Acrylic fabrication questions? I can help!

[Dans85]

Here's some pics of the tank. Dimensions are 60x18x24. Approx 110 gallons. I could finally get some better pics of the areas that need attention. The spot in the front I think will be pretty straight forward, but what about on the curved corner?

[Floyd R Turbo]

Ugh. That's ugly. You can stop the gusset short of the corner. This is one of those that is gonna be tricky. First you have to clean the junk off with a vinegar soak, then clear out all those joints (if they end up with moisture in them, could take a while), then you're going to have multiple gussets meeting up in the corners, and the best way to do this is to pour them all at close times, so make one pour, let it set for 20 minutes, make the next, etc, tipping the tank one direction each time

Then there's the back seam that you cannot see...hope you got a deal on this tank

I would use the 1" gussets on this one. Tank looks like it might be underbuilt to begin with, and whatever is going on with the seams is indicative of a poor welding job, moving the tank too soon after setting the joint, improper support, poor quality material, or a combination of those.

[Dans85]

Ok. Thanks again. I know where another tank similar to this one is that I might look into. This is the first acrylic tank that I've had, so I went into this sorta blind. I guess I know what to look for from now on. If I decide to fix this one, I'll post some pics and progress.

[Scuba_Steve]

I am trying to do my first edge preps. Please let me know how they look, and then maybe talk me through what I am doing wrong.

I am using a 1/2" Diablo template bit on a router table. Template is MDF.

This is really just a practice run to see how the edge looks. IMO, I still see cut marks, although they are very smooth. Much better than the saw cut edge. I tried a second pass and notice no difference.





Opinions/Advise?

[Floyd R Turbo]

Those vertical lines are expected/typical when final routing. You're good

[blackthunda77]

I'm sorry if this has been answered, I did a search on the thread but didn't find what I was looking for. Do you have a picture or a link on how to install and use a gusset. I have a tank that has a leaking seam and I might have to go that route.

Sent from my SAMSUNG-SM-N920A using Tapatalk

[Scuba_Steve]

Originally Posted by Floyd R Turbo

Those vertical lines are expected/typical when final routing. You're good

Thanks man!

[Malign Reefer]

Which is typically used for acrylic tanks, Plexiglas G or Plexiglas GP ?

[Floyd R Turbo]

My brain feels rusty right now... Plex G is the good stuff, GM is (IIRC) the extruded stuff, GP I believe is what some distributors call the generic cell-cast stuff. This is also sometimes called PMACS, it is made by Arkema and has a plain brown paper mask (no markings) but it made at the same factory as Plex G, it is made to compete with other cheaper cast products. Basically, it is the same as Plex G but it maybe didn't pass certain quality checks like thickness consistency or clarity (flecks, surface imperfections, discoloration, etc)

Personally I've noticed no difference between Plex G and PMACS, and the warranty on G only covers a full sheet that has not been machined. So you would have to unmask the entire sheet to examine it, if it was fine, you would have to re-mask it before machining. If you found a flaw, you would have to be one of the few that buys $100K worth of their product a year in order to get paid for re-doing the tank.

That being said, a display tank should still be made with Plex G IMO. PMACS is perfectly fine for sumps and frag tanks, etc.

[Malign Reefer]

Originally Posted by Floyd R Turbo

My brain feels rusty right now... Plex G is the good stuff, GM is (IIRC) the extruded stuff, GP I believe is what some distributors call the generic cell-cast stuff. This is also sometimes called PMACS, it is made by Arkema and has a plain brown paper mask (no markings) but it made at the same factory as Plex G, it is made to compete with other cheaper cast products. Basically, it is the same as Plex G but it maybe didn't pass certain quality checks like thickness consistency or clarity (flecks, surface imperfections, discoloration, etc)

Personally I've noticed no difference between Plex G and PMACS, and the warranty on G only covers a full sheet that has not been machined. So you would have to unmask the entire sheet to examine it, if it was fine, you would have to re-mask it before machining. If you found a flaw, you would have to be one of the few that buys $100K worth of their product a year in order to get paid for re-doing the tank.

That being said, a display tank should still be made with Plex G IMO. PMACS is perfectly fine for sumps and frag tanks, etc.

Thank you very much for the info.

[chriscobb]

Considering building a rimless tank....Dimensions would be 40" x 36" x 24". What acrylic thickness would be recommended?

[Acrylics]

Originally Posted by Floyd R Turbo

My brain feels rusty right now... Plex G is the good stuff, GM is (IIRC) the extruded stuff, GP I believe is what some distributors call the generic cell-cast stuff. This is also sometimes called PMACS, it is made by Arkema and has a plain brown paper mask (no markings) but it made at the same factory as Plex G, it is made to compete with other cheaper cast products. Basically, it is the same as Plex G but it maybe didn't pass certain quality checks like thickness consistency or clarity (flecks, surface imperfections, discoloration, etc)

Personally I've noticed no difference between Plex G and PMACS, and the warranty on G only covers a full sheet that has not been machined. So you would have to unmask the entire sheet to examine it, if it was fine, you would have to re-mask it before machining. If you found a flaw, you would have to be one of the few that buys $100K worth of their product a year in order to get paid for re-doing the tank.

That being said, a display tank should still be made with Plex G IMO. PMACS is perfectly fine for sumps and frag tanks, etc.

We've had a coupla small displays sent back due to the flecks of "stuff" in PMACS back before I knew what it was so be aware, this is part of the program.

Plexiglass G and GM are the same thing, "MC" (melt calendar) is the extruded material. If you're seeing Plexiglass GP, it would be odd as Plex GP is the European version of Cyro/Evonik's Acrylite GP. Evonik owns the European rights to the name Plexiglass. Odd....

Originally Posted by chriscobb

Considering building a rimless tank....Dimensions would be 40" x 36" x 24". What acrylic thickness would be recommended?

Probably 1.5". I've built tanks about that size but IIRC - a little smaller out of 1.25" so I'd "think" 1.5" should be fine

HTH,
James

[Malign Reefer]

Originally Posted by Acrylics

We've had a coupla small displays sent back due to the flecks of "stuff" in PMACS back before I knew what it was so be aware, this is part of the program.

Plexiglass G and GM are the same thing, "MC" (melt calendar) is the extruded material. If you're seeing Plexiglass GP, it would be odd as Plex GP is the European version of Cyro/Evonik's Acrylite GP. Evonik owns the European rights to the name Plexiglass. Odd....

HTH,
James

Here is the link to the GP stuff.

Under the Literature by Supplier link

http://www.piedmontplastics.com/cast-acrylic-sheet/

[Acrylics]

Originally Posted by Malign Reefer

Here is the link to the GP stuff.

http://www.piedmontplastics.com/cast-acrylic-sheet/

I believe they're referring to Chemcast GP, I wouldn't use it despite the low price. There was a company selling tanks a few years ago below what anyone else could charge and offering a lifetime guarantee. I couldn't figure it out until many of those tanks started popping and I was sent pics. *Now* I understood - they were using Chemcast GP and the bond strength wasn't holding up over time (a year or two) and the company folded. It *may* be a better material insofar as strength goes these days, but I also see it crazing a bit faster than other materials on things like small displays.

In short, I wouldn't, but it *may* be okay. Plex G/GM would be preferred if you don't want to spend the money on Polycast/Polyone.

James

[Malign Reefer]

Originally Posted by Acrylics

I believe they're referring to Chemcast GP, I wouldn't use it despite the low price. There was a company selling tanks a few years ago below what anyone else could charge and offering a lifetime guarantee. I couldn't figure it out until many of those tanks started popping and I was sent pics. *Now* I understood - they were using Chemcast GP and the bond strength wasn't holding up over time (a year or two) and the company folded. It *may* be a better material insofar as strength goes these days, but I also see it crazing a bit faster than other materials on things like small displays.

In short, I wouldn't, but it *may* be okay. Plex G/GM would be preferred if you don't want to spend the money on Polycast/Polyone.

James

Thanks James, I think I will stick with G.

[Malign Reefer]

Originally Posted by Acrylics

I believe they're referring to Chemcast GP, I wouldn't use it despite the low price. There was a company selling tanks a few years ago below what anyone else could charge and offering a lifetime guarantee. I couldn't figure it out until many of those tanks started popping and I was sent pics. *Now* I understood - they were using Chemcast GP and the bond strength wasn't holding up over time (a year or two) and the company folded. It *may* be a better material insofar as strength goes these days, but I also see it crazing a bit faster than other materials on things like small displays.

In short, I wouldn't, but it *may* be okay. Plex G/GM would be preferred if you don't want to spend the money on Polycast/Polyone.

James

They have 3 different PolyOne's list in that section, which one would you choose?

[Acrylics]

Originally Posted by Malign Reefer

They have 3 different PolyOne's list in that section, which one would you choose?

Depends, but as a generality - none of the ones listed. I think those are just .pdf brochures for your reading pleasure.

Commercial grade Polycast/Polyone (not listed in the link) is by far the best material but is ~50% more expensive than Plex G/GM. Polyone is a bigger player in the aerospace materials and that's where they make good $$. They still have the commercial side, but have increased pricing a lot over the last few years. They used to be 15-20% more than Plex G but the gap is a good bit bigger nowadays.

Most of the bigger distributors like Piedmont "carry" it as a line, but *very few* keep it in stock.

James

[Malign Reefer]

Originally Posted by Acrylics

Depends, but as a generality - none of the ones listed. I think those are just .pdf brochures for your reading pleasure.

Commercial grade Polycast/Polyone (not listed in the link) is by far the best material but is ~50% more expensive than Plex G/GM. Polyone is a bigger player in the aerospace materials and that's where they make good $$. They still have the commercial side, but have increased pricing a lot over the last few years. They used to be 15-20% more than Plex G but the gap is a good bit bigger nowadays.

Most of the bigger distributors like Piedmont "carry" it as a line, but *very few* keep it in stock.

James

Thanks again James

[chriscobb]

Thanks James....

[Floyd R Turbo]

Originally Posted by Malign Reefer

Here is the link to the GP stuff.

Under the Literature by Supplier link

http://www.piedmontplastics.com/cast-acrylic-sheet/

Plexglas G P-95 is not "GP" - in case that's how you read it. Not sure what P-95 is

[Acrylics]

Originally Posted by Floyd R Turbo

Plexglas G P-95 is not "GP" - in case that's how you read it. Not sure what P-95 is

P-95 is frosted on one side. The "P" means pattern and 95 is essentially the density of the pattern. P-99 is often used as a "non-glare" material for picture frames - textured side out eliminates reflections and adds softness. P-99 is always extruded while P-95 is kinda it's cell cast equivalent. You can also have double pattern, called "DP." DP-70 and the like is often used for patio table tops and shower doors.

James

[Malign Reefer]

Originally Posted by Acrylics

P-95 is frosted on one side. The "P" means pattern and 95 is essentially the density of the pattern. P-99 is often used as a "non-glare" material for picture frames - textured side out eliminates reflections and adds softness. P-99 is always extruded while P-95 is kinda it's cell cast equivalent. You can also have double pattern, called "DP." DP-70 and the like is often used for patio table tops and shower doors.

James

Oh ok, thats how to read that... I'll just stick with G like I always have, thanks again guys!!

[Pivitol]

I was wondering what type of foam or underlayment would be best between the stand and a acrylic tank?

[chriscobb]

What's the best bit for edge prep?

[paphater]

James- I've read in some of your older posts that you recommend installing square rod gussets with WO 40, what's the proper procedure for that?