French cleat size recommendations

[hcowart]

So, I haven't really anything that addresses the size of the cleat in regard to the size/weight of the glass (been searching... a lot).

Any recommendations? My glass will be 22x20, at least 8mm thick with some "pebbles" tack fused on it.

Small scale version: http://elemental.name/?p=985

Planned large scale version (6' x 8'): http://elemental.name/?p=1362

Thank you for any advice/help!

Helen

** edit: there will be 12 panels that are 22x20 that will make up the 6'x8' finished piece. Sorry, must have been tired when I originally wrote this.

[Bert Weiss]

Helen

I suggest you work with Hang Your Glass, a board sponsor above. They have a lot of experience gluing their hanging hardware on glass.

[hcowart]

Bert,

They were my first choice. I love Hang Your Glass standoffs, but the cost is so prohibitive, over $700 for the recommended standoffs alone, I was looking for a less expensive alternative.

Helen

[Bert Weiss]

Bert,

They were my first choice. I love Hang Your Glass standoffs, but the cost is so prohibitive, over $700 for the recommended standoffs alone, I was looking for a less expensive alternative.

Helen

Look at their attachment area to weight ratios and design accordingly.

[hcowart]

Not to sound rude, but why should I design around a display mechanism? I am sure there are many alternatives and I am hoping to learn about them.

[Morganica]

Not to sound rude, but why should I design around a display mechanism? I am sure there are many alternatives and I am hoping to learn about them.

Because the glass won't look nearly as nice in pieces, on the floor?

One thing I've learned when going bigger with glass sculptures, is that the display/mounting mechanics must be engineered in from the beginning of design, or you can wind up with a beautiful work in a box in the closet. (Or, worse still, it takes a nosedive off the gallery's wall a few minutes after installation--that was a very painful lesson).

So, start with the weight and size of each piece--the weight is critical--then pick your cleat material. Once you have that, find the adhesive, and in this case pick an adhesive with high shear strength because its going on a vertical surface. At that point you can figure out how big the cleat should be--the adhesive usually has to spread across some minimum surface area to hold that weight properly.

You've got roughly 3-layers at 20x22in., which is probably about 14 lbs or so of glass. If you run through the HYG website you'll see that you are actually at the edge of workable for a single standoff.

You've also got to figure in the mechanics of hanging the things. If you must slide the glass an inch or so down into the cleat you'll either need to space the work so you have room to do that, or be very careful with your install order...etc.

[Bert Weiss]

Not to sound rude, but why should I design around a display mechanism? I am sure there are many alternatives and I am hoping to learn about them.

Designing around a display mechanism is critically important. When somebody views a work of art, they get a first impression, that most likely has nothing to do with the mechanics of the display hardware. This is what you are shooting for as a designer. If you don't start from this point, the chances of ending up awkward are far greater. If the display mechanism is part of that first impression, chances are pretty good that you failed at the design. The design must provide sufficient surface area to attach the holding structure, and either the piece or the hardware must get the glass to the desired angle relative to the wall. If you don't want to see the attachment hardware, the design must have an opaque area in front of the hardware placement. If you don't consider this stuff from the beginning, you are only dumb lucky if you work it out.

There is not only one way to hang glass on the wall. Understand that a company like Hang Your Glass, will quickly go out of business if their clients lose their glass in great numbers. So, you have 2 choices, you can pay for their expertise and long learning curve, or you can innovate a less expensive alternative. The French Cleat is a good approach. You have to figure out how to attach it with surety. It is best if the hardware and the glass match perfectly in flatness where the attachment takes place. One of the beauties of the Hang Your Glass system is that it doesn't require a large attachment area.

One of the simplest and most reliable systems is the L - screw. You need at least 3. The glass is supported from beneath, and only a minimal bit of hardware is visible. Not as sexy as invisible from behind attachment. But, cheap and effective. I use a short piece of clear vinyl tubing to establish the standoff space and cushion the glass. I've hung large, heavy, amorphous glass sculptures this way.

[Brad Walker]

Not to sound rude, but why should I design around a display mechanism? I am sure there are many alternatives and I am hoping to learn about them.

I remember seeing a piece of Dan Clayman's at SOFA several years ago. It was an impressively large casting, larger than I am, and it seemed to float a few inches off the wall. I just had to sneak a look at the back to see how it was hung. To my amazement, Clayman had cast part or the hanging mechanism into the glass itself (in glass!), so that it was simple to hang securely and unobtrusively. Seeing the hanging mechanism gave me a new respect for Clayman's work and the planning involved.

You're right, there are many alternatives to designing around a display mechanism, but it's one way to make sure the piece looks its best when hung.

[hcowart]

Great - this is what I was wanting to hear - not just "design around the display." I'm only 3 years in to glass and I have not created any wall pieces larger than 12x12 before. I've been searching on different ways to display it and would prefer to use HYG standoffs because they are so perfect for the job. But, as I said before, I can't afford the heavy duty standoffs that I was looking at (http://hangyourglass.com/superduty.html 721-5M - STYLE L), preferring the 1 standoff to 4.

I really do appreciate the info. I just don't know what's available. French cleats looked like a good alternative to the standoffs. I am ordering the Loctite glue & UV light Cynthia recommended in another post.

I have emailed HYG, but not gotten any response on my request for assistance - which I am surprised at. They've been delightful in the past.

I've allowed 5" between each panel, so there is plenty of room to slide them into place and the wall where they are going has plenty of space around it.

Thank you for the information. I'm sorry if I'm not a good communicator.

[Morganica]

Well, wait to order your glue until you know what you're gluing TO. Different adhesives are required for glass to metal than glass to wood or acrylic, for example.

You may also want to consider the size of the panels and placement of the cleats. If you use HYG, you're a little big for optimal holding (I think they top out at an 18" span although I could be mistaken--you'll want to check). You can get around that by using two cleats on a single piece of glass, but that becomes tricky, too. If you don't get the distance between the wall hangers exact, or if the wall isn't straight, (or, or, or) the two hangers can put stress on the glass and eventually cause it to crack.

Ideally, then, you only want to use one per piece. That means that either the cleat needs more surface area (i.e., it's bigger) or your adhesive must be stronger. Sometimes I avoid the whole problem by simply making smaller pieces but more of them. That might be an option for you, too.

And, I gotta say...you'll save money making your own but good adhesive is expensive and making the cleats can be a pain. Sometimes the commercial solutions wind up saving money.

[hcowart]

Thank you. There's so much to learn. And so many variables in this kind of stuff, which is why I'm finding it hard to get it all in my brain.

[hcowart]

So, I got the cleats and the Loctite Impruv 349. Not a very successful venture. The first one I did worked like a champ and the others not so much. I'm in contact with Loctite to see what other options there are.

Fortunately, no glass was broken.

[Morganica]

Oh no.

What happened? What kind of cleats did you buy/make? How did you clean the glass and the cleat before you applied the adhesive? Did you use any silane? How did you cure the Loctite? How much set/cure time did you allow?

[hcowart]

Good news: Nothing broke!!
Bad news: The adhesive didn't cure.

Cleaned the glass with the BE cleaner, alcohol and acetone. Just to be sure it was clean.
Each cleat was "cured" 2 minutes initially with a black light blue bulb and then 1 minute in sunshine.
They were acrylic cleats - I don't know the exact name/brand of the acrylic.
No silane.

During the Aquarium install, we noticed one of the panels had glue draining from behind the cleat. So, rather than trust that just that one was not cure, I took them all back to the studio and spent the next 4 hours re-curing them (I thought) with brand new black light blue bulbs.

They seemed fine after that. But...

A patient probably pulled 2 of the pieces off the wall of the trio, since you can see by the photo below, if it actually fell it would have smashed to bits.

My best guess after talking with the Loctite rep was that I wasn't using a powerful enough UV light (F15T8/BLB tube & a BLB CF 15w bulb). Because plexi is naturally UV-A absorbing (doesn't let it pass through or transmit) up to 300nm (349 cures at 365nm), it's thickness (1/2") and the color of glass used - all these factors were working against me. The manta ray set up like a charm. 40 seconds of my old BLB tube light and it was done. But that had white glass on clear, so that probably helped reflect the UV light up under the cleat.

I ended up putting L-hooks under and on either side of each panel as a safety net. And I'm using DOW silicone to adhere the one cleat that came off - recommended by a local windows/glass guy & his wife that also do stained glass windows. They have a mirror with glass shelves attached only with this silicone that have been on the mirror for over 15 years with no problems.

I thought I had ordered Loctite E-30CL epoxy, but apparently I clicked the wrong item at checkout because what was shipped was 40-FL. I could have kicked myself at that point. Anyway, I'll know more on Tuesday (4/9) how the DOW silicone works out, after it's 72 hour cure.

Below are the links to the install just after placing them all. I'm pretty proud, just wish the glue would have cured!!

Aquarium installation: http://elemental.name/wp-content/upload ... G_7819.jpg
Water panels #1: http://elemental.name/wp-content/upload ... 24x682.jpg
Water panels #2: http://elemental.name/wp-content/upload ... /wave2.jpg

[becky wills]

I would love you all to check out our Adjustabail system - being a glass maker myself - I have been using this system for about seven years, and we had it patented and manufactured because of all my glassy friends nagging me to do so....There are three sizes of Adjustabail and each have a weight limit. We tested around 20 different types of adhesive and the one we sell is cost effective and works. I agree with all of you - the adhesive is THE critical thing...because if that doesn't work...you're piece is going to fall off...so we did mega testing on that front. If you are in the US look at http://www.adjustabail.com or in the UK or Europe http://www.adjustabail.co.uk
Warm Glass UK (where I work as an instructor) now stock the Mini Adjustabail. I am having an Adjustabail stand at BeCon this year - not long to go now, and looking forward to meeting with some of you lovely people on the other side of the pond.

[Morganica]

I hate to say it, Helen, but I've been using the very same adhesive on the very same acrylic (Loctite Impruv 349 and Plexiglas) for years, on opaque glass, and having no trouble at all. And I've hung up to 20-pound pieces from a single cleat without problem. Some of the heaviest have been hanging, moving to different exhibits, and replaced on my walls for several years, so they're pretty stable.

I've found that most adhesives are very fussy about a lot of things, and it's easy to skip one of them and have a joint fail. Sounds like that might have happened in a couple of places. These are my rules for adhesives:

-You really, really need to match the adhesive to the primary function. "Shear strength," that is, they're good at resisting a force pressing sideways/90-degrees to the joint so that it twists off, is extremely important with vertical/wall mounts. Shear is usually the biggest culprit in the failures I've had--one of my favorite adhesives, DP-105, is extremely strong when gravity works with you (as in gluing something to a base) but has absolutely crappy shear strength. Through very sad mishaps I've learned NOT to use it on walls. But 349 has good shear strength with proper application.

-The light source makes a HUGE difference--I tried a couple different lights before I found one that worked every time. (the same Feit bulb you're using) However, apparently the light is less effective with continued use; a fresh bulb always works fairly quickly (in about 5-10 minutes). An old bulb may need several hours (and I probably wouldn't trust it). Fortunately, the bulbs are relatively cheap, so I just make sure I use a new bulb if the set starts taking longer. I'm not sure why yours didn't work, unless your plexiglas was UV-filtering.

-Most good glass adhesives have definite shelf and open lives. In the case of 349, I can get several good uses out of it over the course of a couple of weeks. After that, it gets increasingly viscous, and its adhesive strength starts to diminish until it no longer holds. If the 349 is fairly runny, I trust it. If I have to really squeeze to get it out of the bottle, I toss it. I write the date I first used it on the bottle and if I get much past 30 days open, I toss it. And if I haven't opened it in a year, I toss it. That's an expensive practice, but it's better than losing the glass. Silicone can be very bad for this--I dinged an umpty-ump thousands of bucks' worth of bronze sculpture when a big heavy piece slid off the wall and bounced. Turned out the unopened tube I'd just purchased was well over a year old. I wonder if you had fresh 349? How old was the container?

-The glass must be scrupulously cleaned, abraded lightly, and scrupulously cleaned again before gluing up. I wash it with a good detergent or ammonia cleaner, then with acetone, then rinse with water and let it dry. Then I apply silane. Our guild invited a 3M adhesive expert to speak on glues, and he said moisture on glass was a huge cause of failures--the silane prevents that problem.

-I make sure I have enough surface area to get good contact. That means I must also ensure that the area of the glass to be bonded has no ridges/textures/curves that would prevent it from contacting the cleat at all points. And that the cleat is large enough to support the piece. I test the flatness with a straightedge, rotated all the way around the joint area while I'm watching it at eye-level. If there's a high spot, low spot, bubble, texture, etc, I grind it flat. Is that a possibility?

-If I'm concerned about the long-term viability of the joint, especially in shear situations, I create a "cleat seat," i.e., I use the grinder (or a piece of fiber paper cut slightly smaller than the cleat and put underneath the back of the glass during the final firing) to create a recess for the cleat. It doesn't have to be huge--an eighth of an inch is plenty. Then I grind it exactly to size, prep it and glue the cleat into that recess. Doing that prevents

-Once the joint is glued, I DO NOT reposition it or mess with it. I leave it for usually 24 hours longer than the specified cure time, in a room temperature environment where nobody goes. If I have time I also test the joint for a couple of weeks by hanging, rehanging, pulling on it, etc.

[hcowart]

The glue was definitely in good condition, and it was an unopened bottle before using it on the manta ray, but at least 2 weeks old on the panels.

Must acquire silane.

Will try sanding next time. Love the kiln carving idea to inset the cleat a bit.

I did clean multiple times with alcohol and acetone, but will follow your steps next time. I Di not pay a lot of attention to the exact type of acrylic used, that could be a huge factor. I knew going in that plexi was naturally UV blocking to some extent, but not how much. I've done some research in the past couple days and learned about that aspect of acrylic. (See my info page http://elemental.name/?page_id=1469, and send me in put please!)

Going to try locative E-30CL Hysol epoxy next. Looks promising, and close to the shear strength of the Impruv 349. I also want to try Loctite 3494, as recommended by Loctite. It's a light cured adhesive, but doesn't require it to be UV.

Thanks for all the info. I really do appreciate it. Will be posting on my page or sharing, if that's OK.

[becky wills]

During our adhesive testing - over a period of 4 months - we found that none of the 3M adhesives we used worked - and our 3M rep refunded us for the lot! It's risky using acrylic because it isn't uv stable (unless stated) and - whilst that doesn't matter in the short term...it will matter to your client in the long term.