Acrylic fabrication questions? I can help!

[Acrylics]

Originally posted by skkyy
Also the guy at the platic store recommended I use 16 on plastic that's not milled, like my cuts (table saw)

The plastic shop is generally correct, but 16 has a couple of inherent problems; 1) it's got a bunch of bubbles in the solvent already and these can be difficult to get rid of if you have uneven cuts on the acrylic & 2) the stuff is just sloppy to work with

Should I sand the edges to get it smooth and go with 4 instead?

Only *if* you can sand the piece straight and true, ie., like with a long sanding block and many times when folks sand the edges - they start rounding over that plastic so they don't get a flat edge - this doesn't help

As far as solvent coming back out of the joint, schemo's right on here. Most of the time, folks are better off just leaving it and not trying to sand it off, end up making it look worse.

Originally posted by Fishkiller63
i was going to mitre the them.

It's doable, there are a coupla things to look out for though; 1) 1/2" cast acrylic can vary up to about 1/16" so this can make it difficult to match angles & 2) warped material can also produce difficulties, you're might put down weighted strips to hold the pieces flat. Other than these, just the usual squareness problems associated with this type of gluing set-up. Hmm wonder why they bend these instead of gluing them

Tim, what part of the tank is this going to? top. side, or bottom? Often times this can be a determining factor as to whether you should start over or let it go.

Originally posted by Triterium
When I pulled the pins, the solvent still looked watery. Does this mean I pulled too early or perhaps had too much solvent

Pins work, but they do allow a lot of solvent - too much in some cases. When I pull wires, it looks like *slightly* thickened solvent but not as thick as #16 and I rarely wait more than 30 sec unless we're doing 1.25" +, it just creates too much ooze. From the sound of it - you're doing well
Instead of using actual pins, try twist ties from Hefty bags, slightly thinner, just pull the paper coating of the wire, this will allow less solvent.

HTH,
James

[Eryl Flynn]

Hi Acrylic, my question may have got overshadowed by the bubble problem. I was wondering about building a sump into my stand and using the stand it self as the jig so to speak. Not worried about it becoming a permanent part of the stand just want to maximize the space used.

[Shoestring Reefer]

Eryl Flynn,

If I remember correctly, it is recommended that the joints be horizontal when they are being welded. Doint that may be difficult if the sump is in the stand while it is being built, but I don't know how critical it is, anyway.

[drock59]

So im thinking of building a sump and i need very clear directions of "the pins method." I have done several searches on this and find bits and peices but have yet to find a comprehensive outline of what to do. any help would be great.

[Fishkiller63]

good tip on teh twist ties, i was thinking of stripping some stranded 14 guage wire and using a single strand but i didnt want to use any copper around the tank althoguh im sure it wouldnt really matter. I always get so much ooze. About how long do you wait to pull them?

[Acrylics]

Originally posted by Eryl Flynn
Hi Acrylic, my question may have got overshadowed by the bubble problem. I was wondering about building a sump into my stand and using the stand it self as the jig so to speak. Not worried about it becoming a permanent part of the stand just want to maximize the space used.

I wouldn't recommend it, as Shoestring pointed out - it's best to have thejoints being horizontal. If they are vertical, gravity (it's the law) takes over and the solvent runs down creating weak joints. Plus if built in the stand, you can flip it over or around or route edges, etc.

Originally posted by drock59
So im thinking of building a sump and i need very clear directions of "the pins method." I have done several searches on this and find bits and peices but have yet to find a comprehensive outline of what to do.

Don't mean to make ya search some more but it was posted by Zephrant (for search criterion) and was posted several months (maybe a year ago)

Originally posted by Fishkiller63
I always get so much ooze. About how long do you wait to pull them?

It's going to depend on many factors; type of material, thickness, material temp, ambient air temp, dia of wire, type of solvent, etc., but rarely longer than 30 seconds, 15 seconds being about the average. It's more of a "feel" thing rather than using a stopwatch

HTH,
James

[Eryl Flynn]

Is there a way to build it while in the stand and not use the stand as the jig? I just assumed it would be the best way to make use of the space, no way am I taking the top of the stand off. It is a solid peice cut with opening for the holes in the overflow.

[Zephrant]

Drock- I keep a folder of my DIY posts, so I can pull links out easily. Here is the Pins Method Explained one.


As for the ooze, I don't worry about it much. For a sump, it does not really matter. I would rather have a little extra ooze, than a dry joint that will fail later.

For a display tank, it pays to be more careful, but still, the first concern is that it holds water for a long time, right?

Zeph

[xchrisjb]

That's one of the best links added to this thread. Thanks!

[David M]

Eryl Flynn- so you want to build a stump ? I have thought of that a few times, was going to use glass but was afraid the stand might settle or shift and crack the glass. Acrylic sounds better. If the stand is not in use can't you just lay it on it's side and roll it around to avoid making vertical joints?

[Fishkiller63]

lemem just say having a piece of equipment that is not removalbe is a bad idea. Cut down teh size an inch or 2 and make it so it comes out

[Shoestring Reefer]

And, if you're going the "big sump" route, make sure it's not too tall. I left about 3 inches between the top of my sump and the top of the door opening; I can't touch the bottom of my sump because I can't fit my arm in! A few times, the cap from my skimmer fell into the sump, and I had to spend a long time trying to fish it out with a fish net. NOT a cool situation. Plus, it's tough removing the lights, etc.

I think the "roll your stand around" method may work; also, the holes on the back of my stand are bigger than the door holes in front.

Also-If you're going for a big sump, make sure the stand can handle it. My stand came with a flimsy bottom that I re-inforced.

[Kitzo]

I have an acrylic question I hope can be answered here.

I am in the "planning" stages of building a frag growout tank.
Tentatively speaking, the dimensions will be:
48" long x 36" deep x 12 inches high.

What thickness acrylic should I buy for the bottom and the walls to ensure the weight of the water doesn't break it?
Also, seeing as it will not be very tall will it0 need braces at all?
And finally...lol, do I need to use Weld-On for this or would Silicone be ok?

Thank you.

[Lunchbucket]

Kitzo - i'm not an acrylic guru but i am guessing the PRO's will say 3/8" or so

zephrant or acrylic guy can give you the WORD that is TRUE...not my guess

Lunchbucket

[A Reef Scene]

Great link a whole lot of great info

[A Reef Scene]

When you pull the pins out of the seam, how do you keep the sides vertical once the weight is added? Is that where the tape and the plastic squares come into play?

[skkyy]

Originally posted by A Reef Scene
When you pull the pins out of the seam, how do you keep the sides vertical once the weight is added? Is that where the tape and the plastic squares come into play?

Build jigs that will hold it in place while its drying.. and you can use ducktape or clamps to hold the piece to the jig

Son

[Zephrant]

Kitzo- I would not go with less than 3/8", and would still use a 3"-4 perimeter. Silicon will not stick to acrylic well enough to make a tank out of. It will fail, sometimes quite quickly.

ARS- If you are using 3/8" or thicker, it will normally stand up by it's self. But I still use the plastic framing squares, and double-sided masking tape. You can also set a bucket (just barely touching) on the opposite side as the squares to help hold the acrylic against the squares.

Zeph

[drock59]

i heard soemwhere on this thread that i will need an 80 tooth table saw blade to cut acrylic. The only one i could fin was at home depot for 60 bucks! The saw blade is gonna cost almost as much as the acrylic. Any cheaper saw blades that anyone knows about????

[AcroSteve]

I have a couple of pieces in my new sump that will be attaced in the middle of other panels. No trimming our router cleanup. Just a straight T joint.

What secrets are there to get the solvent in the gap while not having it go everywhere?

When doing it close to the edge, the surface tension of the solvent hitting the edge keeps most of it from running over the edge, but how about when there is no edge around?

It is just a sump, so it is not absolutely critical that it is cosmetically perfect, but I like to keep things neat.

BTW, the baggie twist tie tip I got somewhere for pins is great. Much better than the 24ga pins I was using. they were .024 and the twist ties are .015. Much neater job. Plus I am using 3/8 and 1/2 rather than the 1/4 and 3/16 I was using previously.

Thanks

[Scuba_Dave]

Originally posted by drock59
i heard soemwhere on this thread that i will need an 80 tooth table saw blade to cut acrylic. The only one i could fin was at home depot for 60 bucks! The saw blade is gonna cost almost as much as the acrylic. Any cheaper saw blades that anyone knows about????

This thread has pic of the blade I picked up at HD for $12, it's what I'm using, 150 teeth

http://archive.reefcentral.com/forum...hlight=acrylic

[drock59]

Scuba Dave, thanks for the help, i was starting to get a little worried.

[drock59]

scuba, one more question. on that other thread you said there were some burrs. how did you get rid of those???

[Acrylics]

Originally posted by stranglehold
What secrets are there to get the solvent in the gap while not having it go everywhere?

When doing it close to the edge, the surface tension of the solvent hitting the edge keeps most of it from running over the edge, but how about when there is no edge around?

Try using tape blocks w/ double sided tape to hold the piece in place, there is a pic of it a coupla pages back. As for getting solvent in the gap, the same rules apply, surface tension will draw or "wick" the solvent into the gap, just don't flood the joint.

HTH,
James

[Fishkiller63]

Acrylics:

I have one more question about the pentagon or stretch hex i want to build. Using 1/2" acrylic and gluing mitered edges will i need top bracing for a tank somewher in the range of 20-24" deep, i havent decided on teh final depth yet. Also on the angles is there a maximum angle i should not go over. Im sure glueing 2 pieces of acrylic end to end at 180 degres to make a longer sheet would be no good. Maybe thats more of a question for the physics guys but hopefully you have some experience and no where to stop.