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Author Topic: Team Go Dog, Go! Modified Partial Streamliners  (Read 1007396 times)

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Offline Koncretekid

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #810 on: June 28, 2012, 05:12:36 AM »
If it's any consolation, the pie looks great!
Tom
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Life's uncertain - eat dessert first!

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #811 on: June 29, 2012, 12:16:28 AM »
The sad thing is I was discussed the windshield several times with two plastic experts.  One was equipped for and good at vacuum forming and the other was a good drape former.  I had PETG literature and we talked about drape forming it.  The draping expert said he would do it.  I chickened out and went with polycarbonate.  What a mistake.  It will take me weeks to sand and polish this thing.  Polycarbonate is a material for experienced experts with specialized storage facilities where it can be kept dry.  Vacuum forming molds need some expert craftsmanship, too.  Homeboys like me should use PETG that is draped over felt covered forms.

Offline Peter Jack

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #812 on: June 29, 2012, 12:34:00 AM »
Having had some experience working with polycarbonate I would suggest you hang that windshield on the wall and use what you've learned to build another. By the time you manage to work it to any sort of clarity, even if you do succeed, the varying thickness will lead to large amounts of distortion to the point that you may as well use a piece of metal. The metal would probably be less annoying.

Experience is a great learning tool but too many times I hate gaining that experience!  :| :| :|

Pete

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #813 on: July 01, 2012, 10:48:36 PM »
The defects were oriented across the windshield from one side to the other.  I sand with 220 grit paper at a 90 degree angle to the defects until they are removed.  This is sanding lengthwise along the fairing.

Now I mark a grid on the underside with a Sharpie laundry marker.  The grid is parallel and perpendicular to the windshield sides.  Next, I draw a grid on the top.  The lines are diagonal to the sides.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #814 on: July 01, 2012, 11:07:16 PM »
Now I start sanding.  The object is to sand off the grid so it cannot be seen.  Marks oriented cross ways and length ways show me I need to sand on the underside.  Diagonal marks tell me I need to sand the topside.  Lengthwise sanding was used for these grits:  220, 400. and 800.  Crosswise sanding was used for these:  320 and 600.  I alternated the sanding direction as I worked down through from coarse to finer grits.  This week I will sand crosswise with the 1000 grit and lenthwise with the 1200.  Wet sanding works best.

My oldest daughter and her husband went from Fort Drum where he is stationed to Port Alexander on Lake Ontario.  There was a Harley Davidson rider group meet there.  Thousands of them on choppers.  They filled the town.  She just got off the phone after telling Rose and me what they saw.  All I could tell her was the old saying "there's harley guys and there is everyone else."
   

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #815 on: July 05, 2012, 08:28:13 PM »
Sandpaper is great for finishing lots of things and optical surfaces are not one of them.  The shield was sanded with 220 grit to take out as many blemishes as I could detect.  Then I moved onto 320, 400, 600, 800, and 1000 grits.  Each was sanded at right angles to the sanding direction of the coarser grit.  The sanding was done until all scratches from the previous grit were removed.  This was easy to see.  The coarser grit scratches were across the direction of sanding for the finer grit.

The Micro-mesh pads are a lot better for polishing out the plastic.  The stock removal must be done before they are used.  They are good at smoothing out surface scratches - not leveling.  The pads are sold by Rockler Woodworking, a national chain.  Mine were bought at their store in Beaverton.  The Micro-mesh grits I used were 3200, 3600, 4000, 6000, 8000, and 12000.  The 12000 grit leaves a finish surface with adequate optical quality.  No further polishing was done.

It took 4 hours of wet sanding per grit with 4 more hours each for the 220 and 3200 grits.  That is 52 hours sanding for one little bike windshield.  This should be factored into the time estimate for making a shield with this method.  A big car windshield would be a bit much.

 


Offline oz

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #816 on: July 07, 2012, 05:45:22 AM »
Thanks WW received secret weapon today I aint sure if this gives us an unfair advantage but my lips are sealed as to its power your secret is safe with us!!

Cheers Oz
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Offline thefrenchowl

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #817 on: July 07, 2012, 05:29:58 PM »
Hi, wobblywalrus

When I was repairing airplane UHF radios in the French Air Force, we were making a lot of small polycarbonate tools and screwdrivers on a small lathe...

The only good way we had to polish them afterwards to perfection was tooth paste, it works a treat spread on a mop attached to a hand drill or anything than can spin a bit.

Patrick
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...What exactly are we trying to do here?...

Offline Dr Goggles

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #818 on: July 07, 2012, 07:00:44 PM »
It took 4 hours of wet sanding per grit with 4 more hours each for the 220 and 3200 grits.  That is 52 hours sanding for one little bike windshield.  This should be factored into the time estimate for making a shield with this method.  A big car windshield would be a bit much.

HFS Bo!...52 hours? :-o :-o...you weren't tempted to buckle at any point and use a random orbital ? I've knocked ours back twice using wet sanding following a blast with 180-220 on the R.O.S I've then gone p600, p800, p1200, p2000...being further away means the optical clarity of ours isn't so critical but it's still pretty good. I always find it is the very last passes that are a mongrel on that stuff.
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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #819 on: July 08, 2012, 12:05:00 AM »
Goggs, my experience, too.  I buggered up a PC windshield repair polish on the last pass with a mop wheel on a bench grinder.  It melted the finish and I had to start over.  I was told to slow down the wheel.  I had some luck with mounting the 6-inch diameter mop on a drill press and spinning it at 1000 rpm.

I never used an orbital sander and know nothing about them.  I would have tried it if I woulda known. 

I tried the toothpaste polish and it works good.   

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #820 on: July 10, 2012, 12:34:09 AM »
The finished windshield.  The fit is perfect, the materials are the best, and the finish is wonderful.  Optical quality be funky. 

Offline Peter Jack

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #821 on: July 10, 2012, 11:40:03 AM »
Wobbly, all I can say is you're a much more patient man than me.  :-D :-D :cheers: :cheers:

Pete

Offline oz

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #822 on: July 10, 2012, 11:55:55 AM »
I have never attempted to do anything like that you make it look easy...kinda you have alot of patience
Newcastle born and bred a City built on Coal and Steel and a people built of stronger stuff

Offline Freud

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #823 on: July 10, 2012, 02:15:58 PM »
The windshields, 3, that Frank Martinez made for the Target 550 'liner need NO attention at all.

There is no distortion and as clear as an automotive OEM piece.

I can give you his address if you need it.

FREUD
Since '63

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #824 on: July 11, 2012, 12:11:47 AM »
Sure, Freud.  I can use the address.

The experts around here told me not to exceed 1000 rpm with a 6-inch diameter mop.  The drill press is running at 850 rpm.  This is Patrick's French air force toothpaste polish trick.  The toothpaste is a very gentle abrasive and it works good on this soft plastic.   The saying goes "They wonder why their record went ... they didn't polish their shield with Pepsodent."

This method is not the best way to make a windshield.  A person needs to be perfect in the molding process to avoid distortion. This is hard for a homeboy to do.  In the future I would order one from Kent at Airtech or have one made by Gustafson, Martinez, or another expert.  This is a tight year for money and that explains my motivation.  The distortion is not that bad and I can live with it for now.