Composites Central


Reply
Old 01-14-2017, 09:59 PM   #1
gentlegiant

Member
 
Join Date: Dec 2016
Location: dubai
Posts: 23
Thanks: 13
Thanked 2 Times in 2 Posts



Exclamation Carbon fiber sheet

Hi All,

I need to make a large number of carbon fiber sheets with a glossy finish on both sides.
Can someone please advise what technique i can use to get two side glossy finish through vacuum bagging maybe?
I have seen examples of stacks sandwiched with two glass panels but i dont think this is an efficient method plus i would like my sheet to be structurally strong with a high carbon/resin ratio though not required for this project.
Has anyone been able to use a mylar sheet on top of your stack giving you a glossy finish on both sides, if so how have you gone about vacuum bagging without any flow media.

The next part of my question is more important. Well the truth is i need precision sheets exactly 2.5mm in thickness as there are going to be engraved and cut through CNC so any difference in thickness is going to mess up my entire CNC code every sheet i try.
so the question is how does one achieve the thickness he wants every single time i do a wet lay up or vacuum bagging. I know there are precision sheets in the market.
How do these guys achieve the thickness every single time?
Hopefully someone can help.
cheers
gentlegiant is offline   Reply With Quote
Old 01-15-2017, 12:47 AM   #2
DDCompound

Forum Donor
Composites Expert
 
Join Date: Aug 2011
Location: Germany
Posts: 888
Thanks: 44
Thanked 133 Times in 119 Posts



Default

Hi, the only way you can get what you want is a big press and pressing prepregs.
DDCompound is offline   Reply With Quote
Old 01-15-2017, 01:13 AM   #3
gentlegiant

Member
 
Join Date: Dec 2016
Location: dubai
Posts: 23
Thanks: 13
Thanked 2 Times in 2 Posts



Default

Thank you, i kinda figured i would need equipment, but i also know of people making these sheets with everyday equipment.. any other suggestions guys?
gentlegiant is offline   Reply With Quote
Old 01-15-2017, 03:54 AM   #4
DDCompound

Forum Donor
Composites Expert
 
Join Date: Aug 2011
Location: Germany
Posts: 888
Thanks: 44
Thanked 133 Times in 119 Posts



Default

You can't do it with every day equipment and your exact tolerances. Even two sheets of 10mm glass will buckle and give you +- 0.5mm in an ideal case or even more.
DDCompound is offline   Reply With Quote
The Following User Says Thank You to DDCompound For This Useful Post:
gentlegiant (01-15-2017)
Old 01-15-2017, 04:06 AM   #5
gentlegiant

Member
 
Join Date: Dec 2016
Location: dubai
Posts: 23
Thanks: 13
Thanked 2 Times in 2 Posts



Default

what if i settle for one side finish, can vacuum bagging stacks give me the thickness i require?
gentlegiant is offline   Reply With Quote
Old 01-15-2017, 04:31 AM   #6
gentlegiant

Member
 
Join Date: Dec 2016
Location: dubai
Posts: 23
Thanks: 13
Thanked 2 Times in 2 Posts



Default

Please check this video the largest sheet he created was around 4mm
https://www.youtube.com/watch?v=3uhR4jdFiS4&t=567s
So back to my original question is there some technique we can use to get both sides glossy through vacuum bagging, maybe apply a mylar sheet on top instead of peelply/breather
Would it work without flow media...? Someone who has done this already please help
gentlegiant is offline   Reply With Quote
Old 01-15-2017, 07:58 AM   #7
DDCompound

Forum Donor
Composites Expert
 
Join Date: Aug 2011
Location: Germany
Posts: 888
Thanks: 44
Thanked 133 Times in 119 Posts



Default

I have spoken about tolerance of a double sided finish. He has only one sided finish what is a total different world.
Also his toutorial has some mistakes/imperfections in setup. The bag should nit stretch, the brake zone should be on the part and the flow meter he ist using shows if you have a bag or not, but not if there is a small leak.
A one sided finish can be done by standard vacuum infusion with tolerances less then +- 0.2mm
And he mearsured only one spot of the panel.
DDCompound is offline   Reply With Quote
The Following User Says Thank You to DDCompound For This Useful Post:
gentlegiant (01-15-2017)
Old 01-15-2017, 08:07 AM   #8
jjcomposites

Member
 
Join Date: Aug 2010
Location: IN,USA
Posts: 64
Thanks: 48
Thanked 7 Times in 7 Posts



Default

Consider using the wet-preg technique(wetting out your carbon on a piece of visquine, then covering it up with another piece of visquine, then draw your rectangles on the top layer,then cut them out and place on the glass)Remove the visquine of each layer! The trick is not to use too much resin. It would take eight layers of the carbon I use to achieve 2.5mm .You will need a vacuum pump. Envelope bag the whole thing. The parts will be very close in dimension especially if you use the same amount of resin on each batch. The Mylar or glass you use on top is called a caul plate. You still might have to clear coat the parts as pin holes at the weave might show.
jjcomposites is offline   Reply With Quote
The Following User Says Thank You to jjcomposites For This Useful Post:
gentlegiant (01-15-2017)
Old 01-15-2017, 08:21 AM   #9
jjcomposites

Member
 
Join Date: Aug 2010
Location: IN,USA
Posts: 64
Thanks: 48
Thanked 7 Times in 7 Posts



Default

Also alternate between 90deg and 0deg to achieve a stiffer plate.
jjcomposites is offline   Reply With Quote
Old 01-15-2017, 12:40 PM   #10
gentlegiant

Member
 
Join Date: Dec 2016
Location: dubai
Posts: 23
Thanks: 13
Thanked 2 Times in 2 Posts



Default

dear ddcompound, im as you can tell, pretty new to the world of carbon fiber.. you mention tolerances? what exactly do you mean? flexibility, structural strength?

i was only referring to thickness of the sheet, basically need to engrave into it, not cut through the sheet.
gentlegiant is offline   Reply With Quote
Reply

Bookmarks

Tags
carbon, carbon fiber glossy, carbon fiber sheet, fiber, sheet

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -8. The time now is 08:18 AM.
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

Inactive Reminders By Icora Web Design