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Is plexi UV as good as UV glass?

Posted: Tue 29 Oct, 2019 8:44 am
by Framerkowy
Hey there! :)

It's my first post here. I'm not a professional framer. Everything what I'm doing is for friends or me.

At the begining I need to say my target is to keep all framed things in perfect condition as long as it's possible. That's why I'm in love with Tru Vue museum glass, becuse this is probably the best glass to protect things from fading (my little experience says me that). Of course, there is a one problem - price :D

Now I need make three frames DIN A0 format and... you know what I mean ;) Three big Tru Vue museum glasses cost really big money. This is the main reason why I'm looking for something cheaper, but also protecting framed things. Last time I found Evonik plexi UV 100 glass. Have anyone ever heared about this plexi? For me this company is known only from Borussia Dortmund shirts ;p

I have no idea if this plexi is as good as the producer describes it? Is it really protecting framed things?

I found technical information:

https://www.plexiglas-shop.com/pdfs/en/ ... 100-en.pdf

In section "UV protection" there is stated "offers UV protection of at least 99.7% (at a sheet thickness of 3mm)". A shop in my country has only 2mm thick sheet. Thus my next question is, how good is it when a sheet is 2mm thick?

Thanks in advance for any help:)

Re: Is plexi UV as good as UV glass?

Posted: Tue 29 Oct, 2019 1:41 pm
by prospero
You have to be careful with claims on the UV properties of plexi. It could refer to the resistance to UV light as regards the plexi
itself and not any filtering properties. :roll:

TrueVue Optimum acrylic is the bees-knees in that department. If you think Museum glass is pricey Optimum is on another planet.
A big sheet is around the £5K mark. You could buy a decent car for the same price. :lol:

Re: Is plexi UV as good as UV glass?

Posted: Tue 29 Oct, 2019 2:24 pm
by Framerkowy
You have to be careful with claims on the UV properties of plexi. It could refer to the resistance to UV light as regards the plexi
itself and not any filtering properties.
True. All plastics material are describing as UV proof, but there is a tip, that they are proof itself as a material. Thtat's why my first thought was to buy the first plexi I meet. Similiar story is with glass, because a lot of descriptions say "UV proof". Yes, normal glass is UV proof, but only UVB, not harmful UVA that couse colours fading. There are plenty of inaccurate descriptions and good idea is to ask more experienced people about that, so... I'm here :)

I found more technical information about that glass:

https://www.psp.co.nz/Modules/DocumentL ... cCatId=300

https://www.psp.co.nz/Modules/DocumentL ... cCatId=300

You can read there for instance:

"PLEXIGLAS Gallery® is the best UV blocker among picture glazing materials, offering almost 100 % UV protection. Conventional picture glazing lets in these destructive rays virtually unhindered."

"PLEXIGLAS Gallery® is the best UV blocker among glazing materials. Unlike conventional picture glass (float glass), PLEXIGLAS Gallery® completely filters out destructive UV rays; PLEXIGLAS Gallery® UV 100 provides at least 99.7 % UV protection (at 3 mm material thickness). The colors, canvas and paper of the artwork are durably protected. PLEXIGLAS Gallery® therefore complies with the highest conser-vation requirements."

I understand it as this is really filtering UV. There also you can find the table with physical properties and there is stated UV-trasmission 0.3.

But, and it's still my question, if is it really working? Every producer describes own products as good as they can, so the nice words and tables don't guarantee the product is really working. Maybe is there any person who wroked with Evonik UV plexi and could say few practice words about this glass?
TrueVue Optimum acrylic is the bees-knees in that department. If you think Museum glass is pricey Optimum is on another planet.
A big sheet is around the £5K mark. You could buy a decent car for the same price.
I think I would choose Tru Vue museum glass + a car :D

Re: Is plexi UV as good as UV glass?

Posted: Tue 29 Oct, 2019 2:31 pm
by JonathanB
As Prospero suggests there are lots of pitfalls when discussing various sorts of glazing. Might I suggest you give David Palmer a call at Wessex Pictures in Leatherhead? He's an acknowledged authority on glazing and will be able to give you good advice before you spend a lot of money on something that might not be suitable.

Re: Is plexi UV as good as UV glass?

Posted: Tue 29 Oct, 2019 3:43 pm
by Not your average framer
It's a minefield. You are assuming the people who are making these claims about UV properties understand what they are ready from suppliers published specs, when maybe they don't. UV resistance and UV transmission don't mean the same thing and they may not understand this.

Then if you are cutting it to size yourself, it's not as easy as cutting glass, there are handling issues to avoid scratching the plexi, it not as straight forward when it comes to cleaning, keeping the dust out of the frame during assembly is more difficult because of the static electricity.

What you save by buying your plexi by the sheet needs to be off set again your level of wastage costs. Also cheaper grades of acrylic are likely to not have the best levels of abrasion resistance.

Re: Is plexi UV as good as UV glass?

Posted: Tue 29 Oct, 2019 4:55 pm
by Framerkowy
I don't want to cut or do any othet thing with this. I just only to know if someone used this glass and is able to confirm its features from practice side? I just need to buy three A0 format glasses and look for cheaper option than Tru Vue museum glass. Please, don't consider cutting options and other like that.

I found that Evonik plexi in factory in my country and they are selling A0 format. It's cheaper about 5-6 times than Tru Vue museum glass, what lets keep me a lot of money, but I don't know if this plexi is really working in a way I'm thinking it works. I want to avoid situation when I buy this glass and after few yaears framed things fade out, because it doesn't work as Tru Vue museum glass (really stop UV and prevent fading).

Re: Is plexi UV as good as UV glass?

Posted: Tue 29 Oct, 2019 6:57 pm
by prospero
Bear in mind that things are prone to fading they will if in any sunlight. No amount of UV filtering glass will save them. It might
slow down the rate of fade, but fade it will. Any decent artist will make sure the materials they use are lightfast. :wink:

Re: Is plexi UV as good as UV glass?

Posted: Tue 29 Oct, 2019 8:41 pm
by Framerkowy
Yep, I'm aware that there doesn't exist glass that defend from fading, but it is worth to buy a glass blocking UV light and rate down the fading process, isn't it? :)

I'm not an artist, but I also would to know if this Evonik plexi is worth trusting :?: :?: :?: But I see, not only I have no idea about Evonik products :mrgreen:

Re: Is plexi UV as good as UV glass?

Posted: Wed 30 Oct, 2019 4:48 pm
by Abacus
Have you considered tru-Vue conservation clear?

It has the UV properties you require but is much cheaper than museum

Re: Is plexi UV as good as UV glass?

Posted: Wed 06 Nov, 2019 8:48 am
by Framerkowy
Thanks for all your reply. I have one more question, the last I think.

In description of plexi made by Evonik there is:
PLEXIGLAS Gallery® UV 100 offers UV protection of at least 99.7 % (at a sheet thickness of 3 mm)
What if the sheet is 2mm thick? The protection is weaker?

Re: Is plexi UV as good as UV glass?

Posted: Wed 06 Nov, 2019 9:07 am
by Not your average framer
Although it may sound logical that the UV specification is in proportion to the thickness, that would be an assumption not based on any evidence whatsoever. There must be a qualifying specification somewhere. Anything else means nothing. Remember that the 2mm thick is a separate product in it's own right and therefore it should have it's own specification.

Re: Is plexi UV as good as UV glass?

Posted: Mon 18 Nov, 2019 12:09 pm
by Framerkowy
Thanks you all for your help. I have bought a frame with that Evonik UV plexi and... it turned out this plexi is "AR". Ech, you know what I mean. It doesn't look perfect, because there is a distance between football shirt and the plexi.

Thus I have contacted with Tru Vue distributor in my country and they have Clear Conservation Glass in quite good price. But I have a question to experienced framers - is it necessary to a glass to have any free space in the gap (I mean thickness)?

Image

Producer of my profil says the gap for the glass is 2mm. UV plexi that is 2mm thick has a little free space. I can put in this gap 2,5mm MDF board, but then there isn't any free clearance. What do you think, is it good idea to try change that 2mm plexi to 2,5mm glass? Could the glass be allocated in the frame witohout a free space or it could be dangerous for the glass?