Hello and welcome to the next instalment in this video tutorial series.
In this instalment we're going to be actually making the carbon fibre bonnet itself and
we're going to be showing you the latest techniques for making a medium sized carbon fibre panel
like this and obviously we're using the mould that we made earlier in the series.
The first thing that we've done is prepare the surface of this mould using several application
of Easy Lease chemical release agent which we've done as per the instructions for that
product and now the next thing that we're going to do is an optional step but we're
actually going to spray the surface of this mould using a very special epoxy compatible
polyester gel coat.
Now it's very important at this point that we make it very clear that the GC50 epoxy
compatible polyester gel that we're spraying here is not the same as a normal polyester
gel coat.
Please don't try and use a normal polyester gel with epoxy because it just simply will
not bond and will immediately delaminate.
However one thing it does have in common with a normal polyester gel is the fact that we
catalyse it with a regular MEKP catalyst.
We've mixed the gel up in one of the paper cups that's designed for the cup gun so it's
a case of just putting that cup into the holder and then pressing the lid firmly on and then
we load this into the gun by pulling the spring to hold the cup in place.
Our gel coat spraying cup gun is equipped with a 6ml nozzle which when you're spray
a material a viscous as a gel coat is the ideal choice.
And we're just going to try and gel a smooth even coat over the surface starting and finishing
off the edge of the part to avoid getting any drips on the mould.
We've now allowed this gel coat to cure fully overnight.
Now unlike a conventional polyester gel coat when this cures it cures with a hard finish
and no tack at all and that leaves the perfect bonding finish for the epoxy resin.
The first thing that we're going to do is just wipe around that perimeter of the mould,
clearing any overspray off this flange and that's so we've got a nice clean surface to
stick the bagging tape onto.
We're going to apply the bagging tape all the way around the perimeter of the mould
at this point for convenience really before we put down the bagging consumables itself.
The only other thing that we're going to do before we start is we're just going to look
for any high spots like this on the mould surface which have been caused by a drip off
the gel coat gun and we're just going to flatten those off and that will stop any of those
printing through onto the surface of the reinforcement.
We're going for a laminate of 200 gram carbon, 2mm Lantor Soric and then 2000 gram carbon.
Visually of course the first layer is the most important so we're just being careful
to gently drape this 2.2 twill into the mould.
Often what you want to do is get the carbon to just stick slightly in position and so
what we do is just sprintz a very small amount of acetone onto the carbon and what that does
it just slightly activates the gel coat surface and it means that you can stick the carbon
down onto it.
And once we've done that we just use a pair of shears to cut off the excess material we've
only got to be just inside of the tape line.
And now this is the Lantor Soric which is an infusion core material and we've cut this
just which a pair of scissors about 25mm short of the edge of the bonnet all the way around
and that's just because we don't want the core material exposed at the edge of the panel.
In this close up you can really see and get a good idea of how the Soric core material
feels and behaves.
it's very easy to cut and lay into the mould and then we've got this fine honeycomb structure
around which the resin can flow as an internal core media.
Next we're using some special infusion grade spray tack and just spraying that lightly
over the surface of the reinforcement and then using that to help us position the Soric
squarely and evenly in the middle of the mould which is quite important for us because we
want to maintain an even gap all the way around the edge where the core material ends because
into that we're going to be layering some 200 gram carbon tape.
We're using a 50mm tape here again the infusion spray tack is particularly helpful to allow
us to fix that in place and position it very accurately up against the edge of the soric
we certainly don't want a gap at this point.
We're going to build up 6 layers of the carbon tape so that we've got a match for the thickness
of the Soric.
So you can see we've got this tape nice and neatly butted up against the Soric so we're
just going to add our next layer, final layer of 200 gram carbon cloth all the way over
the surface and then we're just going to trim this just like we did before.
So over the top of this second layer of reinforcement we're just positioning a layer of peel ply
and we're just going hold this in place with a few pieces of the release breaker tape.
The next thing that we want to be thinking about is the infusion mesh in the spiral.
So we're going to position infusion mesh along the front here because we're going to be running
the resin the shortest distance which is from the back of the bonnet to the front of the
bonnet and then we'll also be positioning another strip of the infusion mesh just at
this front edge and that's going to help spread the vacuum.
We're positioning this infusion spiral all the way around this back edge and just holding
it in place with some of the release breaker.
So the final thing to do before we bag this up is to position the resin infusion silicone
connectors.
We've got one at the back here which is the resin feed line so that sits on top of the
spiral.
And then we've got one opposite on the front end of the bonnet which sits on this mesh
and this is the vacuum line so we're just going to tape that in place to stop it moving
down and just pierce through.
We've added some gum tape pleats around the outside of the mould and so we're just sealing
this bag down to the tape.
Now we've got an alternative video dedicated to the vacuum bagging process so we're not
going to go cover it in much detail here but if I just go over what we've got.
We've got the vacuum bag completely sealed to the tool all the way around we've got our
pleats in place ensuring that we've got plenty of bag, plenty of slack on the bag.
At the top of the bonnet here we've got the vacuum line connected to the catch pot and
the catch pot connected to the composites vacuum pump.
And then where we've got the resin feed line at the back of the bonnet this is just clamped
off so what we're going to do is just switch the vacuum pump on and pull a vacuum on this.
Finally before we an infuse we're just going to clamp off this bag and do a vacuum drop
test which is absolutely essential before we can do the infusion.
We've come back to this part now a couple of hours later and we've performed the vacuum
drop test and that's shown us that there has been absolutely no pressure drop in this bag
whatsoever and so that's the point where we can continue.
When you're calculating the amount of resin that an infusion project is going to use of
course you do need to make sure that you allow for the Soric and also the vacuum bagging
consumables we've actually got a handy calculator on the Easy Composites website that will allow
you to do this.
Now you'll see us do this again later but what we're doing here is just mixing a 50/50
blend of the fast and the slow hardener which are available for the IN2 infusion resin.
And the reason we do that is this gives us a medium speed hardener which is perfect for
an infusion of this size.
it's very important to thoroughly mix the resin with its hardener trying to do so without
aerating the resin while we do it but any unmixed resin will fail cure in the part.
So we've allowed the resin just to degas just for a few minutes to get any large air bubbles
out so what we're going to do is release the clamp from the vacuum line from when we did
the drop test.
We're going to turn on the vacuum pump open the vacuum pump supply and then we're just
going to draw the first amount of resin up to this clamp just to remove any air that
it's at this point.
We're just using on of the spare clamps to hold the line on the side of the resin container
and then we just gently unclamp the resin line into the part.
You can see how quickly the resin follows the line of the feed spiral giving it a very
even advance across the part.
So you can see how effective the soric is as internal flow media because this line here
of the resin advancing through the part is not being hindered by the fact that the infusion
mesh it actually stopped at this point and this is still, progressing through the laminate
nicely.
As you can see the resin has now reached the silicone connector on the other side of the
part and the resin is actually starting to be drawn down the vacuum line so what we're
going to do is just let this carry on being drawn just for a couple of minutes and that's
actually extracting some of this aerated resin and then we're going to clamp off the resin
line.
With both of these lines clamped of now we're okay to turn off the vacuum pump and we're
going to leave this part to fully cure.
Now the hardener speed that we've chosen and the ambient temperature that's going to take
about 24 hours.
With this part now completely cured off you can here the resin is absolutely solid it's
now time to remove all of the bagging consumables from the mould so we're now going to start
with the bag itself.
Just removing the peel ply from the back of this laminate has actually started to pre
release it from the mould already so we know we're not going to have any trouble releasing
it and that really is the sign of a good chemical release agent.
So we're just going to get in and tease it up and it's out of the mould already.
With this part out of the mould you can really see all of this hard work has paid off.
We've got a fantastic mirror gloss over the surface of the bonnet from that clear gel
coat we've used.
There's no pinholes whatsoever, there's no bubbles, there's no air inclusions so you've
got to be pretty pleased with that at this stage.
Moving on now to the inner skin moulding we're actually going to be using just two layers
of reinforcement on this which is going to be a 200 gram and a 600 gram because we want
this to be as light as possible, although we're going to have additional reinforcement
in the critical areas, which is where the hinges are and also the catch mechanism at
the top.
This mould has been prepared with several application of Easy-Lease chemical release
agent just like we've done in previous sections and so we'll just be laying the reinforcement
directly onto that.
So the 200 gram cloth is the first one down onto the mould because obviously this has
the flatter finish.
We're going to use some spray tack just on the surface of the mould and this will help
us to position the carbon now it will leave slight imperfections on the surface of the
part but that doesn't matter for the underside moulding that we're working on here.
The next step is to put our second layer of reinforcement down.
So in this case we're using the 660 gram cloth.
Now the reason for doing that is that this will actually give us about 0.6 nearly 0.7
mm thickness of reinforcement but we can do it in a single layer which is not only quicker
to put down but it's also considerably cheaper than three or more layers of a 200 gram cloth.
Another light application of the spray tack will just help to position this heavier 660
gram cloth.
With both layers of reinforcement down now we're just going to trim away the excess reinforcement.
With all of our reinforcement in place we'll just now go on with a standard infusion vacuum
bagging stack which will be peel ply, then the mesh and then the bag itself.
We're just going to cut the mesh approximately to the right size and then we're just going
to hold it loosely in place and we're just going to take some of the vacuum bagging tape
all the way around the edge of the flange.
As before we're just going to add a few pleats made out of the bagging tape and position
these around the edges.
The next thing we've done is position the infusion spiral around the edge and we've
also gone down the sides as well in exactly the same pattern that we did for the top skin.
So we're just going to position the infusion silicone connector on top of the spiral here
and then we've got the other infusion connector ready to go at the front and so on now with
the bagging film itself which we're going to tape down onto these pleats.
So we're going to switch on the vacuum pump start to pull the bag down and position the
bag as it goes down.
Now clearly we've sped up time quite a bit in this shot but this really is a very important
part of the resin infusion process and for that reason if you want to learn more about
how to get the bag down properly then please check our resin infusion video and our video
dedicated to vacuum bagging.
We've completed the drop test now on this bag so we're 100 percent confident now that
there's no leak whatsoever so it's now time to do the infusion itself.
So as before we're going to be using an epoxy infusion resin and for this infusion because
it's going to be taking place relatively quickly a combination of the fast and the slow hardener
together.
With the resin thoroughly mixed now and settled it's time to start the infusion.
Start the vacuum.
As you can see the resin has now reached the other side of the infusion project so it's
time to clamp off the feed line and we can now clamp off the resin line.
So we can now turn off the vacuum pump and leave this to cure overnight or as long as
it takes depending on the hardness speed that we've used.
We've now left this part to fully cure so now it's time to strip off all of the vacuum
bagging consumables just like normal.
with everything stripped off now we'll just remove the part from the mould.
And that is our inner moulding.
Now that we've got the mould out of the way we can have a nice look at this part itself.
It really is incredibly strong and light and all of the detail that we've got on the underside
of the moulding of course has been faithfully reproduced in this inner skin so this is going
to make a fantastic inside for our bonnet.
We've now made both the outside skin and the inside skin for our carbon fibre and so that
concludes this part of the video tutorial.
In the final part we'll be looking at trimming both of these components, fixing the fittings
inside and then bonding them together and finishing it to complete the part.