perspex sheeting - any tips on thickness or brand

[Homerjh]

Hi all, question on this as it is something i want to check before i start.

I have a outdoor dog shed (pic at the bottom) where the tortoise resides (and the kennel bit is fully insulated, boarded and heated!) and want to put some perspex over the windows to help keep the outside area slightly more sheltered from wind and rain, there will still be a 1.2x1.2 meter hole in the front so not looking for an airtight solution.

measuring the gap i can get panels from screwfix for about £40 all in (not looked elsewhere yet), this will be 2mm thick.

so the questions :

How strong is 2mm, could this be fitted without a batten in the middle or the existing metal panel (ie just windows), i can get 4mm which will be strong enough, but that is double the cost so maybe not worth the extra especially if being used with the metal that is there still. Considering things like strong gusts, wouldn't want it breaking with strong winds as its used outside the intended purpose.

Undecided if i will reuse the metal parts or not yet, its not really for security as the door to this area is unlocked anyhow but may

Fitting, i have used it before with a small countersink but that has cracked around the edge, so are there any methods or fittings to screw it securely without cracking. Probably only want 6, 1 on each corner and one in the middle of the long side.

Sun - this is on a South facing garden so in the summer will get direct sun pretty much all day, anything to consider?

 

[MattRoberts]

You can get acrylic / perspex sheets on eBay for less money than that. 2mm should be strong enough not to require a batten, but it depends on how belt & braces you want to go.

As for fixing, probably the easiest way is to cut to size, slot into place and then tack batten along the inside edges to 'frame' it in. Then pop some sealant along the outside edges.

 

[Lons]

Hi
You don't say what size the openings are you need to cover which clearly will affect the thickness you need.

2mm acrylic is pretty flexible and looking at the picture my guess is that the windows are at least 600mm ? If so then I wouldn't trust 2mm if unsupported to be thick enough unless:
You do as Matt suggests and fix it with battens with at least 20mm overlap, plus allowance gap as it will expand and contract or it is possible to fit a couple of supports right in the centre and secure it to the wire grid, not tightly but just enough to stop it sucking out or blowing in. That would save fitting full length battens.

Acrylic will always craze if you drill near the edges and anywhere alse for that matter as the drilling process introduces stress. You should never drill closer than 12mm from an edge, the holes must be oversize and not tightly screwed in fact treat it as you would a glass mirror.

There are other ways of fixing and we used to sell an extremely strong 12mm d/s tape made by 3M, developed to fit polycarbomate into metal bus shelter frames, worked very well but at the time was expensive. Can't remember what it was called but had a green and white check release paper.

Polycarbonate in any thickness would be better for your use but probably to expensive, don't opt for the cheap styrene alternative as it will degrade and break and if you do go for acrylic there is little to choose between brands but 2 types available.
1) More expensive cast acrylic which is glass clear and very durable
2) Extruded in which you can see the extrusion marks if you look carefully. This moves a bit more than cast and is more moisture absorbant (not a problem for you)

A third option is 6 or pref 10 mm twin wall polycarbonate which isn't too expensive though not clear enough to see through.

Whatever you buy, make sure you fit the uv protected side outwards or it will degrade.

As far as suppliers, there are several on line though carriage may be costly so also look locally for " suppliers of semi finished sheet plastics" Amari plastics are one national company or failing that call in to a local sign company and ask where they buy from.

Hope that helps, it's 20 odd years since I was in the industry so things have changed a little. Leading major manufacturers then were ICI (Persex) and Rohm (Plexiglass)

Bob