I want to build a decorative fan design on a gable end (see other thread for drawing) and the half-circle is going to be copper. Hoping I can get some guidance from metal workers on how to fabricate this, as I’ve never done it before.
Basically it’s half of an 18-inch diameter circle, 1 1/4″ thick. I was planning to wrap a piece of plywood with copper sheet metal. First question is what’s the best way to adhere the copper to the plywood?
The second question involves finishing the curved edge of the half-circle (the flat side is the bottom and butts into the flashing on a piece of trim, so not an issue). How can I “fold over” the copper so that the edge of the plywood is covered, and make it watertight? Make relief cuts, fold, and solder the cuts? Is there a better way? Ideally, this top edge would actually bend 90 degrees again at the back to create a flashing type of detail.
And finally, I’m toying with the idea of having a hammered finish. What’s the method? A ball peen hammer, I guess, but what’s the technique?
Thanks for the tips,
Ed
Replies
Ed -
I've never done it but I know you can cold form or cold draw copper if it's soft annealed. Copper tends to work harden, meaning that it gets harder the more its worked so I don't know the limitations of this technique.
If I were doing this, I would start by building a male form out of something like MDF and secure it to a larger sheet. Then try slowly workign my way around the form with a hammer and female section of mold not taking too big a bite at any one place at any one time. Again, you need to locate and use dead soft copper I would think.
Your idea of making this all one piece is, in my opinion, the preferable approach if you can make it work.
Dennis in Bellevue WA
[email protected]
I've never done anything like this before so take this worth a grain of salt, but if I were to try it,
I'd make what ever was in back of the copper water tight, flashed appropriately and even painted, as if it were the finish detail, then just use the copper piece as decoration.
Form the copper how ever you will?
and not use ply-wood in back of it, but maybe a foam backer or something that will not rot, maybe silicone around the edges and a few small nails to hold it in place?
Like I said, never done it, just some ideas.
Never be afraid to try something new. Remember, amateurs built the ark, Professionals built the Titanic.
I have a shrinker and a stretcher for sheet metal. They allow you to do the process you are trying to do without using relief cuts. They weren't very expensive ($110.00 each) and you can get one unit with interchangeable jaws for less. Autobody suppliers sell them. If I can find where I bought mine, I'll post a link later.
Hey Ed, watch out for that greencu fella...next thing you know he'll try to sell a stud stretcher...Do it right, or do it twice.
I do have one off those penile stretchers that I'll letcha have real cheap. It was too small for me. :/
I think I found what you're talking about:
http://www.toolsplus1.com/shrstretch.htm
If I'm not too broke when the time comes, I was thinking of getting a set to do round copper gable end vents 36" diameter, and other decorative stuff. Prices are a bit North of what you remember, so if you know of a better deal, we're all ears.
Thanks --
-- J.S.
Thanks for all the tips--I finally got ahold of a sheet metal guy I know here in town, and he bent it beautifully and then soldered another piece around the curve to act as flashing. Just what I had in mind, and only charged me $40 (think I owe him a beer?)
I fastened it to the gable end yesterday (using construction adhesive on the back of the plywood, aluminum roofing nails on the copper flashing). Got the layout for the clapboards already marked out. Now comes the hard part!
But one thing I was wondering--I think I'm going to let the copper weather to a patina, but am also toying with the idea of polishing it every so often (would look great with the "sunburst" theme). Is it possible to keep copper polished outdoors, or is it just a losing battle? What would you use?
Thanks.
Brasso is a great polish. Spray lacquer is what they put on brass belt buckles and such.
I don't know if you would be fighting a loosing battle outdoors.
I agree with Brasso being great polishing compound, but.....
Flitz is supreme.. IMHO
I use it to clean my brass Zippos. It will even take the adhesive from those miserable
orange stickers of the back.
And then a couple of good coats of clear laq. It really should hold hold for quite a while.
Mr. ED,
Please post a some pics when you get done. I'm anxious to see the results.View Image
You might want to replace those aluminum nails with copper. Glad it worked out.
Use copper nails.
Er. . .I was kind of wondering about that, but for some reason I thought to myself that I've never seen copper fasteners, and I kind of figured that since copper is such a soft metal maybe they didn't make them. But of course I never have worked with copper, so I wouldn't know.
Come to think of it, aluminum is pretty soft too, but I believe copper is softer, no?
Just out of curiousity, what's the reasoning? I've heard that galvanized nails are a no-no with aluminum flashing (although I know reputable roofers who do just that) because there's some sort of corrosive reaction between the zinc in the galvanized metal and the aluminum. Does aluminum have a corrosive effect on copper?
Thanks for the tip. Fortunately I only sunk four nails and they shouldn't be too hard to pull out at this point. Glad I didn't start installing the clapboards yet!
The copper nails may be alloyed to give them more strenth than pure copper. In any case, they work just fine.
When any two dissimilar metals are brought in contact in the presence of moisture and an electrolyte (i.e. dissolved minerals, salts, acids, etc.) one of them will corrode. Chemists determine a number called electronegativity for metals. The further apart any two metals are in electronegativity, the more strongly they react. The scale tells which of the two corrode, for example, with aluminum and steel, the aluminum always corrodes.
It's not good to use dissimilar metals, so you should use aluminum nails for aluminum flashing, and copper nails for copper. I don't know which will corrode the other, or how far apart they are on the scale, but over time one of them will corrode the other.
People often use galvanized nails with aluminum flashing, but it's not a good idea. In a clean environment, such as a roof, you may get away with it for a while, but not forever. If it lasts as long as the shingles then I guess it's ok. But if there were any salt around, or much air pollution, the aluminum would corrode away from the nail before the life of the roof were up.
Hi
If I remember correctly it was called the triboelectric scale. Gold was at the top and then descended. The further apart the metals were the greater the reactivity.
Mac
Not familiar with term, but the galvanic series shows the relationship between various metals
http://www.corrosionsource.com/handbook/galv_series.htm
and a fairly simplistic explanation:
http://www.corrosion-doctors.org/Aircraft/galvseri.htm
It would not be a lossing battle if you could hood wink the neighbors into thinking that it was good luck to rub it once a day. Look at Linclons nose in Springfeild , Ill. Very shinny.
If you want to keep it bright, I'd highly recommend Staybrite. Specifically formulated for metals and it works very well even in a salt water environment. I've used it for years.
Put on say three coats for outdoor exposure. Great for brass or bronze lighting fixtures or whatever. If you want some patina, just let the piece go until you've got what you want and then seal it.
Woodcraft and VanDykes's are two sources. Watch the size of the can you're buying cause the bigger can is usually the better value especially when you add in the shipping.
Knowledge is power, but only if applied in a timely fashion.
ED
Take your wood form and sheet copper to any sheetmetal shop and have them shrink the outside of the circle to fit, they can do this on a roll forming machine. Any good sheetmetal shop will have one. It will crimp the outer edge similiar to the crimp on pipe sections and there-by shrink it to fit your form without seams.
Don't need to buy anything and it shouldn't cost more than 20 bucks if you're able to smooze at all with the shop foreman.
Annealing the copper would also work, but you'd be better of buying cold rolled copper which is 1/8 to 1/4 hard and annealing it yourself. Soft copper can be hard to find. To anneal it, simply heat it to red hot and quench it in water. You can do this up to 17 times as you work it. Working it will restore it's hardness and will require re-annealing. Something as simple as you describe, can be done with one annealing.
I'd still visit the sheetmetal shop.
I'll do it for free, if you bring me the parts.
Good luck
Slater
Kind of like a beer bottle cap, huh? Thanks for the tip, that sounds like a good way to go.
You wouldn't happen to be in midcoast Maine, would you? Darn--I'd have traded you for the favor.
I'll take it to a local shop and see what they can do.
Thanks again.
If you go with a coating to keep them shiny, don't have any sharp edges. The wet coating will pull away from the edge and not protect it. All of the edges have to be sanded or filed smooth and rounded.
Use copper nails.
Side bar:
Here in Rockford, IL, we have a 100 year old memorial hall. A couple of years ago, barrel tiles began falling off the roof. Found out they had used galvanized nails 100 years ago and they started to rust off. Had to take the whole roof off and redo with copper nails. Should be good for another hundred years.
And I suppose I ought to replace the aluminum step flashing over the trim along the bottom of the gable with copper? Since the bottom of the copper half-circle contacts the flashing, and water will run down off the copper onto the aluminum?
I was afraid of that!
In a perfect world, there should be no less noble metals downhill from copper. Look at how much water is going to run across the copper and then the alum. If its not much, don't worry about it. Also, does the aluminum have a mill finish or is it anodized. If its anodized, don't worry about it.
In the beginning stages of this thread someone mentioned copper nails. It just so happens that I got a dozen or so off of a demolition project last Friday. If you can't find any in your area let me know and I will send them to you. Reduce Reuse Recycle
CARPEnter DIEM
Hey, thanks. That's a generous offer and in this day and age it's refreshing these days to hear somebody show some real concern for recycling materials.
However, I just bought some copper roofing nails at my local hardware.
You know, there's an old Maine lobsterman I know from one of the islands around here who's father used to work at the boatyard in Camden during WWII. His dad used to walk around the yard picking up nails to save and reuse--his boss teased him about it, but that's what people used to do and it makes sense. If everybody had that frame of mind (especially with petroleum!) we'd all be a lot better off.
What you need to do is break the electrical contact between the copper and the aluminum, if you can. Is there a way to slip some sort of plastic or suchlike between them? When they're in contact, moisture turns them into a short circuited battery, and the less "noble" metal corrodes rapidly. But break the path for the electrons and they last as well as they would on separate buildings.
-- J.S.
Good idea, I thought about trying to insert some sort of barrier (prophylactic?!) between the copper and the aluminum. Especially since I'd already fastened the copper half-circle onto the sheating with construction adhesive!
But after thinking about it I decided to just fix it thoroughly now rather than deal with potential corrosion problems later. So I pried off the half circle (surprisingly easy--that Titebond adhesive didn't hold very well even though the plywood form and the sheathing were both primed--good thing in this case), removed the aluminum flashing, and replaced it with a piece of 16 ga. copper I had a guy fabricate for me (don't seem to sell pre-made copper step flashing around here).
Now I've got everything back together and am set to start installing the clapboard "sunrays." Will post pics when she's all done.