just about everything that needs to be filled. Ive found the extra time and effort is worth it in the end. The mess is less and the end result is better.

I use mostly Squadron white putty, and I couldnt "putty" until I tried that method either. Another tip I would give you is get a "putty tool" which you can see in the tutorial on his site. Some people swear by toothpicks and other things but that only led to frustration for me, and it helps to have the proper tools for the job. Good luck and let us know how things turn out.

Also, remember to get the right types of sandpaper. (Several ranging from coarse to fine) And use the proper technique. I’ve had great success using the descending method of sanding to achieve a smooth putty seam, that when painted, is (mostly) invisible.

Hi all: I just put this tip on another posting, but it is worth repeating here. For a real good filler putty, I made my own. I took a Dremel grinder to some excess resin pour casting, and produced a quantity of fine resin powder. I mixed a small amount of this powder with a few drops of plastic cement to form a paste.
It will dry quickly so you must work quite fast, but spread it along the joint to be filled, and smooth it a good as you can. After it dries, it can be sanded to a smooth and hard finish that will not shrink. As an added bonus, it adds strength to the model.
May Your Wings Never Fall Off

Depending on the type of model and type of gap I got a few types of putty that I use.

1.) Prethinned putty, I buy mine as is or make my own by mixing thinner and Tamiya or Gunze putty. Apply, wipe off and repeate if neccessary.
2.) Epoxy putty, the one I use comes with a hardener seperate. Mix and apply ir i use the sandwich method, apply to one side of the joint, press together and wipe of excess(won't work if you can see the inside part of the joint)
3.) For badly warped parts I first stitch them together using CA, followed by standard model glue after it is set and than finish off with the prethinned putty method.

I like Squadron Green (big gaps) and White (small gaps), just don't use Testors (hiss).
Also get some wet or dry sandpaper in a variety of grits-wetting reduces the clogging and gives a finer finish.