Acrylic fabrication questions? I can help!

[jc03]

Yes, that is a very bad idea IMO. Silicone does not bond structurally to acrylic. One could argue that the water pressure keeps it in place and the silicone just keeps it sealed, but it will, IMO eventually fail. Think about it, if the overflow box is 1/2 empty, that is a lot of buoyant pressure pushing up on the box. If it breaks loose, you're looking at a significant downtime since the minimum cure time is 72 hours and you really *should* wait 2 weeks before exposing fresh silicone to water. You're better, for many reasons, to use a 5-sides box on the inside and outside and hold it on place with bulkheads -kind of like how Reef Savvy does their overflow boxes, or Glass-Holes.

Perfect. Thanks!

 

[jc03]

Sorry for the late reply - long day yesterday!

The material alone for that tank would be several thousand.

yes you will want to watch for crazing and cracks obviously, I would pay attention to the radius on the eurobracing cutouts and the thickness of the top and bottom panels compared to the sides. Should be 3/4" or more on those, otherwise, they cut a corner making it.

As far as polishing off the paint, that's a tough one because you will need some kind of solvent to remove the paint, which would damage the acrylic. The other way to do it would be to sand it off and then polish the tank, that would be the way I would go. Start with as fine sandpaper as you can get. Like 1200 or higher.

I would say try doing wet sanding at first, but that might gunk up the paper quick. If it does, you might use a random orbital with dry paper but use high grit and once you see clear material, move on. Then go to the wet/dry and work the paint off. After all the paint is off, start with wet/dry at the lowest grit you used in any of the previous steps and make a full pass across all the surfaces.

Get yourself one of these

http://www.amazon.com/Time-Shaver-Tools-Preppin-Weapon-Sanding/dp/B001399URG

#1 timesaver for this job.

Then go through a few other stages of sanding. Usually I find the first 2 stages take the longest. The following stages, you can tell when you have taken off the prior pattern because the sound changes and the paper runs across smoother.

Then follow up with a power buffer and Meguiar's ultra-cut, then swirl free polish. Takes some practice but you can make it look like new - on the outside, at least.

Kind of a silly question here but I'm only removing the blue paint to go with black. I started last night and it's going ok but will take a boat load of time. Has anyone painted the inside of a tank? Would that work?

 

[Floyd R Turbo]

It's a lot simpler if you're going to re-paint. Just sand with a random orbital sander with a low grit, make another high grit pass, and repaint. I thought you wanted to make it clear & perfect again

 

[jc03]

You made my day Floyd!

I'm going to start on these pesky overflows next.

 

[Floyd R Turbo]

When sanding while using a power sander, keep it moving and pass over a large area. You don't want to let it sit in one spot for a long time, or concentrate on a small area because this can cause excessive heating which is bad for acrylic (no matter how insignificantly it seems to heat up the surface)

Use light pressure and just let the sander do the work. You might start with 150 grit and if that's not doing the job fast enough, go to 100. Then make a few passes with a few steps of finer grit, maybe up through 300. Those passes should go fast. If you want to then use the Preppin Weapon and some wet/dry 400 and then 600, that should go very fast as well and give you a nice paintable surface. But you might not need to go past the first 2 passes of power sanding depending on how well the paint adheres and covers up the scratches. My only thought being that even if you paint sanded acrylic, you might still see the sanding pattern - I wouldn't think this would be the case, but I can't say that I know for sure, which is why I mention it. So you might sand down one end and then paint it to see how it turns out before doing the whole tank.

Kind of along the same lines as whenever you get a spot treater for your carpet and says to test in an inconspicuous area, 99.9% of the time it will turn out fine....

 

[jc03]

When sanding while using a power sander, keep it moving and pass over a large area. You don't want to let it sit in one spot for a long time, or concentrate on a small area because this can cause excessive heating which is bad for acrylic (no matter how insignificantly it seems to heat up the surface)

Use light pressure and just let the sander do the work. You might start with 150 grit and if that's not doing the job fast enough, go to 100. Then make a few passes with a few steps of finer grit, maybe up through 300. Those passes should go fast. If you want to then use the Preppin Weapon and some wet/dry 400 and then 600, that should go very fast as well and give you a nice paintable surface. But you might not need to go past the first 2 passes of power sanding depending on how well the paint adheres and covers up the scratches. My only thought being that even if you paint sanded acrylic, you might still see the sanding pattern - I wouldn't think this would be the case, but I can't say that I know for sure, which is why I mention it. So you might sand down one end and then paint it to see how it turns out before doing the whole tank.

Kind of along the same lines as whenever you get a spot treater for your carpet and says to test in an inconspicuous area, 99.9% of the time it will turn out fine....

I had some 1200 and 220 for the random orbital sander and gave it a try last night. I think I'm going to need to drop down to the 100. The 220 after several passes just "scuffed" the blue a bit. I'll keep you updated.

 

[Lou Young]

What is a good resource to get my feet wet and learn about acrylic tank building? I would like to make small simple tanks to hold my clownfish pairs. Any direction would be appreciated. Thank you.

 

[aaron7405]

What is a good resource to get my feet wet and learn about acrylic tank building? I would like to make small simple tanks to hold my clownfish pairs. Any direction would be appreciated. Thank you.

I learn a lot in my early bigginings on this page http://www.melevsreef.com/

but for a over 1/2 " acrrilic thicknes I use weld on 40 with thinner

 

[Floyd R Turbo]

but for a over 1/2 " acrrilic thicknes I use weld on 40 with thinner

Why do you say this? That's just making it difficult IMO. Even James/Acrylics on this thread has stated that he uses solvent for up to 2" thick material. I've done as 3/4" builds before solvent weld and they turn out great.

 

[aaron7405]

I say that what I use, you can use weldon #4 or #16 but I use 40 with weldon thinner , and the quality and straight is great.

 

[Floyd R Turbo]

I don't recall reading anything in this thread about using 40 + thinner. How are you prepping the edge? Flush, or angled? Are you leaving a space for the 40 to fill? How are you applying it?

 

[aaron7405]

this is the thiner I use to diluate 40, you can mix up to 10% will eb better to work and lot less bubles

http://www.eplastics.com/Plastic/Plexiglass_Glue/Weld-on-3061-thinner, do not undestand what you mean with flush.

I sand both end and apply it with a 10 ml surgering with out tip. I no not apy pressuer just the one the weight of the acrulic parts will do the rest and I do put some pices of wood to take oit the air will post some pics in a moment

 

[aaron7405]

In this proyect I use #40 even to glue side by side the 2 curve with the fronts sides.

 

[aaron7405]

Proyect I am working on you can see the woods under the bottomto pull out the air than could be trap.

Also I use blue tape very close the join edge and after I squeeze it I remove it, I set the tape 1/8 before the join so I wont get trap between the 2 pieces. Also i tray to cover or leave the paper mask as long as I can.

 

[aaron7405]

I don't recall reading anything in this thread about using 40 + thinner. How are you prepping the edge? Flush, or angled? Are you leaving a space for the 40 to fill? How are you applying it?

I start to use the thinner becouse even I like the #40 I think was to thick and hard to manage or apply, also when I diluite I notice there were less bubbles and easer to take out with a bit of pressure because it was not too thick, make sure do not apply to much pressure or you will squeeze out the glue.

 

[dattack]

What kind of spacers do you use so you can apply the weld on 40? And how do you remove the spacers for during the gluing process?

 

[aaron7405]

What kind of spacers do you use so you can apply the weld on 40? And how do you remove the spacers for during the gluing process?

No spacers , I apply the glue then I put the piece. Weldon #40 even with thinner is still dense, won't go inside 2 joins by capilatiry, I apply the glue to 1 side them put the other side on top, some will be out so that is why a squeeze and tape, I squeeze so the exced of the inside joint over the tape then I remove the tape while is still fresh. Outside exed will be router.

 

[dattack]

Thanks for the info, never knew there was a thinner for weld on 40. I wonder if this will work with weld on 42 also.

How do you glue the base? Seems like it would be too heavy placing the finish sides onto the base by squeezing out excess weld on 40.

 

[Rascalson]

Do you do you own forming and bending?

 

[Lou Young]

What is a good place for newb to go read/learn about making acrylic tanks?