CAST vs EXTRUDED ACRYLIC | WHICH IS BETTER? 

Dont use the same parameters for engraving each type. They may be exactly the same chemically but the different manufacturing processes creates products with different thermal properties/damage thresholds. You are just looking at the superficial property of "whiteness" without questioning or explaing how that whiteness happens. It is 100% possible to achieve the same level of whiteness with extruded acrylic by using different parameters. You are not alone in claiming cast acrylic is best for engraving. All manufactureres and distributors agree. They all use the same engraving parameter standard that you used and conclude what you have elegantly observed and demonstrated. The video I reference below explains the reason for "whiteness" and demonstrates that cast acrylic and extruded acryilc can be engraved equally white. The much lower cost of extruded acrylic will mean more profit for anyone making a business out of LED illuminated signs. see ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-lBkvdKMnBfg.html

@@SarbarMultimedia I’ll have to look into this. I’ve never been able to get good results running a lot of tests on my machines with extruded but I’ll have to revisit this.

@@MakerExperiment There is no implied criticism of what you have done, you have only demonstrated what many others "know" to be true. However, if you dig into the science a bit deeper ( I have the advantage of a powerful microscope) it becomes clearer where the white comes from and then it is but a small step to achieve the same end result with extruded acrylic. All best wishes for you new journey of discovery. Some more powerful tubes (notably Reci) are great for cutting but have weird low power beam characteristics that may screw your efforts. If you check your beam after mirror1, using very low power (say10%) and you achieve a ring burn rather than a dot, you will be struggling to get the right power to achieve the critical parameters. Typically Reci tubes do not deliver a dot burn until 25 to 30% and that may be too high a power. I am working with a 70/80 watt tube that delivers a dot from about 8% power.

I did the same thing when I started engraving acrylic. I will have to check out Delvie’s. Thanks for the tip!

It makes a huge difference.

Sarah P I’m glad you found the video helpful. I’m sorry to hear that your items didn’t turn out well.

I am also new to this.. But from what I read... Mirror and Gold flim acrylic are extruded... Most other coloured ones are cast (cast has more colour options)... Engraving & working though is best on cast...

Cast is superior in my mind but it could be due to my application. I actually didn’t know I filmed it when that happened. The whole time afterwards I was thinking, man I wish I got that on camera. Luckily it was still recording.

Yeah, I had to learn over time. I’m happy I could help others.

basterbeatz you’re welcome.

Jeff Walston I’m glad it was helpful.

Glad I could help.

Thanks for watching!

Chris LaCombe thanks for watching. Feel free to use the promo code at Johnson’s. It’ll save you some money.

You’re welcome

Greg's Garage I’m glad you found it helpful.

I need to look into getting a strip heater.

Bairon Moreno you’re welcome.

Glad I could help.

Both are pretty close to the same for me. I think it’ll just depend on your application. I honestly don’t use much other than cast unless cast isn’t available in the color I’m using.

I can’t tell much of one but they may be spec’d differently.

It can to an extent. The different acrylic compositions are vastly different in how they're made.

Stephen Trenta thanks for the information.

I use a couple that are all made by Epilog. I use a CO2 to cut acrylic. I chose Epilog because I’ve always had a good experience with their people, they build equipment that will last decades, and it’s made to run a business.

Derek Guay I’d start with a small center mark tool. Then drill a small pilot hole. Then I’d use a stepper drill bit and go slowly. The surface tends to tear out if you don’t use a bit made for acrylic or plastic.

Luke Wehrli may I ask why you’re putting anything under the acrylic if you’re engraving it?

Maker Experiment what I meant is the surface my laser engraver is set up on is plywood, but that leaves a smoke color on the acrylic even if I keep it well ventilated . Not sure what to do! Thanks!

@@lukewehrli3839 That I am not sure about. I'm sorry I'm not more help.

Maybe try a sheet of steel or other substantial metal? Obviously the less reflective the better... BUT, I’m not an expert so PLEASE try at your own risk and always use eye protection!!! You’ll find most CO2 lasers use a metal “knife bed” or honeycomb sheet under the material (as shown in this video at 5:27). Since you’re using what I presume is an open-frame diode laser, it’s a bit trickier. Maybe even try using masking/painters tape on top of the plywood? I’ve seen people use that to mitigate scorch marks when engraving wood. Not sure if it will help in your case, but that’s a simple and cheap test.

It’s hard to say with a mirror as I’ve never engraved one myself. I’d check manufacturer websites and see if any of them did a mirror sample or call them and ask. That’s usually a good way to start.

@@MakerExperiment Sorry.I wasn't clear earlier. The mirror I want to engrave is acrylic mirror not glass. So based on your video, what would the optimal settings be for a 100W laser to engrave through the rear layer of the acrylic? And can I engrave TOO deeply? Thanks!

@@ManorRED honestly, you’ll have to figure that out by testing material with that wattage. I don’t have experience with 100W. I don’t remember what I used for settings on that video but I’d start with a small square and try starting with 50% speed and 50% power and then start adjusting. Or you can do the material grid style test that I normally do.

No. The laser makes it nice and smooth.

I have. The engraving result is poor. I wouldn’t recommend it.

It was 400DPI.

Best of luck!

I’m not sure about the fingerprints. It may be possible to reduce engraving grains by putting the laser out of focus a little which will make the beam wider.

@@MakerExperiment Wow, that's actually brilliant. I will never imagine making it out of focus would be useful someday. I would just assume it is always the best to keep the focus sharp. Thanks for the idea. I shall try it next time!

@cwk0505 let me know if it works.

I honestly don’t know if either will be within that kind of tolerance flatness wise. What are you doing that requires that level of tolerance?

@@MakerExperiment sorry, I don’t need them at that tolerance, I was just wondering which one would be the flattest.

@@bgclarinet my guess is extruded due to the process of how it’s made but I could be wrong.

It’s been a while since I did this so I don’t entirely remember. I’m assuming standard dithering.

제임스씨 matte is better than gloss. Other than that, they’re close to the same in my experience.

Well, keep in mind I made this video 3 years ago and at the time, that was my experience.

Something like this may work, but I’ve never tried it. amzn.to/47GLQtG Places like Home Depot or Lowe’s may have something as well.

@@MakerExperiment I was thinking more like a table saw or circular saw to make straight cuts....

@@johnrichardson1949 you can if you get a plastic cutting blade.

So you want to engrave but it still be black?

@@MakerExperiment Exactly👍

Perhaps using matte black is the key?

@@renauddavies matte black may get you close. It may be hard to achieve this with a laser without painting it or doing something post engraving.

If you use the right settings it should be fairly transparent. You could try a post treatment like sanding and polishing.

@@MakerExperiment Thanks for the answer!!

@@MakerExperiment Extruded acrylic automatically gives you a beautiful flame-polished edge when laser cutting unlike cast acrylic which has to be hand polished or hand torched. At least that's been my experience. What say you?

@@straight_razor if you find a good quality extruded acrylic I agree. The cast you can get a good edge and a lot of it depends on the end use. Some usages need that flame polished edge and some most people won’t notice enough to care.

Try decreasing your air assist pressure slightly. Sometimes it’s too high and that can cause some of that fog.

thanks will try that nest week. I work in Winston Salem Mixxer; a maker space as I am trying to develop a small business with the wife. Retired from manufacturing and was always in crafts, with 40 years of leather tooling, aside from my manufacturing position. We are running a "Rabbit" 80 watt machine

@@johnzill2125 very cool. Best of luck!

@@johnzill2125 the best decision is to use DISH SOAP. Just apply a thin layer of soap on acrylic before engraving or cutting and you will forget about this issue forever) I even couldn't sleep because didn't know how to deal with this problem, and then found this way

@@projex5894 will give it a try again. The firsts time I used it I failed. maybe used wrong soap

I haven’t yet. It’s on my list of things I want to try eventually.

I made a simple brake with three pieces of wood and the top having a 45 degree. I hinged the two together and fastened down the top where I wanted to bend and used a heat gun to bring to temperature before bending

I’ve had a mix of both. When I did this video I think I had a bad batch of extruded acrylic because I was getting better results on cast acrylic. That being said, I agree that should have been the case. The supplier at the time also quit making that product so I wonder if that’s why. I plan to do more videos in the future when I have a better extruded product.

I haven’t done much strength test to be honest so I’m not sure. My guess is epoxy would be stronger.

@@MakerExperiment I havent seen any test or comparrison, perhaps a good video to do for your channel.

@@Tanko3691 I’ll have to look into that more.

Thanks for the tip!

It depends on the look you’re going for and if you engrave it with the masking on or off. A good starting point is around 80% speed, 60% power, and 400 dpi.

Im new in this field, just recently bought an 80w chinese co2 laser using corellaser. is the "pixel" matters? Cause there is an input box in th bprogram where you put 1 or 2 pixels. Im starting to watch all your videos. BTW, Im from the Philippines

@@simpatiko2k5 I’m not sure about that software to be honest with you.

I haven’t tried to be honest.

@@MakerExperiment , just try) As I can see from my little experience, alcohol cracks extruded acrylic, but cast is more resistant to chemicals. Is that common for every type or depends more on producer?

This is CO2. I don’t think a diode will cut certain colors and kinds of acrylic.

I don’t have any true data to back it up. Cast is typically the sturdier of the two because of how it’s made in my experience.

@@MakerExperiment Thank you very much, I appreciate your answer. I'm going to ask a manufacturer directly to save time. Cheers

Thanks for watching.

Lexan is a little bit different than acrylic. It’s typically stronger but won’t engrave very well in my experience.

I made a separate video dedicated to mirror acrylic. If you look through my videos, you should see it.

I’m honestly not that familiar. I don’t have a great answer on this one.

It does depend on the application and I tend to agree with pretty much everything you’ve said. I’ve never found an extruded acrylic that actually engraves well but that’s great if there is.

@cspace123 Just curious why or no one else isn't mentioning that laser cutting extruded acrylic automatically gives you a beautiful flame-polished edge vs cast acrylic which has to be hand polished or hand flamed with a torch to get the same beautiful edge. Hence, for engraving, cast acrylic is generally better but for cutting shapes, templates and router base plates, where there is no engraving, and a flame-polished edge is preferred, extruded acrylic is much better because it saves the extra step/labor in having to flame or polish the edge by hand. What say you?

You’re right. A laser cannot profile, but can a CNC make tight angle cut with no radius? Hahahaha One day I’ll get a CNC. Both machines are awesome.

I mean sure if you want to waste material.

@@MakerExperiment It is not that precious and even less so if there are free cut-offs available. Anyway, I objected to your statement that: "there is no real way to to tell them apart, other than by part number or SKU...". This is a gross omission of essential information in your video.

@@amciaapple1654 Well, I’m not going to tell people to light them on fire and risk them doing something more dangerous. You’re welcome to make your own video.

That's a thin excuse, but even if it is taken at its face value, it doesn't mean that it prevents you from deleting that statement which misleads the watchers of your video that "there is no real way to to tell them apart, other than by part number or SKU...".

@@amciaapple1654 well, I can’t make everyone happy. Feel free to make a better video if you’re not satisfied.

kishen kriz I understand. You’re also welcome to make your own.

Extruded acrylic will have a better cut finish in my experience.

@MakerExperiment , Thank you for the reply. I will try the extruded first. Have a safe Memorial Day weekend.

@DecksNJ you too!