Comparison of adhesive appearances on transparent acrylic

What’s the best way to stick clear acrylic together with a nice, optically clear bond? I tried out the adhesives I had on hand. If you can post any others, please do!

My test objects are pairs of 0.5" circles of Medium Clear Acrylic Proofgrade. These extreme closeups probably make everything look worse than it is.

Water-Thin Acrylic Cement

This looks great, you can’t even see the edges of the adhesive drop. However, it is hard to work with. You need to practice wicking it into the seams, and you need to take great care not to dribble any on surfaces that you want to remain pristine.

Gap-Filling Acrylic Gel Cement (SciGrip 16)

This stuff looked great when I first applied it, but very quickly it took on this curdled appearance. Maybe it all would have been better if I kept it clamped. This was a pretty lazy application though, because I am hoping to find the right product for the lazy builder.

Note that this gel cement leaves strings behind when you dispense it, so you need to be careful that they don’t land on unprotected plastic.

E6000 Craft Adhesive

This looks great, and there’s no curdling at the edges of the droplet, though the seam is still obvious. This adhesive does like to leave strings behind when you dispense, so it takes some care to use.

If you view this object with a bright backlight, you can see that the adhesive has a very subtle haze. This test image is very favorable, but if you had an uneven application on something like a brightly lit mock stained glass , it would probably be noticeable.

(E6000 sticks to everything I have tried so far, including slippery rare earth magnets, and has become one of my favorite adhesives.)

3M 9502 Tape

This 2-sides tape is extremely thin and laser cuts easily, with a perfect edge. When I put it on acrylic, I don’t even have to adjust my cut settings. The bond is pretty clear, but also obvisouly speckled. The speckles are pretty obvious when the object is backlit, even at arm’s length.

This stuff is absolutely the bee’s knees for assembling opaque acrylic signage, though. Unfortunately, it is also pretty expensive!

Thoughts
Even the worst of these candidates might be OK for small parts that won’t be closely examined, or larger parts in favorable lighting. For example, a clear piece on a lighter opaque piece might pass if the whitish artifacts blended in to the background.

If I wanted to stack clear parts on clear parts with the best optical quality, my first try would be to use a few dots of E6000. If that wasn’t satisfactory, I would try the much harder to use water-thin cement.

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Great write up! Thanks for sharing!

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You might try a horsehair flux brush to wick the water-thin adhesive in. Tape your parts together and then tip the brush into the adhesive/solvent. Tap or brush off the extra on the edge of the can. Run the brush over the seam between the two parts and it should wick in while the brush controls the amount and eliminate the drops. I have found that I prefer this method to the dropper bottle in most cases.

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Don’t know it would turn out but you could try the same material, i think laminate, they put between the glass in your car windshield

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This was important reading for me as I use lots of acrylic. I really appreciate your various tests, photos and the write up. I’ve used only the thin ‘wicking’ type of adhesive but will be interested in trying another kind, too. Thanks so much!

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Good tip. I’ll be checking it out. Thank you.

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Good to know. For my application of clear on top of wood, I’m thinking of either using @geek2nurse’s recommendation of glue with a score line to provide a wicking boundary or using veneer as a wrap around the edges and no glue between.

For your sample, I thought that the water thin looked best.

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Very helpful, thanks so much!

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I complained at TAP Plastics the other day about how that stuff dribbles out of the bottle. It turns out there’s a trick to it. With the bottle upright, you squeeze out a little of the air, and then upend it—that creates a slight vacuum that keeps it from dribbling.

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No kidding! $200 a roll??

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Well it is a 180 foot roll but just over $1 a square foot. That’s not is not too bad. If you ever use that much. However I know 3M makes these in smaller sheets with backing but its 3 times as much for a square foot

I have 2 roll ends from my work of similar tape that probably still has 5 feet left on them each ad I’m gonna have to hoard them now :exploding_head:

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You can find smaller rolls or individual sheets if you search around though. The price kinda balances out for me because I’m not having to remake pieces I get glue schmutz on.

https://www.mokeyinternational.com/item/?id=B007Y7CT3S

https://www.amazon.com/gp/product/B007Y7CSAC/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

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I think the material in safety glass is PVB or EVA, and the lamination process keeps it clear. I don’t think it is just an adhesive.

That’s right but the process is good if you could find a clear two sided adhesive

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How exactly do you use this? Put a piece over the acrylic you’re cutting and it cuts it right along with it? Guessing here…

Yep. Peel it off the roll and smooth it down on the acrylic like you are applying a sticker. Laser cut, then peel off the liner and apply.

I have a 2" wide roll and find it pretty easy to apply it to large and small pieces alike. For a big piece, put down strips side by side. It doesn’t matter if there are little gaps in between the strips, at least if you are assembling something opaque.

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the other thing to keep in mind, you don’t necessarily have to coat the whole area of the acrylic to have it work.

when i hung very small acrylic signs on drywall, i used this and just put it in strategic places.

Edit: these signs.

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Thank you…appreciate the tips and the idea. I am definitely going to try some of this.

As @shop said you don’t have to cover the whole piece, too. Depends on what you are doing. But it is hard to apply very small pieces without just as much waste, so it takes some fiddling to figure out how much to apply.

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That is a clean way to hang up signs! Do you know if it can be removed without ripping the paint off the drywall?

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