Removing old covering.

[Doug Moss]

Now I'm sure I'm not the only one who hates re-covering, so how do you experts get the old stuff off?

[Ernie]

Hi Doug, Do you know what the covering material is? Most modern coverings use heat to melt the adhesive, so you can use a domestic iron. The problem is that you can easily leave some of the colour on the airframe, so you'll need to give it a rub with either sandpaper, or use cellulose (nail varnish remover)

ernie

[Paul De Tourtoulon]

Heat gun and rip it off,,,

[leccyflyer]

If you are talking about heat shrink covering, such as Solarfilm or Profilm don't be tempted to just pull it off without using any heat, that's how you end up leaving the colour stuck to the wood, which is then a pain to remove properly. You'll get most of it off smoothly , especially if it's Profilm or one of the better  products, Solarfilm can leave a sticky mess and shards of the colour layer stuck to the wood. To get those off, you can use parcel tape, ironed onto the remaining shards of film layer and pulled off at a variety of angles, which can then y-just leave you with the most stubborn bits to pick off with the tip of a knife blade or by sanding. I don't recommend the use of cellulose thinners, especially if you are planning to recover in a different colour, as it will just drive the colour into the wood and you'll never get it out.

 

There's lots of useful information in previous threads, such as here.

 

 

[Engine Doctor]

Plus 1 for parcel tape with Solarfilm.

[Geoff S]

3 hours ago, Ernie said:

Hi Doug, Do you know what the covering material is? Most modern coverings use heat to melt the adhesive, so you can use a domestic iron. The problem is that you can easily leave some of the colour on the airframe, so you'll need to give it a rub with either sandpaper, or use cellulose (nail varnish remover)

ernie

 

I'm pretty sure nail varnish remover is acetone, which works to soften Cyano, too.

[High_Start]

If it is not Oracover, it likely that the old glue and colour will stay on the wood. I have used duct tape with good results. It takes forever though...

[John Minchell]

All the above pre-supposes that the underlying structure is wood (balsa or ply).  How do you get the glue and colour residue off if the model is a foam one?  Because you can't use heat or thinners?

John M

[leccyflyer]

You can use the same amount of heat as was used to put the covering film on, if it's a veneered foam wing - likewise with bare foam covered with film. Quite a low heat will help the adhesive let go.

[Andy Stephenson]

I've had success removing Solarfilm colour residue from balsa using methanol on a rag and plenty of elbow grease. Methanol won't dissolve foam so it should be OK on EPS.

Profilm is quite a different matter, as the colour and adhesive layers are separate. It is possible to remove Profilm without leaving a colour stain.

[Doug Moss]

Thank you all, the current subject is a Hangar 9 Pawnee. Whatever covering material they use sticks like the proverbial **** to a blanket except, of course, where you need it to, then the clear comes off leaving the colour/adhesive behind.

[Engine Doctor]

8 hours ago, John Minchell said:

All the above pre-supposes that the underlying structure is wood (balsa or ply).  How do you get the glue and colour residue off if the model is a foam one?  Because you can't use heat or thinners?

John M

Hi John . I bought a second hand edf model some years ago. It had been very badly painted with a sort of red lead coloured paint and looked dreadful . It had to com off. I used a mix of parcel tape and gaffer tape . It did alter the surface a little but still looks fine after a couple of light coats of polyester base coat that gave a satin finish. The trouble with foam is that any paint will creep between the cells of foam and cant be removed. EPP ( Expaded PolyPropelene) foam is ok and you can use various thinners and repaint in a colour that suits ( test a piece first ). As you say heat is out of the question with most foams as it ruins the surface .  EPS (Expanded Polystyrene) is best left alone  as its very easy to damage and melts at the slightest hint of any aggressive thinners like cellulose. It can be painted with artists acrylic , water based sprayed on neat . Finish off with Ronseal water based varnish again sprayed neat.

 

[John Minchell]

E.D. - I was trying to renovate one of the first ever foam models - a late 70's/80's Byron 1/3 scale Pitts S1.  Sadly it has defeated me so far - you can't sand off the adhesive and colour left on the surface because the stringers and "sag" of the covering between ribs and stringers is replicated in the moulds and hence detail on the finished model.  You can't use a hairdryer or heat gun to ease the removal of the solarfilm 'cause it melts the polystyrene.  Parcel tape trick pull of lumps of the foam too.  So only option left is fill the holes with lightweight filler and then skin it with glass cloth and then paint it - but that is a lot more weight. 

John M

[Engine Doctor]

Good luck with that one John. I guess foam models were never intended to last so long. Another factor to take into account is the effect of UV on the foam. I kept a small foamy in the spare bedroom that I bought for my grandson. After a couple of years it lterally fell to peices like plastic bags do . Had the room had full sun then I would expect this but it never gets any sun ?