Flattening sheet metal

[CCWKen]

An English wheel is for forming curves in light sheet metal. It is not going to help to straighten fan blades.

Oh contraire, I've used my E-wheel to roll out dimples and wrinkles. Just go light on the pressure and work in steps. But, you're talking about equipment costs that will exceed the cost of new blades. And as already stated, removing dents takes patience and experience. If you have more time than money, get a slapping spoon* and a chunk of flat hardwood for a dolly and go at it.

*You can make a slapping spoon out of a piece of a an old car leaf spring.

 

[ray66v]

Oh contraire, I've used my E-wheel to roll out dimples and wrinkles. Just go light on the pressure and work in steps. But, you're talking about equipment costs that will exceed the cost of new blades. And as already stated, removing dents takes patience and experience. If you have more time than money, get a slapping spoon* and a chunk of flat hardwood for a dolly and go at it.

*You can make a slapping spoon out of a piece of a an old car leaf spring.

NO contraire, an English wheel will not straighten fan blades. It's not a majic wand.

It could help to smooth out the metal, after it has been roughed back into the proper shape, provided the blades are not too thick.

However; if one possesses the ability to repair them enough to finish them on a wheel, they also would be able to do it, without the wheel.

English wheels are not found in body shops because they are not all that useful in repair work.

 

[chickenman]

a sheet of rather hard rubber on a plate of steel and a hard rubber mallet

 

[bcarwell]

Thanks to all for replying with all your suggestions. I hope the pics of the windmill uploaded, if not I'll try again.
Many focused on the metal stretching if I pound and I don't quite understand why I'd care. The fan blades are not high precision with precise joints so who cares if the blades stretch out a bit ?
Interesting technique about shrinking with heat, causing me to look on YouTube and elsewhere and I found some interesting additional information. One idea, though slower, is let it cool naturally so as to not require hardening and annealing. One other suggestion was to cool with compressed air.
As to just buying new blades for $20 each, there are 30 in a 10 foot wheel so its out of the question.
BTW I found that Harbor Freight has a 3 hammer and dolly set for $40 so I'm going to try that. Not high quality but good enough for my purpose. I also found the technique interesting to drive over the blades in sand and will try it.
Farmerford, sorry I'm a rookie so I don't know about Flute and Walling parts (yet) but will let you know if I find something. I see you've discovered the wealth of info and sources on the internet, so keep trying. It seems Aermotor and Dempster are the two biggies and still in business though at one time I understand there were 1000 manufacturers.
And lastly, does anyone have a good technique for removing non hollow, e.g. steel rivets (beside drilling them out) holding the blades onto the frames ? I've got about 200 to do. Best suggestion I've seen so far is to try grinding one side of the rivet and punching them out. Or if you have to drill, using a countersink high speed bit, some oil, and maybe just try to drill off the head and punch it out.
Thanks for all suggestions and help. I'm taking a blade to a metal man tomorrow to see if he can do any good cost effectively...

Bob

 

[CurlyDave]

As a complete amateur in this kind of stuff, it looks like many of those blades will need replacement. If you can get all new ones, they will at least all look the same.

 

[ray66v]

It would be better to just make new blades, than to try to fix most of these.

If you have a HVAC contractor that fabricates in your area, you could possibly buy some sheet metal scraps for a good price.

You could possibly make it look decent as a stationary unit, though I doubt if it will ever look good unless you start over with new parts.

If this thing is actually going to spin at any kind of speed, that looks out of the question right now. If you don't have the disc in a good, balanced alignment, it is going to shake and vibrate until the bearings give out, and it comes apart.

 

[CCWKen]

English wheels are not found in body shops because they are not all that useful in repair work.

They're found in my body shop. I have two. You don't see them in hack shops because nobody knows how to use them. Besides that, few shops "repair" anything. Autobody Steel after about 1976 doesn't take kindly to straightening. They replace parts or slap filler over the dents. And they're not very good at that either. Time is money in a production body shop so the intent is to get the job out fast. Repair is not in the equation. But apparently, you already knew that.

Pull up to a local body shop in a 1908 Buick, 1912 Ford or even a '58 Hudson. They'll laugh in your face if you ask them to repair body damage. Most won't even paint the parts you bring in. Lord help ya if you tell them not to use filler or make a door skin for a '25 Model T. I can't imagine real repairs to autobodies without an E-wheel. So our opinions differ on that.

 

[bjcsc]

Regarding the rivets, the best way to remove them in thin sheet metal is to drill and punch. My idea is similar to ray66v's. I would take my best blade to a wood shop and have, essentially, 'dies' made on a bandsaw from an oak block. Then I would buy a new piece of sheet metal, cut out the shapes, and form each one on a press in between the two dies. Once I made all the ones I needed, I'd make it known that I had others for sale for $19 each...

 

[joes_427_vette]

The english wheel won't help unless your putting a curve in the blade. I have a 1929 Sears windmill that has to be put it. Haven't picked a spot yet but the motor/ gearbox is intact with new seals and ready to spin. Have the 6' fan and a 8' fan for it.

 

[flusher]

Thanks for all suggestions and help. I'm taking a blade to a metal man tomorrow to see if he can do any good cost effectively...

Bob

Those blade look too corroded to me to bother. Just get yourself some galvanized steel sheet stock, a handful of cutoff blades for a 4-1/2 angle grinder, lay out the blade pattern and cut new ones. A waste of time to salvage that rusty junk.