Laminating Extira?

[billp]

I am about to take on a job where I will have to laminate multiple sheets of Extira into 3"thick slabs which will then be cut as "slices" . These slices will then be machined as segments of a file which will be either 9"or 12"tall, and roughly 36 square feet in area.
Since I am a one person shop I will probably opt to use the .5" thickness so I can actually move the sheets around by myself. I'm afraid that .75" and upwards will be a bear. Also since this is going to be VERY heavy in the 3" thick form I willl probably build it right on my table, let the glue/glop dry and then machine the slices. In all I will have either 3 or 4 slices to do this way. As I do the cuts I can knock off surrounding areas of material, and possibly even hollow out some layers to lighten the final piece a bit..
What do I use that will hold Extira quickly and securely? This will be an indoor application so I am not worried about archival assembly materials either. Liquid nails?, Silicone?, Carpenter's glue? Has anybody even tried this yet?

[Brady Watson]

Bill,
This PDF FAQ recommends using polyurethane adhesive to fasten Extira. Above that, where it lists "Laminating" it just tells you to contact your local glue supplier...You'd think they would specify it themselves.

-Brady

[stickman]

Bill,

When we laminate up 3/4" Timblend (particleboard), we use a spray contact adhesive. WilsonART, is the manufacturer of the adhesive, its something that that comes in 16 oz spray cans. You spray it on both sheets, let them dry, five to ten minutes. It might be a little hard to do one personed. You might be able to use the stick method to lay up the sheets. You would be able to glue and machine within minutes of sticking the two sheets. What are you looking to create? Interior or exterior application?

Just my late evening... exhausted thoughts... Speaking of exhausted, anyone cut sheetrock with a shopbot? Yes I said SHEETROCK?

[beacon14]

Bill,

Mind if I ask why Extira if it is for an interior use?

I would be wary of contact cement as it will leave a thick, elastic glue line which could cause telegraphing depending on your finish. Polyurethane would probably work well if you can get reasonably uniform pressure across the assembly during the cure. That may entail a few extra sheets piled on top, and/or walking around on the stack to spread the glue evenly. What about epoxy?

Just the thought of cutting sheetrock with a router gives me the willies. I suppose with a 1/8" rotozip bit it wouldn't be any worse than cutting openings by hand with a rotozip tool, but that's pretty messy too. I wouldn't attempt it unless you have VERY good dust collection - the drywall dust will grind your bearings, rollers, pinions, etc. and be a real bear to clean up.

[Mayo]

How did you plan to slice the 3" thick lamination once it is dry? Or were you going to slice it to size first on a table saw or panel saw, then glue up until you got your 3" thick?

Do you have any 3" long cutting bits?

If you need to wind up with 3" thick pieces or letters that are basically 2D, you could just cut 6 of each (using 1/2" material), put some small drill holes for alignment in each part (do that first with the Bot before cutting out the shapes) and then glue up each, using dowel rods in the drilled holes to keep everything in position.

If you need raised shapes or letters on a background, you could cut those shapes from your 1/2" material, and glue or screw them to a background which you can build like an upside down pan, using a side wall height that would make it appear 3" thick.

[Brady Watson]

Doesn't seem like there is ANY info on the web from people who have laminated Extira 1st hand. Contact cement is probably going to be a no-go. Epoxy would take multiple coats...I'm thinking that something polyurethane would do the trick, and something thin enough to spread with a brush or roller...this rules out PU construction adhesive. It skins too quickly. Gorilla or similar might be the way to go. I imagine that you want a paintable glueline?

Mayo,
I believe that in Bill's post, he is calling the 3" thick laminations 'slices'...and he will have 3 or 4 of these 3" slices (18-24 .5" pieces of Extira TOTAL) for the entire job, if I understood his post correctly.

-Brady

[bryan]

Bill, I'd try the new Titebond III Wood Glue
It waterproof, I've used it to laminater other woood sheeting products together, great strength
Spread easy, Only problem maybe the dry time of 4 hours.

Bryan

[mikejohn]

Can anyone help an ignorant Limey.
Is Extira a high quality MDF?
If so, how easy is it to work?
Do you get a clean finish?
Is it sold in Europe, maybe with a different name?
Thanks
......Mike

[bleeth]

Bill:
I think it's time to get out the weldwood plastic resin glue bucket. I like to do my spreading with a fine notched blade after I pour on the estimated amount. You're not kidding this is going to be one heavy piece but at least with the resin glue your glue line is sandable and finishable and doesn't have nearly the flexibility of either contact cement or yellow glues. I use it with a vacuum press for all my furniture laminating including veneers and bending and have never had a failure. You might scuff the surfaces first as you go for a better bond. If you hate urea glue though then it's epoxy with cotten fiber (I'm an old West System cold molder myself), but then you have to be prepared for long term UV protection.
Dave

[billp]

I appreciate the ideas thrown out so far. Here is the nature of the job , so you'll see what we are dealing with;
The job is actually FOR the Extira company. They have an advertising agency who drew up a display for a trade show, and my part of the equation is carving the main focal point; a 6 foot long alligator cut out of Extira..it will then be mounted on a jungle pond photo backdrop for display..
Issues; we don't have the file yet, as it is presently being modelled from photos provided. Because of this we don't know the true size ( in terms of height of the overall 'gator..). I need that info so I can figure just how many laminations I will need to make up the total height.
Due to the weight of the material 1 inch thick sheets will be really tough for me to sling around my shop, so I am going to try and get .5" sheets from them. My "main slices" can be up to 3"thick as I DO have 3"long ball nosed bits for 3D cutting. BUT The composite piece will now be anywhere from 3-6 slabs of the material and should be pretty beefy after laid up. My thoughts originally were to machine the slices, "hog out" a good deal of the internal areas (while leaving a main block in the center for attachment purposes..), and then trim off the exterior Extira...Slide that slice off onto a rolling table, and build the next one..
SO a good,fast drying glue is needed to not only hold these pieces in place, but to give flat slices which can then be stacked on top of each other to achieve the final height. To add to the fun here, the last memo had the 'Gator being left unpainted so they can see the entire shape in Extira ( as well as every glue line I generate.......), as contrast against the jungle backdrop...This also means my slices will have to be pretty close as well.
Best news in all of this is that to my understanding the piece will only be used for this show, so it's not a case of having to make this ready for a national tour...