fibreglass panels from origional metal panels

[Psychosaffa]

i want to pull a set of fibreglass panels from a brand new set of metal panels.
i was going to clean the inside of the metal panel and use it as a female mold, spray it with pva release agent, then a gel coat, fire on some fibreglass mat reinforced with some cevlar in certain areas and pop it out for trimming.

its the rear wings for a double cab pickup, so there are no complex curves.

is there more to it or am i missing something?

 

[the snooper]

if you used the inside of the original panel the new fibreglass panel would be slightly smaller you really need to use the outer

 

[brightspark]

i want to pull a set of fibreglass panels from a brand new set of metal panels.
i was going to clean the inside of the metal panel and use it as a female mold, spray it with pva release agent, then a gel coat, fire on some fibreglass mat reinforced with some cevlar in certain areas and pop it out for trimming.

its the rear wings for a double cab pickup, so there are no complex curves.

is there more to it or am i missing something?

yea it will be smaller . u will have to make a mold from the outside of the original pannel 1st

 

[Wendelspanswick]

As above, normal method is to make a female mold from the outside of the pattern panel and then use this mold to make your GRP panels.

 

[BrokenBiker]

yeah, make mold from the outside, then fibreglass the inside of the mold and you will have a panel that looks the same as the original. Mounting points may be a bit harder

 

[Psychosaffa]

great minds think alike, buuuuuuuuuuuutt.............. the metal panel is only just over 1mm thick and the fibreglass panel will be a bit thicker, if not double the thickness, so surely using the inside of the panel would be better?

 

[the snooper]

doesn't matter how thick the fibreglass is it will still be smaller

 

[brightspark]

great minds think alike, buuuuuuuuuuuutt.............. the metal panel is only just over 1mm thick and the fibreglass panel will be a bit thicker, if not double the thickness, so surely using the inside of the panel would be better?

as long as your happy with a panel that is 1mm smaller all round and not just the face

 

[Psychosaffa]

as long as your happy with a panel that is 1mm smaller all round and not just the face

i may just be happy with it. this is more of a experiment than a final product.
i will ultimately be using the metal panels to make a female mold and then pulling final products from that.

so regarding the original post. would that work? cause it wont be much different than pulling from the purpose made fibreglass mold.

thanks for all the replies peeps, really appreciated.

 

[the snooper]

if you mold from the inside of the panel then the moulded panel will have a rough exterior finish ie finish wise it will be inside out

 

[Psychosaffa]

if you mold from the inside of the panel then the moulded panel will have a rough exterior finish ie finish wise it will be inside out

its a brand new panel that has been E primered, so it is pretty smooth. should the panel first be waxed, polished and then sprayed with pva release agent to get a smooth finish?

 

[BrokenBiker]

it is only the outside dimensions that are critical to it looking the same, so you take the mold from the outside of the panel, then you fibre glass the mold and when you remove the new panel, the exterior will be exactly the same size as the original, but the panel itself will be thicker

 

[hotrodder]

There's also stiffness of the mold to consider. Sheet metal panels don't have much in the way of stiffness until they're mounted i.e. use the inside of the panel as a mold and you'll almost certainly get a very wobbly part out of it as well as one that's too small. It's even possible that the wing will end up unusable for pulling a proper mold afterwoods too due to distortion

 

[711jrp]

Be careful that there aren't any return edges on the inside of the panel or the fiberglass panel won't release.

 

[Wedg1e]

Strictly speaking, GRP shrinks a bit as it cures anyway so getting an exact-sized mould can be difficult. Approx. 2% shrinkage as I recall, according to cloth/ mat size, amount of resin and how well the mat is wetted, local stiffening , corners etc..

 

[500e]

Some carbon & Kevlar ones we made years ago
We used mirror glaze for release
http://www.ebay.co.uk/itm/like/2514...&ff3=1&ff11=ICEP3.0.0&ff12=67&ff13=80&ff14=95

 

[atomant48]

its a brand new panel that has been E primered, so it is pretty smooth. should the panel first be waxed, polished and then sprayed with pva release agent to get a smooth finish?

I think Snooper is right - if you mould from the inside, no matter how smooth the original panel is you will then be making a copy on top of that mould so the "exposed" surface of your part will be rough unless you spend hrs and hrs sanding? That is why it would be better to do it so that the exposed surface goes up against the mould?

 

[Psychosaffa]

I think Snooper is right - if you mould from the inside, no matter how smooth the original panel is you will then be making a copy on top of that mould so the "exposed" surface of your part will be rough unless you spend hrs and hrs sanding? That is why it would be better to do it so that the exposed surface goes up against the mould?

I want to make a one off grp panel from the inside of the original.

Then later use the outside of the original to make a mold And then pull products from that.

But after hotrodders post, I don't want to damage the original panels as they cost over £600, so may just make a decent mold from the start and pull from that.

 

[atomant48]

I want to make a one off grp panel from the inside of the original.

Then later use the outside of the original to make a mold And then pull products from that.

But after hotrodders post, I don't want to damage the original panels as they cost over £600, so may just make a decent mold from the start and pull from that.

Got ya. Makes sense. So you're saving half the process to get a 'prototype'.

 

[the snooper]

this is not going to be as simple as laying matting and pouring resin, the finished fibreglass thickness is going to be thicker in order to get the strength required so some measurements will have to be changed when making a mold to get the same fit