Composites Central


Reply
Old 08-21-2017, 07:10 PM   #11
KLComposites

New Member
 
Join Date: Mar 2017
Location: Virginia, USA
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts



Default

I've used material from APCM (prepregs.com) with some good and bad results. I have gone through 25 yards of DA4090MX from them and have concluded that a properly controlled convection oven, edge breathing, and P3 release film are the key to getting good results. I feel like I'm making headway with it and will be using more.

If you do end up trying some of their material reach out to me so we can exchange notes. I buy through Competition Marketing (http://www.competition-marketing.com/WP/)
KLComposites is offline   Reply With Quote
Old 08-22-2017, 11:18 AM   #12
Zebra

Composites Expert
 
Join Date: Apr 2016
Location: New york
Posts: 200
Thanks: 0
Thanked 26 Times in 24 Posts



Default

If you are making tubes using some sort of mandrel then you can achieve a good finish by wrapping it but recommend using a smooth release film capable of surviving high temperatures like the smooth Teflon coated release films sold by Composite Envisions (and others). If you use perforated films then you will have the perforation pattern on the surface and will need to sand it a little before applying clear coat.

If you aren't going to use a vacuum then you need make sure the release film is wrapped tight enough to apply pressure evenly around the surface. You can tape it in place. There are special tape-like products sold specifically for this purpose too.

It's best to avoid any trapped air pockets between the part surface and the smooth release film. I apply the release film with my cold roll laminator sometimes but a squeegee works too. The laminator is just a time saver and not a requirement. With the red high temp release film from CE, you can usually see any trapped air under the film.
Zebra is offline   Reply With Quote
Old 08-22-2017, 08:37 PM   #13
Timbuck

Member
 
Join Date: Feb 2012
Location: Australia
Posts: 120
Thanks: 8
Thanked 23 Times in 19 Posts



Default

KISS method.

If your using foam mandrel or dissolvable mandrel.... Just wrap it in your OOA and use high temp heat shrink wrap.
You won't get a perfect Finnish , but it's very good , as it makes it very even flat Finnish and bubble free.

It quite readily avalable from electrical supply places up total about 6 or 7 inch dia maybe be bigger.

Also you can get clear heat shrink tape/film from some composite supply places also comes in many different diameters


Cheers tim
Timbuck is offline   Reply With Quote
Old 08-24-2017, 07:56 PM   #14
Infused

Composites Expert
 
Join Date: Apr 2015
Location: Houston, TX
Posts: 254
Thanks: 69
Thanked 17 Times in 17 Posts



Default

Thanks guys.

Yeah I'm going to apply vacuum. I just need to find a small tube that will fit between the grieve door insulation while not keeping the door open.

I also need to find an OOA prepreg still. I wish there were more US manufacturers and ones that provided curing cycle times.
Infused is offline   Reply With Quote
Old 08-24-2017, 08:01 PM   #15
Infused

Composites Expert
 
Join Date: Apr 2015
Location: Houston, TX
Posts: 254
Thanks: 69
Thanked 17 Times in 17 Posts



Default

Quote:
Originally Posted by Zebra View Post
If you are making tubes using some sort of mandrel then you can achieve a good finish by wrapping it but recommend using a smooth release film capable of surviving high temperatures like the smooth Teflon coated release films sold by Composite Envisions (and others). If you use perforated films then you will have the perforation pattern on the surface and will need to sand it a little before applying clear coat.

If you aren't going to use a vacuum then you need make sure the release film is wrapped tight enough to apply pressure evenly around the surface. You can tape it in place. There are special tape-like products sold specifically for this purpose too.

It's best to avoid any trapped air pockets between the part surface and the smooth release film. I apply the release film with my cold roll laminator sometimes but a squeegee works too. The laminator is just a time saver and not a requirement. With the red high temp release film from CE, you can usually see any trapped air under the film.


I've never used Teflon coated release films. Mainly because I've always used peel ply. I did use some Mylar brown stuff before but it left a textured surface instead.

Does the Teflon coated release film work if wrapping around a cylinder in strands? Like if I cut one inch wide strips and wrap it around the shaft overlapping ends? I know if I did that will peel ply the end edges that are cut will leave strands of peel ply on my part and embed itself basically into the first layer of carbon. Without extreme sanding it's impossible to get out and if I'm using 3k prepreg then it would sand right through he layer.

I'm honestly trying to locate low temperature cure 6k 2x2 OOA prepreg if anyone has a link....
Infused is offline   Reply With Quote
Old 08-28-2017, 09:15 AM   #16
sammymatik

Moderator
Composites Expert
 
Join Date: Jan 2014
Location: Mountain View, CA
Posts: 623
Thanks: 54
Thanked 59 Times in 57 Posts



Default

If you want to make a nice tube, use a metal mold and a inflatable bladder. Then you don't need to use vacuum, you'll have great compaction. If the mold is polished to mirror, the part should come out the same. You don't want or need to use release film if you have a nicely polished mold and use semi permanent release. Plus at 150psi, parts come out looking nice.
sammymatik is offline   Reply With Quote
Old 08-28-2017, 09:28 AM   #17
Zebra

Composites Expert
 
Join Date: Apr 2016
Location: New york
Posts: 200
Thanks: 0
Thanked 26 Times in 24 Posts



Default

Not sure why you would want to wrap it in strands. Seems like a lot of extra work for no reason. Why not just wrap it as one piece?

If it is an unusual shape and you are worried it won't wrap / drape cleanly, then you are better off making a custom silicone vacuum bag to wrap it in. Use sheet wax to replicate the cf thickness when making the silicone bag.

You can get brush-on silicone vacuum bagging rubber from Smooth-on.

Composite Envisions and others sell their prepreg heat cure resin films seperately so you can turn any cf into prepreg if you want. Or... they offer a service to make custom prepreg for you using any fabric you want.
Zebra is offline   Reply With Quote
Old 12-06-2017, 09:19 PM   #18
20_rc51_00

Composites Expert
 
Join Date: Nov 2006
Location: Alberta
Posts: 1,046
Thanks: 37
Thanked 26 Times in 24 Posts



Default

Great post. Will come back and post a few links for sources.
20_rc51_00 is offline   Reply With Quote
Reply

Bookmarks

Tags
ooa, prepreg

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 09:46 PM.
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

Inactive Reminders By Icora Web Design