DIY- "Pins" method of gluing acrylic.

[toddflash]

Thanks for all the great info! I just started putting together my own DIY sump.

I had purchased two 3/8" x 4' x 8' sheets of extruded acrylic. The guy at the plastic shop said it would work fine for a sump but that cast would be better if making an actual tank.

Anyways, I got the sides and the back side of the sump all joined up. It's looking pretty good, sorry I don't have any pictures yet...

Once again, thanks for the info!

Todd

 

[melev]

I'm getting some pretty large filled bubbles inside the container after removing the wire. Should I be removing these somehow, or just let them exist?

 

[Zephrant]

Todd- Your welcome!

Melev- There is a trick on how far to insert them. All the way though, and they wick glue on to the base piece where it can puddle. 1/2 way though, and the glue wicks around the pin and continues down the joint as you glue. It makes it easier to not get bubbles right at the pin.

With 1/4" material, it's hard to not get them all the way though, but with 3/8" or 1/2" it is pretty simple.

I try to glue up both sides at once, then leave it on the end of the table overnight. I've read that others only wait an hour, but I had problems once doing that, so don't risk it anymore. Rotating the project to work on the next side is fine, just be careful and be fast. Disturbing the glue joint after it has set weakens it.

I have had some luck using another pin to poke at the bubbles to get them out. When you pull the pins the big one ooze out, but where they were did not get enough solvent so it sometimes makes a network of small bubbles. Not bad structurally, but unsightly.

If you get big bubbles after it sets, then you did not shim enough or even enough, or your joints were not cut perfectly straight. I know you have made lots of sumps, but it is a long learning experience to get them perfect. That is why I still don't make display tanks, only sumps. A bubble or two in a sump is not a problem, in a display tank it is unsightly.

Zeph

 

[Zephrant]

Todd- Your welcome!

Melev- There is a trick on how far to insert them. All the way though, and they wick glue on to the base piece where it can puddle. 1/2 way though, and the glue wicks around the pin and continues down the joint as you glue. It makes it easier to not get bubbles right at the pin.

With 1/4" material, it's hard to not get them all the way though, but with 3/8" or 1/2" it is pretty simple.

I try to glue up both sides at once, then leave it on the end of the table overnight. I've read that others only wait an hour, but I had problems once doing that, so don't risk it anymore. Rotating the project to work on the next side is fine, just be careful and be fast. Disturbing the glue joint after it has set weakens it.

I have had some luck using another pin to poke at the bubbles to get them out. When you pull the pins the big one ooze out, but where they were did not get enough solvent so it sometimes makes a network of small bubbles. Not bad structurally, but unsightly.

If you get big bubbles after it sets, then you did not shim enough or even enough, or your joints were not cut perfectly straight. I know you have made lots of sumps, but it is a long learning experience to get them perfect. That is why I still don't make display tanks, only sumps. A bubble or two in a sump is not a problem, in a display tank it is unsightly.

Zeph

 

[melev]

Glad you are up, but I don't know if you will see this now (while the glue is soft).... I've taken a few pictures to show you what I mean.

 

[melev]

another

 

[melev]

Ahem.... I said 'another'!

 

[melev]

and another

 

[melev]

and finally, this inner seam. As you can see, it pooled up a lot more than expected. Is this because the wire is too thick, or because I'm using #3 instead of #4?

Do I attempt to cut these off with a straight edged razorblade? Or just call it "good enough".... looks kinda tacky to me, but once it is filled with water, they won't be that visible.

I love testing new techniques on someone else's sump!

 

[geshields]

Melev,

Those are not bubbles you are talking about. The seam looks good. The problem you are having is you are pulling the pins out too fast which will cause the top piece to come down quickly on the bottom and shoot glue out of the seam. In essence, you are shooting weld-on 16 out of the joint(weld-on 3 mixed with some of the dissolved acrylic from the joint)

Greg

 

[Acrylics]

Marc,
You are using extruded acrylic (Acrylite FF), this stuff turns to mush and thus squeezes dissolved acrylic out of the joint if you have too much solvent action. You can switch to cell cast acrylic and work by the same method that you are using now, or cut down on the solvent action by either: A) Not allowing it soak as long as you are in which case you have to be careful of splashing solvent as you pull the pins/wires or B) use a much smaller wire - something along the lines of (< .008") so you don't as much solvent in there or C) (preferred) both.

What happens is that the longer the solvent "soaks" the acrylic - the more acrylic gets attacked by the solvent. When you pull the wires or pins, the weight of the acrylic itself squeezes out much of the dissolved acrylic creating your large ooze bubbles. Extruded acrylic does not have to soak long at all - a few seconds is fine - much longer and you get the "big ooze".

To clean up that much ooze, take a sharp chisel and carefully pry those little bubbles out - they will pry out, just gotta be careful. Then run a light bead of solvent over those areas to "patch" them.

One other thing about using as much solvent as are is that the tank is much more apt to craze when you have that much action. Extruded has a very low tolerance for stress and solvents stress the acrylic - more solvent action = more stress = more likelyhood of crazing.

HTH,
James

 

[melev]

Well, this is a learning experience. I need to get finer wire, that is all there is to it.

I can pull the wire sooner, instead of waiting 30 to 90 seconds then. This was my first attempt in this method.

I did forget about one joint while I cleaned out my skimmer's collection cup, and realized it had been sitting 4 minutes, but was able to pull the wire out easily enough. That joint didn't pool out at all. So I was thinking maybe I should wait longer, not shorter.

I guess I shouldn't be thinking.....

Chiseling out the excess isn't a big deal, but crazing isn't a good thing. I hope that isn't going to happen with this one!

 

[toddflash]

I've been using the pin method and using extruded acrylic without any ill effects! Hopefully going to finish up my 50 gallon sump and start on my CA reactor!

Todd

 

[Acrylics]

Well, this is a learning experience. I need to get finer wire, that is all there is to it.

I did forget about one joint while I cleaned out my skimmer's collection cup, and realized it had been sitting 4 minutes, but was able to pull the wire out easily enough.
That joint didn't pool out at all. So I was thinking maybe I should wait longer, not shorter.

Doing this will leave a relatively weak joint as the solvent evaporates as in this case you're actually trying to get the acrylic pieces to expand to meet each other. Once in a while you can get away with it but not a good practice to follow.

I guess I shouldn't be thinking.....

Oh, Marc.

James

 

[melev]

Got the sump done and built a few minutes ago.

I'll water test it in the morning. So far it looks excellent, and I love these seams far better than most I've done in the past. This method is slower and more aggravating, but the results are good. I just need to get finer wire and avoid the pooling-issue I dealt with on this one.

I noticed that sometimes I was able to remove the wire and the excess glue would bleed out the wire's hole, which would be another reason to avoid it sticking out on the inside of the project.

Doing internal baffles is much harder to get right, I noticed. No matter how much I measure, mark and cut, I still don't always get things tight enough for #3, and end up having to squirt in #16 unfortunately. I guess that is the nature of the beast.

This sump and refugium should hold over 80 gallons.

 

[Zephrant]

To add to the above great tips, I would note that the type of bubbles you are getting makes it look like you waited too long to pull the pins. The goop has skinned over in most places, then when you drop the panel down it burps out every once in a while. By pulling the pins earlier, it creates a fairly smooth fillet, which shrinks down to almost nothing when it dries.

Often just before I pull the pins, I run another really quick line of #4 along the outside. That re-softens the edge, and since it is on the area to be trimmed off, it doesn't make a mess.

I still use standard sewing pins, but I intend to get some small piano wire some day.

Zeph

 

[toddflash]

Hey Zeph,

Quick question for you! I'm in the process of building my sump, everything is going fine until I tried to put the bottom on the tank! So I ran a line of weldon 4 around the bottom lip of the tank (the part where the bottom of the tank attaches to the 4 sides) and pushed the bottom onto the tank. This definately didn't work! Most of the weldon didn't take to the tank and I had no good way to keep it pushed down so that the glue could dry. Well, hindsight is 20/20 but I'm trying to discover a good way to attach the bottom (now that the messed up bottom has become the top of the tank ).

My current thoughts are that I will use the pin method to carefully attach each side of the sump to the bottom panel until all four sides are connected.

Do you agree with how I'm doing this? Or am I trying to build the sump the hard way?


Thanks!

Todd

 

[NAGA]

What solvent your using as well as the material and very importantly is the temperature determines how long those pins should stay in. The thickness of the pins needs to be consistant as well. For anyone interested McMaster Carr sells some stainless wire (Piano wire) in a lot of different thicknesses. For 1/2" material and thinner I would use 10 to 12 thou wire. For 3/4" to 1 1/4" I would to to 16 to 18 thou. A 1/4 lb. coil will cost 7.00 and is a good investment if your going to build sumps/tanks. This time of year 30 seconds is plenty for leaving the pins in before pulling them. Cool weather you might go to 45 seconds. Leaving the pins in too long will leave marks/bubble trails in the seams. Weldon 3 works pretty quick and 30 seconds might be too much. MC Bond is a little slower than Weldon 4 and I have recently learned that adding a little more acid can slow it down some more. BTW this is a great thread!!!

NAGA

 

[NAGA]

For anyone that wants to see what stress can do:

Take some 1" Acrolite FF material

Flame polish the crap out of it and I mean torch it good.

then take some ethanol alcohol and pour it on the material.

It will literally pop apart into small pieces........quite fun to watch!!!

 

[geshields]

NAGA, too funny..:eek1: