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Post Thu Mar 06, 2003 1:39 pm


Ok can someone explain to me what perspex is all about.

I had a brief disscussion on this before when i was requesting an off cut.

Why do people use perspex over Foam PVC?

I understand that if the sign is to be backlit the light must show through the substrate which can not happen with foam PVC. But why for normal no back lit signage do people use perspex??

I've just been to see a site where the existing perspex sign is black and not backlit, the customer is asking for a replacement in perspex.
I have just got prices from cox, amari, silwood plastics and comco plastics who have all quoted £160-£185 a sheet.

I could do this using Forex Top for about £60

I think i must be missing the point somewhere, all the signage i have done over the past 4 years has been done using foam PVC - somebody enlighten me please!!

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Post Thu Mar 06, 2003 4:41 pm

Good question Lorraine. I have often wondered the same thing myself.

I have always assumed that gloss acrylic was available long before forrex top or foamalux ultra was invented. So non backlit signs made from acrylic were made in the days before Top and Ultra hit the market.

A couple of years ago I had a customer request Acrylic signs as this is what had been used before. I suggested using Forrex Top to reduce the materials cost but he insisted on acrylic and was happy to pay the extra. If you look closely at gloss acrylic and compare it to Ultra or Top it does have a shinier finish - but I'm not convinced it is that much better to justify using it.

I tend only to use opal acrylic when the sign is to be back lit - or on rare occasions when it is specified by the customer.

Perhaps others have some experience here and can advise us both if we are missing something.

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Post Thu Mar 06, 2003 5:43 pm

Lorraine, I'm not an expert and I'm sure Robert or Mike will add a more detailed post but as far as Perspex versus Foamex goes:
Perspex is available in a much wider range of colours and sheet sizes are larger. Forrex Top in colours is only available up to 8' x 4'.
Perspex is a much harder wearing material and is less lickly to break, although it is more brittle.
Perspex is much more UV stable than Foam so signs will not fade the same as foam will in a couple of years.
The expansion and contraction rates of perspex are different to foam so it doesnt warp like foam can if fitted without a frame.
I'm sure there are probably other differences but at the end of the day you probably get what you pay for.
We use foam for most signs we do but have used acrylic on a few occasions mainly at the customers request.

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Post Thu Mar 06, 2003 10:38 pm

and not forgetting that Perspex guarantee their material for 10 years

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Post Thu Mar 06, 2003 11:29 pm

Well to be honest i’m no expert the materials in any way, ill try mention a few differences I do know of:

Perspex like Alex said has up to 10-year life. Foamex brands are lucky to have 10 months

There is a high gloss, glass effect, coloured finish with Perspex. Foamalux has more of a high gloss vinyl finish.

Perspex doesn’t warp, buckle in the way that foam boards do…

Perspex on a whole is more durable, tougher and better to work with. Especially in areas of fabrication were the materials need heated and bent… Foamex and the like would melt or discolour…

Perspex has many many different colours.. Foamex is limited to only a few..

Perspex comes in different densities.. Some translucent to allow illumination. Foamex and the like do not have these options…

Perspex also has many different special effects. A new one I know of is coloured translucent frosted. Looks great!
One that is old news now is a two tone one.. Appears as say “navy” during the day but when illuminated from the rear at night the navy turns “white”…

Perspex has been around many years before the likes of Foamex came along. Foamex is basically the cheaper alternative to Perspex. Not cheaper as in the budget market. Just introduced as a plastic alternative were Perspex
is just not necessary. Health and safety signs for one!

There is probably many more that I have missed, but you can see there is a significant difference other than they are plastic and coloured.

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Post Fri Mar 21, 2003 10:14 pm

Rob I wouldent quite say that foamex is a cheaper alternative to perspex
its like wood and cheese, two totally different materials
First of all PERSPEX is a brand name for polymethalmethacrylate (acrylic) sheet, ICI who named it perspex have been around since mike was a lad which is why every one knows its name.

Foamex is a expanded foam board (think thats the best way of describing it), very cheap and easy to work with

Acrylic sheet is usually used in illuminated signage or where illuminated letters are needed, People usually use the foames for cheaper or more temporary signage, although i think its fantastic stuff and i have buit some really interesting things from it...You just need to use your imagination, I use acrylic for making nice signs from and foamex , well i treat it like wood but its faster and easier to work with when you need to build somet

There are still problems with expansion etc of perspex sheet if its not fitted correctly just like foamex and if i remember correctly the coloured foams are not meant for outdoor use (dont know if this applies to the gloss foams)

When i first started in the sign trade 16 years ago there was only really perspex, plexiglass, orraglass (used as roofing in a building in the isle of man which caught fire and dripped burning plastic onto hundreds of people< it soon changed its name after this as it was truly a HORRORGLASS) on the market whic were soon joined by the likes of Altuglass, Repsol and the many others there are flooding the market.

There you go a brief history of perspex

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Post Sat Mar 22, 2003 1:26 pm

For me Forex Top or similar material is fantastic

Just think of how I have been accustomed to making signs over the years

The traditional board
Go down to the local timber yard
Select a piece of 8 x 4 Weather Board Ply (WBP)
Strap it to the motor
Cut to size - watch for those splinters
Quite often it has to rubbed down with fine grade, because of the grain, before priming with aluminium paint.
Rub down again
Undercoat x 2 coats, rub down between coats
Gloss x 2 coats, rub down between

Allow to cure a few days

Now you're ready to start signwriting or vinyl application

Forex Top:

Delivered next day - cut if you want it
Finished ready for vinyl
No drips
No curing
Lovely sheen

No worry of finish, peeling or cracking

Has speeded up my work tremendously


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