diy acrylic overflow on glass?

[acrylic51]

I do overflow covers quite a bit and using a table saw isn't the easiest thing to cut acrylic.....What alot of people don't know is that to get really good cuts on a table saw you actually should buy the blade for acrylic and they are really expensive and you don't get tons of cuts with them.....Not really practical for the occassional DIY with acrylic....
The router actually works the best IMO.......I bought a dovetail jig and took the guide with the teeth off the table and use that as my template, but depending on the size of the overflow cover you might have to make your own jig, but it's super easy.

 

[acrylic51]

To correctly bend acrylic you should use an acrylic heater or bender.....Using a torch of some sort you won't get even heat distribution over the entire bend and you will put bubbles in the acrylic and trust me they are really noticeable in the smoked acrylic.......

 

[sleasia]

The router is the way to go....I was just doing it all backwards before now doing it the melev's reef way, it works fine....
bending the plastic....Well I did get some bubbles on my practice run...but they were very superficial and didn't really bother me....heck ...I was just happy I figured out how to light the *&-#$%$# torch and get the plastic to bend without blowing up the garage.....should I use a heating gun.....please say no or this is going to cost me...none of my neighbors have anything at all in their garages, so...I don't think they have a heating gun to lend.... :help:

 

[sleasia]

by the way the torch is MAPP gas....whatever that is?

 

[sleasia]

Also crox may have the better idea...I called Acrylic tank manufacturers, who made my acrylic 200...they say this is what is usually done on glass tanks...what crox suggests, to make the overflow out of glass and cover it with acrylic...this way it glues to glass but you can still cut the teeth in the acrylic.

 

[bacia]

I got a 75 gal Oceanic tank for free and the over flow is done a little different than what you said. I don't know how old this tank is or any of it's history but the overflow looks like it is factory installed. The tank has drain and return holes drilled in the bottom at the back, left corner. The acrylic runs the whole back length of the tank and on the one back corner the acrylic is bent into an overflow. The whole sheet of acrylic is glued to the back of the tank and sealed with what looks like silicone. Hope this helps.

 

[sleasia]

It sounds like they were using tinted acrylic for a background? and then continued it on over to make the overflow....
well if no one laughs I will show you what I have done...my cuts are clean (routed) but a bit crooked in places...which doesn't bother me because they probably won't be seen anyway...and they are crooked I think, because I did something dumb...I don't think I put the collet together right and I think the bit was loose...so probably I'm lucky I didn't spend the day in the ER...

 

[sleasia]

Now the bending seemed a bit easier the second time...I ended up with only one tiny bubble!!! the important thing I think is to keep the torch moving back and forth along the fold line. Don't let it sit in one spot for any length of time...with a rag or a glove you can periodically test the plastic by trying to bend it a bit. when it is soft enough (heated enough) it will bend without too much pressure. Then when its ready, just bend it down over the table edge and hold in place. I bend a little more than 90 degrees because as it dries and cools it will tends to loose a bit of the bend...so I over bend just a bit.....

 

[sleasia]

then I round both bottom edges to make them fit more snuggly with the contour of the tank bottom. The tank bottom edges are already a bit rounded because of silicone which is already there. And position in the tank to test fit before the piece gets siliconed in place...

 

[sleasia]

Ok is there any special technique to use when applying the silicone?

 

[acrylic51]

Looks good!!!!!!!

Wasn't as bad as what you thought was it!!!!!! I usually sit the overflow in place and take a marker and mark me a couple reference marks on the glass that way I know exactly where to run my beads of silicone.
I then pull the piece out and run my silicone along my lines, and I don't skimp on the silicone, I apply beads on the side walls of the tank as well as the bottom of the overflow as well......Then once my beads are laid I sit the overflow into place an embed the overflow into the nice thick silicone beads and use my finger to smooth out any over run. I then let it setup and then when ready I run a bead on the outside of the overflow along the sides and bottom and also do the same thing on the inside of the overflow and use my finger to smooth things out to get a nice finish....HTH

 

[bojik]

You could do this for the bottom seam put a thick bead on bottom of the black acrylic (near the back edge) set in place and press into place. Then put a bead accrost the front side to make a clean sealing bead.
What i like to do ,asides the initial silicone to afix things, Is take the tube at a ~45 degree angle and put a bead on the seams with the opening facing the bottom and push downward slowly as i squeese the tube. It tends to make a nice clean spread bead which is pushed into the seams. When done right it turns out very clean. Usualy no need to use a wet finger/spoon/butterknife to smooth them. Do that on inside and outside of the seams (tank side and back side of seams), as acrylic51 mentioned.

Just an alternate method you could try. A little overkill never hurts

 

[sleasia]

Tomarrow I'll silicone it as you guys described...once it is in place do you need to tape it or apply any pressure to the piece or just let it sit normally as the silicone sets up...they say not to add water for 48 hours but I'm thinking to be safe I should wait 4 or 5 days...In the mean time...I plan on getting my kids and their friends to help me make a bunch of diy live rock....and start that curing and cycling.

 

[bojik]

If it sits as good as it does for your pictures just set in place settle it with a litle pressure into the silicone. Then do the seams as mentioned above then just let it cure.

 

[sleasia]

ok thanks guys!!!

 

[bojik]

Turn out well?

 

[sleasia]

Yes it did...nice and snug. But I was so paranoid I printed out your guys directions and took them into the garage to read a few times first....I think it is going to work...but I'm not going to press my luck. I don't plan on testing it for leaks with water until next weekend....when you test for leaks do you fill the over flow with water, or do you fill the tank with water. what is the best way or does it even matter.

 

[bojik]

A phrase i like: "just because your paranoid doesn't mean they aren't out ot get you"

IMO a few micro leaks aren't going to hurt it. Many overflows have a few vents in the middle and near the bottom as well as the teeth on top. It looks like you got it sealed up pretty good.

You don't look like you will have any. If you fill it from the back side of the overflow enough weight and preasure might unseam it. If you want to leak test it put water into the main part of the tank slowly. And let it sit every few inches for a while. And watch for seepage as you go so you know more or less exactly where it is. Thats the best way i can think of. :notsure:

 

[sleasia]

Thanks bojik... that's kindof what I was thinking too which is why I asked. It seems safer to fill the main part of the tank, slowly, like you said, because then all the water pressure is pushing the overflow towards the glass instead of away from it...It looks pretty tight after 24 hours, but I (being paranoid about my skills, or lack thereof) will wait until next weekend to test for leaks.
But I'm betting it will hold up well...which means if it does...then we really are totally free to do whatever we want with glass tanks...which is really cool. Because the one thing that bothers me about acrylic is it scratches so easily. Thanks again for all your help and that of acrylic51's...I will update as soon as I test for leaks next weekend.

 

[bojik]

YW The silicone i deal with suggests 48 hours to cure for new construction as opposed to 24 (min) for fixing leaks/reseaming.
I hope that works out well for you.