Where to get a custom screen/frame?

[jason61c]

I might want one that goes in between or directly in front of my roll cage and sits at the same angle, so it doesn't look like an afterthought. How do I go about it?

[khm]

glass will be difficult unless it's flat

you can use lexan with a coating from
plastic4performance.com

they make screens for race cars from the stuff

[jason61c]

I could do it flat.

Would it be a case of making a cardboard template of the screen then onto ply, get the glass cut then make the frame around the wooden template?, its the 'bending' of the edges i'd worry about most.

[Sam_68]

You really need to get a grip on the Chapman ethos, if you're building a 'Seven', you know... never use two components when a single component can be made to serve two (or more) functions!

You don't need a separate frame for the screen, when you've already got a fking great huge roll cage with front tubes that can do the same job for you.

Weld a couple of flat bosses to each front leg of the roll cage so that you can drill and tap them. Flat sheet of polycarbonate drilled to match and bolted to the cage using fairing bolts, via rubber grommets to accommodate any slight flexing.

Job's a good 'un.

eta: If you prefer it in laminated glass, any decent architectural glazing company will be able to cut and drill the glass for you.

Edited by Sam_68 on Sunday 17th July 12:08

[jason61c]

Sam_68 said:

You really need to get a grip on the Chapman ethos, if you're building a 'Seven', you know... never use two components when a single component can be made to serve two (or more) functions!

You don't need a separate frame for the screen, when you've already got a fking great huge roll cage with front tubes that can do the same job for you.

Weld a couple of flat bosses to each front leg of the roll cage so that you can drill and tap them. Flat sheet of polycarbonate drilled to match and bolted to the cage using fairing bolts, via rubber grommets to accommodate any slight flexing.

Job's a good 'un.

eta: If you prefer it in laminated glass, any decent architectural glazing company will be able to cut and drill the glass for you.

Edited by Sam_68 on Sunday 17th July 12:08

Good reply! It is the way that I've thought about doing it, however having looked around most seem to still fit a frame/screen so I thought that there might have been a reason for it.

Being able to take it off with ease would be a bonus too.

What sort of thickness do you think will do and does it have to be treated in any way?

[Sam_68]

jason61c said:

What sort of thickness do you think will do and does it have to be treated in any way?

I believe the standard thickness for laminated glass is 6.4mm, but if you're going to do it in glass you may as well make it IVA compliant (for insurance purposes if nothing else), so quote the relevant BS numbers to your supplier and get kitemarked glass.

The problem with polycarbonate (apart from the fact that it's technically not road legal) is that it's nothing like as stiff as glass, so can be prone to drumming or flutter when used flat on an open car windscreen ...you'd need to maximise support around the perimeter (support pads on the top tube of the cage, and maybe some sort of support channel or angle along the bottom edge too). You can get it thinner, but I'd have thought it would be unwise to go below 6mm thickness in polycarb, either, but speak to someone like Airedale Race Plastics for their advice - they've always seemed very knowledgeable when they've done stuff for me in the past. They'll be able to advise on coatings too. I'm told that the coatings greatly increase resistance to scratching and scuffing, but I've no direct experience.

One thing I would say, from experience, is that windscreens on 'Sevens' are usually pretty worthless unless you run them with sidescreens as well... they make top-notch airbrakes to further worsen the already atrocious aerodynamics, they actually increase buffeting and wind noise a lot of the time, and rain whips round onto the inside face (unless you also use a hood, in which case you'll go deaf, the screen will fog up, and you'll need to be a double-jointed midget to get in and out), so they're more or less hopeless in foul weather.

Personally, I'd stick with aeroscreens every time.

[Davi]

Sam_68 said:

You really need to get a grip on the Chapman ethos, if you're building a 'Seven', you know... never use two components when a single component can be made to serve two (or more) functions!

You don't need a separate frame for the screen, when you've already got a fking great huge roll cage with front tubes that can do the same job for you.

Weld a couple of flat bosses to each front leg of the roll cage so that you can drill and tap them. Flat sheet of polycarbonate drilled to match and bolted to the cage using fairing bolts, via rubber grommets to accommodate any slight flexing.

Job's a good 'un.

eta: If you prefer it in laminated glass, any decent architectural glazing company will be able to cut and drill the glass for you.

Edited by Sam_68 on Sunday 17th July 12:08

If you're welding flat bosses in and are going to use glass, don't drill it, just glue it in place! I put a screen in my UVA fugitive with the windscreen bonding gloop - as long as you prime the glass edge with the special black primer, it's no problem at all.