Working with Acrylic...feel free to ask me any questions.

[ER9]

hey all. i'm a fellow aquarium enthusiast and have alot of experience working with acrylic. if anyone has any specific questions regarding fabricating with it...feel free to ask. i will try to make it to this site on a regular basis to answer any that might be asked. please dont be offended if it takes me a few days to reply as sometimes i can get busy. -ER

[SantaMonica]

Welcome. Nice to have acrylic experts :)

[nickq]

Hi, I am a total acrylic novice, can you help with the following quesions please?
I want to segment a small glass tank as a sump and think acrylic is probably the easiest way to go.

1. What thickness would you recommend? The largest panel I need is 230mm x 243mm.
2. What type of acrylic? I've seen cast acrylic, clear XT???
3. Can I silicone acrylic to glass?

Thanks,
Nick.

[dohn]

How do you join acrylic to acrylic. Like a T

[nickq]

I think we lost ER9.
Any other Acrylic knowledge out there?

[ER9]

Hi, I am a total acrylic novice, can you help with the following quesions please?
I want to segment a small glass tank as a sump and think acrylic is probably the easiest way to go.

1. What thickness would you recommend? The largest panel I need is 230mm x 243mm.
2. What type of acrylic? I've seen cast acrylic, clear XT???
3. Can I silicone acrylic to glass?

Thanks,
Nick.

sorry for my late response. been a hectic week and 3 days with no pc as new harddrive install didn't go so smoothly.

so i'm assuming you plan to use the acrylic simply as dividers within the glass tank? if i understood you to mean that then you should be able to get away with 1/4" plexi with no problems. in this situation i wouldn't think the quality of the plexi would be much of an issue since there would be little real pressure exerted on the pieces. silicone works reasonably well on plexi. not as strong as glass to glass bonding but should hold up well in situations where there would be only moderate pressure.

[ER9]

How do you join acrylic to acrylic. Like a T

i'm not sure if your asking for technique or glue. if its glue...acrylic to acrylic bonding is best done using solvent to weld the two pieces together. weld-on corporation sells most of the commercially used brands today. their #4 solvent is a decent one to use. most good acrylic solvents (the better ones) have high methylene chloride and trichloroethylene (not sure i spelled those correctly) content. unfortunatelly if you live in some states, especially california, you can no longer get them due to recent environmental regulation changes. if your not in california you can still order them online and have them shipped or visit a local plastics shop if you have one. alternatives would be pure methylene chloride solvent or like i mentioned weld-on made products. there are other companies that make them...i would look for acrylic solvent in any descriptions when looking for one to glue plexi to plexi.

you can also use many of the hardware store general purpose glues for plastic. most all will work fine. the drawback is they will not be as strong and you usually sacrifice alot of aesthetics when using them...meaning they may leave chalky residue etc....
these cheap hardware store glues should never be used in situations where quality glue joints are critical. for example any time you are trying to get strong watertight seams that will be under pressure.

for technique....its best to try and glue one piece so its situated on top of the other piece to be glued to. the solvents are water thin and will easilly run out of the seam your trying to glue. time spent preparing and setting up the two pieces so they are stable and squared will be invaluable. for example in pic i'm gluing the smaller piece to the larger against a 90degree backstop to align and stabilize it.

[worley]

I've seen some examples of people leaving 1/2 to 1" extra, over-sizing each piece then cutting off the excess once glued.
Is there any good reason for doing this?

[ER9]

I've seen some examples of people leaving 1/2 to 1" extra, over-sizing each piece then cutting off the excess once glued.
Is there any good reason for doing this?

yes. its better to leave a much smaller amount though. its hard to see in the above picture but i'm actually leaving about a 1/16th inch overhang on the bottom piece. the reason is that its difficult to make a box correctly using pieces that are the exact size of the finish box dimensions. there are a whole host of problems you will encounter when making boxes commercially that will ruin their sellability. the biggest is solvent run. the solvent is so thin that it will run everywhere if not carefully contained. if you glue two edges exactlly edge to edge solvent will drip over, run under and melt the bottom piece, ruining it aesthetically. the other main issue is precise dimensions. acrylic is generally not a flat material and often is slightly bowed. in the above photo you can see i force it against a backstop with the weights to keep it flat. at the bottom of that backstop there is actually a 1/16" underhang. we cut material slightly larger to compensate for the underhang. when the box is completed we route off this edge. it ends up being much cleaner aesthetically in the end as well.

[worley]

Thanks, knew there had to be a good reason for it ;-)
How about cutting the sheets? Yes, I'm a completely acrylic noob :lol:

[ER9]

Thanks, knew there had to be a good reason for it ;-)
How about cutting the sheets? Yes, I'm a completely acrylic noob :lol:

well the tools we use are the basic ones, band saw, jig saw, table saw, router, panel saw, nothing special. the blades are the critical component. they make and sell blades and bits for all this equiptment for cutting acrylic, or more generally plastic. iv'e seen them at all the major home builder/hardware stores here in the states. basically in a nutshell these blades are designed with a very straight tooth set and are ground/hollowed to facilitate quicker material removal. they usually have but not always, larger teeth spaced closer together as compared with wood.

some blades for general woodwork that can be used in a pinch if you dont have to do alot of cutting are for tablesaws, laminate or plywood style blade, bandsaws and jigsaws i prefer blades made for sheetmetal with a courser tooth. of course you will compramise finish a bit with these blades but they will do the job without shredding the edges of your plastic too badly.

[SantaMonica]

You should consider coming up with a mini low-profile version for folks to set on top of their nano's. Would need to include a self-priming pump to pull water up to it, but otherwise would be just like mine but smaller... maybe 2" high and 12" wide. Main requirement would be nice looking, and also that it would keep all light inside. You could match it in size for (or include) a super-slimline T5HO light, but that might increase the height to 3 or 4"

[ER9]

You should consider coming up with a mini low-profile version for folks to set on top of their nano's. Would need to include a self-priming pump to pull water up to it, but otherwise would be just like mine but smaller... maybe 2" high and 12" wide. Main requirement would be nice looking, and also that it would keep all light inside. You could match it in size for (or include) a super-slimline T5HO light, but that might increase the height to 3 or 4"

hmmm...kind of been mulling a couple ideas over in my mind. something i'm definately considering.

[zoa]

What is the difference in weld on glues? ie.......... #16 or #40

Allso I know you said to use a special blade to cut the acrylic. Is there any special name? Can I just use my 80 tooth freud?(spelling)

[kcress]

I just went thru this myself.

There is the water thin stuff that wicks into the joints. That's for smooth cuts that are straight forward.

WO #16 is thick like model glue. It doesn't wick anywhere. You would put it on the surfaces and then press the parts together. It can also glue PVC, ABS, and a few other things to each other or themselves. It usually comes in a giant tooth paste tube with a small nozzle.

WO#40 is a little stronger but comes as a two part mixture. You can get mixing nozzles for it. It costs more. And generally isn't worth the hassle. IMO.

Go to the "WELD-ON" site and look at the product brochure. Short and too the point stuff. Good site.

[snail]

I heard that turning your blade for thin plywood backwards does nice with thin plastic. Is there any truth to this?

[zoa]

Thank you both for the info. It helps a lot.

My local hardware store carries WO#16. In the small and large tooth past tubes.

[kcress]

snail; I sure haven't heard that one..

[ER9]

What is the difference in weld on glues? ie.......... #16 or #40

Allso I know you said to use a special blade to cut the acrylic. Is there any special name? Can I just use my 80 tooth freud?(spelling)

well the main difference in most plastic/acrylic cements is the material thats dissolved/suspended in the glue. basically plastic glues are made using different combinations/ratios of solvents and many also have a particular monomer disolved in this solvent mix. weld on #16 is such a glue and i beleive is mainly made of dissolved acrylic. I dont use it so i'm not 100% its entirely dissolved acrylic. that what makes it a good general purpose plastic cement. Its known as an adhesive because as the solvent evaporates it leaves the suspended acrylic intact which dries and hardens, bonding the pieces of matrial. its a decent adhesive but i wouldn't trust it for bonding an aquarium.

Weld On #40 however is an entirrely different animal. its one of the best materials for gluing acrylic especially. iv'e used it extensively and built my aquariums with it. basically its a two part acrylic resin. meaning you mix the acrylic resin with a catalyst, a chemical reaction occurs which cures the resin. its very difficult to work with and if not mixed correctly can result in a dissaster but its bond can be so strong and its surrupy consistancy so good at getting good glue joints....theres few equal glues/solvents that can match it when gluing thicker material. of course unless you have a multimillion state of the art factory. mainly weld on #40 is usefull when you start trying to glue thicker material, 1/2" or thicker. solvents just dont perform well at that thickness.

as for blade....we use a blade from FS Tool, i forget the model # off the top of my head. in my opinion (and iv'e tried many, many industrial saw blades) theirs are the best. Of course on will set you back a couple hundred dollars. i have been to home depot and local hardware stores (sears) and have seen saw blades made for cutting plastic. they all have the same basic design. 80ish tooth, strait set blades with or without carbide teeth. some even advertise 'tripple chip grind' this is a type of tooth grind that helps remove material fast and prevent melting of the cut. i would look for those details if you want a blade that will give very smooth, clean cuts (appropriate for gluing acrylic tanks)

if your blade (i'm not farmiliar with it) is strait set, similar to a finish blade for wood, and is very sharp i would say give it a try. i have used new, out of box finish blades for wood to cut acrylic and they did pretty well if the plexi is on the thin side. once they get even the slightest bit dull though....they tend to take out alot of chips from the edge of the material.

[ER9]

I heard that turning your blade for thin plywood backwards does nice with thin plastic. Is there any truth to this?

honestly iv'e never tried this before. i started working in a fully equiped fabrication shop so there was no need for me to ever resort to this. i have heard it works well for thin material although i personally would be very reluctant to try it on anything thicker than 1/8". if there is too much resistance and 'blade grab' it could end up ripping the material out of your hands and into the saw. i had a guy put a saw blade on backwards once on a panel saw. he then tried to cut a piece of 3/8" thick acrylic. basically the material was so thick the saw grabbed the surface of its and rolled over it at high speed. it was a pretty scarry situation and luckily a panel saw is mostly hands off so he was safe from injury. i dont think this could happen with a table saw because of their design differences but be careful anyways.

[zoa]

Do you think I could safely put together a box with 3/16-1/4" acrylic that is 17"x4"X" with WHO# 16? It's for my new scrubber. I would want your answer to be based on it being full of water all the time.

[kcress]

ER9 can confirm but I would use the straight solvent not the "glue" WO16.

When you apply #16 to one edge then stick that other edge to some sheet you get ooze out of both sides creating a bead that can be problematic. What happens as you try to get everything lined up and the joint freezes?? This happens very fast an is permanent.

If you are building sumps, etc., you want to put up everything and tape it all together just how you want it. Everything aligned, self supporting, square, and plumb. Then you bring your 'needle applicator' full of the clear water-thin solvent over. You tip it up and hold it to the joints and move it along smartly. You can instantly see the joint suck in the solvent due to surface tension effects. It is very easy. The hardest part is keeping the dang application needle from dripping on the way to and from the actual position you want to use it at. This makes hideous spot marrings where it drips. This is why you want to start with things like sumps where those mistakes mean nothing.

Get a bunch of scrap pieces and practice a wee bit before doing your project. Do this five minutes before doing your actual job. This will get you in the groove.

Use the #16 for those odd jobs or where you are gluing PVC to acrylic. It is also good for gluing some ragged piece to a flat piece or sticking a tag or little square on somewhere where it can't just sit due to gravity.

[ER9]

Do you think I could safely put together a box with 3/16-1/4" acrylic that is 17"x4"X" with WHO# 16? It's for my new scrubber. I would want your answer to be based on it being full of water all the time.

ipretty much agree with kcress on everything he said. its best used for fittings/odd external items. its messy and difficult to use. that being said it probably would work, although it wouldn't look the greatest aesthetically. i wouldn't personally trust it on anything much larger as i would be concerned of its water tight integrity. that being said i would watch it closely for leaks on a regular basis if you decide to use it and be aware of not placing it or avoid placing it above electrical items that could short in the event of a leak or joint failure. if you can get the solvent it would be better but even solvent glued joints might need silicone to become water tight if you are new to gluing with it. test this thoroughly over a couple day period before finishing your box. it can be frustrating to have a leak spring a week later and have to take everything appart. look for bubbles in your finished glue joints especially in all the corners. these are the most problematic areas.

to avoid drips...squeeze the bottle slightly before tipping it over to create a vacuum until you can get the needle in place. if you drip dont attempt to wipe it off...it will only make it worse. let the drips evaporate and use a general plastic polish with cheesecloth to polish away the blemish after its dried. you will never know it was there.

[kcress]

Thanks for the pre-squeeze tip.