Aluminium or Fibre Reinforced Plastic (FRP) as outer skin in a composite panel?

[Peter_n_Margaret]

there are none is the US for sale.

As far as I know there are none in the US at all.
2 or 3 in Europe, several in Africa, couple in South America, several in New Guinea, 400+ in Australia.
Cheers,
Peter
OKA196 motorhome

 

[opp]

A bit on foam hold down .From what we have done. We make are own skins want the woven glass. Most glass skins here in the states is gel-coat and mat very weak .That why it can be rolled up and heavy .Back to the foam we add holes on a angle . That helps locks up and down and side ways movement

 

[ITTOG]

Absolutely FRP skins (both sides), and no frame at all.
The aluminium skin will be subject to minor damage from the mildest mis-treatment and that damage is virtually un-repairable. FRP skin, on the other hand, is as tough as old boots and in the unlikely event of damage it can be repaired.
I would prefer to use closed cell polyurethane foam in preference to styrene. It has much better thermal insulation properties and probably better crush resistance too.
Cheers,
Peter
OKA196 motorhome

What do you use to repair FRP? I did some quick searching on this in the past and it looks like you cannot glass it.

 

[rruff]

What do you use to repair FRP? I did some quick searching on this in the past and it looks like you cannot glass it.

Maybe because of the gelcoat finish. But if you grind that off and resin/glass to the fiber layer, I don't know why that wouldn't work.

 

[ITTOG]

Maybe because of the gelcoat finish. But if you grind that off and resin/glass to the fiber layer, I don't know why that wouldn't work.

From what I remember a gel coat wasn't even mentioned. My take was that the plastic amount is so much higher than glass in an FRP panel that you wouldn't be able to get a repair to stick to the plastic.

 

[opp]

we use frp to make are fiberglass skins it flat so it makes great tooling . poly resin and gel wont stick

 

[rruff]

From what I remember a gel coat wasn't even mentioned. My take was that the plastic amount is so much higher than glass in an FRP panel that you wouldn't be able to get a repair to stick to the plastic.

Isn't the "plastic" polyester resin or epoxy? I'm talking about the skins made for camper construction, not the Home Depot stuff.

 

[ITTOG]

I don't know the camper industry but I do know the plastic industry and it is not resin or epoxy or anywhere close to it.

 

[ITTOG]

Isn't the "plastic" polyester resin or epoxy? I'm talking about the skins made for camper construction, not the Home Depot stuff.

If it is polyester or epoxy then patches would be easy.

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[rruff]

If it is polyester or epoxy then patches would be easy.

This is what Terra Ops used in his build. On that page (or on the website that I saw) they don't say what resin was used. https://www.vetroresina.com/en/p/22/mat-and-woven-roving-FRP-panels.html

However, gelcoat is polyester resin with pigment. So I'm pretty sure polyester resin is used in the matrix.

 

[Peter_n_Margaret]

Gel coat on polyester resin repairs?
Ask any boat repairer or any sailplane repairer.
But the skin is incredibly tough and you must be very unlucky to need a repair (speaking from 16 years experience with ours in the bush).
Cheers,
Peter
OKA196 motorhome

 

[high-and-dry]

This is what Terra Ops used in his build. On that page (or on the website that I saw) they don't say what resin was used. https://www.vetroresina.com/en/p/22/mat-and-woven-roving-FRP-panels.html

However, gelcoat is polyester resin with pigment. So I'm pretty sure polyester resin is used in the matrix.

Thats the same stuff sawtooth ultimate and I used. I have some extra, about 75' x 8.5 feet if any one want to buy it cheap.

Gelcoat is polyester resin with some color and a filler to make it thicker. It also normally has an additive that wont let it cure 100% when exposed to air. That way they can put the gelcoat in the mold, let it cure except the surface thats exposed to air, then they lay the glass and more polyester resin. This allows the glass/resin to chemically bond/mix with the gelcoat.

Also polyester resin does not like to bond very well to cured polyester, thats why epoxy is used for repairs.

 

[ITTOG]

Thats the same stuff sawtooth ultimate and I used. I have some extra, about 75' x 8.5 feet if any one want to buy it cheap.

Gelcoat is polyester resin with some color and a filler to make it thicker. It also normally has an additive that wont let it cure 100% when exposed to air. That way they can put the gelcoat in the mold, let it cure except the surface thats exposed to air, then they lay the glass and more polyester resin. This allows the glass/resin to chemically bond/mix with the gelcoat.

Also polyester resin does not like to bond very well to cured polyester, thats why epoxy is used for repairs.

So the P in FRP isn't really true? Sounds like there is no plastic.

I may be interested in the roll. Give me a price and where you would be shipping from.

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[rruff]

So the P in FRP isn't really true? Sounds like there is no plastic.

Fibre-reinforced plastic (FRP) (also called fiber-reinforced polymer, or fiber-reinforced plastic) is a composite material made of a polymer matrix reinforced with fibres. The fibres are usually glass (in fibreglass), carbon (in carbon fiber reinforced polymer), aramid, or basalt. Rarely, other fibres such as paper, wood, or asbestos have been used. The polymer is usually an epoxy, vinyl ester, or polyester thermosetting plastic, though phenol formaldehyde resins are still in use.

FRPs are commonly used in the aerospace, automotive, marine, and construction industries. They are commonly found in ballistic armor and cylinders for Self-contained breathing apparatuses as well.

 

[high-and-dry]

As ruff said. frp can be many things. Plastic, polyester, epoxy lots of binders are covered under it. When its plastics its normally extruded and pressed, so there is no real gelcoat type surface.