surface filler conciladation.

[Basil]

I am trying to repair some crash damage to a foam wing. that has been stripped of its heat applied foil covering down to the 'Veneer' .It is necessary to fill some areas with polyfilla type product , as suggested by some forum members. In certain areas , mainly where the filler is in thin coverings cracking / loss of adhesion has been noticed. Is there anything that can be applied to it's surface in order to concilidate the filler, as being a wing it under goes flexing etc.The wing is to be recovered with heat sensitive film.

Bas

[Zflyer]

try pva

[Don Fry]

I would use epoxy resin, mixed with an equal weigh of propan2ol (rubbing alcohol, iso propyl alcohol), put some mix into the cracked areas, and warm, warm mind, to get it flowing into the damage. Then mix some micro balloons into the mix, stiff paste, and apply with a lollipop stick to fill. Set it.
 Sand smooth and fill low areas with white glue/micro balloon paste. 
Accept, nasty expensive shopping list if you don’t use these things, but will glue it all together securely.

Out towards the tip, white glue paste would do. Nearer the stress centre area, it needs to hold under load. Depends how precious the airframe is. 

[toto]

Bas,

 

I am going to throw my hat in the ring here ( as an inexperienced modeller ) 

 

When it comes to a flexible adhesive ...... I used to use this .......

 

 

I used it to glue rail track down to baseboards as standard PVA dried out and cracked over time. This stuff is meant to retain part of its flexibility which ...... may be of use for a flexing related surface.

 

Maybe not ...... but it maybe worth looking into to see if its properties offer you a solution.

 

if not ..... no harm done or intended.

 

toto 

Edited September 20, 2023 by toto

[Edgeflyer]

I use pu glue. Put it in the cracks , sparingly, cover with paper based masking tape with maybe a few pinholes. Leave 12 to 24 hours for glue to expand. Sands quite well but strengthens very well. Lightweight too unlike epoxy.

[Paul De Tourtoulon]

I use epoxy or polyurethane glue or inject polyurethane foam, anything which is water based can make the balsa (I can't remember the English word )

bubble up.

[Basil]

Thank you all for your ideas.

Bas

[Engine Doctor]

11 hours ago, Edgeflyer said:

I use pu glue. Put it in the cracks , sparingly, cover with paper based masking tape with maybe a few pinholes. Leave 12 to 24 hours for glue to expand. Sands quite well but strengthens very well. Lightweight too unlike epoxy.

As Edgflyer says PU expanding / foaming glue is ideal for filling cracks . Wipe the surface with a damp cloth prior to applying glue and it will foam more and set quicker . Sands down easily . Different makes vary and Gorilla glue seems to take quite a while to go off . Ive found that covering with cling film or polythene is easier to remove once set. Also if a sheet of thin ply is applied over the cling film it make the expanding glue force itself into the joint.