Polycarbonate vs Arcrylic?

[SS MAYFLOAT]

While I was off work, I took on a task that I've put off since I got my boat. The bridge windsheild was destroyed when I got it.

Anyway I had some plexiglass laying around and made up a form/jig to mould my own. What I had available was lexan (poly) and it worked fine. My practice piece fit great and looks like the original would. Now to buy the material for the actual windshield.

I did a bit of searching and found that lexan (even though claimed to be stronger) scratches easier than arcrylic (plexiglass). Arcrylic is less stronger, and less flexible.

I'm thinking arcrylic is the way to go since it is more scratch resistant. It will not be flexing so I don't think that will be a problem. I did post this up in the boating section, but it got burried quickly.

All I'm asking is some input if any of you have worked with either. Thanks......SS

BTW, I was surprised that this actually was easier than I had first thought it would be. Wished I had made the time to do it earlier on..

 

[MrBigStuff]

Re: Polycarbonate vs Arcrylic?

I don't have much to contribute towards your question but I do have one of my own- how did you heat it for bending?

I fabricated some parts out of lexan not too long ago. They did scratch easily but it was also easy to polish them out.

 

[Bob_VT]

Re: Polycarbonate vs Arcrylic?

You can order a "scratch resistant" grade of lexan but..... hang on to your wallet...... it's going to cost big bucks. Go with the regular lexan and keep it clean.

 

[SS MAYFLOAT]

Re: Polycarbonate vs Arcrylic?

I don't have much to contribute towards your question but I do have one of my own- how did you heat it for bending?

I fabricated some parts out of lexan not too long ago. They did scratch easily but it was also easy to polish them out.

I heat my house with a wood burner. I always had this light bulb shinning in the top of my head that this could be my means of heating the plexiglass. There is 3 sections to my shield, so they are a bit on the short side (42") My wood burner is 38". BTW, I put a 2'X4' piece of aluminum on top of the woodburner for a nice flat surface. I used 1" box tubing to space it up from the woodburner. The ends didn't heat as well and did not get to the 350* that is needed to make the stuff flexible. To remedy that situation, I used my hot air gun and it worked fine. I used a pyrometer (electronic thermometer) to measure the temp. The main thing to be careful of is overheating it. It will bubble and take on any inperfections in the form if you get it too hot (usually over 400*). Sorta like a wood form transferring the woodgrain to concrete. When it is just right in temp, the plexiglass should be very flexible like a piece of cloth. Wish I had a camera so I could take some pics. I'm going to try to borrow a friends and take some pics to show the form and the outcome of my trial piece.

The most time consuming part was cutting out a cardboard (posterboard) template. Curves and angles I am not the best at, so trial and error took the most time on acheiving the right template.

One thing I'm not sure about is what color to go with. The original was gray tint as most are. The cabin windows are mirror tinted blue to match the paint scheme on my boat. I did find a place fairly close that has both the gray and blue 1/4" X 4' X 8' in stock for $170. The cheapest I have found. I only need about half the sheet to make all the sections. I think having extra would be good knowing this stuff is not forgiving to cracking and chipping when be sawed, scribed, and scored. I'm thinking the blue would look great on the boat. This windshield is nothing more than an air deflector and it is nothing that you have to look thru while operating the boat.

Bayliner said that the windshield has not been available for my year of boat for many years. Custom fabs wanted $500 on up. Yeah, it is a bit of work, but I'm a big cheap skate and like making my own stuff for the savings.........SS

 

[Bondo]

Re: Polycarbonate vs Arcrylic?

SS,....

Is there any chance you could fit together Flat glass windshields to do what you want,..??..??

I've got a Pile of taylor flat glass boat windshields I'll gladly Give you if they'll do you any Good......

 

[SS MAYFLOAT]

Re: Polycarbonate vs Arcrylic?

SS,....

Is there any chance you could fit together Flat glass windshields to do what you want,..??..??

I've got a Pile of taylor flat glass boat windshields I'll gladly Give you if they'll do you any Good......

Sorry, Thanks anyway Bondo. Take a look in the pic, it's that plexiglass piece up on the bridge where the helm is. This isn't my boat, but the same year and model. I painted my antifoul blue n my trailer is a tri axle.

 

[Bondo]

Re: Polycarbonate vs Arcrylic?

Ayuh,..... Flat wouldn't work there......

 

[Bob_VT]

Re: Polycarbonate vs Arcrylic?

Look up "sheet UVex" on google. That is the plastic used for snowmobile windshields. you can get it .080 thick and it is durable stuff. Available clear or tinted and you can cut it.

Actually 1/8" lexan is pliable too but you would need to make a frame to hold it in place.

Have you checked a full survice glass shop for advice?

 

[Bob_VT]

Re: Polycarbonate vs Arcrylic?

'http://www.k-mac-plastics.net/cellulose-acetate-sheet.htm' The uvex is actually a brand but it is CAB plastic. Scroll down about halfway on the link and there is bulk materials.

This stuff is real rugged yet pliable for snowmobile windshields. I think it would survive on a boat.

 

[SS MAYFLOAT]

Re: Polycarbonate vs Arcrylic?

Thanks Bob, I'm going to check out those sites. The place that has the plexiglass stuff makes it on site. They sell as well as distrubute to other glass shops.

Problem with going with the thinner material is you will have to have a 100% contact area in the mould. With the thicker, you can get by with miniimal contact areas in a form vs mould. Its hard to explain in writting how I actually did this. I called a friend yesterday (Sat) and he is going to bring his camera over sometime this week to take some pics.

I'm glad I took that Industrial Arts class back in high school (70-74). I had a great teacher. We studied with hands on work with about every level of trades. Plastics was one of those skills. Thats probably what set my mind to do this project.

 

[Bigprairie1]

Re: Polycarbonate vs Arcrylic?

Lexan is generally regarding as being superior in most applications over Acrylic (Plexiglas) because it is less prone to breakage. Plexiglas is a slightly older plastic/technology.
As for the scratch resistance, you're right....Lexan may be more prone to scratching...but it will take more abuse. The general rule of thumb is you trade toughness for hardness. Resistance to scratching is usually tied to hardness....like glass, which is harder than either Lexan or Plexi. The single best example of something that gives both is....da da and surprisingly (or not)....a diamond, which combines clarity with being extremely hard and tough.
You can also buy optical Lexan...but its a few bucks more for sure. It would be used in very high security situations needing resistance to scratching, etc.
You can get probably get the Lexan heat bent locally if you need to. I would probably lean a little more towards the Lexan having had much more success with it.
Keep us posted.
BP