1959 windshield mod

[putback]

Had a heck of a time to find a windshield for this '59 Mohawk. What I have came from a glass '61 ark traveler. Polished up fine, windshield is 3/16 thick. Mounted on the Traveler it measured 55" wide. I can live with that 55 inches on the Mohawk but at 59 inches wide it would look perfect. Two questions. Can I stretch the windshield outward the extra 4 inches without damage to it, or is that a risk? 2nd Question, my Mohawk has more ark in the bow than the traveler did, what is a SAFE way to shave up to 1/4" from the ctr of the windshield where it meets the bow?

 

[Johnny]

wow awesome score !!

as far as the plastic goes, is it the true vintage 1961 formula ?
or, an aftermarket one made in recent years made out of Lexan?
Plexiglass can be gently coaxed with EVEN heat where you want to
alter the shape. Large areas are best heated with a heat shrink
flame gun. The little hobby propane torch will not work well on large areas.
Your best bet on that would be to find a Glass and Plastics shop.
As for removing material, just mark with a sharpie marker and
start whittling it down with some hand rasps. If you are proficient
with power tools, a rotary rasp in a drill would be a bit quicker
but you run the risk of something going wrong pretty quick.
I have used the standard router with the standard wood bits to
cut plexiglass with no problems. Also, Roto-Zip makes a special
upward spiral bit just for cutting plastics. You just have to use a lot of tape
on the surface where the router base slides so you don't scratch it.
With hand tools, you have more control. It may take a bit longer
but you have a larger safety margin to work within.
Oh, the most safest power tool would be a belt sander if you have one.
80 grit and keep it moving so you don't melt too much plastic into the belt.
and go the same direction as the windshield.... not across it.
Your Call. Good Luck !!
and post some follow-up pics after you get it done !!

Oh, your question: yes, you "could" mount the windshield into the 59" position
as you are only extending it out 2" on each side. I would give an
educated response as yes, you can - without any problems.
BUT - if you start to see ANY cracks or crazing, then it is time to heat it.
Another item that would make your windshield look more professional would be
to get some Windshield Rubber from https://www.classicboatconnection.com/windshield_brackets_gasket_rubber_step_pads_frames_Continental_letters_trim.pdf



but, personally, I really like it the way it sits now at 55"......
Just shave the center to fit, attach the rubber strip and clips and done !!

 

[putback]

I'd bet the windshield is 1961. The hand & power tools I have but I've never worked with this material. I'll go with the belt sander. It did spread out to 59"s without any problem. Locked it in place at 59 stood back & looked, not so sure now that it can be done. Once the bow and stern bonnet are painted inside the polished alum gunnels I think the windshield / brackets will look better at 55"s, with everything inside the paint perimeter. Couldn't visualize the end result 'till it was in place at 59". Good advice, thanks. Ordered the windshield rubber from your link. Another question. Rivet and screw holes from two previous windshield mountings, none line up with this one. I can plug them with buck rivets but it would look better without. Only way I know is patch the under side with alum and body panel adhesive then fill / feather with JB, smooth, prime & paint. Any other methods?

 

[Johnny]

Nope, not from my bench seat. You got it.

the belt sander will work just fine to make the contour fit.
Two people to hold it steady helps. If no extra hands are available,
put a blanket on the work table. Another blanket on the windshield.
lots of weight to hold it steady. and gently sand away. I don't recommend clamps.
there are special stainless clips that fit over the rubber gasket to mount the glass to the bow.
But, you can make your own out of aluminum flat bar and polish them as well.
Or, put the clips on the inside and you don't have to deal with the gasket thing.
Patching the holes from underneath is what I have done and it works fine.
Dimple in the hole area on top first with a ball peen hammer so the epoxy will be
larger than the hole when sanded down flush.

Here is a photo of what my windshield looked like after sitting in a barn for 35 years.
The clips are factory stainless. But you can see the profile that goes over the rubber.
Up to you as how to get those done.

Good Luck

The reason I asked about the age of the plastic is that I have had bad experiences with
vintage plexiglass from the '50s up through the '70s that have been in the sun all their life.
It seems like the molecular structure changes and becomes more brittle. Like it crystallizes
from years and years in the UV. This comes from working with old vintage plastic signs
made with plexiglass. Which would be the same for a boat windshield. So just be careful
when handling it while it is off the boat. No sudden bends or anything that could be traumatic.

Take some photos as you go through your process as a tutorial !!!!

 

[Johnny]

dang, just cracked my windshield right down the middle !!
It is a 1959 era. some 2" splinter cracks at the bottom from the mounting holes.
While taking off the top aluminum edge trim, put some cracks there as well.
Applied generic MEK to try to seal the cracks. Normally, the crack seals
itself to be almost invisible. This stuff left the crack looking like a blue toe.
not pretty. Had to drill a hole at the top of the center crack to stop the split.
The windshield is 16" tall and the crack is 8". I think it is toast . . . .
I was really surprised at just how brittle this plastic was !!! Even tho it has
been sitting in a barn for the past 35 years away from the UV, it still went bad.
I will probably use this one as a mold and make a new windshield out of 1/4" Lexan.

BE CAREFUL in everything you do with yours !!!

 

[putback]

Bummer! But you maybe just stopped me from the same fate. Was polishing the alum trim in place by hand, figured I'd remove it tomorrow and use the buffer. Not now. I'll finish it in place. Didn't know about the MEK trick, will remember that one for the future.

 

[Johnny]

Plastic shops have a special blend of MEK for bonding polycarbonates.
I have used regular painters grade MEK on plastics in the past with mixed results.
The specific MEK blend is much hotter than regular and melts the plastics together.
On plexiglass that is over 50 years old, we are taking a chance.... and I lost.
here are some photos I took today . . . . and the windshield is definitely toast.
I got some 2-part epoxy in the twin tubes just to put the puzzle back together
to hold it until I can find a piece of Lexan to make a new one.
I think I will go ahead and buff it out anyway, just for giggles.
The top aluminum band is pretty corroded. Had a really hard time getting it off.
Most of the brass snaps snapped off at the screw so they had to be drilled and punched out.
Don't know if it can be saved or not.
A new one is about $85.

 

[Johnny]

If you expect ANY kind of plexiglass repairs - this is the correct
solvent to use. It is a bit late, but I will get some off of e-bay.
1/4 pint will last 25 years LOL. it goes a LONG way. $11 on ebay, free shipping.
But my plexi is so brittle, it is just not worth the aggravation to save it.
oh, do NOT use SuperGlue to repair large cracks in polycarbonates - it won't work.

Good Luck in yours !! It's gonna look great.

 

[putback]

I'll use that scigrip. I also restore old campers. The old gas/elec 'fridges always have cracked/ broken plastic compartments inside. Never did find a way to repair them that looked clean. I'll give it a try. Your alum trim looks like its gonna be a challenge. In some cases on old airstreams I've had alum trim parts that I couldn't buff out, or find. Powder coating looked good. On this boat the windshield hold down clips, bow nav light, steering shaft shroud, ect are quite ornate and badly blistered/pitted. I'm gonna try stripping/ smoothing them up and powder coating them. Lot of hand detail work, good winter job. Only other color on the boat will be the bow and stern covers and interior. A good contrast color for the trim parts may look good, we'll see. Caught a break on the cast Mohawk badges, good as new!

 

[Johnny]

if you have never used this type of solvent adhesive before, there is a small learning curve.
It works by capillary action into a tightly fitting crack. Unlike super glue, it melts the two
mating surfaces together and the crack should seal and be almost invisible.
This solvent is water thin so it is not a gap filler. The two pieces must be touching to work.

I first became familiar with it to make plastic signs. Take some textured plexiglass and glue
some plastic letters to it, paint the background dark bronze and paint the tops of the letters
with a light bronze or gold color and presto-bango you have a Bronze Plaque for a fraction
of the cost of a real metal plaque. This is the example.... all plastic.

I use the 5cc hypodermic syringe to apply the solvent to the crack, one drop at a time.
The standard 3cc insulin syringe will work also. The solvent is very thin, like water.
File the sharp end off the needle so you don't accidentally poke yourself.
This stuff works on a lot of plastics. Just experiment to see if it will work on your projects.
And, it is very okay to return any unused material back to the original container. Keep it AIR TIGHT.
Wash the syringe with water after use and let it air dry..... will last for ever.

oh, I have seen that TV show where they restore the old Airstreams.
Man, they must buy their Elbow Grease by the 55 gallon drum !! LOL




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