Acrylic fabrication questions? I can help!

[jay24k]

I understand where you are coming from, but if you glue side 1 to the base and then side 2 to the base, can't you tell if it is sitting flat by verifying the edges are touching perfectly? I'm not in any way doubting your method but trying to learn the best method.

[Acrylics]

Feel free to doubt away, I don't mind

Imagine the bottom has a severe "U" shape to it. You glue the ends on and even though the ends sit well side to side, the bottom still has the "U" shape and this is *very* difficult to *completely* flatten out.

James

[jay24k]

That does make sense. I guess it is one of those things when you run into it, then the lightbulb turns on. Probably why I didn't even think about it.

[RyanBrucks]

that's a good explanation, but there is also a slightly different way of explaining it (how I rationalized it to myself after making the same mistake)....

by doing the sides + front/back first, you are basically gluing with gravity on one axis at a time.

my first 'test' tank I made (6" x 6" x 6"), I first fit all the pieces together (with electrical tape to hold in place), and then glued the bottom first, and then later did the sides. obviously things didn't turn out so well.

if you do the bottom first, you cannot move the side pieces on 1 axis anymore, and thus you lose the ability to create an even gap for the pins. instead of moving on 1 axis, the side/front/back pieces will be 'hinged' along 1 side. you're pretty much stuck with the pieces how they were glued to the bottom.

by doing the sides to the front/back, you allow each piece to use gravity to seal down onto the piece below with the solvent. then when you do the whole front/back/sides piece onto the top/bottom, the entire assembly is still moving as one on 1 axis, allowing you to create a gap with pins and then letting gravity do the work.

same basic thing acrylics said, but for some reason it was easiest for me to think of the gluing process as constraining the movement of pieces to 1 axis of motion at a time, if that makes sense.

[jade76]

Can anyone ones help me with a small problem? Ive done 4 sumps now, and when I get glue on the face of the acrylic or when it runs outta my joints , Im having to sand it down. I use 600 then 1000grit and use a buffing compound but it still leavesa haze. HOw do I not leave a haze or better yet solve this problem?

[mfinn]

Originally posted by jade76
Can anyone ones help me with a small problem? Ive done 4 sumps now, and when I get glue on the face of the acrylic or when it runs outta my joints , Im having to sand it down. I use 600 then 1000grit and use a buffing compound but it still leavesa haze. HOw do I not leave a haze or better yet solve this problem?

I know the pros here have a better solution to your problem, but when ever I have to sand on acrylic I use the wet sand paper down to 800 grit and then use a cheap buffing wheel and buffing compound in my electric drill that you can get at Harbor Freight for about $3.

[bchbum189]

try running painters tape around any exposed acrylic, do your gluing and once its past the point it may run, remove the tape.

If you do get glue on the surface, it will depend on the glue,
if its WO 3 or 4, start with 1000 grit, sand up to 4000 or so grit, remembering to sand a larger area each grit up. then hit it with a high speed buffer, machine glaze or novus 3 work well.

Reason you cant get rid of the haze is because you are stopping at to low of a grit and the buffing can only remove faint swirl marks.

You are either going to spend your time sanding to a higher grit, or twice as long trying to jump straight to buffing.

[Jeffrey S.]

Originally posted by Acrylics
Hi Jeff,

Sorry I missed this.

It's relatively simple in the process itself but I'm not sure I'd want to recommend making a 450-500 on your first try. Many of the tools required are similar to carpentry; saws, routers, clamps, etc. The differences are that the tooling is *generally* much sharper than than necessary for most wood jobs. I have different sets of tooling for working with wood & wood composites as many of them are extremely hard on tooling. Tolerances for fitting acrylic are (IMO) +/- .005-.010". Squareness is absolutely critical in this, even a few thousanths out of square will mean either the tank won't sit flat or has the potential for leaking (or worse). There are no fillers or putties allowed, get a scratch? start over unless you want the surface imperfection, a routed edge that is not perfectly smooth and flat should be re-routed until smooth and flat, sanding (even with a block) has a tendency to round over edges.

IMO at a minimum for a tank that size: 5hp+ panels saw, table saw, router table with 3+hp routers, 1"+ diameter straight cutter (primary smoothing of edges), 1/2" spiral flush cutter (for trimming the "flashing"), 1/4" spiral fluted cutter (overflow slots), trim router, chamfer or roundover bit (for easing edges), large flat gluing table, spring clamps, gluing jigs, solvent, applicator bottles, shims, wires or pins

Material weight will become an issue at some point as well, considering a 4 x 8' sheet of 1" acrylic weighs ~200lbs and most 500 gallon tanks will require 5 of them, possibly more if you want colored acrylic. You can by oversized sheets (5 x 8' and 6 x 8' sheets) but these are not stocked at many places. The tank will have to be flipped several times in the process so you have the weight and space issue.

Price out the acrylic you will need to see what it will cost you, then price out a completed tank, compare the differences and then factor in the time, tooling, and the "what if" factor (what if something goes wrong), as well as figure out (as best you can) can you do as good of a job as someone who does it professionally. Compare these and see what works best for you.

Not trying to scare you off as the pride factor is priceless and if you can save $$ - all the better, just that IMO a 500 gal tank is a bit more than I'd recommend for your first try. I'd recommend starting by building a smallish sump or 'fuge then maybe a small (55-120) gallon display tank, then maybe a 250-300 or so, then try the 450-500. At that time, you will have the necessary tooling, experience, and confidence in your abilities to tackle the job.

FWIW if I make it out to be easy, thank you, I had a master craftsman teach me for the first 7 yrs doing this but I've messed up a bunch of stuff over the yrs and still do from time to time (but shh don't tell anybody ). Sux to do it when you have several thousand $$ invested in material and time and have to start over.

HTH,
James

Thanks for the insite James. Much appreicated. Can you shoot me a PM at some point, have a couple quick ones for you.

Jeff

[truthdesigns]

Question:
After I glue my sides, front & Back can I then route the bottom to make if perfectly square?
Hope this makes since

[Acrylics]

Originally posted by truthdesigns
Question:
After I glue my sides, front & Back can I then route the bottom to make if perfectly square?
Hope this makes since

When I glue the 4 sides together, I glue that assembly to the bottom, then flush-cut the bottom so it is true with the vertical panels. Is this what you mean?

James

[RokleM]

16" long, 8" deep, 12" high fuge. Would you bother with any bracing? Euro or maybe just a 2" strip in the middle to prevent too much bowing? I ask, because with a 8" depth, a 2" euro would only allow for a 4" opening in the top.

[RyanBrucks]

what thickness of acrylic would you be using?

a top flange (assume this is what you mean by euro brace?)doesn't have to be 2", it could be 1" thick and still provide some support.

[RokleM]

1/4"

[RyanBrucks]

I think you'd be totally fine with that size tank and no top brace. although lots of people will probably recommend one.

I've only made 5 tanks so far, so I'm far from an expert or even experienced.


one thing worth mentioning is that if you get any imperfections in your seams, the top brace might make an otherwise un-safe tank more safe.

[kgross]

With the 16 inch long I think you would want some bracing on the sides. But I think even a 1/2 inch wide strip glued inside of the top so that the total thickness was 3/4 would be enough to eliminate most of the bowing.

Kim

[bchbum189]

will also depend on how high the water level is. Id say anywhere in the 6"-9" range youll be ok.

[rottface4]

At 12" high the 1/4" would start bowing. If you are going to glue in some baffles then that would help elevate the bowing some. I also agree that a 1" bracing would work great. That will give you 6" of access.

[RyanBrucks]

whats the correct technique for making a non-square piece of acrylic square with a router table?

so far I only know how to do this with a flush bit in the router without the table. just use a template thats square as a worktable and line up one edge....

but on a router table I have no idea how to do it. I can easily use my router table as a jointer by using the outfeed fence offset and making sure its flush with the router bit.
but that doesnt help me make things square.

I experimented on a 6x6" test piece that wasn't square; I tried making it square by holding the piece firmly against the miter gauge but found this nearly impossible and It didn't feel safe. do I just need a miter gauge that clamps the workpiece?

[Acrylics]

Ryan,
You need one square reference corner to make all corners square. If you have one square corner, run the adjacent sides against the fence an the other two sides (the ones that get machined) have no choice but to square the piece up.
*** my disclaimer if you are uncomfortable with this method, please do not use it
I don't like miter gauges either, at all, they are very unsafe IMO.

James

[RyanBrucks]

ah, I guess your method actually requires a fence OPPOSITE the blade. My tiny table only has a fence that is on either side of the blade, and on one side there's an adjustable piece of guide that can offset the outfeet (poor mans jointer).

seems like you'd need a pretty huge table to be able to do that, right? sounds like you'd need to be able to position a fence the width of your piece away from the bit.

[Acrylics]

Yep, my main router table is 60 x 120" so I've room for most things

James

[RyanBrucks]

now I understand why everybody who seriously uses router tabes for acrylic projects makes their own table instead of buying one.

it's all making sense now right now my garage is chock full of crap, so I won't be making any tables anytime soon (

thanks once again!

just what is my garage full of???!!?!?!?







its far worse than that now, as I've got several stacks of drywall and beads, and scrap wood literally covering everywhere..... oh and a new JET jointer

[H20ENG]

Ryan,
Is there a removable leg for your stand that gets put in after the sump? I'd be worried about having no support at such a critical point on the stand.

[BeanAnimal]

Wait until the wife takes out the tanks with the corner of the SUV bumper.

"oops sorry sweatheart!"

[RyanBrucks]

ROFLMAO!

I don't have a wife yet, but I'll ask my girlfriend to park her prius on the far side

H20ENG,
Yes, I added a removable leg. Currently its just scrap wood that fits nice, but I'm going to try and cut a rough mortise/tenon, and place the base of the leg on lifting levelers (already got those on all the wood legs). It will dry fit in the mortise and I can adjust the levelers.

without the removable leg it will sag downwards ~2-4mm after a few hours have passed so Its definitely needed when the tanks are filled. I bought a jack-post that fits so that I can temporarily take the load off the leg and remove it to fit in a large sump or to plumb the returns etc...