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Plexiglas

Contents:

  1. Acrylic tank questions
    by burke-at-boa.cis.ohio-state.edu (Jonathan L. Burke) (Thu, 12 Mar 1992)
  2. The Last Word on Acrylic Adhesives
    by MAHFBF-at-rohvm1.rohmhaas.com (12 Aug 93)
  3. Building tanks...????.....
    by hines-at-socrates.ucsf.edu (Wade Hines) (Tue, 16 Nov 1993)
  4. Building an aquarium (How to)
    by qx01820-at-inet.d48.lilly.com (13 May 94)
  5. Aquarium Photography - tips from rec.photo.advanced
    by chaloux-at-mandolin.mitre.org (Dave Chaloux) (24 Mar 1995)
  6. [M] Three-spot Damsel Spawning
    by laurence-at-cco.caltech.edu (Dustin Lee Laurence) (11 Feb 1993)
  7. Transmission of glass vs acrlyic
    by ()
  8. Acrylic Maint.
    by ()
  9. Scratches on Acrylic: Help.
    by etsang-at-opal.tufts.edu (2 Apr 95)
  10. Melting away acrylic scratches.
    by cap-at-cmu.edu (Chris Paris) (11 May 1995)
  11. Need info on DIY acrilic tanks
    by you-at-somehost.somedomain (Your Name Here) (29 Jun 1995)
  12. Drilling Acrylic
    by Paul Nicholson <paul-at-eisusa.com> (Thu, 13 Feb 1997)
  13. Drilling Acrylic
    by ncampbel-at-ccmail.dsccc.com (Thu, 13 Feb 97)
  14. can you mold plexi-glass?
    by jude/pconline.com (Nathanael Henderson) (5 Mar 1997)
  15. Building a Pentagonal Aquarium
    by jude/pconline.com (Nathanael Henderson) (20 Nov 1997)
  16. Acrylic
    by Thomas Barr <tcbiii/earthlink.net> (Wed, 14 Feb 2001)
  17. DIY Acrylic Aquarium
    by shawn.organ/usbank.com (Wed, 14 Feb 2001)
  18. PlexiGlass (sic)
    by Wright Huntley <huntley1/home.com> (Wed, 16 May 2001)

Acrylic tank questions

by burke-at-boa.cis.ohio-state.edu (Jonathan L. Burke)
Date: Thu, 12 Mar 1992

In article <1021-at-proton.UUCP> radoias-at-charity.llumc.edu () writes:
>Is my plexiglass tank bowing too much?
>
>I recently got a 50 Gal acrylic (Sea Clear) aquarium.  The plexiglass
>thickness is 1/4 inch on all surfaces.  When I fill it with sea water, the
>large surfaces (front and back) bow out 1/2 inch compared to the empty tank.
>
>Frankly, I am a little bit worried, this being my first plexi tank.
>
Upto 1/2 inch in the middle is normal for a 1/4 inch tank.  Any more may not
be normal.

>QUESTION: is the bowing normal for plexi tanks, and does my tank flex more than
>others?  Is it in any danger of breaking?  Is 1/4" the normal acrylic thickness
>used on 50 galon tanks?  I am using it, but I'd rather empty it rather than 
>risk 50 gal on the floor.

The risk is minimal - no different that any other tank (glass or acrylic).
1/4" is a normal thickness for a tank upto about 20" tall. 

There are many different grades of acrylic, all which have very different
properties.  This makes it very difficult to ask if any such number, say
1/4" is acceptable.  Be vary careful when you compare Glass to Acrylic -
the numbers really are irrelavant.  My company used 1/2" acrylic to make
30" tall 600 gal tanks.

Is this safe?
Absolutely!
Is there any bow?
Less than most 5/8" plate glass tanks.  ie: my personal glass 220 (30"tall)
bows over 1/2" and it is made from 5/8".

>Costin Radoias, EE

If you have any more questions, I'll be glad to answer them.

Jonathan Burke
AquArt Custom Aquariums

The Last Word on Acrylic Adhesives

by MAHFBF-at-rohvm1.rohmhaas.com
Date: 12 Aug 93

Hi,

I just finished reading the adhesive section under ftp reefkeepers in the diy
section and realized that there is a lot of confusion out there.  Since I work
for Rohm & Haas, the makers of Plexiglas, I thought I might spread some light
 on the subject.  First let me say that I do not personally worhk in the
acrylic department, but have some experience from working with people in that
department and I am a soon to be materials engineer.  Also, my company is NOT
liable for any of this information.

Acrylic or Plexiglas is actually PMMA (Poly Methyl Meth Acrilate).  When things
 are bilt with it, it is generaly not "glued" but solvent welded.  With glueing
 the adhesive itslef forms the bond between the pieces and permanatly stays the
re.  Solvent welding actually works quite a bit different.  The pieces of
Plexi are placed together in the desired fasion and the solvent is let to wet
or "bleed between the two pieces.  They are then left to cure.  What happens
is that the solvent dissolves the PMMA (in a small region).  The long polymer
molecules from each piece entagle with each other while they are in solution
with the solvent.  The solvent then slowly evaporates leaving behind a joint
of just PMMA with no adhesive.  The solvent we most commonly use is MDC
(Methelene Di-Chloride).  Also I wanted to note here that PVC "glue" is mostly
a solvent with some other additives and works in a similar fasion.  Again, I
am no expert craftsman with Plexiglas, but I do know some one that is.  I am
going to ask him if he wouldn't mind directly answering some questions to the
net, but I can't make any promises.  If he will, I'll post his logon ID.
Hope this clears up some confusion.
------------------------------------------------Frank Fatato             MAHFBF
-at-rohvm1.rohmhaas.com                                             "My man, pots
and pans"  J.M.                                    ----------------------------
My employer is NOT liable for anything posted here.

Building tanks...????.....

by hines-at-socrates.ucsf.edu (Wade Hines)
Date: Tue, 16 Nov 1993

npmoore-at-unix1.tcd.ie (noel patrick moore) writes:

>Does anyone have any information on building tanks .
>I have been keeping fish for years and would like to start building my
>own tanks now.
>  What kind of glass is best ?
>  What kind of silicone ?
>Any information greatly appreciated.

Plexi-glass is best!

One 10'x5' sheet of 1/4" can be had near $100.

With this you can build a tank that with a 5 foot front and
20" x 20" depth and height. 1/4" will work but if you can
get 3/8 it's better but harder to bend.

A 8'x 4' sheet costs around $70. It can build a 4 foot by 16"
by 16" tank or other pertubations.

________________________________________________ 
|                      4 feet                   |
|                                               |
|  1             Bottom                         |
|  6                                            | 16 in. 
|-----------------------------------------------|
|              !               !                |
|              !               !                |
|8             !               !                |
|              !    Top        !  Back          |
|f             !               !                |
|e             ! 4             !                |
|e             !               !                |
|t             ! f             !                |
|              ! e             !                |
|              ! e             !                |
|              ! t             !                |
|              !               !                |
|              !               !                |
|              !               !                |
|              !               !                |
|              !               !                |
|              !               !                |
|              !               !                |
|              !               !                |
|              !   16 in.      !  16 in.        |
|              !---------------!----------------|
|              !                                |
|              !   Waste                        |
|              !                                |
|              !                                |
|              !                                |
| 16 in.       !                                |
________________________________________________|

I recomend a heat gun for bending. Take plenty of
time and have fun.
--Wade

Building an aquarium (How to)

by qx01820-at-inet.d48.lilly.com
Date: 13 May 94
Newsgroup: rec.aquaria

In article <2qtbpeINNrds-at-srvr1.engin.umich.edu>, natee-at-engin.umich.edu (NATHAN R EIDE) writes:
> On this subject, what thickness would you need to build an acriliyc (spelling)
> tank - and where do you find the plexiglass?  Not the same stuff you
> buy at a hardware store - is it?
> 
 Thickness will depend on the volume of aquarium you expect to build, if you
look at the "factory built" units you will notice that they are mostly 1/4" or 
3/8" thick. You can find Acrylic, trade name plexiglass (Rohm & Haas) at any
plastic supply outlet. It is the same stuff you can find at a hardware store,
but I would guess at twice the cost. You also do not have much of a selection
in the hardware stores, if you want to do a professional looking job, you will
need a long length of acrylic so you can "wrap" the front corners. For the
aquarium I built, I had to special order a 12' length of 3/8". You can get any
size you require, up to 20' ($$$) but most distributers don't stock any much
over the usual 4 x 8' sheets. If you wrap the corners you will need to put
together a strip heater to heat and bend the acrylic, the same supply house
should have these in stock. There is a technique for bending acrylic that you
will need to master first (you wouldnt want to destroy $200 worth of acrylic)
once the bend is made, there is no going back, as the heated area has been
distorted, and will always be visable. You need to mark each edge where the
bend will be and line this up on the strip heater. The acrylic should be about
1/4" above the heater, dont let it touch or it will melt the surface and "mark
off" on the acrylic (very ugly). I run a 4' length of 2x4 through a dado on the
table saw to make trough that the heater sits in. Space the other end of the
acrylic sheet with another 2x4 to make it level. Let the first side heat for
about five minutes and flip the panel over. This is *important*, you must flip
the panel over and heat the opposing side to get a clean bend, and you must not
leave any one side on the heater too long. If you do bubbles will form in the
heated area as the acrylic out gasses as it breaks down.(very ugly again) After
10 minutes or so, you will feel the short end of your panel getting "loose",
support it with one hand, and wiggle it to judge how the heating is
progressing. Keep wiggling and bending further and further until you feel that
it will make a 90 degree bend with no effort or "fighting back". At this time
pull the sheet from the heater and make the 90 degree bend. I built a 90 degree
fixture that I could hold the panel against while it cools, it takes about five
minutes before it sets. Tip: make sure that the bend that will become the
outside of you aquarium is the last to see the heater, the outside bend has
farther to travel on the radius and should be the hottest. Use a thickened
acrylic adhesive, not the capillary cement. practice your bends with scrap and
practice your glue up (too much glue looks very ugly also) too little leaves
voids and possible leaks. You won't be able to get those nice 2" radius bends
you see on the better aquariums because the manufacturer builds custom heaters
that are 2" wide, the only heaters available to us are 3/4" (though you could
layout two and get a 1 1/2" bend. I havent tried this though).
Practice, practice, practice...get the technique, its not too hard to learn,
and you will have a beautifull aquarium you built yourself.

KS-at-Lilly.com


Aquarium Photography - tips from rec.photo.advanced

by chaloux-at-mandolin.mitre.org (Dave Chaloux)
Date: 24 Mar 1995
Newsgroup: sci.aquaria

In article <3ksndm$242-at-bbs.pnl.gov>, cr_batishko-at-pnl.gov (Chuck) writes:
|> From: jacobson-at-cello.hpl.hp.com (David Jacobson)
|> 
|> Finally, you should take along a microfiber cloth (or maybe a small
|> bottle of Windex and some Kleenex if you don't mind attracting
|> attention) and clean the window where you are going to be shooting.
|> You said the aquarium will not yet have opened, so maybe it won't be a
|> problem, but normally, the windows are covered with hand prints
|> and kids' nose grease.
|> 

Just don't use windex on any plexiglass our you will have just messed
it up royally (it will glaze).


[M] Three-spot Damsel Spawning

by laurence-at-cco.caltech.edu (Dustin Lee Laurence)
Date: 11 Feb 1993
Newsgroup: rec.aquaria

brian-at-picasso.icd.teradyne.com (Brian Hunter) writes:

>In article <1993Feb8.194721.16718-at-cbnewsc.cb.att.com> dp-at-cbnewsc.cb.att.com (daniel.a.parker) writes:
>>IS THERE A GOOD REFERENCE ON HANDLING ARCRYLIC?  HOW DO YOU DRILL IT
>>SO THAT YOU DON'T GET SMALL CRACKS?

The manufacturers hand out sheets on the finer points of handling and
machining acrylic.  I've seen them at a real plastics place (as opposed
to a hardware store that happens to sell acrylic) for free.  If you
can't find a store that has them, you might try contacting a
manufacturer directly.

>Very carefully, I have found water cooling while drilling helps.  You
>also need a specially ground bit.

You need neither if you can locate a drill press.  Keeping the bit
absolutely steady has been the most important thing in my experience.
In particular, as the bit drills out the last millimeter or so it
seems to try to "break through", catch in the acrylic, and try to
jerk the piece around.  If it does this, it will almost certainly crack
the acrylic.  Best is a drill press and clamp; if you don't have the
equipment, you should try to come as close as possible.

You should also drill a small guide hole before drilling with a larger
bit unless the hole you want is tiny.  I drilled a trickle-filter drip
plate with 120 counter-sunk holes using wood bits with no problems at all
(other than boredom after the first few dozen holes).

Finally, it seems that the ultra-sharp premium-quality bits are actually
more prone to catching and jerking than lesser and duller bits.  On the
other hand, if the bit is too dull it will melt the acrylic rather than
drilling it.  A nearly but not quite sharp-as-new bit is probably best if
you use wood bits.

-- 
Dustin                         "I contradict myself?  Very well, I contradict
                           myself.  I am vast; I contain multitudes."

laurence-at-alice.caltech.edu


Transmission of glass vs acrlyic

by marat-at-ccu.umanitoba.ca
Date: 22 May 92 15:00:16 GMT


Measured light transmission of standard soda-lime glass (typical
window/aquarium glass) and poly(methylmethacrylate) acrylic -
"Plexiglass" brand.

Wavelength (nm)                % transmission
                        Glass                  acrylic

600                     90                      90
500                     92                      90
400                     93                      89
375                     90                      69
350                     78                       9
325                     20                       0
300                      0                       0

The thickness of the glass was 3 mm (glass thickness is metric in Canada)
The thickness of the acrylic was 1/8 " (ca 3 mm).

Borosilicate glass (pyrex) is transparent well out into the UV (at least
to 300 nm) but I don't know if it is available in sheets at a reasonable
price.

Different types or brands of "acrylic" may be different.

Kirk Marat
Dept of Chemistry
U of Manitoba


Acrylic Maint.

by mille873-at-crow.csrv.uidaho.edu (Miller Douglas W.)
Date: 3 May 1994 17:52:46 GMT

  I've just received some booklets published by the manufacture
of plexiglass (acrylic).  Some time ago there was a discussion on
how to remove scratches for acrylic tanks, I thought I would relay
what they had to say.
<Random comma generator on>

  Before sanding, buffing, or polishing clean the plexiglass carefully.
Small scratches can be hand polished using a soft flannel cloth a good 
grade of automotive paste wax.  Deeper scratches can be sanded,however, 
this will cause a variation in thickness which results in optical
distortions.
  If a buffing machine is used it should operate at 3000 to 4,500 surface
feet per minute(SMPM). (1/4 buffing wheel diameter in inches multiplied by
the spindal RPM).  The buffing wheels must be clean before starting 
(preferably new).  If an abrasive compound is used to remove scratches a 
different wheel should be used for the final buffing as some of the 
abrasives will remain in wheel even after cleaning.  If the part has been 
deeply scratched or sanded an abrasive coated wheel is used first.  The 
abrasive is a standard polishing compound composed of very fine alumina
or similar abrasive and tallow.
  The plexiglass sheet is next brought to a high polish by a soft, loose 
buff with no abrasive or tallow is used.  These cleaning buffs should 
be very loose and should be made of imitation chamois or cotton flannel.  
The wheel should be 10 to 12 inches in diameter and run at 3,000 to 4,500 
SFPM.  A hand-applied coat of wax may be used in place of buffing on the 
finish wheel, if desired. 

  If sanding is needed first try 600 grit sandpaper wrapped around a 
rubber-padded sanding block.  Sand over the scratch covering an increasingly 
larger areas.  If this does not readily remove the scratch step down to
400 grit sandpaper.  Sanding should be done in directions mutually 
30 degrees apart, producing a diamond pattern.  If 600 grit is used, step 
back upto 400 grit once the scratch is removed.
  Mechanical sanders should be avoided, since the heat generated can cause
distortions and possible discoloring.  Do not use belt or disk sanders, 
if a mechanical sander is used it should be water or better yet oil cooled.
Once sanding is completed buff the sanded area. 


  I personally can not attest to the effectiveness of these methods and
recomned trying the methods, and buffing compounds/sandpaper grits on a
piece of scrap before fixing a scratch on an expensive tank.  Booklets on 
acrylic fabrication, forming, and painting are published by:

Technical assistance phone (215) 785-8290

AtoHaas north America Inc.
Independence Mall West
Philadelphia, PA 19105

AtoHaas Canada Inc.
2 Manse Road
West Hill, Ontario
Canada M1E 3TP

PS I'm currious if you have an acrylic tank, what size is it and what
did it cost you?  I'm thinking of buying or building myself one,
depending on cost and I was wandering what was popular (looks good) 
and the dollar amount involved. E-mail me at mille873-at-crow.csrv.uidaho.edu
I'll be hear untill the 13Th. (hum... graduating on friday the thirteenth)

Doug Miller  If I don't get the chance to post again thanks for I of the
great info and answering my dumb questions.


Scratches on Acrylic: Help.

by etsang-at-opal.tufts.edu
Date: 2 Apr 95
Newsgroup: rec.aquaria

In article <3lfls3$d1b-at-hpscit.sc.hp.com>, kristi-at-sc.hp.com (Kristi Bittner) writes:
> : For the inside, if you don't want to remove the water nor the fish, you can use
> : a kit called Surface Restoral Kit made by Micro-Surface finishing products Inc.
> : They have some fine wet/dry sand paper called Micromesh.  I have yet to try my
> : kit but my 55g acrylic is badly scratched by my big dogface puffer.
> 
> : I believe the above-mentioned kit is the only tool you can use to remove inside
> : scratches without draining water.  Correct me if I am wrong.
> 
> : BTW, I will use the kit on a marine water tank......
> 
> I've never heard of this before... let us know how well it works, pleeze!!
> 
> thanks in advance,
> Kristi

Okay, I finally used the product Micro-mesh (or Acrylic Aquarium Restoral Kit)
to polish out nearly 95% of all the inside scratches of my 55g acrylic without
draining a drop of water nor take out any marine fish.  It is kinda
time-consuming at first (at coarser grade micro-mesh paper) but as it goes on,
its much easier for the finer grade polishing.

The water will be very cloudy but the guys at Tenecor told me that these loose
particles are inert to fish.  The instruction of the kit does suggest removal
of fish before polishing though.  Anyway, I changed like 40% of the water
afterwards and my fish are still doing excellent now.  If my fish show any
signs of discomfort, I will post to warn others ASAP.

I bought this kit from Tenecor for $34 and the exact same thing runs for only
$24 at TFP!!  I believe you can use very fine wet/dry sandpaper to substitute
for these micro-mesh.  This kit is only enough to polish one face of a show
55g.

I could not believe that it is possible to polish out inside scratches without
draining water so perfect.  It is now like a brand new tank.  The scratches I
had before polishing were from:  1. Fine sand being trapped between algae
scrubber and acrylic glass.  2. Decorative corals falling onto the acrylic  3. 
My hugh puffer keep scratching with his beak.  

Eddie


Melting away acrylic scratches.

by cap-at-cmu.edu (Chris Paris)
Date: 11 May 1995
Newsgroup: rec.aquaria,sci.aquaria

In article <1995May11.131344.4800-at-inet.d48.lilly.com> qx01820-at-inet.d48.lilly.com writes:
> In the trade this is usually called "Flame polishing", and yes, it has been

I've been experimenting with flame polishing the edge of acrylic
(1/4") using a small butane "pencil" torch. I don't see any
discoloration of the acrylic which you indicated is a problem with
oxy-acetylene flames. If I get it too hot, I get the bubbles you
described. If I don't get it hot enough, no polishing happens (of
course). In between those extremes, I get polishing, but the edges of
the edge (the corners) become proud of the face of the sheet. Here's
an approximate picture, with the effect exaggerated.

   _____         _---_
   |   |        /|   |\
   |   |   =>    |   |
   |   |         |   |
   |   |         |   |
   |   |         |   |

Oops, that picture's terrible. I hope you know what I'm talking about
though. Another problem, which you can see in the picture, is that the
edge, which was flat (though rough) before the polishing, became
curved. Thus, flame polishing (using my bad technique anyway) isn't
suitable for preparing the edges of acrylic for butt joining. I find
sanding to be more successful, though annoyingly tedious. The edge
left by a spiral bit in a router is good enough, but doesn't make as
perfect a joint as if I sand. (I'm doing my cementing with methylene
chloride applied by the capillary action method, through a little
needle.)

Please advise. :-)

--
Chris Paris <cap+-at-cmu.edu>    Support censorship -- go to CMU
For information see http://www.cs.cmu.edu/Web/People/kcf/censor/


Need info on DIY acrilic tanks

by you-at-somehost.somedomain (Your Name Here)
Date: 29 Jun 1995
Newsgroup: sci.aquaria,alt.aquaria,rec.aquaria

In article <3ssiks$g58-at-parsifal.nando.net>, Jason Madison <jmadison-at-nando.net> says:
>
>Sorry about wasting bandwidth, as this is a repost, but I keep forgeting 
>to put a subject down, so I bet most people ignored my earlier post 
>(with good reason).
>
>I have been thinking about building my own acrilic tank.  I looked in
>the FAQ, but couldn't find much info on building acrilic tanks (only
>wooden).  Is there a special grade of acrilic that must be used for
>aquariums?  I went to the hardware store and found 1/4 " acrilic that
>looks extremely clear, and I could buy enough for a 4x2x2 with only
>$100.  Can anyone tell me how thick the acrilic needs to be (I know its 
>stronger than glass), and how to seal it.  I know you use a solvent 
>sealer, but do you need a special kind for aquariums or can I get it at 
>the hardware store with the acrilic?  If its as simple as it seems, why 
>havn't I heard more about doing it?
>
>As always, any info at all would be appreciated.
>
>Jason Madison
>
>
>
>

	I would consider trying to get 3/8", unless its lexan.  Lexan is 
much stronger than plexiglass, unbreakable, and about 3 times? the p[rice
I know that
1/2" glass would be needed for a 24" high tank.  I don't have any figures on
plexiglass in front of me, but if you know that plexiglass is <30% stronger
than the glass then 1/4" would be fine.  Also, it would be unwise to make it 
square.  the weakest points will be at the seams.  You can eliminate corners
(weakpoints) altogether by bending the solid piece of plexiglass at the corners.
This will require the correct tools.  I think they're called strip 
heaters/benders (basicaly a 4" by 3' hot pad to heat a section of plexiglass
to a mallable temperature).  Then you can overlap the back seams by about 1".
I was planning on building several until I got the bugs worked out, then 
******* the plans.  But I won't be in a position to do that until the end
of this year.  Use the regular plexiglass glue stuff, but go over all the
seems with silicone to ensure the watertightness.   Hope I have helped.

Steve.


Drilling Acrylic

by Paul Nicholson <paul-at-eisusa.com>
Date: Thu, 13 Feb 1997

RGemmill-at-aol.com asked:

>I'v just purchased a wet/dry filter for my new plant tank.  The sump is made
>of acrylic and I need to drill a hole in the side for a bulk head fitting.
> As this is an expensive piece of plastic and I don't want to screw it up,
>I'm looking for recommendations on how to drill the hole.  The filter is an
>Amiracle 150.

Allways use a cutting fluid, water works very well, when you drill acrylic.
Otherwise your drill will heat up and melt the acrylic and you'll get an
oversize hole. Also use a smaller diameter drill bit to pilot drill the
hole. A pilot hole will reduce the tendancy of your bit to wander.

Paul

Paul Nicholson                  Electronic Imaging Systems, Inc.
TEL 805 532 1068                5148 Commerce Avenue, Unit F
FAX 805 532 1065                Moorpark, CA, 93021, U.S.A.
paul-at-eisusa.com                 http://www.eisusa.com


Drilling Acrylic

by ncampbel-at-ccmail.dsccc.com
Date: Thu, 13 Feb 97

     Ross,
     
     Any steel bit will work*.  I have had better success using a forstner 
     bit though.  Stay away from the flat wood working bits.  I don't have 
     a drill press but I would definitely use it if it was available.
     
     *The CRITICAL thing with acrylic is heat generated from the bit.  If 
     the bit is less than sharp then you will have to drill very slowly 
     (either slow bit speed or retracting the bit often).  Sharp bits can 
     be drilled quicker but you still have to retract the bit often to let 
     the material cool down.  Over heating will result in a crystalline 
     sugar-like melting around the hole.  Also try not to punch the bit 
     through the material when you are almost through the material.  This 
     may chip the back side of the acrylic.
     
     
     HTH,
     
     Nigel Campbell
     ncampbel-at-ccmail.dsccc.com
     

can you mold plexi-glass?

by jude/pconline.com (Nathanael Henderson)
Date: 5 Mar 1997
Newsgroup: rec.aquaria.tech

: >Second. Yes Plexiglas can be heated in an oven and molded into any practical
: >shape. It must be held in the desired shape until it cools. It will retain
: >this shape until it is reheated. The mold should be lined with felt or a
: >material which will prevent the Plexiglas from being scratched.

  What strange advice!  A felt lined mold?  *laughs*

: What's an appropriate temperature for the oven?

  About 300F give or take.  Did I mention melting acrylic in a 
conventional oven can cause an explosion?  *BOOM*  If you're going to try 
it, aim for good ventilation and be carefull.


Nathan H.


Building a Pentagonal Aquarium

by jude/pconline.com (Nathanael Henderson)
Date: 20 Nov 1997
Newsgroup: rec.aquaria.freshwater.misc

: > You can try to calculate the forces,.......
: 
: Nice Idea, nicely put, this is the sort of thing I was looking for. Any
: structural mechanists happen to have some handy equations, or am I gonna
: have to do it the hard way from first principles.

    This may or may not be usefull:

    (1/(.01639whh/2000))^-7  Using (h)eight and (w)idth of the largest
panel in the tank this formula yeilds a thickness recomendation in inches.
The down side is that I created it more for cast acrylic (Plexi-Glas G)
than normal glass.  (I really avoid glass.  Too heavy, too fragile, too
sharp, too hard to work with.  Acrylic is cut and shaped almost as easily
as a hard wood.)   Round up the result to the nearest standard size (1/4",
3/8", 1/2", etc.) and you should be fine.

: a bit of structural design and gbp30 of the right glass feels better
: than a potential living room aquarium 2 inches deep ;)

   If I thought my living room would hold water I'd caulk a panel of
acrylic over the door and call it good. :-)

Nathan H.


Acrylic

by Thomas Barr <tcbiii/earthlink.net>
Date: Wed, 14 Feb 2001

> I am about to build a custom aquarium 48"L x 36"W x 18"H out of Acrylic and
> I need some advice from DIYers.  I've not worked w/ acrylic before and
> would like some tips in terms of the appropriate plastic thickness.  I was
> thinking of using 1/2" is that too much?  Too little?  Is there an acrylic
> water volume calculation formula that will tell me the safe thickness to use?

I'd use 1/2" as a minimum. Commercial companies tend to build very thin and
use structural bracing on the tops. This, after a few years, bows out and
splinters. Looks like crap and you spent all this money. Some bow as soon as
you put water in them. It's also hell to get into the tank since they have
small openings for all the bracing. A tank this size will cost some money
but it always pays to do it right. If you don't plan on using any bracing at
all you will want to go up in thickness perhaps to 5/8 or 3/4.

> 
> Would a center brace be necessary?  I checked out Mel Gross' old post and
> I'd like to avoid this headache if at all possibe.  Are there any
> aquarium-safe acrylic glues?

I am unaware of non aquarium safe glues for acrylic. The regular old
capillary glue does fine. You will need clamps to squeeze the panels
together. You get what you pay for here. Go cheap and you can have a bowed
tank that doesn't last. A center brace may save you some money on the
thickness needed but will detract from the looks.
We build a 60 gallon cube out of 1/2 inch. The 25 out of 3/8th. There is no
bracing and it looks much nicer....especially on a cube. Cost more but it is
what I would want for my tank rather than the cheapest thing out there. We
are going to set the 25 soon for a planted display tank. There are places to
cut corners and thickness is not one of them IMO.
If your trying to do it cheap and don't care as much about the looks, a wood
tank is quite doable and all you need is a single glass face. I've seen some
quite nice 48x48 x 20inch tall tanks (200 gallon tanks)that had nice wooden
frames etc. There are plans for building this on the web and other sources.
One I saw many years ago when I worked at a LFS was a 4ftx4ft tank with a
terrarium in the middle and powerheads (aquaology- anyone remember those?)
so it was like a square donut so your fish could swim in a circle against a
current. Quite neat.
> 
> Has anyone found a DIY Acrylic Aquarium site?

Try acrylic/plastics places, they will build and/or help you.
Regards, 
Tom Barr


DIY Acrylic Aquarium

by shawn.organ/usbank.com
Date: Wed, 14 Feb 2001

Dwight,

I recently finshed making an aquarium from acrylic very similar to your
dimension. I used 1/2" acrylic. I don't have a pressure list for you, but
some type of additional bracing is almost certainly a good idea. I put an
addition stip of 2" x 48" acrylic  lengthways on both sides of the
aquarium. A friend of mine has made over 100 hundred tanks using this
design and he does not have any difficulty. The "glue" you use to fit the
peices together is not really glue, it's a chemical solvent that essentaily
melts the stuff together. Once it sets (I think 24-48 for full strenght) It
should not pose any problems to your fish.
We used my table saw to cut the acrylic, with a special blade with the
teeth having as small is offset as I could find. They make specialty blades
for this but I could not locate one. If you do not have access to a table
saw, see if the source for your acrylic will cut it for you. I bought a
4'x8' sheet, and the place I bought it from was willing to cut it for
something like $7 a cut. You might be able to get it done cheaper, but with
a 4'x8' sheet you should only need 5 cuts or so and then make sure you keep
the scrap so you can make your braces yourself.

I am not a professional acrylic worker and these are just my personal
observations. No guarentee is implied or expressed.

Shawn

You wrote:
- --
I am about to build a custom aquarium 48"L x 36"W x 18"H out of Acrylic and
I need some advice from DIYers.  I've not worked w/ acrylic before and
would like some tips in terms of the appropriate plastic thickness.  I was
thinking of using 1/2" is that too much?  Too little?  Is there an acrylic
water volume calculation formula that will tell me the safe thickness to
use?

Would a center brace be necessary?  I checked out Mel Gross' old post and
I'd like to avoid this headache if at all possibe.  Are there any
aquarium-safe acrylic glues?

Has anyone found a DIY Acrylic Aquarium site?









THanks for all the informative replies that I got regarding the DIY
Water-Changer-Float valve.

I am about to build a custom aquarium 48"L x 36"W x 18"H out of Acrylic and
I need some advice from DIYers.  I've not worked w/ acrylic before and
would like some tips in terms of the appropriate plastic thickness.  I was
thinking of using 1/2" is that too much?  Too little?  Is there an acrylic
water volume calculation formula that will tell me the safe thickness to
use?

Would a center brace be necessary?  I checked out Mel Gross' old post and
I'd like to avoid this headache if at all possibe.  Are there any
aquarium-safe acrylic glues?

Has anyone found a DIY Acrylic Aquarium site?


PlexiGlass (sic)

by Wright Huntley <huntley1/home.com>
Date: Wed, 16 May 2001

> ------------------------------
> 
> Date: Tue, 15 May 2001 17:15:45 EDT
> From: Dennis8425@aol.com
> Subject: Re: PlexiGlass
> 
>  The thing is there are multiple products sold under the name
> of plexiglass.  Some will warp to extremes others like Lexan have
> a minimimum warpage problem and still others in the Acrylic family
> have no warpage near water.  The big secret is knowing which type
> to use for what application.
> 

"Plexiglas" (like "Acrylite," "Lucite," and, I think maybe "Perspex" in the
UK) is a trademark for acrylic plastic (polymethylmethacrylate). "Lexan" is
a trademark for polycarbonate plastic, a totally different (and more
expensive) class of clear material.

Acrylic makes great aquariums. I think it has been well covered in the Krib.
It makes quite poor covers, for the warpage is not controlled by the shape
as in a welded tank. Weld some vertical ribs on it, and it suddenly becomes
a well-behaved cover. Likewise, all big acrylic tanks have an inner rim
around the top to prevent the sidewalls and ends from bowing and warping.

Acrylic can be brittle and can craze or crack following cutting, if
stressed. Good annealing at near the boiling point of water (190F+) is
advisable. Polycarbonate seems tougher and does not need that step.

Every kind of acrylic I have ever used can show the moisture induced
warpage, and I think the way it is formed or formulated has very little to
do with it, unless the shape resists it. It is such a wonderful, cheap
material that it is worth understanding how it behaves and using it rather
than banishing it from wet places.

The rules:

Thin sheets warp, if wetter on one side.

Thick sheets warp less in the same circumstances.

Thin or thick sheets with ribs can be made that do not warp, noticeably.

If possible, anneal by heating to near 200F and very slowly cooling. It will
retard potential future crazing or cracking.

Don't scratch it. It can really crack if under internal stress and not
annealed.

Put the final product between crossed sheet polarizers to easily see the
rainbows of internal stresses. Anneal to reduce or remove them.

Wright

- -- 
Wright Huntley, Fremont CA, USA, 510 494-8679  huntley1@home.com

"The whole aim of practical politics is to keep the populace alarmed -- and
thus clamorous to be led to safety -- by menacing it with an endless series
of hobglobins, all of them imaginary." -- H.L. Mencken

               http://environmental.networkroom.com/


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