Mounting acrylic laser cut letters to substrate

[Pixels Are Bad Mmmkay?]

I'm doing my first job mounting laser cut acrylic letters to white polycarbonate panels. I'm using Gemini 1/4" laser cut letters and since this sign isn't backlit, I'm going to be using letters with 3M (sigh) double sided sticky pads on the back. I payed the extra money and ordered a pounce pattern with the letters. I tried the pounce pattern with a sock full of charcoal and it worked okay, but is there a better way? Like taping the pattern to the bottom of the panel and using a light box type setup? If I use the pounce powder should I lay the letters out and then mark the location with a stabilo and wash the charcoal pattern away first for better adhesion? Also is there any way to apply the letters wet? Any tips would be great as I couldn't find much info on the Gemini site, unless I'm looking in the wrong place.

Also, we will be doing possibly 3 more pairs of these for lighted box signs in the future and that brings me to a question. If applying to a backlit sign panel what kind of adhesive would you use? Would an acrylic cement be the best choice? Or are adhesives such as model glue easier and better to work with? Perhaps Weld on? Has anyone mounted acrylic to polycarbonate and what did you use?

Thanks for any suggestions.

 

[Moze]

I'm doing my first job mounting laser cut acrylic letters to white polycarbonate panels. I'm using Gemini 1/4" laser cut letters and since this sign isn't backlit, I'm going to be using letters with 3M (sigh) double sided sticky pads on the back. I payed the extra money and ordered a pounce pattern with the letters. I tried the pounce pattern with a sock full of charcoal and it worked okay, but is there a better way? Like taping the pattern to the bottom of the panel and using a light box type setup? If I use the pounce powder should I lay the letters out and then mark the location with a stabilo and wash the charcoal pattern away first for better adhesion? Also is there any way to apply the letters wet? Any tips would be great as I couldn't find much info on the Gemini site, unless I'm looking in the wrong place.

Also, we will be doing possibly 3 more pairs of these for lighted box signs in the future and that brings me to a question. If applying to a backlit sign panel what kind of adhesive would you use? Would an acrylic cement be the best choice? Or are adhesives such as model glue easier and better to work with? Perhaps Weld on? Has anyone mounted acrylic to polycarbonate and what did you use?


Thanks for any suggestions.

I'm confused by "double sided sticky pads". I assume you mean VHB tape...?

I don't like pounce patterns. They're messy and it can be hard to make out the lines. Some alternate methods:

- I agree with Pat. If you can obtain the file for the letters, cutting a pattern out of vinyl or even a thin rigid substrate makes for an easy install.

- Tape your pattern to the install surface. Make sure it's flat and can't shift. Notch a couple/few corners of the letters on the paper pattern with an X-Acto knife, being sure the marks make it through onto the install surface and don't extend beyond the edge of the letters. That will give you "registration marks" and allow you to line your letters up. So on a capital letter "T", you would cut an "L" at the bottom left of the leg of the "T". You can also notch the corners ahead of time and use a Stabilo to mark the corners once the pattern is taped down.

- Tape your pattern in place. Assuming you have one line of text, tape the bottom and top edge of the pattern in place with one continuous piece of masking tape. Cut the pattern horizontally down the center so you have a top and bottom half. Leave the top and bottom tape hinge in place and cut the length of the pattern but leave about ¼" of the top and bottoms of all of the letters. You can use the remaining bit of pattern to position the letters.


You can use VHB tape or Lords adhesive to mount acrylic to polycarbonate.

 

[Marlene]

Gemini makes a pattern what has the letters cut out of the paper. all you do is tape it down like any paper pattern then mount the letters in the holes in the paper that are cut out. really easy. plastic moves around when it expands and contracts. I'm making a sign with cut letters on a lexan background and will have studs with nuts on the backs since my letters are opaque. you don't need as many studs as you do with a normal stud mount, only a couple, then I'm sticking the letter down too with Goop glue.

 

[Pat Whatley]

If you sent Gemini the file to cut the letters from then it's easy. Just cut the file from paint mask, reverse weed, apply that to the substrate as your pattern.

 

[synergy_jim]

we laser cut 1/16" offset patterns out of posterboard or cardboard and use those for placement. I am assuming you dont have a laser though since Gemini did the letters. On that case low tack vinyl applied with letters offset and cut out works great.

 

[thmooch]

Left over backing paper, pen plot on Graphtec. call it a day.

 

[Pixels Are Bad Mmmkay?]

The tabs I'm referring to are VHB tape.

As far as the vinyl pattern goes, that is the direction I think we will move toward. I ordered the pounce pattern from Gemini because I figured in some way it would make my job easier, however I'm not convinced on this particular application. I think I will just add the contour around the letters to make a cut file and make my life easier.

Thanks for the help and info. Any more info on welding directly to polycarbonate would be greatly appreciated too.

 

[J Hill Designs]

if it was acrylic to acrylic I would say weld-on, but acryl to poly isnt as good as a bond - I'd just use DST

 

[Pixels Are Bad Mmmkay?]

Oh, one more thing...can the VHB pads be applied wet with Rapid Tac or something similar? It would be nice if I could slide them into position rather than trying to just drop them in perfect every time (I don't know if that would even be a feasible approach).

 

[Pixels Are Bad Mmmkay?]

From what I gathered on the 3M website they make no mention of being able to apply wet. However, they do say that the bond of the adhesive is slow curing over a period of 72 hours and a minimum of 15 psi pressure should be applied to the tape for a good bond when applying. So I'm wondering if this tape is forgiving enough to stick and peel back up immediately if the letters aren't lined up correctly. Some of the letters are thin script and I would hate to have to try to peel them back up for fear of breakage.

 

[thmooch]

Never tried VHB wet. Limit your caffeine intake, it will help keep your hands steady. Not that tough as long as the pattern is good.

 

[CanuckSigns]

You can't apply VHB wet, It's really not that hard to line the letters up using the vinyl template like Pat said, stick down one part of the letter first, than line up the rest

 

[thinksigns]

I normally do a thin inline on the letter and then inline the inline. You don't have to worry about removing the vinyl and the vhb still sticks directly to the wall.

 

[synergy_jim]

why in the world would you need to apply wet?

 

[Moze]

Oh, one more thing...can the VHB pads be applied wet with Rapid Tac or something similar? It would be nice if I could slide them into position rather than trying to just drop them in perfect every time (I don't know if that would even be a feasible approach).

No, VHB tape isn't like vinyl. VHB = Very High Bond. There won't be any sliding of the letters. Align a corner, then slowly lay down the rest of the letter, aligning as you go.

From what I gathered on the 3M website they make no mention of being able to apply wet. However, they do say that the bond of the adhesive is slow curing over a period of 72 hours and a minimum of 15 psi pressure should be applied to the tape for a good bond when applying. So I'm wondering if this tape is forgiving enough to stick and peel back up immediately if the letters aren't lined up correctly. Some of the letters are thin script and I would hate to have to try to peel them back up for fear of breakage.

Correct...the pressure has to be applied directly over the tape (not just to the letter in general) so that it wets out and maximizes adhesion.

And no - the tape is not forgiving. Can you peel it back up? Not really "peel", no. But, yes, you can remove it. If you're dealing with thin stroked letters, you'll want to use a heavy fishing line (60# or so) to remove the letter (slide it between the letters and install surface). You'll need to clean the tape off and reapply new.

The tabs I'm referring to are VHB tape.

As far as the vinyl pattern goes, that is the direction I think we will move toward. I ordered the pounce pattern from Gemini because I figured in some way it would make my job easier, however I'm not convinced on this particular application. I think I will just add the contour around the letters to make a cut file and make my life easier.

Thanks for the help and info. Any more info on welding directly to polycarbonate would be greatly appreciated too.

Lords 506

 

[Moze]

why in the world would you need to apply wet?

Because he's afraid of sticking it in the wrong spot and not being able to re-position it. His thought process comes from applying vinyl wet so it can be re-positioned...that obviously can't be done with VHB tape.

 

[Marlene]

I ordered the pounce pattern from Gemini because I figured in some way it would make my job easier, however I'm not convinced on this particular application. I

next time ask for a "stencil pattern". the problem I see with a pounce pattern is the chalk dust. you'd want to make sure the plastic is good and clean to apply the VHV tape and if you wipe it off to clean the plastic, there goes your pounce pattern

 

[Pixels Are Bad Mmmkay?]

why in the world would you need to apply wet?

I don't know. I've never done these before, hence the reason I'm asking. I would rather know what to do than guess and wind up with stuck letters that won't come unstuck.

Thanks for your help, Moze. You are the man.

 

[Ian Stewart-Koster]

If the whole sign is to be backlit, and the letters are translucent, then the 'pads' of 3M VHB tape will show up as a shadow through the letter when it gets backlit.
If you use a cyano-acrylate glue which is very good, it will still give you a visible mark under the letter, if it's backlit, and if the letters are translucent.

Weldon is a very good glue, if you get the correct one.
Methylene Chloride makes for a good clear/invisible bond between the plastics, but use it with all due safety precautions in place.

 

[Billct2]

For a translucent letter application the method I have used is either ss wire or cotter pins. Old school but it works on exterior signs viewed from a distance. I went by one I did in the early 80s and it still looks good.

 

[synergy_jim]

if translucent, we use Duraco's clear VHB tape or 3M transfer adhesive. Gemini used to do our letters before we bought a laser. They could have put this on the back of the sheet prior to lasing so the whole back had a continuous clear tape backer to avoid shadowing...