Acrylic fabrication questions? I can help! - Page 14

wrasstaman · #**326** 03/02/2003, 11:33 PM

Acrylicman,
I have worked a little with cell cast and built a 50 gallon refugium. Now that I have the confidence I am considering a much larger project. If I used full sheets for the front back top bottom and half sheet sides I would have a serious tank with minimal cutting and waste.
My question is how do you hold the sheets square so you can bond them together at perfect 90s?
Also, what would be the best way to apply the #3 cement? I have used the small bottle with the needle tip but don't know if that would be large enough.
I sure would love to hear your thoughts on any of the above or where here in Ohio to get materials!
Thanks,
Wrasstman

dattack · #**327** 03/02/2003, 11:43 PM

How about acrylic tubing? How do you prep it ready to glue?

I can't seem to get a clean cut. Do I sand it down? If so, what grit?

radioactive · #**328** 03/02/2003, 11:54 PM

Just thought i would add a picture of ACRYLICMAN'S work . I bought a 180g tank for my in-wall project . He does some extremely nice work . The tank turned out exactly as i wanted ....

Zephrant · #**329** 03/03/2003, 03:31 AM

Since A-man fell down a rat hole..

I'll take another stab here.

Allen- Medium speed. I ran some tests with a 60 tooth Triple-chip blade, and slow to medium was best, about 1-2" per second.

BoPeep- Corners are hard, because it is very difficult to get the panels to the exact same size. Very careful cuts on the saw helps. Set the fence once, and cut all the panels. Some people set up the router and a fence and run every panel though it to give a consistent width. I have tried this, and have not had much luck with it on large panels.

Make the best cuts you can, and dry-fit the pieces. Swap pieces around if needed before you glue, sometimes you can mate the large ends together and avoid the problem. Glue up the joint with one side perfectly flush. When dry, take a scraper and scrape down the high side until it is flush with the other piece. Scrape back 6-8" or so to make a gradual change. Make the scraped side the top of the tank where strength is not as important, and put the flush side on the bottom.

CK- Make sure you are feeding the material into the cutter, not "climb" cutting. Use a fence and finger boards too. The router grabs and pulls the material, you can't hold it by hand. Plexiglas is harder deal with than cast acrylic too. Only take off 1/16 or less with the router, and it is FAR easier too. Using a larger bit helps, check out http://www.mlcswoodworking.com/ .

WM- Using a full sheet for the top is expensive, you might want to consider piecing a frame together. You need jigs to hold the sheets together. I bought a bunch of 6" plastic framing triangles, and cut off the corner so it would not touch the joint. Place some double-sided tape on one end, and stick it down to the flat piece. Then you can place a bucket of sand or similar on the outside of the vertical piece, that holds it against the triangles. Clamps work, but you need to make sure the clamp is not holding the vertical piece up, so it can't settle in to the joint.

For the solvent, locate a glass syringe, or get a larger squeeze bottle with a bigger needle at a lab supply company. The cheapo white squeeze bottles don't flow fast enough for large tanks. I just did a 6' tank, and it takes almost two minutes to get all the way around it with my big bottle (large needle). Since I need to pull the pins before 2 minutes is up, it is a race!

dattack- Do you use a "V" jig to cut the tube on the table saw? I have also have decent luck with a 12" chop saw, and strapping the material to the saw with a strap clamp. (Up to 4" dia. tube.)

HTH-

Zeph

_ShotgunShrimp_ · #**330** 03/03/2003, 08:52 AM

first off.. if you dont have a fancy bender is there a sure fire method to bending a piece of acrylic for an internal overflow.
second what do you suggest to attach acrylic to glass... is there a special type of silicone??

ok i guess three questions

what would be the best route to making slots in acrylic (like oceanic style overflow boxs)

_ShotgunShrimp_ · #**331** 03/03/2003, 08:52 AM

GRRRRRR double post

C_Kritter · #**332** 03/03/2003, 11:15 AM

zeph,

sorry to sound lame but what am i looking for in MLCS Woodworking? What is "climb" cutting? Lastly, what is a finger board? I am using a fence and pushing the acrylic piece by hand. Should I use a mitre guage or something to keep the piece from moving. thanks again for all the help.

Zephrant · #**333** 03/03/2003, 07:14 PM

No problem CK- Sometimes I use too many technical terms.

At MLCS woodworking (and other places) you can buy larger diameter bits for your router. A 3/4" diameter flush trim bit leaves a smoother edge than a 1/4" diameter flush trim bit.

Climb cutting- If you are looking down at a router in the router table, the router spins counter-clockwise. If you push the outside edge of the stock in to the right side of the bit, you are "climb" cutting, because the bit tries to grab the work, and pull it in to the bit. If you feed the stock on the left side of the bit, you are cutting normally, which is what you should usually do.

Climb cutting is used in milling for a better finish at times, but I don't recommend trying it on a router. Too much chance that it will pull the work and gouge it.

Finger board: Perhaps more commonly referred to as a "feather board" it is a series of fingers cut in to a piece of wood or plastic. When you clamp it down to a table, it can apply pressure to the work to hold it against a fence, or against the bearing of a router bit. Also used on a table saw to hold the work down over the blade.
See: Feather Board

HTH-

Zeph

C_Kritter · #**334** 03/03/2003, 07:23 PM

thank you master. grasshoppeh learns something new.

C_Kritter · #**335** 03/05/2003, 09:47 PM

zeph,

sorry for making you teach workshop 101 but have more questions. i purchased the 3/4" flush bit and feather board as recommended. the featherboard that you recommended, the feed was from right to left. how can i use this if i need to feed my material from left to right? lastly, can i just clamp the feather board in my router table? as you can see, i have a small router table so if i use the guide that came with the feather board, i will not have enough room to run my material through. thanks again for all your help.

ramonc

Zephrant · #**336** 03/05/2003, 10:52 PM

No problem- I had to take the black plastic disk out of my feather board so it could be reversed. Bad design, the disk sticks up in the way when you flip it over. Peel off the decal with the numbers on it, and there are 2-3 screws under it. Take them out, and completely remove the black disk area. The bubble in it is useless anyway.

Yep, just clamp them to the table. It can be a little hard to get it clamped right, the bottom of the table is usually ribbed, and is hard to get a clamp to set right on. I use a large wooden clamp, or a pair of big C clamps.

Zeph

C_Kritter · #**337** 03/06/2003, 01:11 AM

do you know how far your router can fling a 7" x 20" acrylic piece. well.... i did not find out as it hit my wifes new beemer before it had a chance. ouch! if i can't get this project to go, i can use this router for shooting clay pigeons.

the show must go on.... i tried this evening but still getting rough edges. i'll keep practicing until i get it right.

just to get the project going, is there any other way to prep the edges? can i sand the edges before glueing. i have a wet/ dry sand paper with 220, 320, 400 and 600 grit paper. can i use this?

any suggestions will be much appriciated.

Zephrant · #**338** 03/06/2003, 02:05 AM

Ouch- Not a way to win points with the spouse.

Yep, routers are a little dangerous. If it grabbed it and threw it, you may have been feeding it in the wrong direction. The bearings on my table saw went out tonight, so my saw/router table is in a dozen pieces spread across the floor, or I'd post some pictures for you.

If you can find a local wood-worker it would be worth a beer or two to get some tips from them. I'm happy to type, but it is much easier to understand when you are actually shown on the spot.

Can you upload a picture or two of what you are getting? The goal is not a perfect edge, just one that is flat and true. You will be able to see the pattern that the router leaves, that is fine.

Sanding does not work well, scraping can work though. Take the back of a hack-saw blade, or similar, and drag it across the edge. It is kind of amazing how well it works actually.

Zeph

dattack · #**339** 03/06/2003, 02:17 AM

Any decent router under $150 with a 1/2" collet?

Getting confused on router choices and I hate my craftsman 1/4" router.

C_Kritter · #**340** 03/06/2003, 05:19 AM

double dip

C_Kritter · #**341** 03/06/2003, 05:20 AM

tried to take pictures with my sony digi cam but can't seem to get a good one to show the edge clearly.

i'm determined to get this router thing to work. i took a picture of my setup. is the feed direction correct?

can Novus 3 buff out a 1/4" dent in my wife's car? j/k

boogs · #**342** 03/06/2003, 10:12 AM

You should always feed the acrylic against the direction the bit is spinning - otherwise, the bit will grab the acrylic and either:

a) throw it far away
b) pull it in small steps which will make for a very rough edge

Your pic indicates you're pushing the acrylic through WITH the direction the bit is spinning - turn it around and it should work much better!

Scott

C_Kritter · #**343** 03/06/2003, 10:30 AM

Quote:

Originally posted by Zephrant
If you are looking down at a router in the router table, the router spins counter-clockwise. If you push the outside edge of the stock in to the right side of the bit, you are "climb" cutting, because the bit tries to grab the work, and pull it in to the bit. If you feed the stock on the left side of the bit, you are cutting normally, which is what you should usually do.

Finger board: Perhaps more commonly referred to as a "feather board" it is a series of fingers cut in to a piece of wood or plastic. When you clamp it down to a table, it can apply pressure to the work to hold it against a fence, or against the bearing of a router bit.

Did I misundertand your instructions? Per boogs, I'm feeding on the wrong side. I thought that is why the featherboard's middle assembly was removed to accommodate the left side feeding of stock. Thanks.

boogs · #**344** 03/06/2003, 10:36 AM

Think of the router bit as a spinning wheel. If you push the acrylic against it, and the wheel is spinning in the same direction you are pushing, it will grab the piece and fire it through - you will not get a controlled cut. It's much the same with a lot of power tools - table saw for example. The saw blade is spinning towards you - you're pushing the material you're cutting against the blade, not with it. I have seen people unintentionally run something through a table saw and then pull it back through the saw only to have the piece fly out of their hands and, in this case, put a nice sized dent in their garage door!

Scott

jfinch · #**345** 03/06/2003, 10:52 AM

Quote:

Originally posted by C_Kritter
Did I misundertand your instructions? Per boogs, I'm feeding on the wrong side. I thought that is why the featherboard's middle assembly was removed to accommodate the left side feeding of stock. Thanks.

Kritter,

boogs is right. What you're doing (feeding left to right) is climb cutting. It's done when routing wood that has a tendency to splinter when routed in the proper direction (right to left). Even when climb cutting I always go back and make a pass, right to left, to smooth out the cut.

BTW, when climb cutting be sure to take the material down in small steps or you'll end up with a board (or piece of plastic) imbedded in the wall.

Jon

Zephrant · #**346** 03/06/2003, 09:22 PM

Yep to the above- My instructions were less than clear, next time I'll draw a picture.

Sorry to have confused you-

Zeph

Zephrant · #**347** 03/06/2003, 11:06 PM

CK- My router is in the middle of a table, without a fence on it so at times I flip the feather boards over, so I can run a big tank on the back side of the bit, but I always feed in the same direction- against the spin of the router.

HTH-

Zeph

C_Kritter · #**348** 03/07/2003, 01:31 AM

amount spent in tools to make a $150 reactor: $1500
amount of (beemer) damage that the tools made: $700
finally got a good routed edge: PRICELESS

thanks everyone (especially Zeph) for all your help. i'm sure more questions to come.

Zephrant · #**349** 03/07/2003, 07:27 PM

Quote:

Originally posted by C_Kritter

finally got a good routed edge: PRICELESS

Yeaaaaaa!

Sorry about the beamer.

Zeph

starpolyp · #**350** 03/08/2003, 12:56 AM

hi all!

Just stumbling upon this subject, i have to say that a milling machine is a great tool for cutting acrylic sheets to very precise measurements, with an edge that is perfect for joining. I used to build acrylic aquariums along with acrylic terrarium/reptile habitats.
I stopped years ago after I was warned of the dangers of working with the plastic. the solvents used to join acrylic together is very toxic, along with the fumes. Proper protection sould be used when fabricating acyrylic parts and pieces. The solvents used are easily absorbed in the skin where they ramain stuck in the liver, supposedly for the rest of your life (. This was quite alarming to me, so i found a new passion within the aquarium industry.
If any of this information is false or misleading, please correct me. I only want to warn people of the dangers of working with acrylic, and to advise the use of proper protection when fabricating acrylic.

happy reefing!!!