Acrylic edge finishing - Silvo

[Aussie]

I picked up some acrylic from my supplier today and I asked him about edge finishing... I mentioned flame polishing, he response was to get the best result use a series of fine grit wet and dry followed by silvo.
Have you guys heard of this?
Plan to use it on the weekend and will let you know how it goes.

[martin54]

He isn't 100% correct but it's not bad advice if you have never done it defore
You can flame polish acryl;ic but you would be best experimenting before using it for a project. There is quite a fine line between a nice polished edge & an overturned uneven melted edge You can also cause stress cracking if you apply to much heat.
If you cut it properly then you can get pretty close off the machine, then either a flame polish or an acrylic/metal polish to finish it off. Think Xxray uses the buffing method to polish edges. Look for his posts in questions about anything edge lit. You will also pick up some other good tips from him as well.

You can buy machines specifically designed to polish acrylic edges but they are expensive & you would need to be doing high volumes for it to be worth purchasing one

[BillK]

I’ve had good results using a card scraper to clean up the edges before going to higher grit sanding and polishing.

[Xxray]

I have seen guys get great results from flame polishing, I have always looked at it as better than nothing if you don't have the proper equipment to do it right. If you try it just remember, keep the flame moving, like with a spray gun. Plexi heats up quick and when its flash point is reached it will burst in flame without warning, which may or may not ruin the edge. Also, the thinner it is, the less heat it will take. You will for sure want to practice on scrap first to hone your flame polishing skills before turning it lose on a project.

As Martin said, cut edges should look pretty good right off the saw and in this regards, if you use a blade designed for this material [triple chip 80 tooth], you'll have great results. These cost around $80 and can be found at home depots/lowes [Diablo & Irwin brands to look for] Freud and Amana make great blades as well, but they cost even more and I don't think they are worth the extra premium over Diablo or Irwin. If you use a generic $10 roughing blade then it'll be hacked up and need much work to fix.

My method for crystal clear edges is to first sand out any flaws, I use 120 and/or 220 and use a mouse sander or orbital sander. Sometimes customers want the frosted look, if so I stop right there, work complete. To get them clear I use a floor mounted buffer, has a roughing wheel and a finishing wheel both with their own buffing compounds. After a couple minutes on that the edges are clear as can be.

Downside I guess would be the investment it would take in a quality buffer, unless you happen to have one handy. I tried a handheld, which is slightly better than nothing, but found it unworkable and the results unacceptable. Then I tried a cheap [$250] 8" buffer from amazon, I think I'd prefer a root canal than use that thing again. Then I got this beauty and never looked back, another example of the wisdom of buying the tool you really want first before trying cheap, inferior alternatives.

https://www.acmetools.com/shop/tools/ba ... ial-buffer?

But if all that is a bit much and you only do these once in a blue moon, then flame polishing is a viable alternative.

[Aussie]

Thanks guys for the advice.
Doug... I have ordered a polisher/buffer today, unfortunately we don't have a large choice of machines in Australia... the downside of living in a small country.

Ron

[Rcnewcomb]

I've always wondered how much acrylic you need to be cutting to cover the cost of this bit.

[mtylerfl]

Wowee! I’ll admit I have no idea what makes that bit so pricey!

[Xxray]

It better be made out of double dipped platinum from the land of Oz !

[mtylerfl]

My curiosity got the better of me, so I did some searching around...

It’s called a PCD Polishing Bit. It has diamonds embedded. I don’t know (and couldn’t find) what the acronym “PCD” stands for. Maybe P for “polishing”, C for “carbide” and D for “diamonds”?

Anyway, it’s advertised as yielding a “near optical” polished edge and eliminates the need for flame polishing.

[Roly]

I use a series of wet and dry after the initial sanding to remove saw marks, then I go through the micromesh grades. It takes a little longer but works very well. When I did a series of round coasters I followed the same technique on the lathe

[ozymax]

My curiosity got the better of me, so I did some searching around...

It’s called a PCD Polishing Bit. It has diamonds embedded. I don’t know (and couldn’t find) what the acronym “PCD” stands for. Maybe P for “polishing”, C for “carbide” and D for “diamonds”?

PCD = Poly Crystalline Diamond.

I've never used one and judging by their cost, not likely to any time soon.

[DJ-Bino]

Hi,
I have a few links on the subject here
MCD = monocrystalline diamonds
PCD = polycrystalline diamond
The MCD is the most expensive to manufacture
PCD is much cheaper.

These are just links and not advertising for tool manufacturers.

However, I find the PCD cutter that Randall shows is far too expensive for a PCD cutter. You can get big MCD cutters for the money.

https://www.schell-tools.com/en/pcd-end ... ng-cutters

https://www.vhf.de/en/products/industry ... ond-tools/

https://shop.vhf.de/catalogs/Diamond-tools-W_D.htm

I hope I could help a little with that

Regards
Dieter

[phill05]

We use PCD cutters for cutting stone they chip very quickly and you can't sharpen them yourselves they have to be sent away for re-lapping.
Sometimes I have used a ground and polished lathe tool (parting off tool) held in a wooden handle to scrape the edges of Acrylic then after a quick wipe down with Acetone solvent.

Phill

[KMoffett]

I go along with BillK and Phill05. A sharp scraper following the saw cut gives you a very nice mat finish. I have a small, 1/4" thick scrap of armor plate. Sharpen it on a green wheel. Use it like a draw knife on the edges. Also at a 45° angle to break the sharp edges.