Hi All
I am not sure if this is allowed but I have a carbon fibre composite training centre in Lancashire and offer a manufacturing service and bespoke
training courses to suit individual requirements. We run courses from mould and pattern making to pre preg, we are currently working with a Motorsport
college on their Low cost project. Although we are a business we are more than happy to give guidance on individual projects. If this post contravenes
any of the forums rules please remove.
Regards Chris
Carbon fibre works LTD
carbonfibreworks@aol.com
https://www.facebook.com/Carbonfibreworks-ltd-697837726897522/
If you could do a post on how to make a pre-preg oven from ebay parts..............................
I am interested in various things but from a "man in a shed" rather than the use of a unit.
If the cost of pre-preg can be off-set to the cost of buying resin etc then its also something I am interested in.
So if its going to cost £100 (for instance) for making a part via vacuum resin infusion, but making the part in pre-preg is only going to be £120 then
its the way forward.
(not including the cost of making an oven, buying in a pump etc)
Now the biggest part I am looking at making is the nose of my car (pics in other thread and will be in my photo archive once worked out how too) but
am looking at smaller parts, so the oven can be small (ish)
I think a nice well thought out post inc costs of making pre-preg would be nice.
(looking at all options on making parts)
You might want to try a post on here:-
Ford Transit Forum
Might seem strange, but these boys love their upgrades, particularly the Mk6/Mk7 lot, including me
Carbon fibre bits would be interesting to some of them......
quote:
Originally posted by SmudgerEBT
If you could do a post on how to make a pre-preg oven from ebay parts..............................
I am interested in various things but from a "man in a shed" rather than the use of a unit.
If the cost of pre-preg can be off-set to the cost of buying resin etc then its also something I am interested in.
So if its going to cost £100 (for instance) for making a part via vacuum resin infusion, but making the part in pre-preg is only going to be £120 then its the way forward.
(not including the cost of making an oven, buying in a pump etc)
Now the biggest part I am looking at making is the nose of my car (pics in other thread and will be in my photo archive once worked out how too) but am looking at smaller parts, so the oven can be small (ish)
I think a nice well thought out post inc costs of making pre-preg would be nice.
(looking at all options on making parts)
Oven is simple. Take sheets of Kingspan to build a box, taping the edges with the foil tape. Buy a cheap fan heater and a rheostat with an external
temperature sensor. Combine, and you have yourself a simple cheap oven. Voila.
Pumps on ebay for £40 are the same as EasyComposites sell - check out my other post this evening for a link to an example on ebay.
quote:
Originally posted by twybrow
Oven is simple. Take sheets of Kingspan to build a box, taping the edges with the foil tape. Buy a cheap fan heater and a rheostat with an external temperature sensor. Combine, and you have yourself a simple cheap oven. Voila.
Pumps on ebay for £40 are the same as EasyComposites sell - check out my other post this evening for a link to an example on ebay.
I'm no expert on composite construction but I'm under the impression you really need a 'clave to get a decent fibre/matrix ratio without voids?
It is possible to produce quality pre preg components without the use of an autoclave by using specific OOA pre pregs (out of autoclave) these are
designed to be used under absolute vacuum and do not require the 4-5 bar as used in the autoclave.
You will need a suitable oven as you need to accurately control the temperature and as pointed out its possible to produce your using some basic
components sourced from Ebay etc. I would be careful if using a complete small portable heater as these have thermal cut outs built in and without
modification will not allow you to achieve the desired temperature for a sustained period.
The pre pregs I use and the can supply have cure temperatures starting at 60 degrees however at these temperatures the cure time is very long and a
higher temp of 100 degrees will bring the cure time down considerably. If clients wish to lay up their own components we are can provide oven
facility's to cure the parts.
Regards Chris
Carbon fibre works LTD
carbonfibreworks@aol.com
Here are the main processes used in carbon component manufacture, it is possible to use any of the systems below with some training and relatively
basic equipment.
WET LAY
WET LAY AND VACUUM BAGGING
RESIN INFUSION
PRE PREG
All of the above have advantages and disadvantages and need varying levels of skill and equipment , what you must consider is the Tg ( glass
transition temperature ) of the resins used especially on large components and the use of a post ambient cure procedure for ambient temp cure
resins.
Chris
Carbon fibre works LTD
carbonfibreworks@aol.com
[Edited on 3/6/16 by Carbon fibre works]
quote:
Originally posted by coyoteboy
I'm no expert on composite construction but I'm under the impression you really need a 'clave to get a decent fibre/matrix ratio without voids?
quote:
Originally posted by Carbon fibre works
It is possible to produce quality pre preg components without the use of an autoclave by using specific OOA pre pregs (out of autoclave) these are designed to be used under absolute vacuum and do not require the 4-5 bar as used in the autoclave.
You will need a suitable oven as you need to accurately control the temperature and as pointed out its possible to produce your using some basic components sourced from Ebay etc. I would be careful if using a complete small portable heater as these have thermal cut outs built in and without modification will not allow you to achieve the desired temperature for a sustained period.
The pre pregs I use and the can supply have cure temperatures starting at 60 degrees however at these temperatures the cure time is very long and a higher temp of 100 degrees will bring the cure time down considerably. If clients wish to lay up their own components we are can provide oven facility's to cure the parts.
Regards Chris
Carbon fibre works LTD
carbonfibreworks@aol.com
At 60 degrees you are already above the safe working parameters of a small blower type room heater, much depends on how you wire the system up but if
the motor overheats and cuts out and the heating element is still live the outcome can be disastrous.
Either way anyone thinking of building a curing oven should take advice from a qualified electrician.
Chris
Carbon fibre works LTD
carbonfibreworks@aol.com
quote:
You are not making safety critical parts, or aeroplanes. And air is nice and light!
quote:
Originally posted by coyoteboy
quote:
You are not making safety critical parts, or aeroplanes. And air is nice and light!
No, but not cracking, having bubbles or dodgy surfaces or extra weight goes along with it
Think he means parts should still look nice, no matter which way they are made.
Having air bubbles, dry spots etc ruins the look as well as the strength etc
quote:
Originally posted by SmudgerEBT
Think he means parts should still look nice, no matter which way they are made.
Having air bubbles, dry spots etc ruins the look as well as the strength etc
quote:
Originally posted by twybrow
quote:
Originally posted by SmudgerEBT
Think he means parts should still look nice, no matter which way they are made.
Having air bubbles, dry spots etc ruins the look as well as the strength etc
This is a fundamental problem with people wanting carbon composites for automotive - they expect 2x2 twill, with lovely straight weave and no voids or resin rich areas. Look at the shut lines of a BMW i8 and you can see that BMW have bravely said no more! They need to be fit for purpose, which I agree means little ot no pinholing, but the statement ref cracking etc is just rubbish. Poor laminate design vs load leads to cracking. Slightly higher voidage certainly won't - in fact voids can inhibit cracking!
Nearly everyone wanting carbon wants a nice glossy surface.
What the unknowing public don't know is that a lot of the commercial decorative carbon parts, have numerous layers of two pack clear, applied
very heavily.
We get a polishable surface straight out of the clave, using the right prepreg. Not difficult. It took us a number of years to get the fine art of
smooth high gloss finish on wet layup, without pinholes. Much easier with vacuum.
Cheers,
Nev.
quote:
but the statement ref cracking etc is just rubbish. Poor laminate design vs load leads to cracking. Slightly higher voidage certainly won't - in fact voids can inhibit cracking!