Opinions Wanted A really big one....

Create a Post
S

Scallywag

CGF II, Certified Grumble Framer Level 2
Joined
Jan 20, 2011
Posts
234
Loc
Los Angeles
A customer needs me to quote a frame 8' x 10', that's 96" x 120". I am using a maple moulding that is 1 1/4" x 3" that I will finish. I join big ones like this with 2" wood screws and matching maple plugs. My questions are: Do I make the strainer out of my 3/4 x 1 3/4 stock or should I use a true 1 x 2 or 1 x 3 maybe? Or should I have a welded aluminum strainer constructed? Do I go 1/4" on the plex, or would 3/16 be adequate?
The art is a photogram that will be floated. I am going to use gessoed canvas over coroplast that I will then mount 4 ply to. The 4 ply will be slightly smaller than the piece so seems won't be an issue. Any replies will be welcome. I've done big, but this will be the biggest so far.
P.S. I wouldn't be quoting if the client couldn't afford it.
 
That's a BIG piece :). Even if you have done "large" pieces before, this one calls for some special considerations - including labor and logistics as well as engineering (which I think is woefully inadequate by your description).

Have you actually found a piece of acrylic that wide (the 120 part isn't a problem)? And have a vendor who can deliver it and you won't damage it simply from handling before you even work on it?

You can't go wrong with the welded aluminum strainer - with cross supports and you can drill holes through it and screw it to the interior of the frame.

1-1/4 x 3 sure seems too small for the moulding to me, even with the strainer. You need a huge lip on the moulding - I would mill 2-1/2 x 3 or 3 x 4 at a minimum In your original specs, is the 3" the face or depth?

If it is the face, you are way under scale. Your need at least a 3/8" lip, probably better with a 1/2" - or you can have a smaller lip and undercut it so the acrylic will have adequate room for expansion. That doesn't leave much meat for a rail that is 10' long - even if a strainer is screwed to it from the inside.

If it is your depth, with a 1/4" thick lip and then 1/4" for the acrylic, that leaves only 3/4" for your setback, float board and strainer. I just don't see how either dimension makes sense.

What are you making your setback from and how deep is it? 8 x 10 acrylic will bow, even at 1/4" thick so you need some depth.

Have you considered that an 8 x 10 sheet of acrylic @ 1/4" weighs about 114 pounds? Have you determined how you will lift the piece to maneuver it while working on it? Screws and plugs will hardly support miters as small as yours with the dimensions you give. If the piece is flat, how will you raise it vertically and then lower it off the fitting table?

If we were doing this piece, it would be fit vertically and never laid down on a table. Do you already have an "A" frame fitting station that is lit well so you can see debris and smudges on the acrylic?

Re: your platform, what are you going to attach the rag with?

How will you reach the middle of the pieces being seamed?

What will you do to prevent the rag from warping, especially if you use a water based adhesive?

How will you attach the canvas to the coroplast?

Are you planning on cross gluing coroplast together to make a platform? Are you using 6MM at a minimum?

What will you do to make the joints of the coroplast flat and smooth enough so you will not see a telegraphed seam through the canvas?

I would seriously consider a honeycombed or hexcell platform. I don't think you realize the tremendous weight and stress a 8' x 10' piece has.

Are you gessoing the canvas before attaching or afterwards?

How are you going to hinge this piece?

Do you have doors large enough for the piece to get out?

Have you found a truck large enough to transport it?

Get it from the truck to the client's space where it is to hang?

I would be really interested in hearing your quote :).
 
I've done an 8'x10' frame, and wow. Rob has thought of everything! I'm going to jot down his reply to make a checklist for my next large one.

I was able to get plexi that big, but it had to be special-ordered from Chicago and took some time to come in. I'd definitely use 1/4" next time because I used 3/16" to save weight and it had some slight ripples from certain angles. Luckily it wasn't a deal breaker for my piece.

I concur that the lip should be bigger, and you won't regret a stiffer frame. My frame was essentially a truss box made of four pieces of maple per rail, all jointed together. It was very rigid. Overall about 4" wide and maybe 7" deep on the outside.

Definitely plan on fitting vertically, with a helper.

Take pictures throughout. You'll want to remember what you did. And good luck!
 
Good timing for your post.

I'm in the middle of a project that's 60 x 90 so I have a keen interest in all the information posted. My project is similar in design to yours. I've done larger but not with glazing.

How do you plan to space the acrylic? I plan to rip and finish four legs with a wedge shape, 5/16" at the front and 5/8 against the backer. I have about 1 1/8" between the art and the glazing.

I have the strainer constructed from 3/4 x 1 3/4 pine. It's crossed braced twice and in all four corners.

I plan to travel to the home with the strainer only and install /locate the Z bar for hanging. Z bar will be at the top and the bottom.

With the hard part of the installation out of the way I can deliver the much heavier and fragile finished frame and hang in a few minutes.

Doug
 
Well that's a lot to think about. My frame was going to be 1 1/4 on the face and 3 depth. But I think now with the 1/4" lip it won't be enough. I think I can do a welded aluminum frame that is 1 x 3 that would end up costing about the same if I had to have a wood moulding specially milled. The client thought wood would be cheaper, but at this point..... Anyway I will get on this next week and keep everybody posted, but I'm sure we're looking at $10,000.00 frame.
 
Taking a cue from Rob, at that scale, I'd definitely consider a honeycomb aluminum panel from SmallCorp. The entire construction will be vastly more secure -you may even be able to get away without a strainer. (They may be able to supply the acrylic, too, which will save you on shipping.)

When doing something that large, I like a lip on the frame a whole inch wide.
 
Would this be an option...?

I wonder if our Aluminum Pro Bar with cross braces would be applicable to this project?? It is a wood and aluminum stretcher bar and it can exceed 144". This would primarly be used for stretching the canvas. It can be spliced for ease of shipping and installation.
 
Kim- I thought about suggesting your bars, but the biggest problem is the thickness of the bars and lack of rigidity as the bars are intended to be adjusted. Not the aluminum part, but the bead for the stretcher - especially with the initial moulding dimensions specified. Maybe there is a new product for Richeson- an aluminum strainer!

The other "problem" is the plastic parts used to join the cross supports. They just are not robust enough in this application as the method of attachment is too flimsy. The slotted holes which are necessary and beneficial on a stretcher bar are a detriment in this application. An 8' x 10' piece framed with acrylic has tremendous leverage that a canvas does not. There just is not enough anti-racking from your product to make it suitable for this application.
 
Don't have the go ahead yet, but I've been talking to SmallCorp and they make a cool aluminum honeycomb panel that has strips of wood on the back for tacking canvas to. (Genius). The price will most likely exceed 10K at this point. Especially after all the shipping. Just as a side note, Small Corp has been a pleasure to work with.
 
I did a 6' sq frame last year. For the strainer frame, I used 1/2" x 4 pine, but did two layers glued together. This makes it more resistant to warping and also allows you to form neat half-lap joints on the corners. Easy to do. Join four outer pieces first, overlapping the corners - one screw in each and make sure it's dead square. Unscrew each corner in turn and glue up. Add more screws as appropriate. Then just fit in the other bits. Much stronger and more stable than mitered corners and not a lot of woodworking kit needed.
Cross bars each way - also half-lapped. The outer frame was quite chunky, but especially for a smaller moulding I would advise fixing it to the strainer using fittings with a bit of 'give'. I used some mirror plates (bent at 90deg) that were very thin. Can be bent by hand. Timber that length is going to expand/contract.
 
Create a Post
Back
Top