applying a texture paste/plaster over polystyrene

[tanktrack]

hi guys I am building a base for my Sherman in the sig group and using polystyrene as the base with balsa sides , I wanted to texture it with say plaster , what is the best way to get it to stick or apply it ? any advise is very welcome .

 

[dubster72]

Depends what type of styrene it is; I've used extruded polystyrene & found brushing on some PVA glue helped make it adhere quite nicely.

I always add PVA which i find stops the plaster cracking or becoming to brittle.

Cheers Patrick

 

[eddiesolo]

Hi Steve.

On my Jetty dio http://www.scale-models.co.uk/threads/completed-dunkirk-little-soldiers-1-35-scale-jetty-dio.25398/ the polystyrene (from packing) was coated using a mix of grey fine powder dust and undiluted PVA. This mixture was mixed together, as for ratios I used a plastic cup and added a good dolop of PVA and just added the powder and mixed using a lollipop stick until I got a fine consistency. This was then coated onto the polystyrene using a lollipop. You have to work at it to get it coat and it may take more than one coat. I found that the PVA and then sprinkled powder didn't work as well, however it depends on the powder used.

Hope this helps.

Si

 

[Stevekir]

hi guys I am building a base for my Sherman in the sig group and using polystyrene as the base with balsa sides , I wanted to texture it with say plaster , what is the best way to get it to stick or apply it ? any advise is very welcome .

If the polystyrene is smooth (like what is used to make models) PVA glue would, I think, be essential to get plaster to stick. If it is expanded polystyrene (like in packaging) I think the plaster might stick well because of the rougher surface, but I would still use PVA. Also, a coat of PVA brushed on the top of the dried plaster might help to strengthen it and prevent cracking.

I wonder whether it would be good to add the plaster (fairly dry, not sloppy) when the PVA underneath is still sticky, to get the plaster to stick better? In the other hand, the plaster will not be a very thin layer so I don't think that stickyness would be too important. You are not likely to turn the base upside down!

 

[Gern]

For my D-day beach I used a mix of 50% water/50% PVA and added normal 'pink plaster' to get a smooth paste, then spread it all over the surface. I let it go off for a few minutes then used a cheap paintbrush to get the surface effects I wanted. Now it's dried and set hard I can sand it to get whatever surface texture I want, drill into it to fix things down and paint it however I want. I tried two or three ways to get a powder to stick to a surface coated with glue but none of them worked - you have to mix your powder with the glue.

Gern

 

[tanktrack]

im using polystyrene from packing which I have shaped with a hot wire , it is encased with balsa sheets, thanks for the advise guys I will give it a go with mixing pva to the plaster on a pva coat and see how we get on:eek:

 

[eddiesolo]

im using polystyrene from packing which I have shaped with a hot wire , it is encased with balsa sheets, thanks for the advise guys I will give it a go with mixing pva to the plaster on a pva coat and see how we get on:eek:

Mixing with PVA should give you a better mix than just painting PVA on and adding a powder or plaster. Coat with PVA when dry to seal, once dry AB or paint to the desired colour.

Si

 

[aaron]

I use polyfiller with stones added for texture and a squirt of white glue.I have used it neat without the glue without a problem with it sticking

 

[Snowman]

I just used polyfiller, but it really depends on what you are trying to achieve.......... concrete block - polyfiller? boulder - PVA+water+sand+powder? a region of terrain - a little of every thing?

Each situation has it's own solution.

 

[Stevekir]

If you have undulating ground, the higher levels would be thick with plaster and would therefore add a lot of weight to the dio. In my railway modelling days (30 years ago), and with such layouts often having high ground, I used newspaper wet with thinned PVA draped over balls of scrunched-up newspaper also wet with thinned PVA, to give the desired shape. Once dried, the surface was strengthened with a coat or two of neat PVA. It was surprisingly rigid.

 

[monica]

real cannot add to whats been said,as all are ways that i do use,as i found the PVA glue is so cheap,

i use a mix 60/40,and the if you need to touch up just from the bottle,

if the polystyrene,looks to smooth for you,just ruff it up alittle to let the glue get a hold on things may help as well

 

[Dustbin]

The only thing I can add is : Add some water-based paint to your mix, of the same colour as your ground work, this will reduce the risk of bare plaster showing in the event of accidents.

 

[spanner570]

Everyone has their own pet method. This has always worked for me....

I stick all the polythene to the base with silicone sealer ( from the tube) If higher terrain is required I just stick more poly on top, again using the sealer. This I coat with diluted PVA, I haven't a clue what proportions, I just add water until it's not a thick as it was!

I don't let it dry, just tacky, then add my surface material. I don't use plaster, but tile adhesive. This dries quicker, it can be put on any thickness, won't crack and can be shaped to any contour you care to mention - in one go.

Plaster, unless applied very thinly, will crack, making remedial work necessary.

When all is dry I give the whole thing a good soaking with more diluted PVA.