How to Flame Polish Acrylic (Plexiglass)

ePlastics® shows the ideal way to flame polish acrylic sheet by first milling the edges, and then using a hydrogen-oxygen torch.
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[@TheBinklemNetwork]

That final tip at the end was IMPERATIVE. Thank you very much, I had no idea what was causing this issue!

[@netsurfer10000]

The polished edge looks really good! And it's so simple too ... pretty cool.

[@grantgoldner7940]

wow mazing video, would this also work if I milled a pocket into a acrylic sheet and then flame polished the milled surfaces?

[@camero1972]

Is this example for cast or extruded acrylic? Great video. Thank you.

[@neeleshU]

thank you, very educational. could i ask: we have an acrylic swimming pool divider and it is huge. 45ft long, 2ft high, 2inches thick. It is pretty scratched and hazy. Could i use this method to polish it or do i have to go thru the 200/400/1000/2000 etc grit sandpaper first before flame polishing? thanks

[@qhuynh14]

so can I glue the acrylic first, then flame polish the side? or will that ruin the glued pieces as well?

[@CharlesHess]

Hey, I buy my plastics from youse guys!

[@kamals3582]

If you flame polish an edge of a acrylic shelf used as a shelf for a floating shelf and it has LED edge lighting, will the LED lighted plexiglass shelf edge show any crazing effects?

[@jcrt1]

I wish to cut 10mm diameter colored acrylic rods into 50mm lengths in quantity and polish the cut edges. These will be used in jewelry production so a finished look is necessary. A slight bevel would be nice. These could be chucked on a drill press then spun against an abrasive or buffing surface. For instance a sanding/buffing block fixed at an appropriate angle. Some guidance would be greatly appreciated.

[@Eroc.48]

Do you have a video on how to use weld on 40? Can't seem to find any videos showing how to apply weld on 40. There are plenty of videos for weld on 4 but do not plan on using that type of weld on.

[@alansm136]

Thank you for the series of tutorials. Should the edge that will be glued not be flamed? If the material is flamed should it be annealed after flame polishing so that you can then glue it without crazing the materials? Can you also explain the annealing process please?

[@alansm136]

Many thanks' for your reply

[@charlier2]

Hello, this method will get the same results on polycarbonate ? Thanks for your help!

[@eplastics]

Hi Carlos- You do not want to use this method for polycarbonate because the material is softer and it will bubble. The easiest way to get a shine on polycarbonate is to do a 'chemical polish'. Use IPS 3 or IPS 4 (www.eplastics.com/Plastic/plexiglass_glue) and apply to edges with a Q-tip or pipe cleaner.

[@elliotfranz2231]

I've seen a lot of videos detailing how to flame polish the edges of cast acrylic. Is there a way to apply this same technique to the normal surface? For example, in the case that a surface is milled and must be optically clear following milling, can flame polishing achieve clarity?

[@eplastics]

Hi Elliot- Thanks for the question! Flame polishing is not the best technique for dealing with surface polishing. If you use this method for the surface of acrylic you will get clarity at the spot where the flame is pointed, but the flame will leave marks that "flare out" from the center of the flame onto your material. It works with edges because there is not as much surface area and the flame can be focused with a more narrow area for dispersion. Your best bet is using sandpaper and an oscillating surface buffing wheel for surface polishing.

[@patrickpark8408]

do you have any tips on how to prevent thinner acrylic from warping when flame polishing?

[@sharzanco]

Hi I do sanding before I don't flame polish the bottom part just put glue on sanded edge it will be clean and clear. Or use 3m high viscous glue like honey it's slow but no cracks

[@dyscea]

Why are you recommended to me 7y later? 😆 nice info.

[@popalock85]

So, just so I am clear, one should not flame polish an edge if they plan on welding/gluing that edge to another piece of acrylic, correct?

[@eplastics]

+popalock85 you are absolutely correct. If you flame polish the edge and then try welding/gluing, then the edge will craze and the material will be ruined.

[@artdonovandesign]

+ePlastics, popalock85: Thank you both for that clarification.

[@Stephen8454]

Good to know. Does it work after sanding it smooth?

[@maximillianortiz5160]

Is it possible to glue a crack at the top of the aquarium without removing the water and contents? I have a small crack at the top of the tank and it goes about 1 inch down the front.

[@eplastics]

+Max Ortiz removing the water from the tank may not be necessary if the water is not in contact with the crack. If it is, then water removal is necessary. To apply a water thin solvents (IPS3 or IPS4) into the crack typically requires the plastic to be turned onto its side for application - which would not be possible with water inside. You can find some simple application instructions at the links below: www.eplastics.com/Plastic/eplastics_how_to_videos/How-to-Glue-Plexiglass-acrylic-from-ePlastics-com www.eplastics.com/plexiglass_glue

[@thenewthefarns]

I have been experimenting with this technique using an oxygen-acetylene torch but end up with bubbles forming. Would this be due to getting the piece to hot? From watching your video it seems you have a very high heat but move fast... can you give me an aprox temp where the flame contacts plastic?

[@frimanboi]

Yes sounds like you ran it too hot or moved the torch too slowly over your piece, bubbles or discoloring would indicate too much heat normally on plastics.

[@sumdude4]

Got a few questions about this. Would a butane torch work as well? Also I'm wanting to build some boxes by cutting some locking notches into it. I want to keep it looking clean as possible. How can I keep everything clear and have it all sealed?

[@eplastics]

sumdude4 Flame polishing is Hydrogen + Oxygen in order to get a hot enough flame to ignite the surface of the plastic for a half-second. The heat of the flame is critical, and Butane is unfortunately not as hot and does not result in same shine that is demonstrated in this video.

[@jorgeillueca5260]

@@eplasticsbut still works

[@bodeine454]

Do you have advise on how to fix/bond a hairline crack in a clear plastic automotive headlight housing? Acetone? Two part epoxy?

[@eplastics]

Hi Jeff- we would recommend using an epoxy. You can find an inexpensive one at most hardware stores. One other thing to consider is that when you are fixing a crack in most plastics you should first drill a hole at the end of the crack to prevent it from spreading.

[@bodeine454]

ePlastics, a Ridout Plastics Company Thank you for the info, it sounds like epoxy it will be.

[@yohannicholas7282]

What’s the name of the machine you used to pass the acrylic by in order to remove the saw marks?

[@russthompson154]

it is a "jointer"; basically like a router mounted in a table

[@RyanLee1986]

Am building a 120 gallon freshwater tank. Got it welded, braced, using 1/2" acrylic. Now it is time to flame polish.....wish me luck! Any tips for working on large surfaces?

[@eplastics]

Ryan Lee first off, congratulations on the progress so far. As for flame polishing, just remember to keep the flame hot and long enough to polish the entire surface in one fast pass. Keep the speed as quick as you can, while maintaining the precision and steadiness throughout the project.

[@RyanLee1986]

***** Sounds easy enough. Thanks!

[@Scottforsmith]

I need to cut a windscreen for my motorcycle. The plexi is curved at (being a windscreen) I need to cut out to accomodate where the extra light bar is. What tool would you recommend?

[@eplastics]

+sforsmith first of all, acrylic is not a good choice for motorcycle windscreens. It would not meet DOT specifications for the basic reason that is is very dangerous and sharp if broken. An accident could potentially cause the windshield to be the cause of major injuries. In most cases polycarbonate is used due to it being nearly unbreakable. It would essentially bend or break the mechanical fasteners holding to the frame/fairing. Polycarbonate would also "cold-form” around the frame without as much concern of it breaking during the install (assuming it is thin enough to accept the radius). Most factory windshields are produced via a molding method in mass quantities. You can cut either material with a jigsaw. It will require some sanding to clean up the edges. A router will also work if you have one, and usually produces cleaner cut edges. One extra note: acrylic will flame polish, polycarbonate will not.

[@Scottforsmith]

Thanks Got it

[@Hammerback972]

How do I fix the edge after it's been "crazies" or whatever u said sir? A friend gave me a used piece of acrylic, I would like to mount an amp on it, really needs cleanes and polished, not sure where to start.

[@RolfCJ]

Just cut the end crazed edge.

[@dougpichler501]

What is the deburring tool you are using? It's it just sandpaper on a board?

[@eplastics]

***** We sell a tool for scraping edges here: www.eplastics.com/Plastic_Tools/EDGESCRAPER , however a steel strip, razor blade, the back side of hacksaw blade, or some sandpaper will also do.

[@randerson5726]

What's the edge finishing machine pictured here? Is that something that can be done with a router table?

[@eplastics]

+randerson5726 no. The edge finishing machine is a very specialized machine with a very expensive bit. The bit itself is composed of crushed diamonds and each one costs nearly $1000. There are router bits that offer a polished finish as well, but we have limited experience with them as we found the price of tooling too expensive. It would also require a special spindle speed and feed rate to achieve the clear finish, so CNC machinery is likely required.

[@randerson5726]

+ePlastics, a Ridout Plastics Company So the milling machine in this video is one of these expensive diamond edge finishing machines correct?

[@eplastics]

+randerson5726 that is correct.

[@franklinmichael671]

1:55 if you want to bond them and make it see through what would you have to do? Would the cement make it look like that?

[@eplastics]

The solvent adhesive makes it a clear joint and the flame polishing makes the edges clear. The key to clear glue joints is straight cuts where the pieces fit flush to each other.

[@franklinmichael671]

***** Perfect thanks, and if I need a 3foot long piece for example and I have one that is 1foot long and one that is 2feet long can I glue them to make one long 3foot piece? Or would the part where they joined be visible.

[@eplastics]

Are the acrylic pieces sheets, rods or tubes?

[@franklinmichael671]

***** Large, it's to make an aquarium. The real measurements are probably going to be 2foot tall, 6foot long by 1inch thick and the idea is to turn it into a 2foot tal 12foot long 1inch thick front for the aquarium, but i don't want the seam to be noticeable. The reason I can't but a 12foot long piece to start with is it doesn't fit in the elevator or the stairs.

[@eplastics]

Hi Franklin- A few different things to consider here. First, if you're making an aquarium of that size we recommend going at least 2" thick. An aquarium of that size filled with water will put a lot of pressure on the material, so you want thicker material to prevent it from bending and to provide you with more surface area for the glue to seal when gluing pieces together. Second, it is going to be difficult to hide the seam. No matter what you use to glue the pieces together you are going to see the seam on the front. You also need to be very careful when gluing the pieces together to prevent air bubbles from forming between the two pieces. I understand that a 12 ft. piece is too big to fit in the elevator or stairs, so you might want to consider making it smaller so that it can be one piece that will fit by itself. We sell the material in many increments between 12" and 144" on our website and also do fabrication work if you're interested: www.eplastics.com/Plastic/clear_plexiglass_sheet.

[@416RG]

could you guys give me insight on how you cut your acrylic? table saw? acrylic knife? laser? can you be specific please bc ive searched everywhere ans got answers but i want to get one from acrylic professional's.

[@416RG]

acrylic sheets, into smaller sheets thats all

[@eplastics]

Hi, thanks for the question. We use a table saw with a blade that's 10" diameter x 100 teeth, carbide tip.

[@416RG]

+ePlastics, a Ridout Plastics Company ok thank you

[@CharlesHess]

Would it be worthwhile to use this method on old, foggy headlights?

[@canuckle7shucks]

Doing this for 37years, I just use straight acetylene. Move continuously over edge without stopping, one pass if possible

[@GTgyro]

People, it does NOT need to be anything fancy for the flame, a simple propane torch is what I have been using for 20 years...and you don't need to mill the edges, either. I have cut 1/4" acrylic with a plain old vertical bandsaw, and flamed the edges to perfection with a propane torch a gazillion times.

[@socalplanedoc]

Propane, MAPP, Acetyene will discolor clear acrylic yellow.. stick with hydrogen

[@QF2653]

So propane is out, right?

[@DJHenryGQ]

is there a video on how to make clear acrylic.. white?

[@GahDub]

DJ Henry GQ ...mask the front and paint the back white.

[@pete9124]

In the absence of hydrogen oxygen what is the best gas?

[@grizworth409]

I think he says MAP gas

[@willzville1988]

This is actually much harder than it looks, you can ruin it by putting the flame too close, moving too slow or being off angle - but once you're an expert then you rarely mess up.

[@eplastics]

***** we would have to agree. It is not a "natural" but is certainly one that you can become very good at. The saying "once it clicks, it clicks" applies well here. Spending the time with smaller samples or scrap material is a great way to learn the good and bad ways to flame polish.

[@robgards]

It actually isn't that hard. I've worked in a plastics shop for 8 years and I've only flame polished once. My first time I had to do about 200 parts. Didn't mess 1 up. Just gotta pay attention.

[@zeppy13131]

This is a cool video, but you spoke too quickly and didn't enunciate very well. There were several passages where I really couldn't understand what you were saying.

[@mjremy2605]

PLEASE LEAVE ALL MUSIC NOISE OUT OF A DIY DEMO CHANNEL. SUPREMELY AND INSANELY IRRITATING TO HEAR DRUMS IN THE BACKGROUND WHILE MY BRAIN IS PROCESSING INFORMATION. SILENCE IS GOLDEN.