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Re: [Killietalk] Acrylic bonding

John,

listhub at libros_andante.mn.org wrote:

This issue I have with acrylic construction is not the bond.  As has been
pointed out already in this thread the cement is very thin.  It flows between
the corners via capilary action and bonds the plastic.

Folks should be aware that there are various forms of the plastic cement used for bonding acrylic. Some *is* a pure watery solvent (probably with methylene chloride and maybe other "stuff" like toluene) that wicks by capillary action between two close fitting pieces, or into a crack.

Others are more like regular glues, with some plastic already dissolved to give the glue some thickness and body. Don't use those for tank building, as the seams will be much less invisible, I think. They are for poorly-fitting parts where a gap needs a *lot* of filler. Ugly, tho.


The issue I have with acrylic construction is cutting the acrylic.  For the
bond to work the corners need be near perfect.  I have yet to find the type of
saw to use to cut the acrylic this fine.

I have been told that plywood blades work best, but I have found any good, sharp, fine-tooth carbide blade is fairly satisfactory. Dull blades or the wrong cutting speed leads to some melting and, hence, messy edges. Those won't capillary-bond worth a darn. Don't be afraid to touch up the edge on a belt sander, if it needs just a little smoothing. Use a fence to keep it very square, tho.


You quickly get into a Catch 22 where it costs as much to have the pastic
company cut the stuff as to have them build the whole thing.

How do you cut your acrylic?

With a sharp table saw.


On 03-Mar-04 Odispigna at aol_com wrote:

Hey Tucker:

A great tool every aquarists should have if using Plexiglas tanks is
Methylene Chloride.  It is a non-flammable liquid solvent for bonding acrylic
to acrylic.  The only trick is that you have to make sure your seams line up.
It is like water and if you have a chip or gap it will flow through and not
give you the water tight seal.  I use the tanks and fill with water as soon
as it's dry and have had no problems with a residue.

Methylene chloride should be used with great care. It is a powerful anaesthetic (similar to ether and chloroform) and breathing the fumes around a saw is not a good idea, at all. [Three-finger Willy can tell you why. :-(]

They quit using it years ago, in the operating room, because it also is a strong carcinogen. If you don't want cancer, don't even think of breathing the fumes! Otherwise, it is a great acrylic bonding agent.

Fan or outdoor scene advised, strongly.

Tucker can probably get it in his area from TAP Plastics.



It works almost as if it melts the two surfaces together so if it smears or
gets somewhere you don't want it to, it will leave a cloudy white drip mark. But works wonders for sealing cracks, securing bulkheads, inserting dividers
etc. I get it from Industrial Plastics in NYC on Canal Street, and you can buy a
needle tip applicator. Industrial Plastics website is www.yourplasticsupermarket.com

Or look on the web for a local supplier convenient to you.


john
------------------------------------
John N. Alegre                   o



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