Poly C and Foam

[James M]

I'm looking to cover a foam wing, Flying wings Slipstream, with something other than cross weave tape and parcel tape.  I can't afford to get irons and heat guns to cover with film and read the articles on using Poly C instead.

 

Neither of them mentions how to apply it to foam.  

Was also looking to use it to cover an ST Models Blaze to give it some added protection.

 

Can anyone give me some pointers ??

[Reno Racer]

James,

PolyC, just think of floor varnish - paint it on with a brush in multiple thin coats. You can use a very lightweight glass cloth with it if you want a hard surface. PolyC on its own will just give you a harder coat (something like a thin plastic coat), but you will still be able to dent the foam through it. 

As an aside, I've also used Ronseal diamond hard floor varnish which is cheaper and gives a good hard layer, not quite fibreglass hard, but decent enough. I used this on my Lander hawker Hunter. In fact, I sprayed this on to start with but then noticed no real difference in look between sprayed and painted on, just just painted the rest.

Do you then intend to spray/paint your model?

[andy watson]

Apparantly poly C and ronseal diamond are exactly the same stuff.

 

But you have to buy bigger tubs of ronseal.  The premium poly C charges for making it available in smaller quantities isn't huge in my opinion.

[Doug Ireland]

I didn't know that Andy, thanks for passing it on.

[Grahamd]

"Apparantly poly C and ronseal diamond are exactly the same stuff."

 

Sorry but NOPE

 

Poly-C is manufactured by Ronseal for sealing and hardening wood used on Gyms & Shopping Mall wooden floors (tested with heavy fork lift trucks carry weights), it's trade name is Floorseal XL.

 

Ronseal Diamond is NOT the same, Floorseal XL bonds and laminates at molecular level, Diamond does not, it just seals, and is sold to joe public as it contains none of the ingrediants (apart from the H2o portion) of Floorseal XL due to what can be sold in shops in the EEC.

 

A simple way to cover foam (blue or white) is to use tissue (ask any shoe shop for freebies), and apply just like paint with a brush. The first coat will hold te tissue down and in place, the second coat will make it very tough, apply a 3rd coat and its a job done.

 

 

[James M]

Hi All

 

Thanks for the advise

 

Will order a bottle or two when I get home and test out on my ST models Blaze - need to cover the wing, only had 3 flights and is getting a bit dented due to the tall grass on the landing field.

 

 

[Erfolg]

I am intrigued by the bonding at molecular level. I suspect that many varnish types adhere by  penetrating the the interstitial vacancies of porous materials, solidifying and achieving a mechanical lock.

 

Does Ronseal adhere primarily by some form of bond, such as covalent, establishing weak attractive forces such as VanderWAals. If so will not the chemical composition of the substrate become critical?

 

Come on you chemists, for you, in principle this  will be dead simple.

 

By the way I have used Ronseal Diamond and Ordinary water based wood varnishes, they both work well for my uses. Glass sheafing.

 

An after thought. I have found that Blue Foam puckers up very, very, slightly, when varnished. If however, a light coat of varnish is applied, allowed to dry, then cut back, very, very lightly, the next coat with the glass cloth has no effect.

Edited By Erfolg on 06/07/2010 18:54:36

[Doug Ireland]

Yep, that's something that keeps me awake at night too Erfolg!

[Myron Beaumont]

Erfolg

Funny you should mention interstitial vacancies of porous materails . We worked with balsa (because  it is very light ,ie wt per volume   and then along comes foam . As you might have guessed ,I know nothing ! BUT ,why not use a can of this new fangled primer used for finishing/repairing plastic bumpers on these modern cars . You know the bumpers I mean (they don't like being hit ! ) I have had the misfortune to have had to use it in preparation for normal spray aerosols . It works as well !

Available at our favourite shop -Halfords

Myron NE1 -ex  Classic car rebuilder

[Erfolg]

Hi Myron

 

I have never used or even know of these bumper repair kits. I understand that most bumpers are made from EPP with a hard outer shell. I would suppose that these cans are foaming? Could well have use in modelling.

 

Blue Foam is very cheap (8'*4'*50mm is approx. £10) though, from Sheffield Insulation anyway. It is an extruded polystyrene, so similar to Expanded polystyrene in many of its properties. It does not like solvents, such as Evostick, does not like all Cynos. As yo will know, it is susceptible to dinging.

 

But sheaved using a water based varnish in conjunction glass finishing cloth, it produces a relatively hard wearing shell.

 

WBV is now a firm favourite of mine. I guess like many users I started using it on wood floors, then stairs, lastly models. It is so very convenient, practically no fumes, what ever brand. All brands seem to work for those that try them. I guess like PVA, all pretty much the same, yet different enough to notice, enough for some to be prepared to die in a ditch.

 

I have tried to get comparative data sheets, but it does seem that some brands are bought in and badged. Here particularly full data can be illusive, even general telephone data. Although products sold via Screwfix have data made available from Screwfix, whoever the supplier is.

 

My main problem with data sheets for WVP, is what do I want to know, for modelling applications? I guess a properties comparison with laminating resins? Are all useful? 

 

 

[iawnski]

hi guys, if you use poly c that is clear, can you add a small amount of dye to it to c see were u have applied to ?if so what dye would be compatable with poly c

[Bob Cotsford]

I mixed some artist's water soluble acrylic to mine - comes out just like doped coloured nylon over glass cloth.

[Erfolg]

The method i have used is to use is that prior to glassing i have sprayed artist inks straight onto the timber (ply. balsa etc). There is no reason not to spray diluted acrylic paints.

 

Dependant on the colouring media determines the effect. If transparent/translucent ink is used the grain is clearly visible. Solid opaque inks/paints produce a solid colour.

 

I vignetted my colours, because I am lazy and had assembled old wings and tail to a new body. Vignetting got me from one colour to another. No need to clean the airbrush, as the overspraying helped transitions.

 

Very little pigment is required, therefore for inks, measuring weight increase is not possible unless chemists jewellers scale are used.

 

The final finish after WBV will be a high gloss if some cutting back and polishing is embarked upon.

[iawnski]

thanks bob will try that as i have some acrylic ,but no polyc  will order it now

[iawnski]

just a thought can i use poly c  and 6oz cloth direct on epp  foam ?

[Tim Mackey]

Yes - ( I take it you have received my emails re: PSSA weekend etc )

[iawnski]

yes mate did reply 1st thing