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A Modder's Guide To Acrylic

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[USRF]Obiwan 14th March 2008, 10:26 Quote
After all those years, the Orac3 is still one of the best looking mods around. And a very nice article.
undertheradar 14th March 2008, 10:53 Quote
This article has a bunch of problems with it. I dont use acrylic for computer mods, but I have years of experience with acrylic for reef aquariums, building reactors, flanges, aquariums, fixtures, etc. There are several things in that article which are just plain wrong, or not the best way to do it. For instance, that type of saw blade pictured/suggested in the article is one of the worst blades you can use for acrylic.
undertheradar 14th March 2008, 11:00 Quote
One thing of importance: much of the 'cast' acrylic in the US isnt cell cast. Its something called 'continuous cast'. Its poured like cell cast, but on a constantly moving conveyor belt (like a 1/2 mile long) a bit like how plate glass it made when you think about it. Its a bit different than cell cast as far as strengths and problems though.

90% of the acrylic work I do is done by a laser CNC or CNC router... thats the way to go, and usually pretty easy to find someone you know who can do this for you. Most people who work in factories, engineers, etc tend to have access to one... one computer store local to me actually has a laser CNC in their back room...lol.

There is a multitude of articles on sites like reefs.org and reefcentral.com (mostly in the DIY sections, sort of like the aquarium version of the modding community) about working with acrylic. You can ask there as there are several professional fabricators there who are more than willing to help.
Da Dego 14th March 2008, 11:57 Quote
Quote:
Originally Posted by undertheradar
This article has a bunch of problems with it. I dont use acrylic for computer mods, but I have years of experience with acrylic for reef aquariums, building reactors, flanges, aquariums, fixtures, etc. There are several things in that article which are just plain wrong, or not the best way to do it. For instance, that type of saw blade pictured/suggested in the article is one of the worst blades you can use for acrylic.

Undertheradar, would you mind elaborating?

I've worked with acrylic in modding since 2001, and I've found a fine-toothed plywood-panel blade to be a great way to cut it without marring the edge beyond recognition.

I don't attest that these ways are the ONLY way to do it, so if you have some actually constructive tips, then by all means - fire away. But if you're just going to say "Oh this is so wrong," that's not exactly helpful. Particularly when you can look on the net at large or in the forums to find that we as modders have been doing some of these things for years to great success.
theevilelephant 14th March 2008, 12:34 Quote
great article, as someone who works as DT Tech (the guy that cleans and maintains workshop machinery) i might get some of the students to look at this too see what you can do with acrylic. Also please dont use band saws for acrylic unless its yours and you have the right blade, it makes a huge mess, clogs blade and machine and stinks.
vaderag 14th March 2008, 12:34 Quote
I've done a bit of acrylic work in the past, but mostly forgotten all the techniques - this article has re-awakened my idea of building an acrylic case - thanks :)
speedfreek 14th March 2008, 16:38 Quote
If I ever went to watercooling I told myself I would make my own reservoir, now I have a good idea how to.
Thacrudd 14th March 2008, 17:04 Quote
I really appreciate the good read! Flame polishing makes a bit more sense now lol. Orac3 is the case that I happened across a few years ago and it is what got me into PC case modding (I did a bunch of xbox's before) A few comments :

1. the sawblade pictured is what I've used and have had wonderful results from in the past.
2. I do alot of my cutting now on my bandsaw, 80" blade, 15TPI, and it works great.
3. Superglue is a very bad bonding agent for clear acrylic. It creates a foggy residue around where you used it, not just the exact spot you put it on. I would reccomend it for anything except transparent materials. (just my experience)

If you were making a seamless bond, would you flame polish the 2 edges before you put them together?
Yemerich 14th March 2008, 18:03 Quote
Well, using a blow torch for polishing the edges is good. biut if you have a sandwitched acrilic the results arent that good. So, a blow torch is only good for single pieces.

My last four mods are all acrylic. And i have one going on here in bit tech. It's the Odinn project.

In MY experience, polished edges doesn't bond together well. So i don't think a really seamless weld is possible. The glue used to weld acrylic is cloroform based and is fairly easy to find - at least where i live.

Another good thing to save u some work is to "scrape" the edges. This way you can save more than 50% work on sanding.
If you need to bond 2 polished faces together, sand them with 400 or 600 grit sandpaper to have a more resistant weld.
For drilling the acrylic, you need blunted HSS drill bits. This prevents the acrylic to cause splinters.
The high quality acrylic (the ones that are not recycled) doesn't melt when u saw it, have no odor and is much harder to get foggy when the glue hit its face.
Still the best way to get polished edges still is by sanding it by hand, and polishing with sheep pelt.
I don't have a table saw, but the people who cut it for me use "wydea" blades to cut it.

Cheers people!
MJudg 14th March 2008, 18:12 Quote
Wow! Nice article!
I also love acrylic and LUMINA is the best example of beauty and functionality of this material!
talladega 14th March 2008, 19:21 Quote
WARNING!!! Watch out for the IPS Weld-On containers! They may explode in your face like it did mine!!!

seriously. lol. I finally unscrewed the lid and then there was a metal tab i needed to get out so I was prying it open when BOOOOOM! The metal tab hits my eye and I get the solvent all over my face and in my eyes.

Maybe im the only one this has happened to?


Nice tip about flame polishing. I'll test that out I think. Does it keep the edges very staright and flat too?
Cheapskate 14th March 2008, 19:40 Quote
I have to disagree with some of what has been said. (This is for the noobs who have never heard my constant preaching.)

You missed the biggest reason why you should avoid extruded plexi: It melts if you try to cut it with a powersaw.
If you are doing a lot of straight cuts on plexi, invest in a $100 table top wetsaw/tilesaw. They can cut through any thickness or type of plexi with great results. They work on polyprophelene or cast and extruded acrylic. On my tile saw I have cut 1 1/4" thick cell cast plexi successfully.

Flame polishing will never look as good as sanding and polishing. -and why would you want to take a torch to something you put a lot of work and money into?

Like Yemerich said, I sand the edges I plan to fuse together with 150 grit sandpaper. Faces I just leave polished.

@Talledega - Sounds like you should have put it in the fridge for a while.:)
I'ts good practice to puncture those kinds of caps before removing them. Treat them like a shook up Dr. Pepper can.
The_Beast 14th March 2008, 22:28 Quote
There are some good tips for the new be moders
Teknokid 14th March 2008, 23:19 Quote
Yeah, i found it good, although the UK company mentioned is a bit dear :(
personally im gonna start getting myn from ebay, excelent deals from there im finding.
Nice article :)
Matticus 15th March 2008, 01:30 Quote
Nice article.
Though on page one "perpex" has a closing tag before it, so no Italics.
This has sort of reminded me to actually bother to make something from acrylic, so thanks :)
Project_Nightmare 15th March 2008, 01:36 Quote
Good thing this article came out before I started the case mod I'm planning! I wish there were more articles on using acrylic like this one.
cc3d 15th March 2008, 02:34 Quote
There is a technique for mixing acetone with scraps of the plexi you are joining to make a goo (glue) that will bond plexi fantastically. I can't recall the details, but I am sure it is 'findable'
wywywywy 15th March 2008, 03:07 Quote
Nice article. Many thanks.
One question though - what is the best tool/method to mitre 45 degree on acrylic sheets?
talladega 15th March 2008, 03:12 Quote
Quote:
Originally Posted by Cheapskate


@Talledega - Sounds like you should have put it in the fridge for a while.:)
I'ts good practice to puncture those kinds of caps before removing them. Treat them like a shook up Dr. Pepper can.

I've had it in my room in for like 3 or 4 months. lol There was no warning on the thing about it being under pressure at all. Looked. Afterwards. :) It said to cut out the metal tab and the utility knife wouldnt cut through so i was prying it open and it blows up in my face. It probly would have sprayed out even from poking a hole but atleast my eye wouldnt have gotten hit. That hurt for a while. Next time.... :D

Do the tighten the screw on lids to 10,00Lbs of torque or what? I couldnt unscrew it with my hands. Had to use a tool. :o

mmmmmmmmmmmmmmmmmm DR PEPPER!!!!!!!!!!
sethnmalice 15th March 2008, 06:49 Quote
woah....what happened to using a dremel???
Bluephoenix 15th March 2008, 18:32 Quote
Quote:
Originally Posted by sethnmalice
woah....what happened to using a dremel???

dremel works fine for most of it provided you use the right bits, but its mostly good for wood/aluminum/steel

the article is fantastic as a beginners guide.

from personal experience, one of the things to watch if CNC milling acryl/plexi or similar is to check what coolant they use. Certain coolants will stain the acryl/plexi permanently, sometimes soaking in a good way. the coolants used to mill aerospace parts are particularly guilty of this.

however, the coolants that do not stain are your best friends, as because the flow is high volume, you can mill almost any type of acryl/plexi with a very high degree of precision. the easiest way to find someone who will do CNC milling work is to pull out the phonebook, or look for local part manufacturing shops.
undertheradar 15th March 2008, 22:19 Quote
Quote:
Originally Posted by cc3d
There is a technique for mixing acetone with scraps of the plexi you are joining to make a goo (glue) that will bond plexi fantastically. I can't recall the details, but I am sure it is 'findable'

Its not acetone, but close. IPS Weld-On, the stuff you use to bond acrylic (usually #4, #3, or #16) is the best. If you are in a bind, and want to make your own, its actually MEK. If you blend about 50/50 by volume of acrylic scrap and MEK... you have a grade of weld-on somewhere between #3 and #4 (#3 sets faster, #4 gives you more set time). Recently, Weld-On has changed its formulations though... so what the new formulas are now are anyone's guess. The old stuff was better though, thats what I hear from the fabricators, so Ive stocked up on the old #4 and #3.

As for saws, the problem with those fine tooth 'panel' blades is that on any sheet that is thicker than the height of the teeth, the sheet melts to the blade. So even though having a blade with more teeth is preferred, if those teeth are short, chances are you will end up burning the acrylic. This can end up blackening the edges, or be more subtle... sealing the surface of the acrylic so it cant be bonded with regular solvents (like abrasion resistant acrylics). The trick with acrylic and any saw is you have to cut fast enough that it wont melt and bind, but slow enough that you dont end up chipping. With those panel blades (like the one shown in the article), this 'sweet spot' or middle ground is overlapped, or it doesnt exist... you are going to get one or the other it seems... IME.

The best blades I have used (besides just buying an acrylic blade) are the finer tooth carbides. The tips of the blade are wider than the main disk of the blade, so friction is minimized. If you rub a little blade wax on, it will cut the acrylic like butter. Still, even with a belt drive table saw (direct drives arent very good for acrylic) and a sweet fence ( I use a powermatic table saw, one of the best made), you still get some chipping and want to polish up the edges. So I tend to do all 'show' cuts with first a saw, and then finish them up on the router lift. Once again, you want to go fast enough not to chip, bit slow enough not to chip... 18,000 rpm is the speed you want on the router as well, and just a straight 1/2" cutting bit works well.

I suggested the DIY forums otherwise at Reef Central. There are guys there who know EVERYTHING about acrylic, because its their business to.

Oh, and as far as extruded vs. cast... unless you are doing heat shaping/bends, I bet for most of your projects extruded will be just fine. For the aquariums, cast is a must because it holds up to pressure better, and bonds better. Of course, like I said, it depends... as its not just 'CAST' vs. 'EXTRUDED', but Continuous Cast, Extruded, and Cell Cast. Also, I suppose I need to include for the EU guys... the grade of acrylic made in the US vs. China vs. EU is very different. The EU extruded is much higher quality than the US (more expensive too), so good its used in many applications that would warrant cast if in the US. The 'cast' coming out of China is also dangerous to work with, as its actually recycled and mixed with some nasty plasticizers in the process which release when the acrylic is heated. Using a drill bit or dremel even can release black smoke and fumes like you woulnt believe... I had to run out of the basement when I did it myself it was so potent. The good stuff should almost smell sweet when you cut it... not like a toxic dump. If you work with something that smells like that, work outdoors with it. Its bad juju. And forget using an oven for heat forming... I doubt it wouldnt burst into flames before it hits 250. The chinese acrylic is poured like a resin into the specific shapes desired, like casting a glass jar almost, because they wouldnt want to have to machine it later.
Edvuld 16th March 2008, 00:02 Quote
Interesting read, some good tips to try out next time!
Cheapskate 16th March 2008, 19:03 Quote
Quote:
Originally Posted by talladega
I've had it in my room in for like 3 or 4 months. lol There was no warning on the thing about it being under pressure at all. Looked. Afterwards. :) It said to cut out the metal tab and the utility knife wouldnt cut through so i was prying it open and it blows up in my face. It probly would have sprayed out even from poking a hole but atleast my eye wouldnt have gotten hit. That hurt for a while. Next time.... :D

Do the tighten the screw on lids to 10,00Lbs of torque or what? I couldnt unscrew it with my hands. Had to use a tool. :o

mmmmmmmmmmmmmmmmmm DR PEPPER!!!!!!!!!!


My way of opening cans like that, (5 gallon cans of Kilz go off like bombs too,) Is to tap the edge facing away from you with a sharp nail. to hold the nail in place, your hand has to be covering the lid. When it goes POP the contents paint the inside of your hand.(:D Loaded statement!) I had one fly off never to be seen again, so I learned to be cautious.
-I think the lids are the real reason channel lock pliers were invented. -In particular for the ones on PVC glue.:D You want the lid on pretty tight anyway. I didn't get the lid on my Tap solvent right one time, and I started to hear a hissing from the cap. It was the sound of my 'spensive glue going away!

@undertheradar - I think cc3d was talking about a trick to make gel glue using shavings, acetone, and MEK, (from the Mod The Nation Forums?)
-I do love the smell of good plexi. It is kinda sweet, now that you mention it.:D The cheap stuff smells like something you put on your yard to kill bugs.

@wywywywy - For me: tile saw:) I'm not sure I'd try it on a table saw. It would chip like crazy. Do you want a bondable edge? If you're going for just a decorative bevel, then I'd try a router or just file it down.

-Seth has a valid point. One of the best ways to cut extruded plexi is with a dremel. Everything else gums up.
wywywywy 17th March 2008, 09:25 Quote
Ah, tile saws. And yes I want a bondable edge.

I've never used one of these though.
So just a case of rotating the table top 45deg, then cut?

And if I am to buy one, I would guess 600w is more than enough?

Thanks.
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