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VIDEO TUTORIAL

USED IN THIS PROJECT

Although not necessarily an exhaustive list, the following tools and materials, supplied by Easy Composites, were used in this project.

The quantity shown below is the approximate amount used in the project rounded up to the nearest available kit size or quantity.

TOOLS & EQUIPMENT
EC.4 Compact Composites Vacuum Pump + UK Lead Thumbnail
VP-EC4-UKEC.4 Compact Composites Vacuum Pump + UK Lead£249.95 /each

OV301 Precision Composites Curing Oven Thumbnail
OVEN301OV301 Precision Composites Curing Oven£1749.00 /each

Total £0.00
MATERIALS & CONSUMABLES
ST150 Vacuum Bagging Sealant Tape 15m Each Thumbnail
VBST150ST150 Vacuum Bagging Sealant Tape 15m Each£5.50 /roll

R120 P3 Perforated Release Film (1500mm) 5m Folded Pack Thumbnail
AFR120-P3-150-5PKR120 P3 Perforated Release Film (1500mm) 5m Folded Pack£4.75 /pack

BR180 140g Breather Cloth (1520mm) 5m Folded Pack Thumbnail
AFBR180-152-5PKBR180 140g Breather Cloth (1520mm) 5m Folded Pack£9.75 /pack

XT135/B 415g 12k Tooling Prepreg Carbon (1250mm) 1m Roll Thumbnail
XT135B-C1212T2-415(1250)-1XT135/B 415g 12k Tooling Prepreg Carbon (1250mm) 1m Roll£92.90 /roll

XT135/S 250g 3k Tooling Prepreg Carbon (1250mm) 1m Roll Thumbnail
XT135S-C311T2-250(1250)-1XT135/S 250g 3k Tooling Prepreg Carbon (1250mm) 1m Roll£87.60 /roll

Total £0.00

VIDEO TUTORIAL

How to Make Prepreg Carbon Fibre Moulds Using Tooling Prepreg

In this video tutorial we demonstrate how to use our XT135 Carbon Fibre Tooling Prepreg to create highly accurate and temperature stable composite prepreg moulds ideal for then using in the production of prepreg carbon fibre parts.

The pattern we use to create the mould from was a CNC machined block of our EB700 epoxy tooling board which had been sealed with S120 tooling board sealer and then prepared with several applications of Easy-Lease chemical release agent. For full details on how we machined and prepared the pattern, see the preceding tutorial video in the series; Precision Patterns and Moulds from 3D CAD by CNC Machining Epoxy Tooling Board.

Being a small mould, we decided to laminate it using only 3 plies in total; one layer of XT135 Tooling Prepreg Surface Ply and two layers of XT135 Tooling Prepreg Backing Ply. For larger moulds or where more rigidity is required, a total of 4 backing plies is recommended.


INTRODUCTION

Introduction

Introduction

XT135 is a specialist tooling prepreg system designed to produce dimensionally accurate carbon fibre composite moulds using vacuum bag and oven cure only (out-of-autoclave). To achieve the highest possible quality of mould-tool, XPREG® XT135 needs to be processed correctly. The key areas of importance being the pattern surface compatibility, the layup and bagging procedure and the cure and post-cure cycles.

Prepare pattern

Prepare pattern

Fully Compatible Pattern Materials

XPREG XT135 tooling prepregs are suitable for use with chemically compatible pattern/tooling materials with a suitable service temperature; these include:

  • Epoxy tooling board such as the Easy Composites EP700
  • Epoxy resin surfaces such as gel-coat or prepreg components
  • Aluminium/steel
  • Glass platens

NOT Compatible Materials

XPREG® XT135 is NOT suitable for use with the following tooling materials due to either service temperature or chemical compatibility constraints:

  • Polyester pattern surfaces, such as those used for traditional ‘fibreglass/GRP’ moulds
  • Polyurethane model/tooling board (due to cure inhibition of epoxies by polyurethane at elevated temperature)

All patterns should be post-cured (if required) before use to ensure that their full service temperature is realised. If in doubt of the compatibility of any mould material, we would strongly advise conducting a test prior to component manufacture.

Release Agent

We recommend the use of chemical release agent, particularly Easy-Lease™ Chemical Release Agent which has proven to be perfectly reliable when used with XPREG® XT135 compatible mould surfaces. The release agent should be designed for use at elevated temperatures and compatible with both epoxy prepregs and the pattern surface.

Traditional mould release waxes or PVA will not provide a release for prepregs and should NOT be used. If in doubt, conduct a trial to test for suitability. Porous pattern surfaces such as epoxy model board should be sealed using S120 Advanced Board & Mould Sealer or similar prior to release agent application.

New mould surfaces should have at least 6 applications of Easy-Lease™ prior to layup, please refer to application guidelines for further information. 1 further application is recommended between every component release, especially for complex components.


TUTORIAL BREAKDOWN

Making the templates

1. Making the templates

Templates help you to cut the pre-preg to shape without waste. A simple method to make the templates is to apply masking tape over the surfaces of the mould and then transfer that to the pre-preg. Using a marker pen you can draw around the templates giving you precise cut lines for the pre-preg itself.
Laminating

2. Laminating

Laminating should be conducted in a clean and dry working environment at 17-20°C this temperature range provides the optimum tack level and workability for the material.

XPREG® XT135 comprises of a surface ply (XT135/S) and backing plies (XT135/B) the surface ply can be identified by the combination of red and blue protective film and has a fine glass fibre scrim on one side. The backing material has a blue film and white paper combination and has one very resin-rich side (black/tacky) and one fairly dry carbon fibre side.

The surface ply should be laid glass scrim (blue film) side down against the face of the pattern, subsequent backing plies can then be laid resin-rich side down up to four layers, in smaller tools 2 backing plies is usually sufficient to produce adequately stiff moulds.

Debulking

3. Debulking

Debulking will help to improve consolidation and therefore reduce the likelihood of voids therefore we recommend a standard debulk procedure on the surface ply and after the second backing ply when more than 2 backing plies are be laminated ; Apply P3 perforated release film followed by a breather cloth, vacuum bag and hold at full vacuum for 20mins, remove vacuum bagging stack and proceed with subsequent plies of XPREG® XT135.

Vacuum bag

4. Vacuum bag

Release Film

A P3 perforated release film with suitable service temperature should be applied onto the entire open surface of the prepreg, care should be taken to ensure an intimate contact without bridging is achieved. If required, the loose film around the perimeter of the part can be occasionally secured in place using flash/release tape.

Breather

Breather should then be draped over the perforated release film over the entire area of the laminate and underneath the through-bag connector in such a way as to ensure an air path from the connector to the laminate surface.

If multiple moulds are being cured in the same bag then breather should be used between each laminate to ensure a continuous air path between them.

Vacuum Draw-down

The vacuum bag can then be applied and vacuum should be drawn gradually, taking time to position and reposition the bag as air is removed.

It is essential to the quality of the end result that during the pull-down the bag should be adjusted and positioned such that it does not bridge or stretch anywhere on the component’s surface. This is a critical step to ensure proper consolidation of the laminate. Air may need to be re-introduced to allow repositioning if bridged or stretched areas are identified.

Hand tools (sometimes referred to as ‘dobbers’) should be used to to push the vacuum bag firmly into the inside of tight corners or details. After correct layup, consolidation and bagging, it should be impossible to feel any ‘bridging’ or movement when pressing a suitably shaped hand tool into corners or details of the moulding. Towards the end of the bagging process, if there is any doubt over whether the vacuum bag is sufficiently large to to avoid bridging then the bag should be abandoned and a new larger bag made.

Initial cure cycle

5. Initial cure cycle

This initial cure cycle is recommended in all tooling applications this low temperature cure on the pattern ensures optimal dimensional accuracy and exceptionally low void content. This should be conducted for a minimum of 16hrs, increasing the soak time from 16hrs to upto 48hrs can reduce the effects of surface print-through.

High temperature post cure

6. High temperature post cure

The post cure cycle is required to achieve the full service temperature of the mould. A slow and controlled ramp is essential to ensure best surface finish and dimensional stability. The post cure should be conducted free-standing (off the pattern) for large mould structures it may be advantageous to support the mould during post-cure to minimise the risk of warping.


DISCUSSION (22)

Please share any questions or comments you may have about this video tutorial.


Philipp
Is it possible to use PU board for epoxy prepreg patterns, if the board is sealed properly with S120?
Easy CompositesMatt
No, unfortunately not. Although it would be totally reasonable to expect that S120 would create an impervious barrier between the PU and the epoxy, thus avoiding the problem of hot PU board inhibiting the cure of the epoxy, our experience (and testing) found that the cure inhibition still occurred unfortunately, therefore, PU board's can't be used with epoxy prepregs, even if they are treated with S120.

Philipp
Is it possible to use PU board for epoxy prepreg patterns, if the board is sealed properly with S120?
Easy CompositesMatt
No, unfortunately not. Although it would be totally reasonable to expect that S120 would create an impervious barrier between the PU and the epoxy, thus avoiding the problem of hot PU board inhibiting the cure of the epoxy, our experience (and testing) found that the cure inhibition still occurred unfortunately, therefore, PU board's can't be used with epoxy prepregs, even if they are treated with S120.

Sagar Thapa
HOW DOES THE DEPTH WORK? How do you determine how THICK is it going to be from the inside? If I am making handlebars, and I want them to be of certain thickness, do I just keep layering them up?
Easy CompositesMatt
Yes, that's exactly what you do. Each type of reinforcement has a natural thickness when it's vacuum bagged. We call this its consolidated thickness. With carbon fibre, there's a really simple rule of thumb which works very accurately. In short, you can divide the weight (in gsm) of a carbon fabric by 1000 and that will be its consolidated thickness in millimetres. So, a 200g carbon cloth will be 0.2mm thick, a 450g cloth will be 0.45mm thick. Then, just add up the number of plies (and ply weights) to achieve the thickness you need.

Sy Tran
No gelcoat needed?
Easy CompositesMatt
Correct, no gelcoat needed. The special surface ply actually has a filled resin-rich layer which works like a gelcoat and provides the gloss black surface you can see on the finished mould.

Royal REvue
Is there a way to soften the prepreg resin ?
Easy CompositesMatt
You can gently apply a small amount of heat using a heat gun which will slightly soften the pre-preg and make it more tacky.

G Andersson
Would it not be easier to conk cut the negative mold right away?
Easy CompositesMatt
We did discuss this (and show it) in the preceding video where we explained that it is possible to CNC machine the female mould directly from epoxy block however such a mould would have a much higher CTE and really only be durable enough for prototypes and small runs. By taking the mould off the pattern at low temperature (when the pattern won't expand much) and then post-curing the mould off the pattern at high temperature you can produce a highly accurate, very low CTE mould and use it at up to 135°C (in the case of the XPREG XT135 system).

Israel Burkett
Is there a software that can take a cad file and plot a template for a CNC drag knife?
Easy CompositesMatt
Yes, there are lots of ways that you can export surface templates out of your CAD software. It can be quite an involved process where there is drape, overlaps and fibre orientation to consider but it's certainly possible (and very often done for volume production).

Greg Reynolds
Do you have to let the whole roll defrost or can you just cut a section you need? Great vid!
Easy CompositesMatt
You have to thaw the whole roll before you can take it out of the sealed bag, otherwise you can get condensation forming on the roll which could contaminate the prepreg. Once it's thawed, it's common to cut off a length to make a shorter roll to work from. You then re-freeze the larger roll and work from the smaller one. The out-life is 4 weeks at room temperature so it's very practical to work this way and you have the confidence that when you go back to the larger roll you know you're working from fresh material that has most of its out-life left.

Wyn Lewis
How about making a split mould? Use polypropylene as barriers the sane as I would with Uni-Mould?
Easy CompositesMatt
Hey Wyn, hmmm, not really. When you're making a prepreg mould like this you really need the pattern to be a sturdy thing - you'll be laminating quite hard against it and also vacuum bagging against it and so temporary barriers (with filleting wax etc) are not really an option. If you're making a split mould and you're starting from a CNC machined pattern then of course you can design and machine the mould to include the flanges already but if you are starting from and original part and need to add temporary barriers to make your splits then your options are to either take a quick 'splash mould' off the part and barriers and then use the splash mould to make a splash part (which would now include the flanges) which you could then use to take the prepreg mould off - or you could use our EG160/EMP160/EL160 high temperature epoxy tooling system instead.

goober
Are all the bagging materials recyclable? there seems a lot of waste materials in carbon fibre production!
Easy CompositesMatt
It's possible to recycle some or most of the bagging materials although often they're not. The bag in particularly is generally discarded because of the risk of it having been punctured at some point during the demould or handling. The argument in defence of the waste in production would be that that lighter components increase efficiency during the life of the part that more than offsets the greater environmental impact of their production. Certainly this is very true in examples light aircraft components where saving 1kg on an aircraft door for example will save a huge amount of fuel and therefore pollution over the life of the aircraft.

Martin
If I want to make a motorcycle fairing, can I lay this over the original part? And will it mark the original part?
Easy CompositesMatt
The fairing and any flanges you add to it would need to be suitable for the temperature for the initial cure portion of the mould curing cycle which is 65°C for it to survive the mould making process.

Tengiz Adamashvili
With XPREG® XC110 would it be possible to make something as strong and reliable as a wheel rim 'out of autoclave'?
Easy CompositesMatt
For the most critical structural applications, such as a supercar wheel, it would be recommended to use an autoclave because this will ensure minimum void content however with proper technique (including debulks every few layers) then it would be possible to use an out-of-autoclave process (i.e. the XC110 system). It's worth pointing out that the XC110 does have a slightly lower Tg (110°C vs 130°C of the XC130 system).

HeartOfGermany
Why make a mold out of expensive carbon fibre, why not just fibreglass? For a mold I would think fibreglass would be sufficient.
Easy CompositesMatt
These moulds are made from tooling pre-pregs using carbon fibre for durability and especially the low Co-efficient of thermal expansion offered by using a carbon fibre matrix which will match the parts likely to be made in it. This reduces the chance of warping and distortion during the cure process.

Oscar Cuchilo
Is there any reason to make the mould from the part instead of machining the mould? It could have saved the step of fabricating the mould.
Easy CompositesMatt
Moulds machined from the model board can be used but generally do not have the same durability and lifespan as a properly made mould.

acidrain55
What is the life expectancy of that mould with that process making those parts 50 parts? and if it was a vacuum forming mould better or worse?
Easy CompositesMatt
Depends on the cure cycle, how hard it is to demould etc but a good quality mould could well last hundreds of pulls with a little care and maintenance.

chris h
Could this be laminated and made into a replacement bow on an old crossbow? I have an old one that isn't sold anymore and parts are hard to find.
Easy CompositesMatt
In theory yes, although you would need careful consideration of the actual lay up of the part to match the original.

JimmeeAnimALL
Awesome stuff <3 . Lets say one is totally quality freak , and one spotted some imperfections on the mold surface. Can it be sanded / processed before further casting ?
Easy CompositesMatt
Minor imperfections can be lightly sanded and polished out if necessary.

Tengiz Adamashvili
It feels wrong to put masking tape over release agent. Needs to be the other way around. Finish with masks and only apply release agent when everything is ready for laying
Easy CompositesMatt
Well, it might feel wrong to you but we would suggest this is the correct way to do it. Masking tape doesn't stick to the release agent surface at all, it removes with no trace whatsoever and - as you can see in the video - the mould will fall off the pattern just fine. If you put the masking tape onto the pattern before you've applied release agent then it will stick and will leave traces of the adhesive on the pattern which could contaminate the release agent when you apply it. That said, each to his own!

Tim Bradley
Did anyone catch how long was the initial low temperature cure and then the high temperature post cure, and what was the temperature curve for the high temperature post cure?
Easy CompositesMatt
I would recommend you read the full processing guide for the XPREG XT135 Tooling Pre-preg system as it details all stages of the cure and post cure including graphs and tables to help you program your PID oven controller. You can download the guide from the XT135 product page.

Faruk Basar
Can I start the first layer with backing ply without using surface ply? does the release agent still do the job? I d like to make a pipe with large diameter by using an aluminium pipe.
Easy CompositesMatt
The surface ply is specially formulated with the extra resin needed to give a good quality mould surface finish so you can't really just use the backing ply.

BeyerT1
Why not just print out sections that you need to cut? I mean, you do have a CAD model of the green pattern I assume, just unwrap faces and print them out and then use that to precisely cut the carbon fiber pieces.
Easy CompositesMatt
Yes, you could do this. To do it right it's slightly more complicated than a simple 'unwrap' because of the way that a woven fabric will distort and conform. There is a plug-in for Fusion360 which understands the complex way in which woven fabrics 'drape' and so can do all the distortion compensation. For a small, simple mould like we made in this video it's much quicker to just do what we did here rather than do the unwrap modelling and then set up with a drag knife on a CNC machine but for larger or more complex moulds it can become worthwhile.

Tengiz Adamashvili
Which of your prepreg carbon fibers is most suitable for the manufacture of carbon fibre wheels, like those produced for the Koenigsegg. In his YouTube video Christian mentioned that their prepreg is made of a special mix of resins that will withstand high temperatures. Thank you.
Easy CompositesMatt
XPREG®XC130 is our autoclave-cure toughened epoxy prepreg that would be suitable for applications like the wheels you linked to. Generally a wheel would not be a specifically high temperature application. There will be radiated heat from the brake discs but there is also plenty of cooling from airflow so I would not generally think that they would need to have a particularly high Tg resin system. The standard XC130 prepregs all use 'high strength' fibre and are at the higher end of the performance spectrum for conventional carbon fibre prepregs.

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USED IN THIS PROJECT

Although not necessarily an exhaustive list, the following tools and materials, supplied by Easy Composites, were used in this project.

The quantity shown below is the approximate amount used in the project rounded up to the nearest available kit size or quantity.

TOOLS & EQUIPMENT
EC.4 Compact Composites Vacuum Pump + UK Lead Thumbnail
VP-EC4-UKEC.4 Compact Composites Vacuum Pump + UK Lead£249.95 /each

OV301 Precision Composites Curing Oven Thumbnail
OVEN301OV301 Precision Composites Curing Oven£1749.00 /each

Total £0.00
MATERIALS & CONSUMABLES
ST150 Vacuum Bagging Sealant Tape 15m Each Thumbnail
VBST150ST150 Vacuum Bagging Sealant Tape 15m Each£5.50 /roll

R120 P3 Perforated Release Film (1500mm) 5m Folded Pack Thumbnail
AFR120-P3-150-5PKR120 P3 Perforated Release Film (1500mm) 5m Folded Pack£4.75 /pack

BR180 140g Breather Cloth (1520mm) 5m Folded Pack Thumbnail
AFBR180-152-5PKBR180 140g Breather Cloth (1520mm) 5m Folded Pack£9.75 /pack

XT135/B 415g 12k Tooling Prepreg Carbon (1250mm) 1m Roll Thumbnail
XT135B-C1212T2-415(1250)-1XT135/B 415g 12k Tooling Prepreg Carbon (1250mm) 1m Roll£92.90 /roll

XT135/S 250g 3k Tooling Prepreg Carbon (1250mm) 1m Roll Thumbnail
XT135S-C311T2-250(1250)-1XT135/S 250g 3k Tooling Prepreg Carbon (1250mm) 1m Roll£87.60 /roll

Total £0.00

DISCUSSION (22)

Please share any questions or comments you may have about this video tutorial.


Philipp
Is it possible to use PU board for epoxy prepreg patterns, if the board is sealed properly with S120?
Easy CompositesMatt
No, unfortunately not. Although it would be totally reasonable to expect that S120 would create an impervious barrier between the PU and the epoxy, thus avoiding the problem of hot PU board inhibiting the cure of the epoxy, our experience (and testing) found that the cure inhibition still occurred unfortunately, therefore, PU board's can't be used with epoxy prepregs, even if they are treated with S120.

Philipp
Is it possible to use PU board for epoxy prepreg patterns, if the board is sealed properly with S120?
Easy CompositesMatt
No, unfortunately not. Although it would be totally reasonable to expect that S120 would create an impervious barrier between the PU and the epoxy, thus avoiding the problem of hot PU board inhibiting the cure of the epoxy, our experience (and testing) found that the cure inhibition still occurred unfortunately, therefore, PU board's can't be used with epoxy prepregs, even if they are treated with S120.

Sagar Thapa
HOW DOES THE DEPTH WORK? How do you determine how THICK is it going to be from the inside? If I am making handlebars, and I want them to be of certain thickness, do I just keep layering them up?
Easy CompositesMatt
Yes, that's exactly what you do. Each type of reinforcement has a natural thickness when it's vacuum bagged. We call this its consolidated thickness. With carbon fibre, there's a really simple rule of thumb which works very accurately. In short, you can divide the weight (in gsm) of a carbon fabric by 1000 and that will be its consolidated thickness in millimetres. So, a 200g carbon cloth will be 0.2mm thick, a 450g cloth will be 0.45mm thick. Then, just add up the number of plies (and ply weights) to achieve the thickness you need.

Sy Tran
No gelcoat needed?
Easy CompositesMatt
Correct, no gelcoat needed. The special surface ply actually has a filled resin-rich layer which works like a gelcoat and provides the gloss black surface you can see on the finished mould.

Royal REvue
Is there a way to soften the prepreg resin ?
Easy CompositesMatt
You can gently apply a small amount of heat using a heat gun which will slightly soften the pre-preg and make it more tacky.

G Andersson
Would it not be easier to conk cut the negative mold right away?
Easy CompositesMatt
We did discuss this (and show it) in the preceding video where we explained that it is possible to CNC machine the female mould directly from epoxy block however such a mould would have a much higher CTE and really only be durable enough for prototypes and small runs. By taking the mould off the pattern at low temperature (when the pattern won't expand much) and then post-curing the mould off the pattern at high temperature you can produce a highly accurate, very low CTE mould and use it at up to 135°C (in the case of the XPREG XT135 system).

Israel Burkett
Is there a software that can take a cad file and plot a template for a CNC drag knife?
Easy CompositesMatt
Yes, there are lots of ways that you can export surface templates out of your CAD software. It can be quite an involved process where there is drape, overlaps and fibre orientation to consider but it's certainly possible (and very often done for volume production).

Greg Reynolds
Do you have to let the whole roll defrost or can you just cut a section you need? Great vid!
Easy CompositesMatt
You have to thaw the whole roll before you can take it out of the sealed bag, otherwise you can get condensation forming on the roll which could contaminate the prepreg. Once it's thawed, it's common to cut off a length to make a shorter roll to work from. You then re-freeze the larger roll and work from the smaller one. The out-life is 4 weeks at room temperature so it's very practical to work this way and you have the confidence that when you go back to the larger roll you know you're working from fresh material that has most of its out-life left.

Wyn Lewis
How about making a split mould? Use polypropylene as barriers the sane as I would with Uni-Mould?
Easy CompositesMatt
Hey Wyn, hmmm, not really. When you're making a prepreg mould like this you really need the pattern to be a sturdy thing - you'll be laminating quite hard against it and also vacuum bagging against it and so temporary barriers (with filleting wax etc) are not really an option. If you're making a split mould and you're starting from a CNC machined pattern then of course you can design and machine the mould to include the flanges already but if you are starting from and original part and need to add temporary barriers to make your splits then your options are to either take a quick 'splash mould' off the part and barriers and then use the splash mould to make a splash part (which would now include the flanges) which you could then use to take the prepreg mould off - or you could use our EG160/EMP160/EL160 high temperature epoxy tooling system instead.

goober
Are all the bagging materials recyclable? there seems a lot of waste materials in carbon fibre production!
Easy CompositesMatt
It's possible to recycle some or most of the bagging materials although often they're not. The bag in particularly is generally discarded because of the risk of it having been punctured at some point during the demould or handling. The argument in defence of the waste in production would be that that lighter components increase efficiency during the life of the part that more than offsets the greater environmental impact of their production. Certainly this is very true in examples light aircraft components where saving 1kg on an aircraft door for example will save a huge amount of fuel and therefore pollution over the life of the aircraft.

Martin
If I want to make a motorcycle fairing, can I lay this over the original part? And will it mark the original part?
Easy CompositesMatt
The fairing and any flanges you add to it would need to be suitable for the temperature for the initial cure portion of the mould curing cycle which is 65°C for it to survive the mould making process.

Tengiz Adamashvili
With XPREG® XC110 would it be possible to make something as strong and reliable as a wheel rim 'out of autoclave'?
Easy CompositesMatt
For the most critical structural applications, such as a supercar wheel, it would be recommended to use an autoclave because this will ensure minimum void content however with proper technique (including debulks every few layers) then it would be possible to use an out-of-autoclave process (i.e. the XC110 system). It's worth pointing out that the XC110 does have a slightly lower Tg (110°C vs 130°C of the XC130 system).

HeartOfGermany
Why make a mold out of expensive carbon fibre, why not just fibreglass? For a mold I would think fibreglass would be sufficient.
Easy CompositesMatt
These moulds are made from tooling pre-pregs using carbon fibre for durability and especially the low Co-efficient of thermal expansion offered by using a carbon fibre matrix which will match the parts likely to be made in it. This reduces the chance of warping and distortion during the cure process.

Oscar Cuchilo
Is there any reason to make the mould from the part instead of machining the mould? It could have saved the step of fabricating the mould.
Easy CompositesMatt
Moulds machined from the model board can be used but generally do not have the same durability and lifespan as a properly made mould.

acidrain55
What is the life expectancy of that mould with that process making those parts 50 parts? and if it was a vacuum forming mould better or worse?
Easy CompositesMatt
Depends on the cure cycle, how hard it is to demould etc but a good quality mould could well last hundreds of pulls with a little care and maintenance.

chris h
Could this be laminated and made into a replacement bow on an old crossbow? I have an old one that isn't sold anymore and parts are hard to find.
Easy CompositesMatt
In theory yes, although you would need careful consideration of the actual lay up of the part to match the original.

JimmeeAnimALL
Awesome stuff <3 . Lets say one is totally quality freak , and one spotted some imperfections on the mold surface. Can it be sanded / processed before further casting ?
Easy CompositesMatt
Minor imperfections can be lightly sanded and polished out if necessary.

Tengiz Adamashvili
It feels wrong to put masking tape over release agent. Needs to be the other way around. Finish with masks and only apply release agent when everything is ready for laying
Easy CompositesMatt
Well, it might feel wrong to you but we would suggest this is the correct way to do it. Masking tape doesn't stick to the release agent surface at all, it removes with no trace whatsoever and - as you can see in the video - the mould will fall off the pattern just fine. If you put the masking tape onto the pattern before you've applied release agent then it will stick and will leave traces of the adhesive on the pattern which could contaminate the release agent when you apply it. That said, each to his own!

Tim Bradley
Did anyone catch how long was the initial low temperature cure and then the high temperature post cure, and what was the temperature curve for the high temperature post cure?
Easy CompositesMatt
I would recommend you read the full processing guide for the XPREG XT135 Tooling Pre-preg system as it details all stages of the cure and post cure including graphs and tables to help you program your PID oven controller. You can download the guide from the XT135 product page.

Faruk Basar
Can I start the first layer with backing ply without using surface ply? does the release agent still do the job? I d like to make a pipe with large diameter by using an aluminium pipe.
Easy CompositesMatt
The surface ply is specially formulated with the extra resin needed to give a good quality mould surface finish so you can't really just use the backing ply.

BeyerT1
Why not just print out sections that you need to cut? I mean, you do have a CAD model of the green pattern I assume, just unwrap faces and print them out and then use that to precisely cut the carbon fiber pieces.
Easy CompositesMatt
Yes, you could do this. To do it right it's slightly more complicated than a simple 'unwrap' because of the way that a woven fabric will distort and conform. There is a plug-in for Fusion360 which understands the complex way in which woven fabrics 'drape' and so can do all the distortion compensation. For a small, simple mould like we made in this video it's much quicker to just do what we did here rather than do the unwrap modelling and then set up with a drag knife on a CNC machine but for larger or more complex moulds it can become worthwhile.

Tengiz Adamashvili
Which of your prepreg carbon fibers is most suitable for the manufacture of carbon fibre wheels, like those produced for the Koenigsegg. In his YouTube video Christian mentioned that their prepreg is made of a special mix of resins that will withstand high temperatures. Thank you.
Easy CompositesMatt
XPREG®XC130 is our autoclave-cure toughened epoxy prepreg that would be suitable for applications like the wheels you linked to. Generally a wheel would not be a specifically high temperature application. There will be radiated heat from the brake discs but there is also plenty of cooling from airflow so I would not generally think that they would need to have a particularly high Tg resin system. The standard XC130 prepregs all use 'high strength' fibre and are at the higher end of the performance spectrum for conventional carbon fibre prepregs.

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