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Need Help Need help with welding clear acrylic to colored acrylic for a LED sign

Martin Radev

New Member
Need help with welding clear acrylic ( laser cut letters) to colored acrylic. These are mounted inside a LED sign box from ACP.

The problem we have is that when we weld the clear acrylic to the colored acrylic using solvent adhesive for acrylic (Technicol 108), bubbles appear on the next day. We even tried with chloroform, but the effect was still the same. The overall effect of the sign looks really good, but the problem is the welding of the two acrylics.

The bubbles reflect the black inside of the ACP and look unacceptable as if the inside is very dirty.

Can anyone recommend a different technique so that when we weld the clear acrylic on top of the colored, there would be no bubbles of imperfections.


New Member
We have also tried welding clear cutout letters on top of colored acrylic. We get the same bubbles. We never found a solution to the problem.


New Member
i know 3M has some type of adhesive that might work, a old co worker of mine use to call it airplane glue cause they used it for that type of jobs. I feel alot of your end results are gonna be bubbles. Good Luck


New Member
I kind of like the bubble effect, but those should be push thru acrylic letters. When you are getting into adhesive welding, look at 3M's Jet Weld system.

Edit: It's like hot glue, but for welding and is industrial strength


New Member
Wow! Besides the bubbles and black marks, that thing is beautiful. Wish I could do that. I love the blue.


New Member
We've had success in relieving the bubbles by putting the parts into a pneumatic press and squeezing them. With Acrifix solvent which had a longer dry time and more surfactant in it than we were accustomed to the job yielded nearly optically clear joints. Set and dry times were longer, but it was worth the end result and not having to use a UV based adhesive.


New Member
Have you tried laminating the 2 different color sheets with a clear adhesive film and then routing them.