Acrylic fabrication questions? I can help!

[dcforester1]

Looks great, how do you get the design where the bulkheads go? Do you have a template? the part Im talking about where the "bump out "is?

Thanks Derek

 

[thejuggernaut]

Thought I would show how I set up my router table to clean up the edges before welding my seams. The process is easier than I thought and has given me a good result so far.

The 1" acrylic strip is actually my fence. I had the acrylic supplier cut it for me on their machine, so I know it is perfectly straight. I confirmed it with a 60" level that I have and it is straight as can be. I made the wooden fence when I was remaking the kitchen counter doors last year, and it is just sitting there to hold the vacuum hose. It works really well at collecting all the acrylic. After cleaning up 4 pieces of acrylic, I couldn't find one shaving of acrylic in my garage. I used a pencil and marked every piece of acrylic with a dot, that way I can keep track of which side I am routing. If I were to do this allot, I would definitely put a smooth piece of white formica on top of the table. The table is two sheets of 3/4" MDF laminated together to be 1.5" thick. I waxed the table so it is somewhat water resistant, but you still have to be careful because the table gouges easily. When I am not using the router I can slide it out of the base and I have a huge 4X8 work table.

I sure am ready for this thread to jump to the next page. Those pictures of Peter's broken tank are depressing to have to keep scrolling by.

 

[silentscream]

Looks great, how do you get the design where the bulkheads go? Do you have a template? the part Im talking about where the "bump out "is?

Thanks Derek

Regrettably I did not use a template. Had I used one, I think it would have come out better, but I'm probably being hard on myself. The first step was determining where the bulkheads would good, once I settled on a location I routed out 3 holes. Then I drew the perimeter on the paper backing using only straight lines. In each corner I routed a 3" hole using a template I made from a piece of wood cutout with a 3" hole saw. Then I cut a straight line using a straight piece of acrylic as an edge, connecting each hole to remove the bulk of the material. I had one sharp corner left on the bulkhead "bump out" which I rounded off using a scrap circle piece left over from a hole saw cut out I made for a template on cutting out 1" bulkheads. I used double sided tape to stick the circle to the sharp corner to guide my router.

Had I used a wooden template, I could have obsessed over the wooden part before transferring it to the acrylic. In the end it looks good to me, just not perfect. But it was my first full sized project.

 

[silentscream]

Juggernaut,

I am jealous of your dust collection. If you couldn't find one piece of acrylic snow in your shop, you sir, are a champion. My garage looks like I'm manufacturing fake snow for Christmas nativity scenes!

My router table is 2 piece of mdf laminated together as well. I used a water based polyurethane to help add some protection and get things to slide along a little easier. It works good and I haven't needed to use any wax or lemon pledge to add slickness.

 

[thejuggernaut]

Well my dad bought me a shop vac a few years back for Christmas, and I'm pretty sure he go the largest one they made. It is 6.75 hp and holds 20 gallons of dirt. I made cabinet doors last year and it would collect 99.9% of the wood chips. It's pretty impressive.

 

[dcforester1]

Thanks for all the info guys. I can't wait until my fish are out of my basement and back in the DT. I have a few projects I want to make.

Thanks Derek

 

[thejuggernaut]

Two questions.

1. What do you guys use as a scraper. I tried a razor, but it barely takes any material.

Reason I ask, is because after you weld the front and back to your sides, and want to weld the top, I still get a tiny little lip that I can catch with my finder nail in the corners. Some are perfectly smooth but 1 or 2 have had a little (probably 1/32"-1/64" or less) lip. How do you smooth out those corners to ensure a perfect corner seam, or am I splitting hairs and it is fine.

2. What do you you guys use to shine up the edges after you flush trim the box. I've seen people use MAPP gas but I've also heard it is a big no-no and can lead to crazing. Really don't want to use a 5-6 stage sanding process though. Is there anything that is a happy medium.

 

[Floyd R Turbo]

I use 2 pieces of wood (I think 3/4" plywood) that I put a few heavy bolts through (with washers) to hold a standard box cutter razor blade in between, tighten the bolts and it holds it nice and tight.

I use this for the specific thing you are describing. When you bond 2 panels together, it's rare that you get it 100% perfect on both ends of the joint. Inevitably, you end up with a tiny lip that you can feel with your fingernail. But usually, I end up with a smudgey little area there anyways because as I'm lining things up after pulling the pins, using my fingernails to feel how things are lining up, this wicks some solvent over to the edge and I end up with some dried up solvent on the surface of the corner that will eventually be part of the top/bottom joint. You need to take this off anyways or you will end up with bubbles in the corner, usually.

So I take the scraper and position the blade so that it is across both pieces of the joint, give it a slight angle toward the corner of the joint, and scrape. Here is where another trick I've learned comes into play - do this BEFORE you flush trim the vertical joint. The reason is that the downward pressure you apply when scraping across the assembly is fine until you get to the outer corner, where all your pressure is now right on that point and this tends to result in a bit more material being removed with each pass. The result is that you essentially will end up rounding off that corner and you will have a gap in the joint. If you leave the lip on while scraping, this area will get flush trimmed off so you don't care if it gets rounded.

I leave all the lips on until the tank is fully assembled. Leaving the lips on the side/front & side/back joints results in a little more material right at that outside corner, and this further reduces the tendency for air to get into the joint at the corner (which are prone to it, since there are 2 sides for the solvent to evap out of). Then if it does you just trim it off and you're usually ok

On the MAPP gas. No flame polishing, IMO. The happy medium that I have found is using a roundover bit (usually only 1/8" on material less than 1/2" thick, 1/4" past that) and then wet sanding. On vertical outer seams you can get away with a bit less than you would for a scratch removal on a flat panel. I use 600, 800, 1200, then 1500. Sometimes 400 depending on how good the corner round bit worked (not always perfect). But all you need to know is that the first pass/grit, do this one well enough to make everything smooth (take out the router bit pattern, completely) and then all the progressive passes are pretty much smooth sailing. When you are done with the 1500 pass, then make a pass with Meguair's Ultra Cut and a Black & Decker random orbital buffer ($35 at lowes) with the blue sponge pad, and then if you want another pass with the Swirl Free polish. Use lots of blue tape to protect the areas you don't want scuffed up by sanding or polishing. Takes a bit of practice.

Alternatively you can go straight to the polisher, if you don't care about seeing the router marks. The polisher will diminish the rough-cut look of a router-trimmed edge, it will shine it up pretty well actually. You can also achieve this by using a 3-stitch wheel on an arbor bit & drill at high speed. Using the Meguiars, or another plastic polish usually is OK too (on outside of tank, can use about anything because it never gets in contact with tank water). Again, use plenty of blue tape to protect the area you don't want hit with the buffing wheel.

 

[thejuggernaut]

Thanks!

You answered all my questions perfectly. I used a regular razor just holding it and did it the way you described. At a 45 angle towards the corner. I think putting it in the block like you said will give me more control and keep the blade square. When I was just holding the blade, it would bend and I was afraid it would round over the corner, so I did it sparingly. Do you do all those stages of polishing on the scrubbers, or only on display items? That seems like allot of work!

 

[Floyd R Turbo]

Oh heck no man that would take forever

When I make a nice "sale" frag tank, I'll polish it up. Beyond that it's only if someone wants it done, so things like sumps, frag tanks, etc...no.

I have only made a few display tanks or frag tanks that someone wanted polished.

For the razor blade, try using the ones that are trapezoid shaped, like for a box cutter. Those do not flex.

 

[thejuggernaut]

That's what I figured. I'll probably skip the sandpaper and go straight to the rubbing compound for this external box, just to see what kind of finish it gives me. If it doesn't look good I won't care cause it is outside and behind the tank! lol. I'm definitely going to make me a scraper!

 

[ganjero]

Would I be safe to use 1/4" acrylic to build a sump/refugium that is 48"Lx18"Hx12"W? It will have two baffles dividing the sump in three sections of the same size (16" apart) but no euro bracing. Also, I will have an overflow hole that will only allow a max water depth of 14".

Thank you,

 

[thejuggernaut]

I got the external box mostly finished.

<a href="http://s1383.photobucket.com/user/tstanley01/media/IMG_2202_zpsm4jd8lkx.jpg.html" target="_blank"><img src="http://i1383.photobucket.com/albums/ah305/tstanley01/IMG_2202_zpsm4jd8lkx.jpg" border="0" alt=" photo IMG_2202_zpsm4jd8lkx.jpg"/></a>

Here are the spacers that Floyd discussed earlier. They allow for the box to clear the upper rim on a standard tank.

<a href="http://s1383.photobucket.com/user/tstanley01/media/IMG_2203_zpshefu7v7d.jpg.html" target="_blank"><img src="http://i1383.photobucket.com/albums/ah305/tstanley01/IMG_2203_zpshefu7v7d.jpg" border="0" alt=" photo IMG_2203_zpshefu7v7d.jpg"/></a>

I can't decide if I want to run the drain system in a standard Bean style with a p-trap on the siphon line, or run it like this. I had the tank originally with a side overflow and the siphon on the bottom without a stand pipe and it worked perfectly. The pump would shut off and the water would drain. When you restarted the water would slowly rise and begin to flow down the open drain. I will probably try it both ways and see which one I like better. The idea of the box draining completely when I shut off the pump appeals to me a little.

 

[silentscream]

Nice work! I'm out of the loop though, what do the spacers do?

 

[Floyd R Turbo]

Would I be safe to use 1/4" acrylic to build a sump/refugium that is 48"Lx18"Hx12"W? It will have two baffles dividing the sump in three sections of the same size (16" apart) but no euro bracing. Also, I will have an overflow hole that will only allow a max water depth of 14".

Thank you,

I think 1/4" is too thin for an 18" tall rimless sump, regardless of baffle placement. I would go with 3/8", and even that will bow a bit. even adding a strip brace across the 48" dimension would help greatly. You have to think of the worst-case scenario, where the sump is almost full, like on a power outage.

 

[thejuggernaut]

Nice work! I'm out of the loop though, what do the spacers do?

Without the spacers, the box would sit flush against the back wall of the tank. That would make it impossible to raise the external box up to where it was flush with the top of the tank, because it would hit the black trim on a standard marineland or all-glass tank. The spacers allow it to be offset from the tank and clear the trim. Once I get it all mounted, I'll take some photos if it is still difficult to visualize.

 

[Floyd R Turbo]

<a href="http://s1383.photobucket.com/user/tstanley01/media/IMG_2202_zpsm4jd8lkx.jpg.html" target="_blank"><img src="http://i1383.photobucket.com/albums/ah305/tstanley01/IMG_2202_zpsm4jd8lkx.jpg" border="0" alt=" photo IMG_2202_zpsm4jd8lkx.jpg"/></a>

There is an issue that you are going to run in to when running it like this, the siphon and OC are way, way too high, and the emergency as well

While this belongs on the BA thread I will comment here, if you want to post over there you can as well

The "modified" BS external box comes with it's own set of unique circumstances. One is that the box will fill up very fast until it reaches the water level in the tank, at which point it will slow. As far as the timing of how the system operates, it's different from the base BA setup.

My recommendations

1) you need the top of the E drain to be 2" from the top of the ext box. This allows for it to kick in and flush the box if needed. You have it very high up

2) the OC and siphon really should be set into a slip on the flange side bulkhead because the extra height added to the assembly will make it borderline dangerous to operate. The siphon will get almost fully submerged during startup

3) In the standard BA, the OC and siphon do not have to be at different levels. In the external box, maybe. But the oc won't kick in full until the airline is closed off, and that depends on where you place that. The standard recommendation is to tie it to the very top of the E drain pipe, facing down. my mod with the p-trap is similar, you place the top of the p trap (the one with the hole) at just below the top of the e-drain. The level of the siphon can be very low, and the OC up a bit higher and this widens the range a bit where the siphon will operate running full with little to zero flow in the OC.

4) you don't have a hole/airline on your OC? You need that. I'm guessing you knew that but just mentioning it to be sure

The biggest issue by far is the bulkheads and the height of all the pipes. On startup, your box will very likely overflow or come close to it as shown.

Very nice acrylic work BTW

Nice work! I'm out of the loop though, what do the spacers do?

They stand the external box off the tank so that it clears the trim and the top of the box can be placed flush with the top of the trim

 

[ganjero]

I think 1/4" is too thin for an 18" tall rimless sump, regardless of baffle placement. I would go with 3/8", and even that will bow a bit. even adding a strip brace across the 48" dimension would help greatly. You have to think of the worst-case scenario, where the sump is almost full, like on a power outage.

Thanks for the answer. Do you think is too thin even though it will technically be 14" tall (there is a drain that does not allow more than that)?

 

[silentscream]

Never mind, I read the post better and got my answer!

 

[Royce7586]

could 1/4" be used to do a 48" x 12" x 12" display? I would do a euro brace, If not could it do a 36" x 12" x 12" Would probably only fill to 10.5 to 11"