Model Boat Mayhem

Mess Deck: General Section => Chit-Chat => Topic started by: Ewan on May 16, 2015, 03:27:36 AM

Title: Curved windscreen
Post by: Ewan on May 16, 2015, 03:27:36 AM
Help !!
I have 58inch model of Atlantic challenger and need to replace curved windscreen made of 1-2 mm some sort of green vinyl
Newbie
Ewan KUWAUC
Title: Re: Curved windscreen
Post by: Martin [Admin] on May 16, 2015, 07:44:28 AM
 
Is there anything left of the old one to make a template?
Title: Re: Curved windscreen
Post by: imsinking on May 16, 2015, 10:37:33 AM
Sounds like the poly carbonate lift up visor on a full face crash helmet (it's what I use anyway), need to cut it to a cardboard template to get the shape & then physically BEND the S O B   >>:-(  it wont do what you want . . . . wont glue down too well either, need clips to hold it in position . . . .looks good when it's done . . .
Bill
Title: Re: Curved windscreen
Post by: Ewan on May 16, 2015, 10:39:55 AM
Hi yes I have the whole thing
Thanks
Title: Re: Curved windscreen
Post by: Ewan on May 16, 2015, 10:42:45 AM
Thanks I'll try that
Title: Re: Curved windscreen
Post by: tigertiger on May 16, 2015, 11:23:01 AM
Make a wooden former to the curve you want.
Polycarbonate goes soft and floppy when heated. I don't think a domestic oven will get that hot, but try it first. If not heat it on a flat surface with a hot air gun, but be careful not to overheat one spot and bubble/burn it.


You need a clean set of safety gloves, the orange or white softer woven/knitted type. Pick up the poly carbon sheet, place over the former, clamp one edge to stop it slippling, and then rub with the gloved hand to make it take the form you want. It will cool to firmness quickly.


Best way is to cut it oversized and then trim with a fretsaw or fine band saw. You can then plane the rough edge by dragging a modelling/Stanley knife blade down the edge (see fig).


Sorry if I am insulting your knowledge of trimming plastics.
Title: Re: Curved windscreen
Post by: Ewan on May 16, 2015, 12:40:24 PM
Thanks for that
Title: Re: Curved windscreen
Post by: w3bby on May 17, 2015, 06:12:26 PM
If using Lexan (polycarbonate) then it should be dried before heating and forming. It can otherwise form bubbles as trapped water turns to steam. Industrially this takes a long time in a warm oven with circulating dry air.

If I remember correctly the best temperature for thermoforming polycarbonate is around 190C.