Thermoforming Mirrocraft windshield successful

[MrMirro71]

Hi, all. I just wanted to share my windshield thermoforming experience. My boat is a 1971 Mirrocraft Ski-N-Troll 14' originally bought by my grandfather in 1972 and left to me in 2009. Over the last few years, the original windshield had developed cracks and broken pieces that I glued back in. After searching for a replacement windshield and finding none, I researched thermoforming one for myself. I measured the windshield and drew the flat shape in cad. A local acrylic signmaker cut 2 windshield blanks out of one 4x8sheet of 3/16" clear acrylic using my cad file and a CNC router. I made a cardboard template for the interior curvature of the wraparound windshield and translated that into a scrap plywood form. For thermoforming, I have the luxury of an old Scotchlite heatlamp actuator used for making vinyl signs in my department where I work. Long story short...2 new windshields for a total investment of $125. I ran out of season before final install, but I have submitted a pic of my test fit.

 

[Psiclown]

Re: Thermoforming Mirrocraft windshield successful

Looks great! Nice job.

 

[1fishbone]

Re: Thermoforming Mirrocraft windshield successful

AWESOME!!

How long did it take under the heat?
Was much force used to form it while under heat?
Any idea what temperature?

I need to make a windshield for my 'frankenboat'...finding one is impossible!

THANKS

 

[MrMirro71]

Re: Thermoforming Mirrocraft windshield successful

Thanks, guys.

I put one side in at a time...maybe 30 minutes per side. It drooped down almost all the way on its own. I used a squeeze clamp for the last 2 inches or so. I think these lamps are around 250-300 degrees. Enough to soften the acrylic, but a test scrap of lexan didn't budge.

 

[Cadwelder]

Re: Thermoforming Mirrocraft windshield successful

Acrylic (plex) will form at slightly lower temp than lexan but 300 degrees should certainly form the lexan as well.

 

[MrMirro71]

Re: Thermoforming Mirrocraft windshield successful

If anyone near me with a similar boat needs a windshield, send me a pm...I'd be happy to help. The beam is 60", the windshield is 57" wide and 17" tall.

 

[MrMirro71]

Re: Thermoforming Mirrocraft windshield successful

Update: got the frame straightened and installed, drilled mounting holes and put it on the boat minus the gasket. Might get new white one, my original black one is a bit dry.

 

[Woodonglass]

Re: Thermoforming Mirrocraft windshield successful

EXCELLENT ! Workmanship. Could/Would you post the CAD drawings of the Windshield and go into a little more detail on the process? I know for a fact there are a LOT of iBoaters that would LOVE to have more knowledge on this subject, INCLUDING ME!!!!!!

 

[wacko1]

Re: Thermoforming Mirrocraft windshield successful

View attachment 89740Update: got the frame straightened and installed, drilled mounting holes and put it on the boat minus the gasket. Might get new white one, my original black one is a bit dry.

I have a 1971 Mirrocraft and have been looking for a windhsield the past three years. It's a 16ft seafoam green with a 50HP motor, and I like the boat a lot. I certainly don't have the expertise you do for the forming, but was wondering if you would be interested doing a windshield for me and. If that's a possibility, give me a ball park cost, and perhaps we can solve my search problem.

 

[MrMirro71]

Re: Thermoforming Mirrocraft windshield successful

PM sent to Wacko1. I am by no means a thermoforming expert...I'm a tinkering engineer. A few new pics to close out this thread.

 

[Howard Sterndrive]

Re: Thermoforming Mirrocraft windshield successful

nice work!
sounds like you could run a little part time business there

 

[Georgesalmon]

Re: Thermoforming Mirrocraft windshield successful

Old friend of mine worked at Mirro back in those days (still works there actually). Told him about this post and he said what you did was very similiar to the way the factory did it. They had a two part mold (also plywood) though, a male and a female if you will that they squeezed the plastic between. Thay also had a simple plywood box large enough for the whole windshield with wooden dowels in it to hold the plastic windshield up. They had three heat lamps inside and just kept checking the plastic with gloves on to see when it felt pliable enough. Then put it in the mold and clamped it closed until cool. Very Nice job figuring that all out on your own and creating what you needed.

 

[MrMirro71]

Re: Thermoforming Mirrocraft windshield successful

Thanks, George. I thought the original widshield had a slight curve from top to bottom, but I wasn't sure. The two-part mold explains that. It was so warped from the weight of snow and ice over the previous 10 years that I couldn't tell. Ask your friend if the form is still in the back room somewhere...I know it was a different company then. I love this boat and the memories from my youth. The motor is the original 1972 Johnson 25. The topside color is General Motors' Bamboo Cream, mostly original. I have the 1971 MirroCraft sales catalog with the complete lineup.
Next project: a mooring cover that will snap into the hull like I remember.

 

[Georgesalmon]

Re: Thermoforming Mirrocraft windshield successful

Sorry, he says the mold never made it from The original Mirro aluminum company up to Gillett, WI where the company resides now. The company was renamed Northport. I was plant manager there for about 10 years from about 1989ish. Then it was bought by a poontoon boat company who owned it for awhile and just purchased from them this year by four of the managers. Hang on tight to those plastic MirroCraft logos on the side of your hull. They can NOT be replaced by the factory and they get a lot of calls asking. My son is one of the four that own the company now.

 

[Tdcesar]

Re: Thermoforming Mirrocraft windshield successful

If anyone near me with a similar boat needs a windshield, send me a pm...I'd be happy to help. The beam is 60", the windshield is 57" wide and 17" tall.

I am rebuilding this exact boat and can't find a windshield anywhere. Could you help me?

Thanks

 

[2hansondeck]

Any chance you still have the equipment for the Mirrocraft windshield? I just acquired a '68 14' ski & troll and need a windshield.

 

[GA_Boater]

Re: Thermoforming Mirrocraft windshield successful

If anyone near me with a similar boat needs a windshield, send me a pm...I'd be happy to help. The beam is 60", the windshield is 57" wide and 17" tall.

Any chance you still have the equipment for the Mirrocraft windshield? I just acquired a '68 14' ski & troll and need a windshield.

Closed.