Acrylic Fabrication Q & A

[TaylorPilot]

We do not use chemcast exclusively. We use Arkema, Chemcast, polycast, lucite and bayer. For the colored stuff in .236 or under we use chemcast. For structural building, as in sidewalls of sumps and any larger capacity items, we use arkema plex g and polycast. We stopped using Evonik a few years ago after receiving some bad material. It was their chinese manufactured Acrylite GP brand. We will never use any chinese or non Americas manufactured acrylic in any of our products.

Great write up by the way Floyd R!

I shouldn't have said almost exclusively. I guess my point was that for small projects the stuff works fine, and if it is what you can get locally, I wouldn't shy away from it for small stuff like an ATO or dosing containers. I would advise it over some of the other no-name cast products most companies stock from the Philippines or China. But yes, I agree, I wouldn't use it for building displays or large sumps. I've always considered your products to be top of the line. Those laminate lid sumps are some of the nicest ones I have ever seen!

 

[Turbo's Aquatics]

@mixer911 im glad you mentioned Acrylite, that used to be #2 or #3 on the preferred list until it was switched to China, then it's been up for debate. I know one guy that uses it a lot and like it but I've always shied away from it unless it was all I could get in a pinch. Only ended up using it once for a 180 sump and it turned out good (several baffles)

What was wrong with the batch you got that made it "bad"? What thickness material?

 

[Brian Kim]

Thanks you for all these valuable information you are sharing with us.
I have a simple question.
Where can I buy acrylic cut to size here in NYC, thanks in advance.

 

[SerpentSlick]

Great info so far! I'm gonna follow along!

 

[Turbo's Aquatics]

Try Sabic Polymershapes, Laird Plastics, Port Plastics, Regal Plastics. Those are the bigger ones that have branches across the states

 

[Brian Kim]

Try Sabic Polymershapes, Laird Plastics, Port Plastics, Regal Plastics. Those are the bigger ones that have branches across the states

TYVM

 

[TaylorPilot]

I prefer Laird, atleast in Houston, the have the largest selection and in house stock of Arkema. It is worth mentioning that most of these stores aren't setup as retail stores, so it could take awhile to get you out the door if you just walk in. I would call ahead, get pricing and tell them what you need. That way they know when you are coming and what you are getting. They can have you in and out allot faster that way.

 

[Brian Kim]

I prefer Laird, atleast in Houston, the have the largest selection and in house stock of Arkema. It is worth mentioning that most of these stores aren't setup as retail stores, so it could take awhile to get you out the door if you just walk in. I would call ahead, get pricing and tell them what you need. That way they know when you are coming and what you are getting. They can have you in and out allot faster that way.

Thanks

 

[cromag27]

Just a couple things to add......

Stay away from astari niagara acrylic. cheap junk.

Thin solvents like weld-on 3 and 4 have a shelf life of about one year after you open the can. learned that the hard way.

Not sure if turbo mentioned this already, but water vessels need time for the joint to completely strengthen up. this varies depending on the acrylic thickness. I believe James posted some guidelines in the other thread about average wait times.

And don't forget that acrylic absorbs water. I believe it reaches full capacity at three months?

 

[Brian Kim]

Thanks for all the information. Turns out we do have Sabic Polymershapes and Laird Plastics here in NY, they are both only about 30 min away from my house.
I've always wanted to build an acrylic frag tank, nothing big, I would say around 30 gallon and all this information is encouraging me to give it a try.
I don't have any tools nor am a handyman so all I can do is hope they don't mess up with the measurements lol.

 

[cromag27]

Yes, the ATO is 16" x 16" box, 24" tall. I guess I could put an internal baffle of sorts, just leaving a few inches on the top and bottom (to allow it to empty equally), if you think that would help.



I will be following along to make sure my welds are of good quality! Funny thing is I was originally of the mentality that it will "normally only have about 10" of water in it". That is until I read your post above...didn't even consider an extended down time when it will be holding several additional inches.

I was planning on using the pin method, but I may hold off on building it until you finish this series...lol.

 

[Turbo's Aquatics]

I would put the shelf life of an open can of WO3/4 at a month or so, after that evap weakens the mixture quite a bit.

Acrylic does absorb water, roughly 16 weeks and it is at capacity. It also expands which it why you don't exact-fit acrylic baffles in glass.

Curing times depend on material thickness. I'll have to dig up the figures but off the top of my head, 3/8" is a week, 1/2" is 2 weeks, then 1 week for each additional 1/4". So that's a month for 1", 2 months for 2", etc. the reason is water absorption. The welded acrylic absorbs water at a higher rate until it cures.

I will also have to dig up a post by James on the 2-part vs solvent and joint strength. The gist of it is that whatever the "weld-on 40 is stronger than solvent joints" crowd tells you is not exactly the case. It's just not that simple; there's a lot more to it. 40 joints are much more complicated and easy to screw up if you don't know what you are doing.

 

[cromag27]

I emailed scigrip a while ago and they told me one year. but I'm sure they were not specific to our type of application. so I'll now go with your answer.

 

[TaylorPilot]

They are talking about an unopened container (atleast I hope). Once you open it, the clock starts ticking...I would get the little 4oz containers if you are going to buy it that way. Consider them one time use things, if you are going to only do one project. Don't put it on the shelf and expect to use it a year from the date you opened it. If you are going to be doing projects more frequently it become smart to buy your own chemicals and mix them in small batches, so they are always fresh and consistent.

 

[tonkaoz]

Ok i will try that. One last question when im done buffing what do you use to clean off the buffing residue with ? You dont just leave it do you . I would think even after i wipe it down some residue is left behind. I would also think it would be poisonous to everything i want to put in the tank . Maybe clean it with vinegar or just leave it and fill it

 

[dbl]

Exactly what I was thinking about. Thanks for sharing.

 

[MAMAS]

This is a great article! I have been building DIY galss + acrylic baffled sumps and overflows for people locally for a few years. I have just recently ventured into building 10% acrylic sumps and knew most the technics. One thing I have struggled with is the "fillet". I know that the entire process is an art, but everyone makes mistakes from time to time. Once the vertical panel is unpinned, I have had a few joints with "extra squeeze" fillet if you will. Is there a way to clean this joint up when it happens or is it a done deal? Sanding an polishing seem to work for scratches or a mistaken drop of WeldOn in the middle of a panel, but I cannot figure out how to clean up a seam. Any tips other than mastering the wick:application:speed:angle would be appreciated!

Edit: Sorry, I posted from the wrong account

 

[mrbee2828]

Sorry, this is the account I meant to post under!

 

[Turbo's Aquatics]

Ok i will try that. One last question when im done buffing what do you use to clean off the buffing residue with ? You dont just leave it do you . I would think even after i wipe it down some residue is left behind. I would also think it would be poisonous to everything i want to put in the tank . Maybe clean it with vinegar or just leave it and fill it

Good question! I learned the basics of this technique from Conde of LS Fishguys fame, got him on the phone and he talked me through it. He recommended cleaning the tank with bleach to get rid of any residue. This only applies to the interior of the tank of course, but the stuff is kind of greasy so bleach is good, and it won't damage the acrylic. I'm sure vinegar works too but since one is an acid (vinegar) and the other is a base (bleach) I'm not sure if there is a specific reason to use bleach, but that's what I go with

This is a great article! I have been building DIY galss + acrylic baffled sumps and overflows for people locally for a few years. I have just recently ventured into building 10% acrylic sumps and knew most the technics. One thing I have struggled with is the "fillet". I know that the entire process is an art, but everyone makes mistakes from time to time. Once the vertical panel is unpinned, I have had a few joints with "extra squeeze" fillet if you will. Is there a way to clean this joint up when it happens or is it a done deal? Sanding an polishing seem to work for scratches or a mistaken drop of WeldOn in the middle of a panel, but I cannot figure out how to clean up a seam. Any tips other than mastering the wick:application:speed:angle would be appreciated!

Edit: Sorry, I posted from the wrong account

I know what you're talking about - the dry solvent profile on the inside corner of the joint. FWIW I've seen big tank builders leave this, it's just one of those things that I guess you have to accept as part of the process. To get that out, you would have to do some very specialized sanding followed by a TON of polishing. Sanding and polishing is generally a total PITA so when it comes to these areas, unless you want to charge buku extra for that little fine detail...your call, but I just leave that alone! Our LFS has a 1500g Tenecor tank made with 1.5" acrylic and I can see that same bead along the vertical seams, but then again I work with acrylic so the first thing I look at are the fine details. I pointed it out to my wife and she looked at me like "whatever, look at all the pretty fish and coral"

 

[mrbee2828]

Thanks, that's basically where I'm at with it as well. I watched Tanked and my family is usually the same way your wife is. "Really? You are looking at the stand welding???" I hate the show and I watch it for the technique when they do the builds. The do a 2 part and literally pour it on out of the mixing cup. It's all over and I always think... how they hell to they finish that off? lol I just finished this with the help of the owner a few weeks ago and there were a few spots I wasn't to proud of but what can you do? https://www.reef2reef.com/threads/lcs-300dd-build.195492/page-3#post-2592873