I am going to glue strips of 1/8″ x 3/4″ x various lengths of anodized aluminum into 1/8″ x 3/4″ dadoes I have cut into a wood stave core door that is laminated with Black Walnut. These aluminum strips are going to be decoration on an exterior door that is completely covered and will never see rain or snow or the sun. I need a glue that will bond aluminum to wood. What glue will work best? Epoxy? Contact Cement? Anybody have any experience trying something like this?
Paul
Replies
Hi Paul,
While reading your question, one thing came up my mind: double-sided turning tape (there is a good one from Lee Valley - clic.
My second choice would be Epoxy. I had very good results with metal, but never tried with aluminum.
Good luck,
Serge
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Paul, The wood in your door will move due to changes in humidity in the air. The Aluminum will change length relative to temperature. You need something which stays very flexible and which has thickness.
If you want something which will really hold it better than anything, I suggest 3M 5200. You can find it at marine stores in black or white in a caulking tube. You can use something like silicone, but it is not nearly as sticky.
I will stress again the thickness. think of it as a rubber band. You know how far it will stretch length-wise, but how far will it stretch in thickness? You will be dealing with shear with this application.
You should also leave a space at the ends, if it miters together. If you make it tight, and it gets really hot, the aluminum might buckle if you don't give it anywhere to go that way.
You can find out how much if you google aluminum, heat expansion, coefficient etc. X the length. It may seem small in thousandths, but that is all it will take. :
Keith, here are some pictures of what I am doing. The aluminum will be able to expand lengthwise and in it's thickness because it is not trapped on the edges or the top. There are no miters. In the pictures the aluminum is only laid in place, they have not been glued yet. On scrap I have tried gluing the aluminum to wood with, Titebond III, two part epoxy and PL 300. The Titebond doesn't hold at all. The epoxy is WAY to messy, expensive and a pain in the butt, but it holds. The PL 300 never did get dry even after waiting 24 hours, the aluminum slid right out of the dadoes. I have used silicone adhesive caulks before and they work pretty good in the bathroom. I live in Cleveland, OH right close to Lake Erie. We have plenty of boat stores here. Tomorrow I will head out and find me some of that 3M 5200 and experiment with it like I did with the other glues. If you have any other advice please feel free.
Paul
You are not going to find the 5200 is any easier to use than the epoxy. However there are tricks that you will need to use. On both sides of the dado, you will need to mask, and also the face of the aluminum. When you press it in, you will need to finger it off. Wear gloves, because this stuff is hard to get off of your hands. I don't think I would have done the core like you have chosen, but maybe you are luckier than I am. I think the dado needs to be deeper also, but I can't tell for sure how deep they are. If you go to a West Marine store, ask for a catalog. They have very good advice pages on almost every subject, such as caulk and bedding, setting windows or hardware etc. Oh, the 3M 5200 may take a couple of days to dry under the aluminum, but when it does, it is tough as the tires on your car.My biggest concern for you though is your core, and gluing to that lumber core birch veneer which may not be up to what you are putting on top of it. But then I don't know exactly what you chose, or why. It will be interesting to see what others say, although it would be even better if you posted this over on the woodweb forum to see what a more professional readership has to say. Here is a link if you are not familiar.http://www.woodweb.com/cgi-bin/forums/aw.pl
Keith, if the 3M 5200 is not going to be any easier or less messy to use than the epoxy then I may as well go ahead and fight with the epoxy, because I already have $65 invested in it. If I had a choice now I would have liked the aluminum to be thicker and the dadoes deeper but it is already done and the aluminum strips already bought and paid for ( 8 strips of 1/8" x 3/4" x 96" cost me $88.) As far as gluing to the Birch veneer on the stave core door that is not the case, my dadoes have gone deeper than the birch and I am into the core. I am curious, how would you have built the core on a project like this?
The polyurethane glues (Gorilla etc)are supposed to bond to metals. Have you looked at them?
To much foaming with the Gorilla Glue for this project. If I was painting this project instead of staining I might consider Gorilla Glue.
I didn't offer the suggestion to make it either harder or easier, but right for the job. The epoxy is just too rigid for this unless you know how to mix it for maximum flexiblity, which you obviously don't. I am happy that you have the epoxy for future use. I normally spend a lot more than that just to have it on hand. Here is a link for you.
http://www.westmarine.com/webapp/wcs/stores/servlet/SiteSearchView?catalogId=10001&Ntx=mode+matchallpartial&keyword=3m+5200&Ntt=3m+5200&N=377+710&y=0&x=0&storeId=10001&Ntk=Primary+Search&ddkey=SiteSearch
There is an engineering solution to what you're trying to do. Several recent high-profile buildings (the one on the particular Modern Marvels show detailing this material was in Dubai) have the exterior surface (aluminum panels) held to the external frame of the building with high-strength tape.
At first glance, it would seem that any sort of tape would not have the permanency or adhesive qualities required for a "failure is not an option" project like a building, but this stuff is specifically engineered to hold the two surfaces tightly to each other regardless of the differential expansion of the two materials.
It is made by 3M and is called very high bond tape, or VHB. The reason it works so well is that in addition to being very sticky, it is visco-elastic in a very wide range of temperatures and conditions. The visco elastic properties of the VHB tape means that the two bonded surfaces can put quite a bit of shear on the tape, and it will deform but not let go. Here's a link to the 3M site:
http://solutions.3m.com/wps/portal/3M/en_US/VHB/Tapes/
Thanks for the link. The 3M VHB idea is what the fellow in post 2 suggested but he said to use 2 sided turners tape. That would solve all the mess I'm having with this epoxy. Lay a strip of tape in the dado and slap the aluminum on top of it. That's the way to go. I have to do some more reading at the 3M site and see which tape would be best for my application. What I'm thinking about mostly is how much would the tape raise my aluminum strips above the surface of the door.
Paul
Keith has a very valid point regarding the expansion issue of the metal vs. the wood. But it depends a lot on the environment. Still, better to do it right. You stated several times that the glues were messy to use. I'm thinking that you are applying too much. Having glued metal to interior work on a number of pieces, I've learned that it doesn't take much to simply keep the metal in place. It's not a structural item so an absolute glue bond isn't necessary. So, a thin bead of the marine stuff, poly glue, or epoxy will hold the aluminum but not seep out. Perhaps a bit more glue is called for at the ends where the metal may catch on something or where curious folk will pick at it. Another glue that I think would work is plain ol' contact cement. Apply to the bottom of the dado and the back of the metal only, not to their sides.About your door core: One doesn't see lumber core plywood so much these days... at least I don't where I live and work. But it used to be rather common. Your core is essentially a sheet of lumber core ply. The wisdom in using this stuff, as I have always understood, was to deal with it as if it was solid lumber. The critical issue then is: seasonal expansion/contraction across the grain. If indeed your door core acts like this, then you will encounter some rather unwelcome buckling, delamination, twisting, etc. All things that are contrary to what we all desire in a door. I think I would have played it safe on this and chosen a more stable inner core. Say, multiple layers of baltic birch or Apple Ply. Even a particle board or mdf core would work although I've always tended to prefer plywood. Marine ply would be a good choice... it has virtually no voids and is a quality material. In any event, it looks like the door is essentially finished except for the inlay, so it's purely academic now. There was a discussion on this forum some time ago (eight years maybe?) that concerned a fellow building a solid walnut door with some sort of cross inlay or some factor that could cause fits to its proper behavior. Was it a border of steel? I can't quite remember. Anyway, this discussion created great debate, a pleasure to read. As these things can do, the thread included some rather heated opinion. I don't think there was ever a follow-up regarding the door's outcome... pity. I wonder what others think about the chances of this projects happy ending? My opinion is that all will be OK, assuming good craftsmanship, proper framing, proper hinges and all other aspects that can affect the outcome of an exterior (shielded from the weather or not) door. By the way, I like the design very much. I, for one, would like to see a finished photo.
Paul,
I would bolt/screw the two together. Drill oversized pilot holes to allow movement. If you want the fasteneres as a design detail, drive them from the outside. Otherwise, the inside.
Chris @ www.flairwoodwork.spaces.live.com
- Success is not the key to happines. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
The tape option sounds good, I have used a construction adhesive made by Dow Corning, #995. It comes in a caulk tube, and is very durable and expands and contracts with wood or metal. Good Luck, Chris
You might want to consider "trim tape" from the local auto parts supply. It's a rubber tape that's really sticky on both sides, used for attaching trim to automobiles - plastic to metal/rubber to plastic or metal etc. Pretty good in all weather.
If you decide to use tape to do this job, it'd be wise to choose one of the 3M VHB tapes. They are designed for exterior building applications, and have been tested extensively for the purpose.
I haven't called 3M for this particular product, but have for other items. They have a very helpful sales application staff, and will save you quite a bit of time wading through the technical documents.
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