Bonding polycarbonate which will stick underwater
Bonding polycarbonate which will stick underwater
(OP)
Dear all
First time poster but Eng-tips has been a great resource to me recently.
Is there an adhesive or bonding for two polycarbonate sheets that will stay in seawater?
The sheets are about 12mm thick and need to stay put for up to 3-4 weeks.
I have been told that Cyanocrylate will work on dry land but it is water soluable so wouldn't under water.
Would Methylene chloride work?
Thank you in advance
Becky
First time poster but Eng-tips has been a great resource to me recently.
Is there an adhesive or bonding for two polycarbonate sheets that will stay in seawater?
The sheets are about 12mm thick and need to stay put for up to 3-4 weeks.
I have been told that Cyanocrylate will work on dry land but it is water soluable so wouldn't under water.
Would Methylene chloride work?
Thank you in advance
Becky






RE: Bonding polycarbonate which will stick underwater
Chris DeArmitt PhD FRSC CChem
RE: Bonding polycarbonate which will stick underwater
Mike Halloran
Pembroke Pines, FL, USA
RE: Bonding polycarbonate which will stick underwater
Silicone will safely make a seal but not a high strength bond.
RE: Bonding polycarbonate which will stick underwater
RE: Bonding polycarbonate which will stick underwater
OP:
Cyanoacrylate may be too weak for your bond, i.e. if the bond must resist significant shear forces, but water submersion shouldn't rule it out. It's used e.g. in human surgical applications, and in aquariums for bonding coral starts, so it can't be "water soluble", or even weakened much by water immersion.
Mike has a good suggestion, I think he's made it before, because we used that stuff to seal an extension to our 10,000 gallon water tank, it has held up pretty well in spite of some unforseen flexure/vibration of the tank walls.
If your proposed bond needs high strength, maybe consider an epoxy.
RE: Bonding polycarbonate which will stick underwater
The above quotes are verbatim to the best of my typing ability and include all grammatical errors included in the original documents.
It can be seen from the above data that PC can be solvent welded with DUE CARE, but it is susceptible to solvent stress cracking and joints should be made to reduce stress to acceptable limits while ever residual solvents are present.
I have often seen methylene chloride used with success. Care should be taken in handling methylene chloride due to OH&S issues with chlorinated hydrocarbons.
Regards
Pat
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RE: Bonding polycarbonate which will stick underwater
3M may have a double sided tape that may work, but that is pure speculation on my part. You would need to contact their tech support in your area.
Regards
Pat
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RE: Bonding polycarbonate which will stick underwater
Sorry for the ambiguity Compositepro and btrueblood: the bonding will occur on dry land thankfully , just be submerged at a depth of about 30m for a couple of weeks. It sounds like Cyanocrylate would not be strong enough to support those forces. Buit I shall investigate the other adhesives mentioned.
Kind regards
Becky
RE: Bonding polycarbonate which will stick underwater
RE: Bonding polycarbonate which will stick underwater
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
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RE: Bonding polycarbonate which will stick underwater
RE: Bonding polycarbonate which will stick underwater
Getting slightly out of my element, but... once the solvent has evaporated, isn't the weld just as strong as if the material had been molded to that shape in the first place (assuming proper wetting and pressure of both surfaces)? The CA should temporarily "melt" the two surfaces, allowing them to bond as one structure once the solvent evaporates. Once evaporated, there's nothing to hydrolyze, other than the original base substrate, no?
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Bonding polycarbonate which will stick underwater
CA is not a solvent-weld "glue", it's a polymerizing adhesive glue. The CA resin polymerizes in contact with moisture, and most rapidly when it's a thin film in contact with a surface. CA might melt and weld with an acrylic plastic substrate, but the OP was talking PC.
I think you are right regarding solvent bonding in general, e.g. PVC cement in pipes.
RE: Bonding polycarbonate which will stick underwater
With solvent bonding of plastics you need a joint design with large surface area contact. Pressure helps a lot and some heat at the appropriate time can help.
Regards
Pat
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RE: Bonding polycarbonate which will stick underwater
Thanks for the advise. I ended up using Bostik ExtruFix for the polycarbonate edges and seemed to work fine. The polycarbonate was submerged for a period of about 4 days with some drilling debris hitting it (but apparently not very bitg and not with much force as there were no scratches) and the bonding held fine. There is no evidence that I can see of crazing
All the best
Rebecca
RE: Bonding polycarbonate which will stick underwater
Dan - Owner

http://www.Hi-TecDesigns.com