DIY - Perspex windows, need advice

[m1nder]

I am restoring an old Norman 17. I have stripped it down to the bare grp shell. I will be installing new windows. As you can see from the image, some of the windows require bending. Can I do this myself with perspex sheet?

I would appreciate any advice. Many thanks

 

[Rigger Mortice]

Yes....and No!
This http://www.theplasticshop.co.uk/plastic_technical_data_sheets/working_with_perspex_manual.pdf
gives you the know-how about doing it. I'm told that it is easy to do when you know what you are doing. All I know is that, when I played around with some off cuts, it was a disaster. Luckily, I was only playing. I didn't need to bend anything on the job I was doing.

 

[Aja]

They look to me that they have been local heat bent using a tool. I would be very wary of trying to bend a sheet that large. When it breaks it will create shards. If you go ahead, wear plenty of protection.

Regards
Donald

 

[Spuddy]

I've done some pretty basic thermo-forming of acrylic so here's my twopennorth. So far as I can see from the photo there's quite an extreme bend in the front windows. One way to do this would be by drape forming: make a former out of wood skinned in ply - it will probably look a lot like the supports that brickies use to make arches on building sites. I've heard of such being then covered in velvet to reduce scratches during next stage. Find acrylic - I gather that cast acrylic has a wider plastic temperature range than extruded acrylic i.e. cast stays floppier longer which is good. Find an oven big enough and heat at about 160 degrees C for longer than you might at first think as acrylic is a good insulator. Whip out (with gloves), drape over former and allow to cool. Try to arrange some ledges/strips on the former so you can position the hot sheet sharpish. You might need to form an oversized piece and trim to final shape after.
This works OK on small items but seems a lot of bother for you with maybe 2 formers or 1 if being canny. Let's hope somebody has a better solution.
This works

 

[Plevier]

I needed a less curved window than that. I had it done by Project Plastics. They explained that they would have to make a mould to the right curve, heat and drape an oversize sheet because it shrinks, and machine it afterwards.
Consequently it was about £150 for that one against about £40 each for my flat ones.
They did it very well though. Smooth machined and bevelled edges and perfectly located screw holes.
You could try with a heat gun, but I've seen a number of people try to do light aircraft canopies that way and results have usually been totally unacceptable.

 

[m1nder]

They look to me that they have been local heat bent using a tool. I would be very wary of trying to bend a sheet that large. When it breaks it will create shards. If you go ahead, wear plenty of protection.

Regards
Donald

They are the old ones, they are awful, have since been ripped out.

Crikey, there must be a solution to this problem. Are there companies out there who might do this kinda thing?

 

[VicS]

Firms who specialize in supplying and cutting perspex for boat windows will be able to form the new windows to the required profile using the old windows. ( drape moulding)

In the Solent area TP boat windows ( formerly Talking Plastics) and Sunlight plastics

In Colchester, Project Plastics and UK Plastics Fabrications.

In Kent maybe Seaclear Windows or Hadlow Marine

"Up north". Maybe Eagle Boat Windows

Mine were done by one of the Colchester companies

Avoid anyone who wants to make moulds first. ( that rules out Project Plastics it would seem although I thought other people had had them done there)

 

[Rigger Mortice]

These http://www.kellettwindows.co.uk/applicationspleasureboat.html say that they know the Norman range. They may even have the original moulds/former.

 

[m1nder]

Firms who specialize in supplying and cutting perspex for boat windows will be able to form the new windows to the required profile using the old windows. ( drape moulding)

Vic
The only old one is the homemade one pictured. The other one was missing when I purchased the boat.

 

[m1nder]

Forgot to mention folks, I'm in Ireland. But many thanks for the replies, very much appreciated nonetheless.

 

[Tommyrot]

As previously mentioned, make a former, but I used heat guns (paint stripping type) to soften the sheet. Bends like rubber when it's warm enough.
Did the screen on this without too much trouble...

 

[Davy_S]

In my yoof I used to work at a plastic fabricators, an oven is better than a heat gun, but best of all was Glycol (spelling?) similar to antifreeze.
Place the sheet into a shallow steel tank with heat under it, to judge the correct temp use old offcuts. We used to make lids in this way ie 50 off lots a similar lid to a printer lid, drop them straight onto a former. Dont know if they still use the stuff now, might be a elfin safety thing.

 

[PetiteFleur]

Just a thought, what thickness are they? If they are thin, say 2/3mm then it may be possible to just bend it and snap into the rubber moulding? Using the thin Makrolan? type. Obviously not suitable for ocean going boats but probably OK for pottering on inland waterways. If thicker say 6mm then previous methods talked about is thr way to go.

 

[DownWest]

I made an oven out of tin sheet, insulated with blankets and heated with an element from an old oven. Put a small fan in to even out the heat. Used a drape mould faced with formica to curve 10mm sheet into spiral curves on a radius of around 1mt. Also made a small allowance for 'springback' Temp was 120 C.
It is very important to keep the surface clean, even small bits of dirt will dimple the surface, affecting the optics.
This was my first attempt, but I got some advice from a friend who had done some for advertising work.
After one sample, the rest worked out fine. Project was the side panels for a marble curved staircase.

A

 

[m1nder]

Thanks to everyone for the replies. I actually found a plastic fabrication company near enough to me. Rang them and they say they can do it. Might be just a case of bringing them in oversized rough cuts, getting them to do the bends and them trimming myself......or not, we'll see.

 

[Chiorino]

Thanks to everyone for the replies. I actually found a plastic fabrication company near enough to me. Rang them and they say they can do it. Might be just a case of bringing them in oversized rough cuts, getting them to do the bends and them trimming myself......or not, we'll see.

Hi, I'm hoping to get stuck into one of these in the near future and having had trouble getting windows done in Ireland before was wondering if you'd mind sharing who you are getting to do them and what sort of money they're looking for. Thanks.

 

[m1nder]

Hi, I'm hoping to get stuck into one of these in the near future and having had trouble getting windows done in Ireland before was wondering if you'd mind sharing who you are getting to do them and what sort of money they're looking for. Thanks.

Hi
In the end I decided to DIY the windows, I am currently in progress making moulds. The plastic fabricators are very expensive. It would have cost me €400 for three small windows after spending €500 on the boat.