×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Making silicone bladder for composite molding

Making silicone bladder for composite molding

Making silicone bladder for composite molding

(OP)
I've seen several good posts on composite bladder molding, but I'm wondering if anyone has some specific recommendations for:

1) Silicone materials, sources, methods to use to make the bladders
2) Wall thickness of the bladder

FYI we can't used a trapped solid rubber mandrel since it would be trapped in the mold due to the bends in the part.

Thanks

RE: Making silicone bladder for composite molding

I once saw a college club use a bicycle tube as their bladder. It was for a one off part but it worked quite effectively, squeezing out a decent amount of resin. What is the diameter of the part you're trying to make?

www.compositescentral.net

RE: Making silicone bladder for composite molding

(OP)
Thanks, I've heard about that. My part is about 0.75" in diameter, but varies.

I suppose was post was a little vague, but I was just wondering if there are rules of thumb for building bladders. We'll experiment with some silicone molds.

RE: Making silicone bladder for composite molding

One important thing is to make sure that your bladder is more or less circular when inflated. Uneven shape = uneven pressure = uneven resin content. You can try getting a inner bladder that about the same size as the outside tube but then you run the risk of folds in your material. If you can try picking a bladder that stretches some so you can vary the pressure and have nice flat surface

www.compositescentral.net

RE: Making silicone bladder for composite molding

Ingear,

Try the silicone from Smooth-On.  They are at www.smooth-on.com.  I have used the silicone that they specify for moulding as well as their dragon skins 10 minute.  The ten minute is colorless and quite elastic but does run a little bit.  The material for mould making is green and more stiff.  Either of these can be sprayed or brushed as well as injected into a mould using an epoxy gun to make a tube.  I have used with epoxy and polyester, vinyl ester and they work fine.

Good Luck

Mike

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources