Kiln drying STEEL?

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I saw a guy going over some hot-rolled steel bar with a blow torch recently. When I asked what he was doing he said he was evaporating the moisture from it. Sure enough - I watched it myself. The process is that he'll fabricate the chair, blow torch the whole thing, then rub beeswax all over it. Seems pretty labor intensive. I'm wondering if we couldn't just put the whole dozen chairs in our wood kiln for a few days and achieve the same effect. Any thoughts.
JP ************************************************* Also posted to rec.crafts.metalworking
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Jay Pique wrote:

Don't see why not if he's not counting on the torch flame doing something--certainly the kiln heat would be sufficient for surface moisture.
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dpb wrote:

Could he be burning the milling oil from the steel before he paints it? That would be the quickest way I could think of to get rid of it completely.
I don't think the blow torch would be hot enough to remove the stress from the metal in the recent fabricated piece.
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On Fri, 19 Sep 2008 14:52:48 -0700 (PDT), Jay Pique

My thoughts are that if it's moisture you're trying to get rid of, just set 'em out in the open sun for a couple of hours. Refinished some lawn furniture recently. Used a pressure washer to knock off loose paint. Left them out in the sun for a couple of hours to dry, set them in the shade for a couple of hours to cool off, sprayed them. No problems.
But, I don't think it was moisture the guy with the blowtorch was after. Like another poster surmised, it was probably mill oil he was burning off.
Tom Veatch Wichita, KS USA
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On Sep 19, 9:23 pm, Tom Veatch wrote:

Now that's interesting. The whole story is this. One of our guys and a metalworker built a table for a client. It's made from pieces of hot-rolled steel that had further been cold bent into curves. They welded together the parts, sanded it and then applied a coat of beeswax. And it rusted. So now the metalworker thinks that if he heats the steel really well it will evaporate trapped moisture and then they'll seal it out with beeswax. (I know, I know....) In any event, since it sounds like it's not moisture they're burning off anyhow, the whole question of whether a kiln would work is pretty much moot. (Obviously wouldn't be hot enough to burn off oil, either.)
Now for the real question - how do we prevent this table and chairs from rusting? Not much response from the metalworkers <grumble>.
JP
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Jay Pique wrote: ...

Has to be an impervious coating of some sort.
Depends on what look is wanted, cold bluing could do or powder coat or even painting.
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Not much response from the metalworkers because they're laughing too hard about the moisture "trapped" in the steel.
Paint it.
John Martin
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It's called hot dip galvanizing. It has been around a long time, it is inexpensive and works very, very well. Steve
wrote:

Not much response from the metalworkers because they're laughing too hard about the moisture "trapped" in the steel.
Paint it.
John Martin
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Could we fabricate the whole chair or table, then take it someplace to be dipped? Or do we have to assemble it from pre-dipped steel - in which case I gather we'd have rusting issues at the welded joints, right?
I can't wait to unload a ration of crap....errr...."inform the metalworkers" on Monday!
Thanks all.
JP *********************************** Just scorping the seats.
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In article

It is normal to dip the complete assembly.
--
Stuart Winsor

For Barn dances and folk evenings in the Coventry and Warwickshire area
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Jay Pique wrote:

You need to call around to your local plating companies and find out what size tanks they normally have set up. I'd go with chrome over galvanized--hot dip galvanize isn't all that pretty a finish and plated zinc isn't very hard. Nickel is _very_ tough (it's used as protection on aircraft propellers) but doesn't stay shiny without regular polishing. How large a piece can be handled depends on how big a tank is available.
If the tanks are large enough they should be able to do the whole table, although they may need to do some fiddling to get the electrodes placed for even coverage. Welding up from precoated steel means that you've lost the protection at the welds. A better option might be to make it in several subassemblies that can be bolted together--note--if you're using tapped holes, either tap them _after_ plating or plug them for plating.
This really sounds like you might be ahead of the game to use stainless.

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On Sat, 20 Sep 2008 08:51:52 -0400, "J. Clarke"

now where did you get that silly idea from???
name the propeller that uses a nickle coating????
Stealth Pilot
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Stealth Pilot wrote:

Hamilton-Standard 54460 and 24PF are two examples that use a bonded-on sheath over the outer portion of the blade leading edge. You can see them on a 54460 at http://www.flickr.com/photos/goldorak/417313975 /. The new 8-way that replaced the 54460 on the E2 is another--you can see the sheath clearly at http://www.flickr.com/photos/kensaviation/1896504667 /. Those sheathes are plated on a mandrel then removed from the mandrel, trimmed, and bonded to the blade. There is also a process involving plating nickel over conductive rubber--the rubber prevents cracks in the nickel from propagating into the blade. Don't recall where all that was used--some 54H60 variants for hovercraft use had it and I recall vaguely that it was used on the 63E60 in a similar application--it's been a long time and the 63E60 was past its prime when I was working at Hamilton.
If you ever fly on a propeller-driven commuter airliner, look closely at the blades and you'll see the sheath unless it's been painted over, which it's not supposed to be except along the edges. Carbon black in the paint, which is electrically conductive to bleed static off the blade, tends to corrode the nickel.
As to how I happen to know this, my first job out of college was as a project engineer in the Blade Group at United Technologies Hamilton Standard and my area of specialization was erosion protection.
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J. Clarke wrote:

John,
Isn't that section of the prop heated for ice protection?
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B A R R Y wrote:

Centrifugal force takes the ice right off outboard, the prop deicers are on the inboard end and the spinner On an older commuter airliner like the DHC-7 you can see the heater as a rubber piece bonded onto the blade.
In http://www.flickr.com/photos/clearskyphotography/1218007750/ you can see the heaters on a solid aluminum blade if you look carefully--there's a foam cuff inboard with a rubber covering, but on top of that there's a deicer attached--you can see the edge of it about 1/3 of the way back on the top left blade. The little tab that sticks up is part of the heater but isn't itself heated. The shiny strip along the leading edge is likely where dust and rain and whatnot have eroded the anodize off the blade, although the Dutch may have painted it for some reason. The tips would have been repainted recently. http://www.flickr.com/photos/cmphoto/2505031128/ shows a different model of that prop (both the P-3 and the C-130 use the 54H60 but with different blade tips--nobody ever told me why the difference). http://www.flickr.com/photos/cmphoto/2530724870/ shows the heater very clearly. Note the clear tape at the ends of the heater--that's one that I haven't seen before on that prop but would bet that it's polyurethane tape that's there to protect the outer edge of the heater--the outer few inches of those heaters would wear through long before the rest and the polyurethane tape was an approved modification on the commuter airliners when I left the company--it's very likely that someone after me got it approved for that use on the P-3. http://www.flickr.com/photos/78436618@N00/2497802331/ is another with a clear view of the heaters--on this one they've been cut back a little bit--not sure if it's far enough to get into the wires or not--but that's the area that would wear through.
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On Sun, 21 Sep 2008 08:14:24 -0400, "J. Clarke"

centripetal force and inertia exist. centrifugal force is a misnomer. Stealth pilot
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Stealth Pilot wrote:

<rolling eyes>
Most engineers don't have time to write book every time they refer to the mechanism by which water is retained in a bucket that is swung in vertical circles on the end of a rope. We just call it "centrifugal force" and recognize that that's shorthand for a long-winded explanation and get on with life.
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J. Clarke wrote:

LOL - Just thinking of the fortune you (I/we) passed up by not selling a rubber stamp with this explanation...
:-D
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Morris Dovey
DeSoto Solar
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On Sun, 21 Sep 2008 04:57:52 -0400, "J. Clarke"

alright you got me there :-) hovercraft props!!!!
I dont recall seeing the leading edges you mention on commuter turbo props but I'll believe you.
most props are forged 2025 aloominum with an anodised surface hardening. the polished prop effect is achieved by wearing off all the anodising and polishing the remaining aloominum. the leading edge treatments I can recall are more like icing cuffs or polyurethane tapes.
seriously though I do believe you on the hovercraft props.
Stealth ( Hovercraft props!?!?) Pilot
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Stealth Pilot wrote:

I think that the term for the sort of commercial aircraft that would have Hamilton props is "regional" airliners these days.
The C-130 and P-3 have 7075 blades (note, not 707_6_--Hamilton props are about the only place that 7075 is used and Alcoa used to have to run special lots for Hamilton). The Hamilton commuter props have a fiberglass or Kevlar shell over an aluminum spar, which may be 2024--I honestly don't recall what they were using on those spars. The 54460 on the E-2 had a fiberglass shell over a steel spar--don't know what they're doing on the new 8-way. If you look at the photos of that prop on flickr you'll see that inboard of the nickel sheath the leading edge is smooth--the deicer is molded into the fiberglass--the wires are stitched into place during layup. The 24PF had a glue-on rubber heater, but the newer ones have gone to the integral heater.
Here are a few that show the sheathes more or less well: http://www.flickr.com/photos/thomasbecker/2290167447/ http://www.flickr.com/photos/kensaviation/398359395/sizes/o / http://www.flickr.com/photos/redteam/2384048553/ http://www.flickr.com/photos/mrottler/2112446280 / http://www.flickr.com/photos/capitals_of_tin/448098062/sizes/l /
Good clear prop close-ups are rare.
By the way, those polyurethane strips--I'm the guy who got the first one certificated, for the 24PF on the DHC-7.

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