Roof covering

[Coromar]

Hi everyone, and Happy Christmas to all,

 

Can anyone tell me how to cover a roof with a paper napkin to make it look like a cloth covering.

 

I am building a parcel van, and I will need 2 pieces of plastic to form the roof, so I hope the paper napkin would hide the join.

 

Any other ideas would be welcome.

 

Best wishes,

 

Paul

[Simond]

Paul,

 

Assuming your roof is styrene, you’ll join the two halves with MEK or other solvent, I guess. I recommend you strive to make the joint as inconspicuous as possible before you cover it. You can file, fill, sand, and scrape to get a smooth finish.

 

Canvassed roofs were planked under the canvas. You can scribe the planks if you wish. Probably a good idea to mark and drill holes for ventilators, if required, at this stage. Easier to fill & hide if Cap’n Cockup comes to visit!

 

Ensure that your “canvas” doesn’t have any odd embossing, and that it will cover your roof with a decent margin to spare (actually, the canvas was probably applied in strips across the roof, so joins are potentially prototypical - check photos).

 

Start at one corner, locate your tissue in place and apply a drop of solvent on top of the tissue, using a fairly large brush. Keeping the tissue taught, apply solvent along one cant-rail until you get to the other end. You’ll see it soak in and you’ll see where it has glued. You should now have a tissue attached firmly to one side of the roof.

 

In the middle, stretch the tissue gently, and brush solvent across the roof to the other cant-rail. Then simply stretch and glue to compete the remaining corners.

 

Just to be turbo-clear, you put the brushful of solvent on top of the tissue, and drag it along, keeping the tissue taught.

 

Don’t touch the roof anywhere you’ve applied solvent until it’s well dry - a couple of hours. And do this in a well-ventilated space, not an airing cupboard, nor near the budgie!

 

When it’s dry, check for any areas that haven’t glued down and repeat the solvent application as required. Trim the excess “canvas”.

 

And you can apply the rain strips from micro strip in a similar way, I mark the mid point & end points of the rainstrip, attach microstrip with a drop of solvent in the middle, then at each end, ensuring I have a smooth curve by eye, then a quick loaded brushful of solvent will lock the microstrip to the roof.

 

A spray of rattlecan white primer, and you’re ready to weather to taste!

 

Best

Simon

Edited December 19, 2018 by Simond

[Spitfire2865]

I work in Gauge 3, so quite a bit bigger than 7mm. I use actual fabric as when caked in thick paint, looks quite the part.

For smaller scales, Id consider something like fine silk even.  

But for a paper napkin, Id say spreading some pva down across the smoothed roof and laying it on gently would work.  Just put some clips on the hanging ends to help keep it taught while drying.

[Simond]

Very fine woven fabric will certainly look more like canvas than the random fibres of a paper tissue, but the cost may be a consideration. It has to be extremely fine or may appear coarse & overscale. I don’t know what the thickness of canvas used on roofs was, but let’s estimate one eighth of an inch. In 7mm scale, that would be 73 microns approximately. The threads would ideally be about one third of this. That’s really very fine indeed, like “baby hair”!

 

I don’t think PVA will adhere well in the long term to styrene.

 

But if the roof were wood, I would not scribe planks, I would cover it with cartridge paper, and would certainly use PVA for that. All my brass toplights are done this way, it’s described in David Jenkinson’s Wild Swan book on plastic coaches.

 

Best

Simon

[Coromar]

Hi Simon,

 

Thank you for taking so much trouble in guiding me to a "canvas" roof cover. That is just what I wanted to know.

 

Best wishes,

 

Paul

[Coromar]

Hi Spitfire,

 

Thank you for your ideas. I envy you for having room for Gauge 3 !!

 

Best wishes,

 

Paul

[Spitfire2865]

Hi Spitfire,

 

Thank you for your ideas. I envy you for having room for Gauge 3 !!

 

Best wishes,

 

Paul

Oh I definitely dont have the room. But I do love building them!

[O-Gauge-Phil]

Just as an aside ,I paint the roof, then when dry give it a second coat, I then take a tissue split it apart to form a single p!y. Apply necessary folds to represent the prototype and brush it down with more paint. Remove any excess paint and leave to dry. When dry sand off the excess bits round the edge that overhang.

I've done it like this for the last 40 years and they still look OK to me. So far none have lifted.

 

Phillip

 

Edited June 18, 2019 by O-Gauge-Phil
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