View Full Version : More advice re framing - behind perspex/plexi glass

05-01-2008, 09:35 AM
Hi there,

I am looking for some more info on framing pastels behind perspex. I have looked throught the forum and have found some really useful help, but there is a few questions that I couldn't seem to find the answers to.

As I am moving more and more over to pastels, and with this comes the problem of shipping a framed painting as most of my clients prefer them to be framed.

I am absolutely terrified of the glass breaking and ruining the pastel paintings so perspex is my other option.

This in turn creates a new set of problems, hopefully somebody will be able to help.

I know you need to leave a signifiacnt space between the perspex and the painting to avoid ghosting, although I am unsure of what would be a recommended gap and of course this problem is worse the larger the painting because there will be more flex in the perspex.

Some advice on this would be brilliant, and suggested depth of space between perspex and painting in relation to a painting size.

Also where do I get anti static spray from, I am based in the UK

This in turn then leads to the problem of the rebate not being deep enough, does that mean I am restricted to mouldings that only have a very deep rebate or is there anything that I can use to essentially deepen the rebate? Or is that not advised because then maybe you can't tape the back of the frame package.

I am based in England so if anyone could advise me of any products available over here it would be fantastic.

Thanks you in advance for your help.

I apologise if I have missed anything in previous threads


05-01-2008, 09:53 AM
Sarah, thank you for asking the question, as I'm curious to know too.

I'm thinking of actually putting the painting directly on the glass/plexi. I've seen a pastel framed in that way, and it is healthy and crisp even after 50+ years. But then again, the indoor 'climate' in Sweden is very dry, so there's no danger of mould. England is more humid, but not much so.

Am looking forward to the replies to your question.

05-01-2008, 10:01 PM
My experience with framing is limited, but I use plexiglass and use a double mat for spacing and have had no problems. When I double mat, the matboard next to the artwork is hidden - it is cut with a larger opening - so that any pastel dust that falls will fall behind the visible mat. The width of the two matboards (I'm using regular width - not the thicker matboard) is not sufficient to have any problems with the rebate (or rabbet, using the American spelling), but I would always double check the rabbet width of any frame you buy.

I ordered anti-static spray from pictureframes.com (that might too expensive for non-USA buyers, not sure what their international shipping costs are), but I believe that photo stores often have this sort of thing.


05-02-2008, 07:32 AM
Hi Charlie, it is such a difficult subject. I am guessing there isn't too much of a problem on the smaller pieces such as up to 16x12 inches, but I am not sure.

I work up 20x16 inches sometimes more and of course the frame and glass/plexiglass area is then at least 20x24 inches if not more. I have no idea on the flex and whether that would then be a problem.

Thanks Don, what sizes are the paintings you are framing under plexi, it would be good to have a guide so I know where there isn't a problem and then perhaps for larger piece have a bigger gap.

I don't want to have to turn back to my acrylics, because I struggle over framing and shipping problems.

I have gone through all my mouldings and checked the rebate sizes. I will discard anything that is less than 10mm, and I do have a couple that go to 15mm, but they don't look that nice :crying:

Thank you for your response :)


05-02-2008, 09:17 AM
I have used plexi on frames up to 18" x 24" with the double mat. Adding another layer of spacer is certainly a possibility, especially if you have even larger pieces. The Plexiglass I have used is around 1/8 inch thick (3mm) so it quite rigid, even at 18" x 24".


05-02-2008, 02:21 PM
Thaks for that info Don,

The plexi glass that my framer supplies is about 1.2mm, so I think I will have to leave a bigger gap. I would guess it is quite flexi being that thin.


05-02-2008, 03:37 PM

There is museum quality acrylic sheet (Plexiglass is a brand, not the product).
Now, lets not forget that framed glass is far resistant than a sheet of glass on its own.
Afterall how many times when kids, we hit windows while playing football and those didn't break ?

Kind regards,


05-02-2008, 04:40 PM
You are right Jose, plexi glass is a brand name. Over here in the UK it is referred to as acrylic glazing as you say, I guess the term/name we use, perspex, could also be a brand name.

I am thinking more and more about sticking with glass, either way it seems you will get problems. I just have horrible visions of the glass breaking and scratching the life out of my art, and then the nightmare of how I fix it for the client. I guess I would offer a FOC replacement. I can't see them shipping it back to me in a rescuable state :)

The only thing that concerned me about framing behind glass is the exhibition and shows quite often ask for acrylic glazing (not that I am exhibiting at the moment but I aim to be soon) so I am going to have to deal with the problem at some point and I like to be prepared. No last minute nightmares.

Anyone elses thoughts on this would be most welcome


05-02-2008, 08:08 PM
Hi Sarah,
I strongly recommend you stick with plexiglass for shipping your artwork, and as you mentioned, when you ship for exhibitions, most will require it anyway. When framing, I use plastic spacers that are made specifically for this purpose. It’s an “S” shaped piece of plastic and your plexiglass goes in one of the openings and is held 1/8” away from your pastel painting. I’ve been using them for several years and can’t imagine framing without them! They are available from a very nice gentleman (Greg) whose website address is: http://www.frametek.com/. He also offers rabbet depth extenders so you will most likely be able to use your existing frames, even if the rabbet is not deep enough.
To figure out how deep a rabbet you need, you’ll need to add:
• the thickness of your plexiglass (I use 1/8” museum uv/non-reflective) for sizes up to 20 x 24
• thickness of the frametek spacer (I use the ¼ inch #FS-6)
• the thickness of your painting & it’s surface
• the thickness of your backerboard (if you use one – depends on your painting support)

I don’t know that it’s possible to ship a pastel without having at least some of the dust fall onto the plexiglass. In order to deal with this issue, I offer a $40 “cleaning credit” with each of my framed pieces. Though it is a bit of a hassle for the collector, it allows them the option to take the painting to a local framer and have the piece disassembled, cleaned and then reassembled. It’s not always necessary, and I’ve only had two collectors feel it was, but that’s how I have resolved the issues of shipping framed pastels. Luckily, I generally sell my work unframed. Best of luck with your framing!

05-02-2008, 09:29 PM
Hi again,

I've shipped framed pastels abroad, namely to USA and until now nothing has happened.
Of course that I understand that for an exhibition they may want acrylic, even for safety reasons.
If the pastel is to be placed where children may reach it - and children can reach places we can't even think - then I do agree that acrylic may be the best solution.
Afterall, art can be very important, but life is more.

Kind regards,


05-06-2008, 08:27 AM
This glass versus plexi thing has also become a bit of an issue for me too. So far I have been totally UNimpressed with acrylic sheeting, which is far too flexible for my liking, especially on larger pictures (say 20 inches or longer), and has a nasty habit of bowing in towards the pastel surface. Several pieces I've purchased ready-cut to size have had nasty surface scratch marks on and were quite unusable. I've not seen any available that is thicker than a couple of mm, and it's not really enough.
I believe that Royal Mail UK now will not insure a parcel where the frame contains glass (don't quote me on that; it might be that they won't insure the actual GLASS....needs checking again).
Anti-static spray...I've yet to find any, personally. At the moment, I'm offering to post a framed pastel picture with everything but the glass, and substitute the glass with a piece of board. It does mean the buyer has to get their own glass, which could deter the purchase in the first place....but nothing's easy.
As for exhibitions, I've never known any of my local organisers reject glass. I think the whole safety thing has gone crazy; glass has been around since before the Year Dot, now suddenly it is Public Enemy Number One.
Appreciate this post sounds a bit negative, but I do understand what you're trying to do. Give everyone else's suggestions a try. The spacers might be just what you want. The only other way is to forget the framing altogether, and just post the picture on it's own (maybe with a mount), as a "sandwich" between two sturdy boards, to prevent slippage and rubbing.

05-06-2008, 05:00 PM
I've only framed two paintings with acrylic---came with the frame package from graphicdimensions.com. The stuff was thin and scratched easily, however, I expect that a better quality acrylic glazing is just fine.

For shallow rabbets you can use a step shaped _T (without the left part of the T ---best I could do with the keyboard characters) fastener. The lower part screws to the frame and the upper lip goes over the frame package. They come in several sizes.

If you stick with glass, there is a clear plastic that can be adhered to the glass and should breakage happen keeps the glass from falling onto the painting. Available from framing supply places. In lieu of this stuff just criscross the glass with masking tape. I use styrofoam peanuts in the shipping carton and thoroughly bubble wrap the painting, so far so good.

As for antistactic spray I have used laundry antistactic spray or even the anti static clothes . Seems to work.

I like the suggested idea of placing a covering over the frame opening and having the purchaser take the piece to the framer to have glass inserted.

05-06-2008, 10:05 PM

I suggest a non-glazzed approach. With a electrified frame and a static control field.

Kind regards,


05-07-2008, 05:06 AM
:D :D :D Electrified frames!! Well you never know in this day and age, they might just catch on!
Trilby's suggestion about the stick-on clear plastic is a good one; I'd forgotten that stuff existed. Should check it out myself......

05-07-2008, 05:49 PM
LOL Jose :lol:

You have made me laugh for the first time today - no I am not a depressive, I have just been bothered by a wasp about 2 inches long :eek: I have never seen anything like it!!! and my lovely 18 month old daughter decided that sleep was a very bad idea last night and today :D

Thanks everyone for your help and comments. Now I had thought of this clear plastic sticky stuff, and have tried to look for it but I can't find it anywhere!?!?

Does it have a specific name?

I can't really picture what you are descibing Trilby, sorry most probably lack of sleep. :D Do they have a name? Thanks for your help :)

Skywatcher, I ship with parcelforce and I must admit I haven't checked their insurance. Not because I don't care, but as far as I am aware as soon as you mention fine art/paintings behind glass most people wouldn't dream of insuring it, and because most of my work has been in acrylic I would be happy to send them compensation for the glass without worrying to much about the damage to the painting. Now broken glass sliding all over my pastels fills me with sheer horror:eek:

Thank you Sandy for your help and suggestions, that info is really useful. Are the rebate extenders easy to fit because I am no good with drills and screws and such?

I am beginning to come to the conclusion that whatever you decide they are all going to bring their own problems and I should pick one and stick to it.

Slow catching on aren't I....

05-10-2008, 07:32 PM
The rabbet spacers come in different sizes and you do actually need to use a drill to install them.

If you do decide to use glass, I highly recommend using the plastic stuff you put on glass for shipping. In the US it is called glass skin and is available from Airfloat systems, the folks who also make great reusable shipping cartons for paintings.

As for the acrylic, if you are going to use it, ideally it it would be the framing/museum quality. Acrylite OP3, P99 is the non-reflective UV rated acrylic and comes with paper on it to keep it from getting scratched. To control static and for cleaning there is a GREAT product here, called Novus, and it does wonders for cleaning acrylic – just be sure to clean off any large particles first so they don't get embedded (I use canned air for this).

However you end up going, best of luck!