cutting acrylic, somebody help

[RyanBrucks]

I have my 3/8" acrylic sheets, and I am ready to start building my first DIY acrylic tanks.

Tonight I decided to start by cutting the top frame piece for one of my 36x18x18 tanks. I drilled 4 holes about 2" inset from the corners of one of my 36x18" sheets. I then tried to use a jigsaw with standard T-shank blades rated for wood and plastic.

This went horribly. My jigaw has a laser projection, so you'd think going in a straight line would be easy, but no matter what I did, the cut would always go to the left at least a few degrees, completely ruining my cut. Trying to rotate the saw didn't work since it started vibrating pretty bad so I stopped. The teeth on the blades are oriented in 2 alternating directions, sloped left and right (bosch t-shank jigsaw blades, 10TPI progressive, if that means anything)

Am I using the wrong blades? Am I cutting wrong?

[iairj84]

Well first of all it's going to be really difficult to cut straight lines like that with a jig saw. I would use a table saw if at all possible. The 10 TPI seems way too little (TPI that is) as it's finish type work and you want a cleaner cut. You'll go through the finer tooth blades faster but they will give you a better cut. Same goes with table saw blades....

That being said I've never cut acrylic of that thickness so I can't say exactly.

[RyanBrucks]

I"m not really familiar with table saws.

can you please give me more detail about what kind of table saw would work best?

I finished cutting my top piece with the jigsaw. The cut is messy and wavy, but its an interior edge only so it will serve its purpose. I'll use this lid for my high-up RO holding tank so its out of sight :)

I'll be going to lowes tomorrow to look at some table saws, since I want the rest of my cuts to be alot cleaner. Does anybody recommend anything?

also, if a table saw uses a large circular blade, how do you make the end of your cuts square if you are making an interior cut? Do you have to finish the cut with another kind of saw?

[iairj84]

A table saw is essentially a saw that has a table on it that will allow you to push the work (wood, or whatever) through the blade. It spins a lot faster than a jig saw and will cut a lot cleaner. All saws come with a fence on it that will allow you to cut a certain length and keep it straight all the way down, which is what you need.

Table saws aren't cheap and even for a benchtop one (which is all you would need for cutting acrylic) it would run at the very least $100 which isn't too bad if you're going to use it a lot... Plus the cost of a decent fine toothed blade and you're looking at $150 out the door.

Like I said I haven't cut that thick of acrylic before so I can't comment on the ability to cut it that thick.

[Playa-1]

Table saw with the appropriate blade is the way to go.
You could rent a table saw, or consider a used one from a pawn shop, craigs list, or they're is always the store where you can get you wallet a nice haircut.

[SWSaltwater]

You should probably drill you corner holes and then use a router to cut it out. You will need to make a guide for this.

[coralnut99]

The smaller bench-top table saws really need to be fastened to a solid work surface. The really cheap ones will "walk", and the vibration will mar the acrylic surface. Whatever tablesaw you choose, keep the protective plastic on until you're finished cutting. The base of the jigsaw also left quite a trail on the sheets you worked with initially.

[speartheman]

what I used to cut acrylic is my tile saw makes nice clean cuts

[suthrnmn]

tile saws have diamond blades and are cheap to rent!!

[RyanBrucks]

well I went to home depot and lowes this morning and looked at table saws and routers.

all the table saws they had that I would want are in too big of a box to fit in my car I think, so I'll have to borrow a friends truck. I've been wanting a table saw anyways (will come in very handy when making my tank stand), but I don't really know what to look for in a table saw. Does anybody have a good link on table saws and how using the fence works? I'm still fuzzy on that. I was hoping to be able to mess with them at homedepot, but none of the displays had the fence installed.

I did pick up a plunge/router, and it had a guide accessory so I picked that up too. Got a 2flute 1/4" bit for it. Also got some clamps.

Going to try making some more cuts on the interior piece that I cut out last night. I don't need this piece for anything so its my scrap :)

My primary reason for getting the router is to improve the edges of my adjoining acrylic pieces so the solvent will go in without bubbles, but since its a pluge router I can also try using it for the lid cutouts. I'll test this on my scrap, and if it works well enough using the guide accessory, I may not need a table saw, but I will want one eventually anyways.


Thanks for all the suggestions.

[Donw]

The fences are all pretty straight forward. I dont think its possible to teach someone to use a tablesaw over an internet forum. If I were you I'd spend some time watching the New yankee work shop on pbs and find a friend or coworker that has some experience. Really would hate to read a post about you loosing a finger or hand.

Don

[BenjieC]

you might want to start by reading this thread. It should answer a lot of your questions. http://archive.reefcentral.com/forums/showthread.php?s=&threadid=169326

[coralnut99]

<a href=showthread.php?s=&postid=11174292#post11174292 target=_blank>Originally posted</a> by Donw
The fences are all pretty straight forward. I dont think its possible to teach someone to use a tablesaw over an internet forum. If I were you I'd spend some time watching the New yankee work shop on pbs and find a friend or coworker that has some experience. Really would hate to read a post about you loosing a finger or hand.

Don

Since it sounds like you're pretty new to such tools, I think Don's given you the best advice of any of us.

While most if not all of us will tell you to invest wisely in the tools you select and buy the best quality you can afford, this doesn't address the knowledge and experience you need to handle tools like a table saw and router safely.

[Donw]

I think if I were starting over with tool purchases I would get a festools saw before I got a table saw. They are easier to use and cost about the same as a elcheapo table saw. Add some of their other accessories and you could almost go without ever buying a table saw. This is a production quality tool a 10 year old can easily manage.
http://www.mcfeelys.com/product/561188/Festool-TS-75-EQ-Plunge-Cut-Saw-Includes-55quot-Guide-Rail

Don

[ErikS]

<a href=showthread.php?s=&postid=11174332#post11174332 target=_blank>Originally posted</a> by coralnut99
Since it sounds like you're pretty new to such tools, I think Don's given you the best advice of any of us.

While most if not all of us will tell you to invest wisely in the tools you select and buy the best quality you can afford, this doesn't address the knowledge and experience you need to handle tools like a table saw and router safely.
Ditto! A big honk'n DITTO!

A table saw can be great or extremely dangerous - knowledge is key.

Do you have a woodcrafters nearby? They offer classes in tool usage. Also check with local schools - including community colleges.

Norm is a good example, though he does some risky operations (most required by TV) - he gets by with them through experience.

A TS is a tough purchase - there are so many levels to choose from. A lot comes down to room, usage, & needs. You can go from a few hundred to thousands.

[RyanBrucks]

thanks guys.

I'll spend some more time reading and researching before thinking about a table saw. I added the yankee workshop to my DVR list so I'll try and catch some of it whenever it records. Also found a coworker who uses a table saw regularly so I'll get him to give me a live demo of one.

I've used a router before with no problems (wood not acrylic), so I think I will still try cutting my scrap acrylic tonight and see how it goes.

I think I need to go back to home depot though to get some more lumber to lift my sheets off the workbench enough to clamp on a straight edge guide (which the guide accessory will run along).

[stugray]

Here are some hints I pasted from some of my other posts:

First, I use a ryobi portable table saw with an 80 tooth carbide blade. My router is mostly used by hand ( I dont have a router table ) with a "laminate trim bit" the bit is the type with the bearing at the end.

Here are some ways to cheat and get glueable edges and the pieces all match without an expensive table saw or router table:

Ok then,

Lesson 1: How to get perfect joints before gluing.

I learned a few things early on:

1 - If you cut with too rough of tools, you will stress the acrylic, and it will stress-crack ( known as crazing ) when you glue it to another piece.

2 - If there is any 'texture', or 'saw marks' on the cut then you will have bubbles or crazing in the joint when it's glued.

The pros cut with a table saw ( or water jet if you're really serious ), the sheets slightly large, then they run it through a professional joiner to get perfect edges. I have learned another trick:

A - I cut the acrylic ( true plexiglass gives smoother cuts ) on my portable 10" Table saw with a new carbide blade ( only used for acrylic ) that has the maximum # of teeth I could find. I cut the sheets to about 1/8 to 1/4 larger than the final desired dimensions.

B - Next I clamp the piece to something with a very straight edge that is thin ( I use another sheet of acrylic with a factory edge if I have one ). I let the sheet that I want the perfect edge on, to be on top, and to stick out from the straight-edge ( below ) about 1/16".

C - I use a router with a laminate blade ( this is one with a carbide blade, and a roller bearing guide on the end ). You adjust the height so that the roller bearing runs below the sheet you want to cut, and along the straight edge. Now by running the router down this edge, you will take 1/16" of an inch off your sheet, leaving behind a perfectly smooth edge ready to glue. If it's not perfect, any oops can be removed with 400 grit wet sandpaper.

The edge must be perfectly straight, and smooth.

The two ENDS of the sump must be exact dimensions on all 4 sides. The BACK & FRONT need perfect top and bottom edges, but leave the length ~1/4" long ( the top & bottom edges must be smooth & perfectly straight, the ends just rough cut ).

The BOTTOM ( & TOP if you choose to make a single piece top ) should be slightly oversized in both dimensions ( len & width ), and all edges can be rough cut.



And:



Ok,

now you should have two end pieces, and a front & back, that are all exactly the same height.

The ends are router cleaned on all four sides, the front & back are cleaned on just the top & bottom, but a little long.

I use an old mirror for an assembly table because it's flat & easy to clean.

Set up all four sides on the table ( vertically, just like the final version ), and tape them together with masking or electrical tape.

I like the electrical tape, because it can stretch, and make later steps easier, BUT - the E-tape can react with the solvent leaving marks.

NOTE: The front & back panels are a supposed to be a little long so the end pieces should be setback ~1/8-1/16" in from each end.

It takes a few adjustments to square them up, but you can get it perfect with some patience

Once the leftside, back, rightside,front are all flat & square ( and TIGHTLY taped together ), the whole assembly must be flipped onto it's front ( or back ), without falling over like a house of cards.

If the taping job was adequate, and the assembly table big & flat, maneuvering it & flipping is easy.

Now once we have two joints horizontal & squared, check to make sure all four pieces ( R,L, Front, & Back ), are still tightly taped and squared up.

Disclaimer: if you try the above with thin material, and non-square cuts, the results will be less than optimal

Next is Gluing using the Capillary method:


Finally, read the thread link above for glueing.

When all sides & top & bottom are glued, you just trim off all of the pieces that are sticking out using the router with laminate bit.
I done right, you will have perfect edges.

The first time I did this, I tried to make all the pieces the final dimensions with smooth edges everywhere, but it way too much work compared to this method.

Stu

[RyanBrucks]

"B - Next I clamp the piece to something with a very straight edge that is thin ( I use another sheet of acrylic with a factory edge if I have one ). I let the sheet that I want the perfect edge on, to be on top, and to stick out from the straight-edge ( below ) about 1/16".

C - I use a router with a laminate blade ( this is one with a carbide blade, and a roller bearing guide on the end ). You adjust the height so that the roller bearing runs below the sheet you want to cut, and along the straight edge. Now by running the router down this edge, you will take 1/16" of an inch off your sheet, leaving behind a perfectly smooth edge ready to glue. If it's not perfect, any oops can be removed with 400 grit wet sandpaper."

Ah, thanks for that!!! Those two parts were exactly what I was still fuzzy about. Seems like it would work much better than using the guide accessory I have.

I do not have a blade with the roller bearing, and I did not see them at lowes or HD either. I might have missed them since I didn't know I needed that, but I'll take a look later tonight and if not I can order some online.

Cheers!
Ryan

[Myrddraal]

A trim bit is one of the handiest router bits you can have IMO, next to a spiral cut bit.

[RyanBrucks]

the last remaining piece of my router puzzle is.....
whats the best way to elevate the material off the workbench so that clamps can be used to adhere the straight edge? my workbench is much longer than my acrylic.

i was thinking of just getting a big 4x4 and cutting it into lenghts about as long as my acrylic, and laying them down parallel. would this work ok?

[Donw]

<a href=showthread.php?s=&postid=11175689#post11175689 target=_blank>Originally posted</a> by RyanBrucks
the last remaining piece of my router puzzle is.....
whats the best way to elevate the material off the workbench so that clamps can be used to adhere the straight edge? my workbench is much longer than my acrylic.

i was thinking of just getting a big 4x4 and cutting it into lenghts about as long as my acrylic, and laying them down parallel. would this work ok?

For small panels I just use my bench itself as the straight edge and let the bearing ride on the bench.

Don

[RyanBrucks]

hehe I was thinking that too, but when i actually looked closely at my bench the first thought was "no way is that even removely flat"

It's an old wooden bench that came with my house, so it has any number of marks cut into it. In fact I've cut into it a few times myself.

guess I could just get some dense particle board factory-level and screw it over the existing wooden lip

[djmx2002]

Hey i don't mean to hijack this topic but i've seen this sew blade

http://www.amazon.com/Irwin-11870-10-Inch-Plywood-Plastic/dp/B0002UKS7I/ref=sr_1_1?ie=UTF8&s=hi&qid=1194995705&sr=8-1

anyone know if it is any good to cut acrylic?

[RyanBrucks]

that blade certainly looks like it has enough teeth.... but i'm the noob not the expert :)

I did find a trim bit made of carbide with a ball bearing roller. I just got done with my first time cutting the acrylic with my router.... man what an improvement over the jigsaw :) Was able to completely smooth out the rough edges I cut, and also was able to use the plunge attachment to make interior cuts with ease.

I used another 36x18 acrylic sheet to act as my guide in both cases. For the trim cut I placed the guide sheet below (so the bearing was the guide) and for the plunge cut I placed the guide sheet on top, so that the outer edge was the guide for the circular exterior of the router. I used plastic C-clamps to keep them together and it worked really well.

For the plunge cut I used a 3/8" bit, but I think i'll try and find a thinner bit since I think there will be less friction and waste.

I wasn't prepared for just how much plastic flake waste shoots everywhere (good thing I had gloves, safety glasses, long sleeves and beard :) I looked like a snowman when I finally looked at myself, until I shook off like a wet dog.

My router has a shop-vac attachment that should suck all the flakes up, so I'm definitely going to use that next time.

My garage has gotten pretty messy with all my recent tool additions so I think I need a day or so to clean things up before I embark on the task of making all the cuts, which will take a while (4 tanks being built).

Thanks for all the help in this thread!

[RyanBrucks]

one more question for everybody.....

when trimming an edge, is it a good idea to pull back the protective paper coating to the depth of the cut? I noticed that the paper doesn't cut and instead just flaps down or up... possibly changing the distance of the guide bearing from the lower sheet.

Given, I was trimming off about 1/8 of an inch (because the existing edge was my crappy jigsaw cut), so this might be less of an issue with a more realistic 1/16 - 1/32 cut.

I didn't see any of the DIY acrylic guides suggesting to peel off any paper before routing... so should I or no?

[H20ENG]

You just have to set your bit to go beyond the paper. I only peel it back before gluing.

Just wait to you get one of those acrylic flakes up your nose! :lol:

[RyanBrucks]

haha...... yes I can tell they are quite hot at first!! maybe i'll get a mask also :) last night i got the tiniest piece of plastic in my eye using the jigsaw, and that was definitely my cue never to cut plastic without protective glasses again.

luckily they cool off enough by the time the hit me that they didn't melt onto my shirt or pants. the shopvac attachment will be a huge help. I only have a regular household vacuum cleaner but it looks like it should still work (haven't tried yet).

[Donw]

<a href=showthread.php?s=&postid=11176339#post11176339 target=_blank>Originally posted</a> by djmx2002
Hey i don't mean to hijack this topic but i've seen this sew blade

http://www.amazon.com/Irwin-11870-10-Inch-Plywood-Plastic/dp/B0002UKS7I/ref=sr_1_1?ie=UTF8&s=hi&qid=1194995705&sr=8-1

anyone know if it is any good to cut acrylic?

I cant tell but it doesnt look to be carbide. I use this blade, I dont think there are many that will cut as smooth.

http://www.mytoolstore.com/tenryu/propla.html

Don

[Chris Witort]

As with most things in life, there is more than one way to skin a cat. I never skinned a cat, but that's what I hear. The way I machine acrylic (and most pros that don't have CNC machines) is as follows. Under mount a router in a large worktable (Formica top is best), get a fence that is a little longer than the worktable. Rough cut the panels about .5" oversized, or have your acrylic vendor do it for you. Clamp your fence to the table ( fence on the left cutter on the right) about .25" larger than the finished width between the fence and the cutting head (I prefer spiral down cut .5" diameter x 1.25 cutting length. Feed the panel through the cutter while keeping the acrylic panel pressed against the fence. Now run other panels that need to be the same size. Reset the fence to the finished distance from the cutter, flip the panels so the previous cut edge is against the fence and cut your panels. You now have panels that are perfectly straight and exactly the same width. Repeat for other sides as needed. Without Computer cutters you cant get better cuts than this method. Disclaimer: Your ability to use tools properly and safely are you responsibility, Your results will to a great degree depend on your skill. Proceed at your own risk.

[Radioheadx14]

just be careful with table saws. about 15 years ago my dad (who has been a carpenter all his life) got over confident and nipped the end of his fingers off. make sure you use a guide to push the ends of the pieces across the blade when cutting thin pieces

[suthrnmn]

regarding expensive table saws.....Ive buillt several very nice stands using only a hand held circular saw and a miter saw. You can set up a "fence" by simply lining up a "straight" piece of metal on the wood and "attaching" it with a couple of wood vises. Then just run the circular saw down the fence. It is a lot easier than you think and it really dose not have to be that accurate....with in reason of course. Main thing is to take your time and think each move all the way through, wear your eye protection, keep your fingers out of the way and leave the beer in the frig till your done for the day!! good luck

[RyanBrucks]

Well I've been pretty busy lately but finally made time to experiment with using the router. I can see that its great for getting the perfect edge, but I definitely need a circular saw too.

Decided to make a 6x6x6 tank using some scrap first so that don't mess up the expensive acrylic :)

http://reefcentral.com/gallery/data/500/167670acrylic_sheet.jpg

suthrnmn,
Yes I'm starting to agree with this now that I've pretty much learned the whole 'fence' concept using clamps and a "straight edge" (the factory cut acrylic, which is pretty nice as-is). No need for the table if you're using a square.

http://reefcentral.com/gallery/data/500/167670acrylic_workshop.jpg

I used a circular orbit sander with 220 fine grit on my 6x6 piece and it gave a nice smooth edge. The plunge router is perfect for cutting our interior lids, but I can see I need a circular saw to reduce the amount of waste for other cuts, since cutting through a whole sheet of acrylic, even with a 1/4 size bit seems pretty wasteful.

Tomorrow I'm going to get a circular saw and parts to make some a fence, and finish cutting the other 6x6 panels so that I can try my hand at the solvents next. Also my girlfriend Caroline was kind enough to grab me some ball point needle size17s. Now if only I could find the electrical tape I stashed in some drawer last year..........



oh, and I present to you my next DIY concept....

http://reefcentral.com/gallery/data/500/167670phoebe.jpg

the puppy refugium!

[Donw]

Dont sand it with the sander after you cut it smooth. Its to hard to keep the sander 90 so you could end up with gaps.

Don

[RyanBrucks]

ill pick up some larger sheets of higher grit paper and sand it on the flat table with a guide as I"ve seen people suggest.

I ran out of sheet sand paper, so I was testing the sanding on the bottom piece of my 6x6x6 test tank just to see how it looked.

[cannarella]

Remember when using a router that if yo are cutting around the outside to go counter-clock-wise. Opposite for the inside. This make the router stay against the work. Never do a climbing cut, the router can get away from you. Check out this article from Highland Hardware.

http://www.highlandwoodworking.com/library/routersgoleft.pdf

They also have other articles that you may be interested in to keep safe and add ideas.

http://www.highlandwoodworking.com/index.asp?PageAction=Custom&ID=3

I have taken several classes there and they are so helpful and stress safety.

[RyanBrucks]

Finally got around to finishing my 6x6x6 test tank with pretty good results. Over the weekend I assembled my 35 gallon frag tank.

http://reefcentral.com/gallery/data/500/16767035g_frag_01.jpg

I used weldon#4, and size17 pins. for the most part I got bubble-free seams, but in a few places bubles crept in during the setting process. I waited about 35 seconds before pulling each pin, and quickly set the piece after pulling the pins (with my helper, caroline, of course).

Do these bubbles look serious to you guys? Should I add a brace piece to add strengthen to these corners?

http://reefcentral.com/gallery/data/500/16767035g_frag_seams_01-med.jpg

Tomorrow I'm planning on running my router to remove the overlap from the edges. I think this would expose some of the bubbles on the outside; would it be a good idea to run another small bead of weldon#4 after that?


Thanks,
Ryan