Glueing clear acrylic sheet perfectly clearly?

[Ian Stewart-Koster]

Hi All,
8 years ago a customer wanted some 20mm thick clear acrylic, with a half-depth 1" rebate all round, and a design lasered on the bottom.
We have 20mm white, black, and opal, but not clear. The job did not warrant buying a big sheet.
So had a go at gluing two 10mm sheets together. And failed.

I was told to sandwich them, then put methylene chloride on the edges, and capillary action would suck it in giving a perfectly clear seal.
The result looked like a sick octopus till I ran out of Methylene Chloride. I gave up the idea, but used that method for joining 1/4" or 1/2" sheets on their narrow edge, and other repairs, with no problem.

Lately another customer/friend wanted something made from 20mm clear, and the idea of joining two 10mm sheets 400mm square, came up.
I tried once again, only this time I flooded the bottom sheet, put the top sheet on, and slid them a little, pressed and waited. Yuk. Despite being clear, it has contour lines like dendrites or root tendrils where I am guessing there are minute density changes or something.

I tried again last night only this time I thickened some chloroform with some clear acrylic routed shavings, into a mild syrup of about runny milk consistency, so evaporation would be not so fast. I then filtered it in case dust specks were there, and flooded the bottom sheet with that using a solvent-proof syringe, and sandwiched the two together.
It still left some tiny fake bubble-looking marks, where no air bubbles exist. Like bits of fizz in a few places.

Any hints on how to make a better job of it would be appreciated, before I give up!

 

[SignosaurusRex]

 

[letterworks]

Weld on 40 2-part glue, and there are some European guys with product and methods (YouTube, serralox or something like that). But really, beg borrow or steal the correct thickness.

 

[Ian Stewart-Koster]

Thanks - I've just been offered an offcut of 20mm so I'm set.

 

[CanuckSigns]

I would think a vacuum press would help a lot with this, but I would check with a local plastic place about getting a piece cut, there is a plastic place near us that will do that and it's great for this situation.

 

[Ready]

Hi All,
8 years ago a customer wanted some 20mm thick clear acrylic, with a half-depth 1" rebate all round, and a design lasered on the bottom.
We have 20mm white, black, and opal, but not clear. The job did not warrant buying a big sheet.
So had a go at gluing two 10mm sheets together. And failed.

I was told to sandwich them, then put methylene chloride on the edges, and capillary action would suck it in giving a perfectly clear seal.
The result looked like a sick octopus till I ran out of Methylene Chloride. I gave up the idea, but used that method for joining 1/4" or 1/2" sheets on their narrow edge, and other repairs, with no problem.

Lately another customer/friend wanted something made from 20mm clear, and the idea of joining two 10mm sheets 400mm square, came up.
I tried once again, only this time I flooded the bottom sheet, put the top sheet on, and slid them a little, pressed and waited. Yuk. Despite being clear, it has contour lines like dendrites or root tendrils where I am guessing there are minute density changes or something.

I tried again last night only this time I thickened some chloroform with some clear acrylic routed shavings, into a mild syrup of about runny milk consistency, so evaporation would be not so fast. I then filtered it in case dust specks were there, and flooded the bottom sheet with that using a solvent-proof syringe, and sandwiched the two together.
It still left some tiny fake bubble-looking marks, where no air bubbles exist. Like bits of fizz in a few places.

Any hints on how to make a better job of it would be appreciated, before I give up!

Just an FYI... From Wiki.
Dichloromethane (DCM or Methylene chloride or MEK)
Toxicity
Even though DCM is the least toxic of the simple chlorohydrocarbons, it has serious health risks. Its high volatility makes it an acute inhalation hazard.[21][22] It can also be absorbed through the skin.[1][23] Symptoms of acute overexposure to dichloromethane via inhalation include difficulty concentrating, dizziness, fatigue, nausea, headaches, numbness, weakness, and irritation of the upper respiratory tract and eyes. More severe consequences can include suffocation, loss of consciousness, coma, and death.[1][23]

DCM is also metabolized by the body to carbon monoxide potentially leading to carbon monoxide poisoning.[24] Acute exposure by inhalation has resulted in optic neuropathy[25] and hepatitis.[26] Prolonged skin contact can result in DCM dissolving some of the fatty tissues in skin, resulting in skin irritation or chemical burns.[27]

It may be carcinogenic, as it has been linked to cancer of the lungs, liver, and pancreas in laboratory animals.[28] Other animal studies showed breast cancer and salivary gland cancer. Research is not yet clear as to what levels may be carcinogenic.[1][23] DCM crosses the placenta but fetal toxicity in women who are exposed to it during pregnancy has not been proven.[29] In animal experiments, it was fetotoxic at doses that were maternally toxic but no teratogenic effects were seen.[28]

In people with pre-existing heart problems, exposure to DCM can cause abnormal heart rhythms and/or heart attacks, sometimes without any other symptoms of overexposure.[23] People with existing liver, nervous system, or skin problems may worsen after exposure to methylene chloride.[9]

 

[Ian Stewart-Koster]

Thank you.
I am aware of many of the 'dangers' of the product - as well as its uses. I am surprised to see they call it MEK though. It is NOT MEK, and the inclusion of it in that statement leads me to wonder what other pieces of fiction the story contains?
The majority of acrylic glues used to be based on methylene chloride/chloroform - so were most automotive & household paint strippers for much of the past 45 years.

Acute inhalation etc etc is not in my best interests so it does not happen.
I've used it for the last 10+ years, and dizziness, headaches, nausea etc as you describe have never been experienced-if you take simple steps to maintain your health - don't spill it on yourself, and try not to inhale it. That's easy to achieve.

Golly even H2O is lethal if too much is taken too quickly - or it gets into your lungs - yet we need it to survive.

 

[Killahcam]

just buy some 1" acrylic your going to either kill yourself with solvents or your going to spend the same amount redoing it

 

[Ian Stewart-Koster]

I did buy some in the end - but it was still a worthwhile experiment, and worth asking...

Thanks.

 

[johnnysigns]

UV glue would give near perfect/perfect results. We've had success just using acrifix and using a pneumatic press to squeeze the parts together. That worked for our workflow as the part was only 7"H x 11"W and it was getting married to a small base. With the pneumatic press, the bubbles didn't stand a chance though. Any spillover from the acrifix was almost completely transparent.

 

[MikePro]

wouldn't a UV curable epoxy and vacuum bag do the trick here?