pre-preg pinholes.. driving me crazy


Author
Message
roger sbk composites
roger sbk composites
Supreme Being (107 reputation)Supreme Being (107 reputation)Supreme Being (107 reputation)Supreme Being (107 reputation)Supreme Being (107 reputation)Supreme Being (107 reputation)Supreme Being (107 reputation)Supreme Being (107 reputation)Supreme Being (107 reputation)
Group: Forum Members
Posts: 17, Visits: 163
this is the third part that comes out exactly the same and i've done 3 diff things so far.... my kitchen oven minum is 76c so i leave that 2 hours and then take it to 110c this time i added peelply on the edges but nothing... the stack is as fallowed  2 layers of pre-preg aviation no face side... ... eassycomposite unperforated release film and breather all over the mold put inside a bag and full vac... any ideas guys... this is dirving me crazy already 


Replies
morepower
morepower
Supreme Being (1.8K reputation)Supreme Being (1.8K reputation)Supreme Being (1.8K reputation)Supreme Being (1.8K reputation)Supreme Being (1.8K reputation)Supreme Being (1.8K reputation)Supreme Being (1.8K reputation)Supreme Being (1.8K reputation)Supreme Being (1.8K reputation)
Group: Forum Members
Posts: 242, Visits: 1.2K
Ok... Cool.. I know Nick from 666 and I know who made some of his moulds... long story and quite dull or not depending on who's side you hear....lol.. I had use of his hugger mould (made by the guy who made some of the 666 moulds) and it was full of stress cracks... I dont think they looked after the moulds too well at times..lol.

The pre-preg my be one of the problems as it sounds like it is an autoclave only pre-preg. The only off the shelf out of autoclave pre-preg that works is either VTF261 from Cytec in Derbyshire (50 meter minimum order now apparently) or Easypreg from Easy Composites (it is the same stuff.....). I know it works but I also have to say people have had some issues with pin holes with it too as it is not a guaranteed pinhole free finish even though you can get those results.

I use a material from another supplier which works very well but is not one they sell as a comparable material to VTF261, I just happen to have found a way to make it work.. It is part breather stack and part curing shedule and it took me 6 months of testing to find a way that would work each time I laid up a part.

The oven is not a secret and not hard to make up to be honest but it has to be well controlled and very little temperature difference between the top and bottom and I have at worst 1 degree difference top to bottom... it takes anything from 30 minutes to a day to set up how it works though.... If you imagine a open box with one side open. You need to make it so air is blown down one side (a narrow channel is enough) to the deepest point of the box then flow back out of the box again. Then you need to have a sliding door to close and stop all of the hot air just spilling out again. It has to let some air out but keep most of the heat in... The door slides to let me control how much air comes out.. Too much and the oven loses temperature... Not enough it also loses temperature but will over heat the fan heater... You need to keep air flowing at all times.... 
One of these will do..
http://www.ebay.co.uk/itm/3KW-10200BTU-Industrial-Workshop-Square-Fan-Space-Heater-Electric-Fire-2580-Kcal-/201006642821?pt=UK_Home_Garden_Hearing_Cooling_Air&hash=item2eccedf685
You will need a controller and relay plus a box to fit it all into.. eBay is your friend......lol. The hard part is sorting out the wiring to keep the motor going when the heating element is turned off by the controller.. You will need to remove the over heat protection from the box or find one which will let you get up to at least 90 degrees.. That heater has two one for the lowest power setting and 20 degrees I think and the second one is up to 65 degrees on medium and high power... Get an electrician to sort it out..... it is not hard but does take some thinking about... Then you have the oven.... 

You will need to work out how to get your material to cure yourself though... each pre-preg is different... 





 
Matthieu Libeert
Matthieu Libeert
Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)
Group: Forum Members
Posts: 955, Visits: 3.4K
I've made this video a few months ago, using the prepreg for Easycomposites.

Just like morepower says it's a matter of some trial and error in the beginning and you working with good materials is probably the start.
You can not use autoclave designed prepreg for Out of autoclave prepreg making... Easycomposites sells a finishing prepreg, it is a bit more resin rich giving a pinhole finish!
It's also very easy to put down because it has a tackfree backing. It is very important to lay your prepreg down against the mould. A perfect vacuum without leaks is a must! you may not have any bridging  into your releaselayer at the bag and the bag must be tightly against the materials/moulds....

by saying all of this, a lot can go wrong...but after a while you kind of get that feeling when you know everything will go well...

Matthieu Libeert
Founder MAT2 Composites X Sports
website:
www.mat2composites.com




GO

Merge Selected

Merge into selected topic...



Merge into merge target...



Merge into a specific topic ID...




Threaded View
Threaded View
roger sbk composites - 11 Years Ago
roger sbk composites - 11 Years Ago
wozza - 11 Years Ago
morepower - 11 Years Ago
roger sbk composites - 11 Years Ago
roger sbk composites - 11 Years Ago
morepower - 11 Years Ago
matthieutje65 - 11 Years Ago
roger sbk composites - 11 Years Ago
morepower - 11 Years Ago
matthieutje65 - 11 Years Ago
morepower - 11 Years Ago
roger sbk composites - 11 Years Ago
morepower - 11 Years Ago
roger sbk composites - 11 Years Ago
roger sbk composites - 11 Years Ago
baja_patient - 11 Years Ago
roger sbk composites - 11 Years Ago
morepower - 11 Years Ago
roger sbk composites - 11 Years Ago
roger sbk composites - 11 Years Ago
roger sbk composites - 11 Years Ago
morepower - 11 Years Ago
fgayford - 11 Years Ago
combustioncraig - 11 Years Ago
roger sbk composites - 11 Years Ago
Djekouk - 11 Years Ago
roger sbk composites - 11 Years Ago
Djekouk - 11 Years Ago
     Cool design :-)
Djekouk - 11 Years Ago
morepower - 11 Years Ago
roger sbk composites - 11 Years Ago
Djekouk - 11 Years Ago
                 No problem let go on pm
roger sbk composites - 11 Years Ago

Similar Topics

Reading This Topic

Explore
Messages
Mentions
Search