Replacing windshield on 1964 Starcraft Jet Star

[lakelover]

I think the time for replacement is finally here, after struggling to see through my original 1964 windshield for another boating season. I've done a fair amount of research on different methods and how I think I'm going to do it but given the materials cost, I want to proceed carefully. This will be a slow-moving project, I think.

What I've decided is to use Lexan and cold-bend it into the form of my present frame. Most of the info I've read says the Lexan is more UV resistant than Plexiglass. I measured the thickness of the windshield with digital calipers the best I could without detaching it from the deck, and came up with a thickness of .195", or about 3/16". I haven't looked around thoroughly yet, but locally, I can get Lexan in 1/8 or 1/4". Besides that not being the full thickness that the frame can hold, a big concern I have, (especially for the 1/8"), is it stiff and solid enough to hold up to 65-70 mph towing?

And a concern I have for the 1/4" or even the 3/16" thickness, is will I be able to cold-bend it or will it be too stiff?

I'd welcome thoughts & suggestions! Anyone done this before?

Molded type of windshield:

Hard to see through, especially when the sun shines from ahead!

About 3/16" thick (.195):

Deck fastener type:

 

[Woodonglass]

I'll be sending you a Lengthy PM on the subject!!!

 

[lakelover]

OK, thanks!

 

[Woodonglass]

I posted it here...
http://forums.iboats.com/forum/boat...7423-bending-plexiglass-for-curved-windshield

 

[lakelover]

OK, thanks!

Edit: Huh? A double reply, compliments of the forum.

 

[jigngrub]

I guess you've tried the headlight restoration kit method of trying to clear up that plexi?

Something that may sound weird, have you tried wiping the plexi down with WD40? This is a temporary fix but the WD40 can be reapplied whenever needed. Since you plan to replace it anyway, trying the WD40 won't hurt anything.

 

[lakelover]

jig, it's not so much surface problems as it is crazing that goes through the entire thickness. I have polished the surface, but mostly what you see is "inside" the plastic.

Thanks, Wood, lots to study there...

I guess you can't expect a lot from 50 year old plastic!

 

[jigngrub]

Give her a wipe down with the WD40 just for schicks and giggles to see what happens, it may not do anything or it may surprise you.

 

[lakelover]

Here's some interesting info I found:
Plexiglass vs Lexan Matchup



I don't know how many times we have been asked the question - What's better: Plexiglass or Lexan?

Depends. What's the application? Let's match up some KEY properties to see:

Plexiglass (acrylic sheet) aka Lucite, Plexiglas, Perspex, Acrylite

• 92% light transmission - clearest plastic sheet available - about 15% cheaper than polycarbonate
• large variety of colors available
• light pipes through the sheet edges
• does not yellow or discolor in the sun - 10 year warranty regarding 2% loss max.
• optically water clear in all thicknesses
• inert - no outgassing
• thermoplastic - working temp of 180F continuous
• burns very nicely after you remove a flame source - fire rating UL94HB
• scratches - can be restored by sanding and buffing
• resistant to breaking - when breaks pieces are large and dull edged
• recyclable
• easily bonds with solvent adhesives to itself and other plastics
• hydroscopic (will absorb a small amount of moisture on side facing moisture (warps)
• available up to 4" thick as a monolithic cast sheet, and thicker via custom casting

Lexan (polycarbonate sheet) aka Tuffak, Makrolon

• 88% light transmission - very clear - about 15% more expensive than Plexiglas acrylic sheet
• limited colors available (white, black, bronze, gray, sign colors)
• light does not pipe through sheet edges
• untreated sheet discolors in 5-7 years of sun exposure - UV coatings available to extend 15 years
• inert
• optically clear - loss of some light transmission in higher thicknesses (5% in 1/2")
• thermoplastic - working temp of 275F continuous
• self-extinguishing fire rated 94V0 - UL rating depending on thickness
• scratches - cannot be restored by sanding and buffing
• resistant to breaking (virtually impossible to break)
• recyclable
• easily bonds with solvent adhesives to itself and other plastics
• bullet resistant grades are available - all grades of BR levels
• hydroscopic (will absorb a small amount of moisture on side facing moisture (warps) and therefore difficult to thermoform without pre-drying
• available up to 1/2" thick as monolithic extruded sheet, up to 2" as a molded sheet

Applications:


Plexiglas Acrylic Sheet:
Safety glazing (up to 17 times stronger than glass)
Boat windows and hatches
Machine Guards and Electrical covers
Display cases
Brochure holders
Picture Frames
Lighting
Anywhere you need a clear, impact resistant, easy to cut and maintain sheet

Polycarbonate Sheet:
Safety glazing (unbreakable)
Bus Windows
Machine Guards and Viewing ports
Anywhere you need a clear, unbreakable, high working temperature, easy to cut sheet


From:

 

[sphelps]

Interesting stuff LL .. I've been thinking about replacing mine also ...

 

[lakelover]

About a week ago, I ordered a 4' x 8' sheet of 1/8" (.118 actual) polycarbonate sheet from Home Depot for $167....still easily beats the cost of having one fabricated 3 or 4 times over. That will give me enough so that if I screw up the first attempt, I'll have enough left over to try again. I took the free ship-to-store rather than pay $55 to have it trucked from Texas to NY. Delivery is expected by 10/13, good thing I'm not in a hurry.

Even though it's a little more expensive than Plexi (acrylic), I'm thinking that it's so much easier to work with. This project gave me an excuse to buy a new Makita jig saw....an easy justification, I think! Everything I've read says it's easy to cut, drill and bend. I'm not concerned with the UV degradation over time because it will be under cover practically all the time the boat's not in use.

 

[Woodonglass]

You know of course...

 

[lakelover]

Oh, I've still got a LLLLONG way to go!!!

 

[Tnstratofam]

I think I would rather it were " He who inherits all the cool tools from the outstanding restorers on this site wins!" Just sayin!

 

[lakelover]

The Lexan is IN! A day or two behind schedule, but worth the wait. I picked it up at Home Depot yesterday & was very impressed with the packaging it came in. It was enveloped in very sturdy cardboard and well-taped, oversized to protect the edges. The package did have a few tears & dents in it, but I inspected the sheet before taking it and none of them reached through to the surface. Not bad for having come from Texas to NY.

I have to be away for the next couple days buttoning up the camp, but I'm looking forward to getting started. Also have to pick up some mat board at a local art supply store for making the template.

I'm not sure if I'll be able to adhere to the 20mm in-from-the-edge guideline as shown for drilling, but I think it will work out OK.

 

[Woodonglass]

TIP: Use 2 Layers of Blue Masking Tape On BOTH sides when Drilling or cutting the Lexan. It really helps with chipping. Also use a spray bottle with soapy water to keep down the heat. I highly recommend using a Steel cutting blade in your jigsaw for cutting the Lexan. It seems to work the best for me.

 

[Watermann]

Interesting project, I replaced the plexi in my Chief's lower windshield with the same PC and the glass business bent it for me with heat. The material covering the lexan is like shrunk wrapped over it, If you peel it off it won't ever go back on and it does a great job of protecting the glass from scratches when cutting. Be sure to leave it on until you're ready for fitting the glass in the boat.

The choice for windshield material.

 

[lakelover]

Thanks for the info x 2!

 

[lakelover]

Today I bought 2-32"x40" sheets of mat board for my template at AC Moore after finding a coupon online for 55% off an item. Gotta keep the costs down! Then I got down to business and made my template. The mat board is thick enough so it doesn't sag too easily and it cuts easily with scissors.

I found that it worked best when I placed the windshield bubble-side-down on the table and laid the mat board on top of it. Since I had to hang it off the table and trace from the bottom, I used a canvas bag full of tools to weigh it down and hold it in place so it wouldn't topple off the table. It's a little awkward this way, but I got a very inaacurate trace trying to do it with the inside of the windshield lying on top of the cardboard.

I think making the template will be the most critical and time consuming part of this project. But what do I know, I've never done this before! :lol:

First I made a mark about in the middle of the windshield so I could have a point to join the two halves of the template. Since the windshield is small and quite a bit shorter than the two pieces of mat board, finding the exact middle wasn't critical, as long as I had a reference point marked.

So the plastic cutout won't be too large, try not to let the cardboard sag, keep it tight to the edges. My original windshield has about a 3/4" bubble to it:

Looking up from underneath for tracing....awkward, but more accurate. My first tracing doing it with the windshield lying curve down on the mat board was kind of inaccurate. The first half I did required a lot of adjusting after cut-out, that's why you can see sections of mat board on one end of the template.

Keep track of the placement of the template:

Finally traced, cut out, and removed:

Stuck back on windshield as a test fit...remember to trace any mounting holes to the template:

And just for giggles, I fit it into the top frame (seen upside down here), it seemed to fit pretty well, although I'll have to shim it because it's about 1/2 the thickness of the original:

I had to fudge the broken corner. I originally thought I could flip the other half-template and duplicate it, but it turned out not to be perfecly symmetrical, so I just extended the lines 'til they met:

 

[lakelover]

There's other information on doing a windshield replacement. I'm just hoping to add a little to it. Here are some other references to check out, a combination of which I'm basing my work on:

http://forums.iboats.com/boat-restor...at-577021.html

http://www.shareaproject.com/pages/p...t,p,68,00.html

http://forums.iboats.com/forum/boat-...om-2004-update

Edit: Plus all the free advice I get here!