Resin 'castings'

[Mallard60022]

Hi. With resin 'castings' (e.g. PDK boiler mouldings and those delightful Golden Arrow loco bodies) what are the issues (if any) re. painting? I have heard it suggested that it can be difficult to get paint to adhere well. As I have not had the experience of using these products (yet*) I would appreciate any thoughts or advice. *I have some small resin detailing cab castings to work on for my 4mm ES1.

It strikes me that if resin based boat hulls and and some car bodies (are F1 body parts resin or fibre glass?) can be painted (or is the casting pre coloured in the mix?) then the aforementioned mouldings, after thorough cleaning, should take paint quite well? However, the above model rail castings may be a different 'product'? The Hornby Skaledale range is advertised as 'decorated' poly resin; is this the same 'mix' as the PDK/GA stuff?

Many thanks, 36E

[ozzyo]

Hi. With resin 'castings' (e.g. PDK boiler mouldings and those delightful Golden Arrow loco bodies) what are the issues (if any) re. painting? I have heard it suggested that it can be difficult to get paint to adhere well.

 

Mallard,

 

give the resin casting a good clean with Cillit Bang (the green one, degreaser) then prime with a good quality aerosol primer ( I use Teroson etch primer). and you should have no problems.

 

OzzyO.

[jwealleans]

I had the same advice from Jon Hall for the resin cast ferry vans he did me. A good scrub and rinse - that's quite important as there's something in the cleaner which can stop paint adhering - then when thoroughly dry, prime. I used Games Workshop Skull White on mine and haven't had any problems.

[Bruciethefish]

As above, a scrub in warm water with a little detergent is usually all that's required. If the surface of the castings are very shiny, however, then it's a good idea to use a mild abrasive to give the primer a 'key'; I generally use an offcut of 'Scotchbrite'...

[Re6/6]

A few years ago I built some resin bodied wagons (I forget who the manufacturer was..maybe Appleby) the instructions said leave the casting to soak in vinegar overnight, then clean and rinse thoroughly. I also read the same advice on the old place .

[Oldddudders]

(are F1 body parts resin or fibre glass?)

I think you'll find they are often carbon-fibre, which has remarkable strength-with-lightness, but is an absolute pig when shredded across the track, as it pierces tyres at the drop of a hat!

[Mallard60022]

I think you'll find they are often carbon-fibre, which has remarkable strength-with-lightness, but is an absolute pig when shredded across the track, as it pierces tyres at the drop of a hat!

 

Oh yes, of course; carbon fibre. A bit like the masts I used (and broke frequently) when I windsurfed! Wonder if the drivers ever get little bits (from the busted parts) in their finger tips like us when using our fibre glass pencils during modelling?

Cheers 36E

[craigwelsh]

The solebars on my mineral wagons are resin castings i've done. Mine have normally had a bit of a brush with the fibreglass when i've been cleaning up the stuff soldered through them. I spray with Games Workshop black primer as they sell resin kits along with their plastic and whitemetal offerings so its perfect.

[coachmann]

When these resin moulding were first put to use in the model railway hobby they were an absolute pain in the kneck. My first experience of the difficulties in getting paint to key without looking as if I was spraying oil or orange peel was with a GWR open-cab Pannier. The whole loco body was resin.

 

Soaking in cellulose thinners would not do the trick and we suspected a release agent had impregnated the resin. For a while I refused to touch the 'milky bar' stuff. The outcome was to use Halfords plastic primer on the resin parts but not allow it to get onto the attached metal parts! Once cured it was okay to use normal metal primer on the metal and on top of the plastic primer. I should perhaps add I always used cellulose paint, not enamel.

 

Another problem is the resins inherent instability. It expands and contracts quite alamingly, so you spray a boiler handrail only to find it has unpainted bits showing beside the handrail knobs on a warm day but is okay indoors. Take it ourside in the cold and the unpainted bits shows again! If a locos etched running plate has been securely bolted to a resin boiler, watch out for bowed metal! As on real locos, an allowance has to be made for this movement.

 

DJH, for one, cured the problem when they adopted pewter in place of resin.