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Gluing plexi

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Marko

Sun Jan 14 2007, 11:44PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

Hi guys

This thing bothered me for long time. I loved the idea of using dichlormethane or some other solvent to soften the acrylic and make popwerful welds.
Only thing I found working is superglue, but it's still rather poor.

I was asking around for it but nobody gave me any clue where to get some dichlormethane or something better than it.

Diging around garage, I found some old fiberglass degreaser wich said to be mixture of buthanol and dichlormethane.
But, when I tried it, it didn't work at all. Even after left hours and overnight to soak it simply didn't do anything.

My guess is that, even while well sealed, degreaser was probably years old and juice just evaporated.
Maybe concetration wasn't high enough, or I did something basically wrong?

I would be thankful to anyone who can give me some tips on it.

Should I try a new, fresh bottle of degreaser? How fast should 'proper' methylene actually soften up the plexi?

Thanks for help..

ragnar

Mon Jan 15 2007, 12:18AM

Registered Member #63 Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425

If methyl-ethyl ketone (MEK) doesn't work, would you consider Acrifix? It's pretty expensive, but very neat and very handy... you dispense it from the tube as a clear goo, and it polymerises into methyl methacrylate under ultraviolet light.

Superglue isn't much fun if you get blooming/crazing on the surface, but if that's the only problem, try putting your part in front of a fan whilst it cures... it should disperse the fumes before they condense on the rest of the plastic.

Hazmatt_(The Underdog)

Mon Jan 15 2007, 01:05AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

The way to go

IPS Weld-On #4 and #16

#4 for syringe use with a fine tip. Very runny, like water. Allow capillary action for the best welding, sets in about 15 seconds.

#16 is thickened as a gel. It takes a little longer to set, but its good stuff.

Both are rock solid for Acrylic. Super glue and epoxy didn't work for me at all, but this stuff is amazing.

Dr. Drone

Mon Jan 15 2007, 01:31AM

Registered Member #290 Joined: Mon Mar 06 2006, 08:24PM
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Posts: 1673

IamSmooth

Mon Jan 15 2007, 02:26AM

Registered Member #190 Joined: Fri Feb 17 2006, 12:00AM
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Posts: 1567

I don't know if anyone mentioned it in the past, so please forgive me if I am repeating someone else's post, but I use the high-end PVC cement. I think it makes nice welds. Maybe the other stuff is better, but this works fine for me.

...

Mon Jan 15 2007, 03:55AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

At Ortel we needed to make a plexi box so we used some epoxy from McMaster (I have no idea what it was called, but it came in a 10:1 dual syringe dispenser and stank like mad and I should be able to find it again, but I think it was pretty expensive) that gave a nice strong bond despite the horribly rough cut edges.

Something to consider, roughen up the edges and use some garden variety epoxy.

ragnar

Mon Jan 15 2007, 09:02AM

Registered Member #63 Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425

You'll find a new, 'fresh' bottle of Acrific the best solution... Apply glue, leave it out in the sun or under a fluoro lamp for a while, easy! The acrific bond is stronger than the plexi surrounding it, you can't go wrong. Really.

Failing that, superglue in front of the fan is the easiest solution since I'm guessing you already have superglue and already have a fun... just try it!

Marko

Mon Jan 15 2007, 09:35AM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

Thanks everyone

But, before I lose myself in all your fancy stuff, why methylene dichloride decided not to work this time?

I actually got the idea from Hooper's thread, where he suggested it for smaller pieces (wich is more than enough for me).

I don't care even if I need to soak overnight, I just need something that will work.

How concetrated it needs to be if not 100%? ( I used mixture of MDC and buthanol)

Regarding other stuff, I saw that UV-curing acrifix thing but only in bosnia, I'l se if I can order some if I happen to need it.

Weld-on cement isn't that expensive at all, if I pass near it, I'l surely pick a tube!

Failing that, superglue in front of the fan is the easiest solution since I'm guessing you already have superglue and already have a fun... just try it!

Superglue simply, no matter how well is plexi polished, makes poor bonds. In most cases I can easily separate pieces by hands. It's simply not worth the expensive plastic.

Got to go to school now.. cheers!

...

Mon Jan 15 2007, 06:12PM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

For superglue you need ROUGH edges, take some 220 grit sandpaper and put some scratches in there to give the glue some grip.

You can only use polished edges with a chemical that is going to weld them together, for everything else you need rough edges.

Bored Chemist

Mon Jan 15 2007, 06:22PM

Registered Member #193 Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022

Methylene chloride boils about 40C ( I can't be bothered to look it up). Butanol boils at about 117C
Whatever mixture of these compounds was present at the start, unless it was perfectly sealed, it will have been losing CH2Cl2 a whole lot faster than butanol.
If you wanted you could try distilling the mixture to get relatively pure CH2Cl2, but I wouldn't bother. Epoxy works pretty well.
Butanol won't glue perspex bur CH2Cl2 will

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