Edit: Hills using canvas. Was: Anyone know about canvas?

[olicana]

I'm looking to buy natural cotton canvas sheet to make a 'desert / arid' table cloth. I've found a supplier who does it in a 9 feet wide bolt in two weights: 7.5 oz and 10.5 oz. I don't know how thick that makes them. I'm guessing I should go for the heavy one but, is this too stiff / thick to lay well over hill shapes, etc.

Any advice would be appreciated. Thanks.

[Atheling]

This is probably in the wrong section James.

It should be in the General Wargames Discussion Board or something along those lines.

However, I can tell you that at Uni I painted on 10oz minimum (usually 12oz or heavier, depending what the shop had in at the time) but that was for quite heavy impasto oil paintings!

If it's for a terrain mat then I would go heavy as it will be more likely to have a tighter weave as well being made up of thicker and therefore stronger strands of fibre.

You could go the whole hog and go for a tight weave Burlap  (Joke)

[olicana]

I needed a quick answer (today), as I was at the checkout, so I took the scatter gun approach. Got into trouble it seems: I didn't realise it was crossing a line by cross posting to more than one board. Whoops, sorry everyone.

Anyway, thanks for your reply. I've taken your advice and gone to a different company selling 12 oz in a 2.18m wide bolt. Ordered 5m and it came in at less than £50 including delivery and VAT. Much less than the first company (by £20) so, many thanks.

In a week or three, when the big Napoleonic game I'm playing is done and dusted and my table is clear, I'm going to cover it with a poly groundsheet, lay out the canvas and paint it, using a 6" wallpaper pasting brush, with fairly weak strengths of tea and coffee for a 'desert / arid' look play mat. The canvas is unbleached so it has a beige look to it in any event, the tea and coffee will simply serve to break up the 'one colour look' with natural shades of light khaki and brown. My wargame room will smell like Starbucks for a week or two but, hey ho.

I haven't a clue how it will look but, I'm strangely confident that it's going to work. I think the trick will be applying the tea and coffee stain in fairly weak dilutions, overlaying them with more only if required.

[vexillia]

James a word of advice if you are using real tea and coffee.  Don't use them fresh! 

The polyphenols, in tea especially, are very reactive and that's why the tea darkens with brewing.  It will continue for some time after it's cooled down. 

For control, far better to make a brew, and leave it overnight and dilute it to the shade you want. You don't want the tea stain darkening whilst on the canvas.

It's amazing what you learn from a career in laundry detergents!

Have fun.

[olicana]

I shall heed that advice.

Thanks, Martin.

[Ethelred the Almost Ready]

It will be the best smelling game in town.  Will the caffeine give your game and extra kick?

[BillK]

@olicana, strangely coincidental your post, I was just considering using tea and coffee grounds as dyes and canvas to make a larger groundcloth. Looking forward to seeing pics of your results and some step-by-step commentary. I am considering black, red and green teas to get some subtle variations in color.

Also interested in which canvas you went with... after much looking around I'm currently looking at Melca Drop Cloth-Tarp, 100% cotton cream, 6x9 foot, with side seams only. It is the side seams only, nothing cutting across the table width, that really caught my eye. Reasonable price online.

@vexillia, thanks for the info concerning polyphenols, it will make a huge difference realtive to the strength of the hue and how/when I dilute the tea.

Cheers,
Bill

[olicana]

Cloth arrived today. Looks pretty good, and a nice pale beige to work from.

In the end, I bought this stuff, link below. I found the company good to deal with, carrying a solid up front price with no hidden extras (includes VAT and free delivery in the UK by TNT). Mine was delivered two days after ordering. My cloth was 5m long (16.4') by 2.18m (7.1') wide - it cost £49.50 all in - which was the best price I found after some (but, not extensive) searching. The price was a little better than some, and much less than some others (after hidden the extras mounted up).

https://www.forrestfabrics.co.uk/100-cotton-12oz-canvas-natural-fabric-218cm-super-wide/http://

It's going to take a few weeks before I start as I've got a big game running for the next couple of weeks. Then I'll start. Currently, I'm collecting 2 litre pop bottles to store cold tea in. I reckon it will take buckets of the stuff but, I might be wrong. I've also ordered a large poly dust sheet to protect my table top during the process.

My biggest worry is the drying between applications. Once it gets to the just damp phase I can hang it out on the line, but, until then I know it has to stay flat to stop the tea all running in one direction and making one side darker than the other.

As for extra colour, I might shade some weak tea with acrylic ink. I have a few brown, orange and red Intense Ink Blocks (by Derwent) kicking about the place - you can grate them and add water to make your own ink - mixing the ink in with hot tea before cooling over night should be easy enough. I don't think I'll need much, and as long as it's added to the scheme whilst everything is sodden it should softly blend / bleed in quite nicely - not too much or dark is probably the key. I'll store that in some jam jars. Plus, there is always the coffee for 'brown', though I'm going off the idea of that for some reason.

Thinking about it, I suspect most time will be spent in the preparation of the 'stains'. Actually applying the stuff should be fairly straight forward.

One last thought, though I haven't experimented yet, is should I apply the tea to a damp cloth, or should the first application of cooled, stood overnight tea, be heated up in the microwave to help it soak into a dry cloth on first application. I have a funny feeling the cloth will repel water slightly unless it's rubbed in well - 12 oz canvas is a heavy duty cotton, the weave is pretty tight and it's not been washed before.

I'll keep you posted.

[Atheling]

One last thought, though I haven't experimented yet, is should I apply the tea to a damp cloth, or should the first application of cooled, stood overnight tea, be heated up in the microwave to help it soak into a dry cloth on first application. I have a funny feeling the cloth will repel water slightly unless it's rubbed in well - 12 oz canvas is a heavy duty cotton, the weave is pretty tight and it's not been washed before.

You've got me there. From that point is was stretch the canvas over a frame then apply the Gesso in order for the canvas to shrink and get a tight paintable surface.

One thing I would add, is that Canvas will shrink so it's probably just as well you went for a decent 12 ounces

[olicana]

I know about the shrinkage, I think it's about 12%, after washing and drying. Which is quite a lot.

Question is, is wetting the same as washing: the latter being more in the way of wet pummelling the fibres. No scientific knowledge or experience on my part but, I'm expecting somewhat less than 12% by only wetting it.

As said, I will not be able to machine wash my cloth because it's so damn heavy (and my washing machine is brand new this summer and my Mrs would kill me if I broke it by overfilling it with three times the recommended weight). I might put the canvas into the bath to get wet before hanging it out to 'half-dry'. Somewhere deep down, I feel the canvas will take the tea better if the cloth is already damp.

[Atheling]

I know about the shrinkage, I think it's about 12%, after washing and drying. Which is quite a lot.

Question is, is wetting the same as washing: the latter being more in the way of wet pummelling the fibres. No scientific knowledge or experience on my part but, I'm expecting somewhat less than 12% by only wetting it.

I honestly couldn't tell you as I (unsurprisingly) never washed a canvas before painting on it

As said, I will not be able to machine wash my cloth because it's so damn heavy (and my washing machine is brand new this summer and my Mrs would kill me if I broke it by overfilling it with three times the recommended weight). I might put the canvas into the bath to get wet before hanging it out to 'half-dry'. Somewhere deep down, I think the tea might be better applied to an already damp cloth.

That could work. Maybe try to find some way of stretching it too to avoid it going out of shape (no idea how- sorry- I'm not being much use).

[BillK]

This is an interesting problem/solution set.

Can you work outside? If so, then perhaps sprying the canvas with the hose, letting it sit for a short while, and then working in the teas, dyes, and inks while it is damp gives some advantage. Warm sunlight and the force of the hose should give decent penetration of the fibers.

[Billchuck]

If you’ll have some waste canvas, you can cut some of the scrap off now to test with. If you have issues using just water, you can try spraying it with isopropyl alcohol. They may help the ink soak into the fibers.

[olicana]

I hadn't considered that it might go out of shape.  Cotton material shrinks, but it doesn't usually become 'distorted'. What would we do with shirt collars if it did that! I did briefly think about pinning it to the frame of the table like a painting canvas but I think that risks the cloth not shrinking evenly through warp and weft - providing it does that, there shouldn't be any distortion as it's 100% Egyptian cotton.

I think keeping it flat is probably the key, and my table is certainly that. I would like to do the staining outside, and I do have a large flat hard surface to work on outside but, Yorkshire isn't renown for stable dry weather and my window of opportunity is short (one week at the end of August, whilst I have the house to myself for the week).

As for 'pre-soaking' it. I now wonder if a simple hand pump spray might be best: wetting / dampening it with a fine mist of water, perhaps with a small amount of detergent mixed in to help it soak in.

[Atheling]

I hadn't considered that it might go out of shape.  Cotton material shrinks, but it doesn't usually become 'distorted'. What would we do with shirt collars if it did that! I did briefly think about pinning it to the frame of the table like a painting canvas but I think that risks the cloth not shrinking evenly through warp and weft - providing it does that, there shouldn't be any distortion as it's 100% Egyptian cotton.

I think keeping it flat is probably the key, and my table is certainly that. I would like to do the staining outside, and I do have a large flat hard surface to work on outside but, Yorkshire isn't renown for stable dry weather and my window of opportunity is short (one week at the end of August, whilst I have the house to myself for the week).

As for 'pre-soaking' it. I now wonder if a simple hand pump spray might be best: wetting / dampening it with a fine mist of water, perhaps with a small amount of detergent mixed in to help it soak in.

I used to lightly soak canvases in water (then let it dry) before stretching on a frame; but this was more to make it tighter still when combined with the gesso stage.

When I have done quick-ish "sketch" paintings on unstretched canvas it always went out of shape- I was using oils with turpentine so not water based. I really cannot add any more as I simply don't have any experience with unstretched canvas for wargames mat purposes except for what I have said. Certainly not very large pieces of unstretched canvas.