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Ralph
02-20-2003, 02:17 PM
I built engineering models for a year and we worked mainly with acrylics. This is what I learned, mostly the hard way.

Acrylic plastic is the most commonly plastic sheeting used with aquariums. Plexiglas is the trade name for the same stuff, and there are others too. There are advantages to using it and some disadvantages too but it is often a good option for the home DIYer.

It comes in about any color you can imagine but clear and white are the most common. It is normally used in sheet form and comes in any thickness you'll need. Larger cities have fabricators (they make mostly display cases) that will sell you sheets or actually cut them to size for you. Acrylics have also been showing up in hardware stores as an alternative to glass windows. The price varies but is in the neighborhood of glass. For the 12 pack of Dr. Pepper though, my local fabricator lets me go through the scrap bin.

Leave the paper on the sides of the sheet, it protects the plastic while you are working on it and you can use it for drawing cutting lines and doing calculations. Safety glasses and gloves are recommended.

I use a circular saw or table saw with mine. Hack saws can cut it if you are patient, fine toothed hobby shop hand saws are better than hack saws and you will build up those arm muscles. A fine blade is highly recommended, I use a 150 tooth on my 7 1/4" circular saw. Larger teeth can lead to chipping (flying pieces of hot plastic). And feed it slow, kickback's a mother. You'll get some burnt plastic buildup along both sides of the cut, just let it cool about ten seconds and then run the shaft of a screwdriver along the piece and the stuff flies off. We also used hot wire cutting tools for fancy cuts. Exposed ends of cuts can be buffed and polished smooth (practice on scrap first).

If you have to bind the pieces, use acrylic solvent, it actually dissolves the contact points of the two pieces to be joined which rebond together (almost instantly) making the joint stronger than the plastic sheet. The fabricators sell it or you can get it over the internet. It is a clear liquid applied with something that looks like a syringe (there is also a bottle applicator). Be careful not to drip the solvent on exposed acrylic because it will blur the clear sheets. If you need a waterproof joint, the pieces have to be flush (and I mean touching everywhere) before any solvent is applied, it won't bond over gaps. And use the solvent in ventilated areas.

It is possible to make bends in sheets but it is a little advanced and requires a machine with heating coils. Done well, it looks great though.

I make tank covers mostly with the stuff but we've all seen those acrylic aquariums. It's also used for tank dividers, wet dry filters, in-tank stuff, etc.

Advantages: it is light, easier to work with than glass, clear, strong, doesn't react with water, reasonably priced, no special tools needed, doesn't shatter with normal use, and allows room for your imagination.
Disadvantages: scratches easily, can bend or sag over time, doesn't like longterm sunlight or high heat, and usually needs thicker pieces than glass.

Go ahead and fill in any gaps I left in this info and add any experiences you've had with acrylics.

02-20-2003, 04:01 PM
No experience here, but boy you have given me a great start...

Thanks a heap for the tips, Ralph....... :)


BTW.... I think this one should have a sticky....

02-20-2003, 04:13 PM
Nice write up Ralph. I guess I am one of the lucky ones here. A good friend of mine owns an acrylic business, I just call him up and tell him what I need..... 8) 8)


Randy

Ralph
02-20-2003, 05:24 PM
Thanks Julz, you're great.

Randy, you are lucky, that's a valuable offer your friend has made.

I remembered something: drilling holes in acrylics.

The important thing with drilling holes is to have a strong, flat backing. I use a thick board underneath the plastic. It prevents blowouts on the other side. Just drill right through into the wood. It will often bind when breaking though so be prepared and slow down near breakthough.
Also, drilling holes near the edge of the plastic is to be avoided because it will usually crack at some point.
If you have to bolt or screw something down or together, don't bind (squeeze) it tightly, that also leads to cracking.

I'll apparently be adding more as I remember all the mistakes I made while working with our friend, acrylic plastic.

RandalB
02-21-2003, 05:48 PM
Hey Ralph,
You make tanks at all?

RandalB

Ralph
02-21-2003, 06:22 PM
I looked into it Randal but it's the same situation as with glass, buying the raw materials costs about two times what a new tank already made costs. The aquarium fabricators must get some killer prices by buying in quantity.

The only way it would be cost effective is if you had a cheap source of plastic or if you were doing a odd shaped custom tank. As a minimum, you would need access to a shop type table saw and a large work table with a bracing set up. It sounds discouraging, but it is doable for people in the right situation.

thebaglady
02-23-2003, 06:22 PM
Hi Ralph, This is an interesting post. :)

I've never worked with acrylics, but you say you use it mainly for tops? I have made my own tops out of plastic lighting sheets and it works out pretty slick. A little off the topic, but I thought I'd share:

It's sold readily at Home Depot etc... It's the stuff used for large fluorescent light fixtures. It comes in an opaque white or a fairly clear version. I usually get the clear stuff since I have plants in several tanks.

It's easy to cut using a metal straight edge (as a guide) and a box cutter or Xacto knife to do the cutting. I usually score it several times and then just "snap" it. It will break fairly cleanly all along the score, provided you've given equal pressure from start to finish. Corners are tricky but not impossible with practice. It's so cheap and large, it's OK if you screw up a little :-\ No big deal. Just try again.

Wear safety glasses while working with this stuff too 8)

After I get my piece, I attach a marble, a small rock, an empty snail shell etc... w/ some silicone for a handle to open it and after 24 hrs. curing, Voila....new top!

Forgive me if this tip has already been posted. I'm new here and haven't read everything. Will I ever read everything? ??? No way possible!! :P

Richman
02-23-2003, 07:00 PM
Hey baglady,
That's a great tip. I have a few tanks I need lids for. I have tried pane glass in the past but it is too flexible. Quarter inch glass is really too thick. And I don't like to spend that much on something I'm going to use for a lid. I'll go down to Home Depot and check this out.
Thanks.

daninthesand
02-23-2003, 07:37 PM
Hi peoples.

I don't mean to rain on anybody's parade, but be careful with the lens sheets available at (for example) Home depot. They are nice and thin so easy to work with. Trouble is they warp over time. If you are spanning a small tank, say 10 inches across it might do. But anything wider or longer it will warp. I'm looking at the two that I have now and yep, they're warped. They still keep the fish from jumping out, but they ain't pretty and they do nothing for keeping any heat or moisture in.

I even have used 1/4 inch acrylic and it also warps. And so does 1/2" thick. I've seen that warp just as much.

You might get away with it if you plan on making a sort of shallow box to use for a lid. The side pieces might keep things in line, but I have no experience with that. My acrylic lid attempts have all been with flat sheets with no support.

Just trying to save you a bit of cash in case you had not considered this.....

Richman
02-23-2003, 09:05 PM
Thanks, Dan ;)

RandalB
02-23-2003, 10:57 PM
Too bad Ralph,
Would have been happy to trade an RO unit for a nice Acrylic tank....
Wet Dry maybe?


RandalB

Denny
02-24-2003, 12:35 AM
ralph

this is a great thread. can you give me any names of suppliers where a business like mine may be able to set up an account to get the reduced prices? i would love to do some one of a kind stands with acrylic tanks. and i may even be able then to give forum members reduced prices ;)

what technique do you use to get the solvent into the seams and not the sides of the sheets? masking tape?

denny

Denny
02-24-2003, 12:47 AM
oh yeah,i almost forgot. if you are drilling holes in plasic, wood or many other materials and you want to avoid blowing out the bottom side, just drill deep enough for the pilot to break through, then drill from the other side to finish the hole ;) no blowouts and a professional look every time.

denny

thebaglady
02-24-2003, 01:46 AM
Dear Daninthesand & all,

Yes, I should've mentioned that the fl. light fixture tops work best on small tanks....21/2, 51/2, 10s. They don't warp on these. They can be cut to fit snuggly into the lip of the tank trim so there's minimal evaporation.

One nice thing is that you can cut small openings, any size or shape, easily. If all you want is an opening for an airline tube, just notch off the corner. I keep killies and those darn fish will escape through even the smallest orifice. >:( Best not to give them any easy out!

But I think one of the main reasons I used these on some of my tanks was because of orientation. I have a lot of tanks banked one next to the other, with the short sides out. Perfecto and All-glass glass canopies just don't open as easily.

How about that Norah Jones sweeping the Grammy Aw?
I was surprised. Jen K.

Ralph
02-24-2003, 02:08 AM
Denny,
I don't have a lot of experience on the supply end of plastics, but my impression is that it is run by salespeople and they remind me of car salespeople. To find the best prices, go as far up the supply chain as you can, form a relationship with the sales rep, and talk yourself into a good deal. You may not be doing the quatities that merit time by the manufacturer and they might refer you to a distrubutor.

The solvent actually works by capillary action. Run the applicator down one side of the joint, making contact at the joint, while gently squeezing the applicator. You can actually see the solvent being pulled in and forming the bond (and where you missed a spot too). It's really easy, the trick is making sure the joint is a flush fit before applying the solvent.

Great ideas everyone. I avoid the sagging on tank lids by using thicker plastic and tank crossbraces.

The grammies are always a mystery to me, Bonnie Raitt was the only person I liked who ever won one, and that took them 20 years.

henryD
03-03-2003, 12:35 PM
Yes.....the acrylic sheets do warp. I found this out the hard way. But there is a way around it.

What you need to do is make a brace for the middle....

For instant in a 55 gallon tank you have 2 openings...
each opening is 23 1/4 by 11 1/2.

So what I do is cut a sheet that exact size or a little smaller to allow for the fitting of filters or anything like that.

Then I would cut a 1 in by 11 1/2. I would place this in the middle to help support the middle. If you use the solvent and glue the inch bar then it would strengthen the overall sheet. For larger sheets use a couple of more bars.
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thebaglady
03-03-2003, 08:53 PM
I have a question now...is there any way to keep the joint between two pcs. of acrylic operable? Would a bead of silicone run down the length of the joint work?

I'm thinking about as this relates to tops again.

Ralph
03-03-2003, 11:11 PM
Hi Jen,
Silicone can be used for a flexible joint. I had a friend who used silicone to make a hinged lid. I lasted about four or five months. Metal hinges can be used too, they have to be bolted on though, screws will crack acrylics big time.
Kyppyk (how do you pronounce that?), I like the crossbraces. Mine are on the tank, but attaching acrylic crosspieces to the top work too. You can actually attach those pieces turned vertically to get a real strong antisag brace.

Denny
06-05-2003, 10:46 PM
I have since gotten a fabrication book on acrylics from the manufacturer that has great info in it.

They recommend a table saw with a 10" 60 tooth triple chip grind blade for cutting.
Jen- you can get hinges made of acrylic that mount to the two pieces with the same solvent that you use to join 2 pieces together.-slick.

if anyone has any fabrication questions you can contact me and I can try to help you out. I finally found a few distributers so this summer i will start Making some acrylic tanks to tie into my stands.

Haywire
08-08-2003, 03:51 PM
Ralph,

Something from my RC plane days may be valid here, for hinges on small balsa parts there is a fabric hinge, it's nothing but two peices of fibreglass that is joined down the middle, and you glue it on both side of the hinge. I imagine it would work just as good with plastics.

limige
12-09-2003, 12:28 AM
aren't there different types or grades of acrylic?

what type or grade is best for tanks?

drew22to375
12-26-2003, 06:33 PM
Here are a couple of links related to acrylic.

http://reefcentral.com/forums/showthread.php?s=&threadid=96763
This is a good post about projects with acrylic. You can get answers from a person that works with acrylic for a living. You may have to join the forum to view it tho. But it is definately worth it and its free.

http://www.usplastic.com/catalog/default.asp
This company is a supplier of plastic and acrylic. many useful items.

zfish
12-30-2003, 09:23 PM
Ralph,
I am wondering about tank repair. I obtained several acrylic tanks from someone that had to get rid of them because he was moving into a smaller house. His movers did some damage, not real severe but they have some cracks usually from one to three inches. I was at Lowes and notice they have acrylic sheets of Lucite acrylic in 1/8 and 1/4 inch sizes. Will this work for repairs? Would the 1/8 inch be enough? The acrylic tanks have 1/4 inch acrylic. They do not need to look good. They will be used as breeder and grow out tanks.
Dan

Haywire
01-01-2004, 09:58 AM
I bought some acrylic and the solvent from a local warehouse/retailer he provided the common solvent supper runny syringe stuff. I described what I was making (a fluidized bed) and he recommended a second glue for making my joints watertight it's in a tube and less runny. I'll be playing with the solvents later this week so I'll let you know how it works

limige
01-16-2004, 11:27 PM
for sure let us know.

well i spoke with someone today who suggest only using weld-on 40. but he uses a different technique. he routers his edges with a slight angle, puts the angle to the outside and fills it with glue (weld-on 40) and uses a syringe with a large diameter needle for this. glues front to the sides, then the back, and the bottom lastly top. leaves overhang and routers them flush once the glue has completely dried and polishes the edges. he also says plexiglas acrylic will work for most people, if your doing a very large tank maybe spring for polycast. but most impotant use the correct thickness, he suggest 1/4 for up to 55 gallons and 3/8 for 55-100gal. and 1/2 for 100-250?

anyway, this is second hand knowledge from someone who is supposed to of have done this professionally for many years. i'll give it a try and let everyone know how it works out!

mike

Greg Richardson
06-21-2005, 12:40 AM
I obtained a 55 gallon acrylic tank that had a pipe coming up through the bottom.
I want to eliminate that thus I'm left with a hole about 2.5 inches in diameter I need to get rid of.
Looks is not an issue here.
What materials would you use and how would you go about doing it?

Cosmo
06-21-2005, 06:41 AM
not sure if anyone answered this, but yes, you can get acrylic hinges that glue to the acrylic top. I have a 90 gal that has these for the acrylic hood.. suspect you could use a wood hood to so long as you mounted something to connect to the acrylic hinge base... the hinge uses an acrylic "pin" like a large cotter key to keep the two pieces together.

Greg, can't you get a large bulkhead and plug the bottom? I think Custom Aquatics carry them in that size (but they may not be cheap :( ). or perhaps you could simply glue a 4 x 4 piece of acrylic over it? (that would personnaly make me nervous though)

JIm

Greg Richardson
06-21-2005, 08:31 PM
I'll check that bulkhead possibility out. Thanks!

Yep, was thinking of just patching it on top and bottom and use firing strips to even out bottom so weight not directly on patch area and level.