# Salvaging cracked acrylic cubes?



## Cavedweller (Oct 18, 2014)

In the process of drilling airholes in some AMAC boxes, I cracked one. The crack goes from the top opening down about 2.5 inches. There's no way a sling can push open that crack, but I'd like to glue it shut just to keep the crack from expanding. However, I'm not sure what type of glue to use. Thoughts? 

Also, I definitely need to get some drill bits for acrylic.


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## Spinster (Oct 19, 2014)

Super glue could work, but I'd be concerned about toxicity to the animal inside. Silicone aquarium caulk might be a better alternative, it's non-toxic when cured. 

For plastics I melt the air holes, rather than drilling. I grab a nail with pliers or vise grips, then I heat it with a small torch until it's nearly red hot. You could use a chef's torch or a torch lighter. 

Another option is using a rotary tool (Dremel) as opposed to a full sized drill. This allows finer control of the speed and helps prevent overheating and/or cracking.


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## BeeMan (Oct 19, 2014)

Hot glue. It may not be pretty, but neither is a crack.


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## Cavedweller (Oct 19, 2014)

Thanks for the suggestions, everyone. 


Spinster said:


> Super glue could work, but I'd be concerned about toxicity to the animal inside. Silicone aquarium caulk might be a better alternative, it's non-toxic when cured.
> 
> For plastics I melt the air holes, rather than drilling. I grab a nail with pliers or vise grips, then I heat it with a small torch until it's nearly red hot. You could use a chef's torch or a torch lighter.
> 
> Another option is using a rotary tool (Dremel) as opposed to a full sized drill. This allows finer control of the speed and helps prevent overheating and/or cracking.


That was my concern with superglue as well. Unfortunately there's no way I could fit caulking in this very thin crack. 
How frequently does the nail need to be reheated? (I don't own a torch though) How long does it take to push the hot nail through the acrylic? 

I found an old thread on here where a user swore by diamond tipped drill bits made specifically for acrylic. But if I can't find those for sale, I do actually have a Dremel.



BeeMan said:


> Hot glue. It may not be pretty, but neither is a crack.


If I use hot glue, how long do I need to air it out before adding bugs? (I have no idea if it has toxic fumes)


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## Nich (Oct 19, 2014)

Super glue will be fine. It is used as a staple in the reef hobby to mount coral fragments to rockwork and the like. Once the cyanoacrylate cures it will not leach anything, and even before it cures it does not leach anything toxic...it is even used on human wounds. Hot glue on the other hand is literally a type of plastic, any plastic that has a low melting point can potentially leach its compounds depending on the temperature.

Reactions: Like 3


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## ratluvr76 (Oct 19, 2014)

if you don't have a torch you can heat your nail on the burner of an electric stove. At least if it's a traditional style stove top, not ceramic or glass top.


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## Cavedweller (Oct 19, 2014)

Nich said:


> Super glue will be fine. It is used as a staple in the reef hobby to mount coral fragments to rockwork and the like. Once the cyanoacrylate cures it will not leach anything, and even before it cures it does not leach anything toxic...it is even used on human wounds. Hot glue on the other hand is literally a type of plastic, any plastic that has a low melting point can potentially leach its compounds depending on the temperature.


Thanks, that's really helpful info!


ratluvr76 said:


> if you don't have a torch you can heat your nail on the burner of an electric stove. At least if it's a traditional style stove top, not ceramic or glass top.


I've got a gas stove. Now that I think about it, that's just like a big torch, right?


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## ratluvr76 (Oct 19, 2014)

Cavedweller said:


> Thanks, that's really helpful info!
> 
> I've got a gas stove. Now that I think about it, that's just like a big torch, right?


Yup. It is. Also, people use super glue directly on T's that have ruptured abdomens and other injuries causing hemolymph with some success from what I understand...

Reactions: Like 1


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## viper69 (Nov 29, 2014)

Cavedweller said:


> Thanks for the suggestions, everyone.
> 
> That was my concern with superglue as well. Unfortunately there's no way I could fit caulking in this very thin crack.
> How frequently does the nail need to be reheated? (I don't own a torch though) How long does it take to push the hot nail through the acrylic?
> ...



I drill all my containers now.

Depends upon how thick the plastic is and how hot the nail is, re reheating the nail.

I use hot glue, I let it air out for a week. But I'm overly cautious when it comes to chemical fumes. Just because I can't smell it, doesn't mean it won't kill my T is my thought. Though I'd like to know what others do on this topic.

As for drilling acrylic specifically, there are acrylic bits which you can buy. Now, I haven't bought one because I thought they were too pricey I use garden variety, all purpose drill bits with a typical hand drill and hand drill press.

The real key to drilling acrylic is to be patient and drill slowly. If you drill too fast, it melts the plastic. You know you are drilling the appropriate speed when the piece of acrylic comes out from the hole in one solid piece. That's when you get PERFECT holes, trust me, I've done it.

A Dremel can be used, but it's not ideal at all because Dremels spin faster than a normal hand drill (corded or cordless), thus causing acrylic to melt. I had moderate success w/my Dremel.

Reactions: Like 1


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## Cavedweller (Dec 2, 2014)

I agree, better to error on the side of safety with chemical fumes and pets. 

From my research, it seems that a black oxide drill bit is the right type for this sort of thing. I just placed an order for some yesterday (the hardware store didn't have black oxide 1/16 bits). I'll let you guys know how it works out when they arrive. 

I used to have a fancy Dremel kit for model building with a crapton of attachments, would you believe it got stolen when my house was burglarized?


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## viper69 (Dec 2, 2014)

Cavedweller said:


> I agree, better to error on the side of safety with chemical fumes and pets.
> 
> From my research, it seems that a black oxide drill bit is the right type for this sort of thing. I just placed an order for some yesterday (the hardware store didn't have black oxide 1/16 bits). I'll let you guys know how it works out when they arrive.
> 
> I used to have a fancy Dremel kit for model building with a crapton of attachments, would you believe it got stolen when my house was burglarized?


Well I've never seen a black bit specifically for acrylic, doesn't mean it doesn't exist of course. The bits I have seen are shiny metal, single fluted too. That's part of the key for acrylic bits, they are single fluted if I recall correctly.


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## Cavedweller (Dec 3, 2014)

Dang, I didn't know that! The person at the hardware store who helped me said black oxide was the way to go, and I couldn't find much info to help online, outside of black oxide being used on plastics.


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## viper69 (Dec 3, 2014)

Cavedweller said:


> Dang, I didn't know that! The person at the hardware store who helped me said black oxide was the way to go, and I couldn't find much info to help online, outside of black oxide being used on plastics.



When I did my search (not on the forum-that's a different search) on the web, it only took 0.38 seconds to get results. Clearly you didn't call my friends at Google :biggrin:

4 words >> Google: acrylic drill bit

What type of search did you go on Google? Or did you even do one?

I'm guessing you didn't search at all.


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## Cavedweller (Dec 6, 2014)

I think the exact wording I searched was "drill bits for acrylic". 

In the end Google didn't lead me astray! My new black oxide bits just arrived and oh my god they make this so much less painful. It took less than half the time to drill all 48 air holes. I drilled 3 boxes in no time at all.

Reactions: Like 1


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## viper69 (Dec 6, 2014)

Cavedweller said:


> I think the exact wording I searched was "drill bits for acrylic".
> 
> In the end Google didn't lead me astray! My new black oxide bits just arrived and oh my god they make this so much less painful. It took less than half the time to drill all 48 air holes. I drilled 3 boxes in no time at all.


What type of bit were you using before?


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## Cavedweller (Dec 6, 2014)

Just ordinary steel ones that have been sitting around in the utility room since the dawn of time. I totally destroyed the 1/16th bit, but these black oxide ones are supposed to last twice as long.


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