Acrylic Fabrication Q & A

[traumajeff]

Normally an 8' tank would have a 3" perimeter and 3x 6" crossbraces every 24". Removing one opening would mean you would want to add 2" to the crossbrace width, making it 8" and make the perimeter 4.5".

This also assumes that the material is good and the proper thickness. For an 8x2x2 that would be 3/4" walls (normally a 24" tall tank would be 1/2", but James/Acrylics recommends jumping up a thickness at 8' to keep deflection down). I can't tell what your material thicknesses are but it looks like it's at least 1/2" on the top and walls?

If it is 1/2" then I wouldn't narrow the perimeter to less than 6" on the sides, and you're already at 4" on the front. I'd be careful about the back euro width because of the trapezoid opening on the back, which is flush with the back panel and generally makes for a weak spot in the structure. So you don't want to expand the side holes toward the back as a square opening because that would decrease the euro width between the corners of those holes and the trap, which is exactly where it will crack out if it does. What you *could* do is expand backward making a 5-sided hole that maintains the distance like this

But even that might be pushing it. If you did this, you would want to maintain minimum 3" diameter (1.5" radius) inner corners with no jagged edges (smooth curves, all around) and then a 1/8" roundover on the top and at least scrape off the sharp edge on the underside. The point is that any sharp corner, transition from straight to inner corner, edge, etc that has a point on it is where the stress will focus. That's one thing I did learn from my discussions with a guy from Cyro...even taking a few passes with a razor blade at a 45 degree angle to a fresh router cut edge will remove all the point stress. Rounding it (either router or sanding) is even better. It's not just a presentation thing, it is a structural/stress reliever.


Water jet does not leave a weldable edge. Weld-on #16 is junk, lots of fillers, not good for structural joint. It has it's place, you can use it for non-structural items, and you can use it to build up layers on a leaky joint like a baffle in a sump, and some have used it to seal up a poor exterior joint but it's shaky even for that. That being said I've seen at least one frag tank at a show that was built with saw cut edges and probably 10 layers of 16 on the inner corners, I thought that sucker was going to blow right in front of me but he said it lasted for years!!

Thank you so much for the advice! Great ideas and points!

 

[cromag27]

That's what they all say.

but he said it lasted for years!!

 

[TherealplexiG]

Ok a couple questions, I know we shouldn't use a laser to cut then bond due to it will make it craze but what about a water jet?? Is weld on 16 ok to use haven't seen anyone mentioning that one.

Waterjet sucks when it comes to acrylic. I had lost 500$ there once. . 16 sucks too when it comes to structural build.. BTW what are you tryna build?

 

[singleshot]

Waterjet sucks when it comes to acrylic. I had lost 500$ there once. . 16 sucks too when it comes to structural build.. BTW what are you tryna build?

Just some frag tanks only 10-15 inches tall.

 

[cromag27]

What @TherealplexiG stated is still correct. even for frag tanks.

Just some frag tanks only 10-15 inches tall.

 

[singleshot]

That's fine I have other ways to cut it and I can order different glue I just happened to have those two things on hand and wanted to see how they would work.

 

[TherealplexiG]

That's fine I have other ways to cut it and I can order different glue I just happened to have those two things on hand and wanted to see how they would work.

That sounds rude, or I may be wrong..

Anyways you can laser it firstly to get those cuts.. Not the most accurate thing and not recommended by many...after those cuts on laser you can route taking off 1/4th inch on the router table..its doable, give it a try..

 

[cromag27]

Not rude at all. language barrier maybe?

 

[TherealplexiG]

Not rude at all. language barrier maybe?

That's exactly what I thought.. Language barrier..

 

[singleshot]

Not sure how that sounds rude but wasn't meant to be.

 

[ourcoralreef]

Since this is acrylic q & a i figured idd ask here i purchased a used deltec reactor (to build a chato reactor) and the tube turned yellow is it possible for me to remove some if not all of the yellowing
(Its possible the yellowing occurred because the person use the reactor for GFO) i don't know what they used it for

 

[cromag27]

Gfo will stain acrylic. I don't know if there's a way to get it off.

 

[TherealplexiG]

Since this is acrylic q & a i figured idd ask here i purchased a used deltec reactor (to build a chato reactor) and the tube turned yellow is it possible for me to remove some if not all of the yellowing
(Its possible the yellowing occurred because the person use the reactor for GFO) i don't know what they used it for

TRY NOVUS! Could remove that yellow stains, If the acrylic has yellowed due to UV exposure then it won't bling again...HTH

 

[ourcoralreef]

What do you guys think of peroxide and some oxyclean read a article
http://www.exisle.net/mb/index.php?...g-plastic-the-stain-isnt-permanent-after-all/
That a couple of people removed yellowing from plastic

 

[TherealplexiG]

Give it a try, whether it works or not we will come to know... But I think it won't.. Haven't read the link...

 

[Triton Marine]

Question...do any if you have ovens for your fabrication? I'm looking into getting one just having a difficult time deciding on which one. Any opinions on some?

Thanks

 

[Turbo's Aquatics]

Unless you are bending acrylic for bowfront tanks and stuff like that, you don't need an oven. Forget that annealing BS, it's completely unnecessary.

 

[TherealplexiG]

@Triton Marine
Question... What do you need an oven for?

 

[Triton Marine]

@Triton Marine
Question... What do you need an oven for?

We are thinking about getting more in depth on tank building plus other projects. Bow front tanks and others, but depends on a lot of things to see if it's really worth it.

 

[Lowell Lemon]

We are thinking about getting more in depth on tank building plus other projects. Bow front tanks and others, but depends on a lot of things to see if it's really worth it.

The best ovens I have seen are the vertical ones that allow you to hang the sheet and roll it in and out on a roller assembly. Kel Tech Plastics in Tacoma, WA has one you might give them a call and see who built it for them. Steve Keller is the owner. The vertical prevents marking off on the sheet during the heating cycle.