Ask A Scientist© General Science Archive

name         Warren
status       other
age          60s

Question -   Thank you.  We have a Stiffel lamp that was tipped over
   and it broke one of the three decorative alloy braces that holds the
  globe in place.  They're not making this lamp any more and we finally
  found a new globe but not a brace. I tried fixing the broken one with
  super glue, then super glue with a piece of flat wood on the side,
  silicone, and rubber sealant but nothing would hold.  I'm wondering if
  there is an epoxy that will work on an alloy.  Could you help me with
  that question?
 Thank you, WCJ
   
 First, I have to admit my ignorance. I'm not sure what a "Stiffel lamp"
 looks like. Not withstanding, I do know something about sticking things to
 things
 
 1]     OH! ARGH! The Superglue marketing/advertising propaganda sucks in
 another unsuspecting would-be user. All "super glues" depend upon the
 polymerization of cyanoacrylate (CA) monomer. This reaction requires that
 the CA be exposed to the atmosphere in order to "cure". A butt metal joint
 prevents this, or at least seriously impedes it.  Super glues work for
 porous substrates like wood or paper, or skin that can "breath". It does not
 work well on metal or glass. I don't care what claims are made. Also, the
 cured resin, poly-CA, is not a strong adhesive. Again, I don't care what the
 product literature claims.
 
 2]        But what to do? FIRST AND MOST IMPORTANTLY, strip any residual
 adhesive from the would-be joint. Use the following sequence of stripping
 steps:
 a.    CLEANING: Soak the joints in warm water for several hours.  If that is
 not feasible use a wet rag. This will soften the residual adhesive to some
 extent. Carefully brush the joint with fine steel wool to remove adhesive,
 and roughen the surfance. DON'T USE STEEL WOOL PADS THAT CONTAIN SOAP. Do
 this 2-4 times.
 b.        Repeat "a." using xylene, then acetone (available at hardware
 stores of paint stores). CAUTION: These solvents are highly flammable, so
 take appropriate precautions. You have to get the silicone off, or nothing
 will stick. Of course, test these procedures on an inconspicuous part to
 make sure something unexpected is happening.
 
 3]        Your idea of epoxy is a good one; however,  DON'T USE THE EPOXY
 ADHESIVE APPROACH UNTIL ALL OTHER OPTIONS HAVE BEEN ELIMINATED.  IT IS
 ALMOST IMPOSSIBLE TO REMOVE. I believe there are epoxy adhesives
 specifically formulated for metals. Try your local hardware, or home-supply
 store.
 If the piece has enough cross section, you could drill one or more holes
 perpendicular to the break surface in each piece and insert a dowel to
 reenforce the joint. Matching the hole exactly could be tricky however.
 4]         Before doing 3], make some inquiries. Ask an industrial supply
 store, a metal fabricating shop, or a hobby / crafts store. There may be
 something especially formulated out there that I don't know about.
 
 Good Luck
 
 Vince Calder

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 Connie
 
 Other things equal, the higher the temperature, the shorter is the life of
 the bubble. The reason for this is that the rate of evaporation of water [in
 the bubble's skin] increases dramatically with increasing temperature. This
 makes the thickness of the film smaller and also changes the relative
 concentration of the components of the bubble solution.
 
 Search the Web for "bubbles". There is a wealth of info there. There are
 also several elementary books you can order from Barnes & Noble or Amazon.
   
 Vince Calder
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