Notices
Composites Fabrication And Repair Carbon Fiber, Kevlar, Fiberglass and all the newest high tech composites

Mold Considerations

Old 03-27-2004, 05:23 PM
  #1  
Senior Member
Thread Starter
My Feedback: (1)
 
Join Date: Jan 2002
Location: San Bernardino Calif
Posts: 3,757
Likes: 0
Received 1 Like on 1 Post
Default Mold Considerations

Mold Considerations

I have my plug all made up for the cowling of a small Piper. It is sanded and sealed to shape, and up front it has a prop shaft hole and two irregular shaped ovals for engine cooling all cut in. I am planning on using standard fiberglass cloth and polyester resin for making the finished parts.

Question is about the mold.

Just about at set up time, it is customary to trim off the excess fiberglass hanging over the edges of the mold. In planning the mold, I want to be able to cut out the cooling and prop shaft holes also while trimming off the excess. My thought is to carve along an edge down in the cavity of the mold which underlies at the three holes up front.

The mold has not been made yet, but should I set in outward aimed plugs to the three holes such that they will create depressions in the mold which I can cut against.

Or, is there a better way yet?

I do not want to carve out three holes in the hardened fiberglass cowling the next day.


Wm.
Old 03-27-2004, 05:42 PM
  #2  
Senior Member
 
Join Date: Dec 2001
Location: Elk Grove Village, IL
Posts: 391
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Mold Considerations

The way I handle these inlets and shaft outlets is to put only the minum amount of glass and resin in those areas. Usually just the gelcoat and one layer of glass. All the rest is done with the usual multiple layers of glass and resin. When you pull the part from the mold you will see that the "thin" areas are quite weak. Just cut them out (I use a Stanley knife) and then sand the edges smooth. That way you don't have to use your Dremel and a carbide tip to clear the unwanted lay-up out of the part. Regards.
Old 03-27-2004, 07:10 PM
  #3  
Senior Member
Thread Starter
My Feedback: (1)
 
Join Date: Jan 2002
Location: San Bernardino Calif
Posts: 3,757
Likes: 0
Received 1 Like on 1 Post
Default RE: Mold Considerations

I don't even own a Dremel tool/set. However, would it be fair to state then to do the standard gel coat lay up.

Then when it comes time to go further in the process, at the inlet area just put on lightweight cloth and resin. Blend in heavier weight (or multiple layered) material onto the sides and resin blend in.

I am still a bit shady as to how the holes would then be prominent enough to cut out. I still need a bump or hollow in the mold where these inlets are, correct?


Wm.
Old 03-28-2004, 01:41 AM
  #4  
Senior Member
 
Mike James's Avatar
 
Join Date: Jan 2002
Location: Anchorage, AK
Posts: 2,565
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Mold Considerations

Here's how I prepare holes in plugs for molding...

I don't try to do a lighter layup in the area of the holes. I just mold the whole thing, then cut the openings.
Attached Thumbnails Click image for larger version

Name:	Wt59226.jpg
Views:	20
Size:	63.6 KB
ID:	116093  
Old 04-03-2004, 08:57 AM
  #5  
My Feedback: (5)
 
dreadnaut's Avatar
 
Join Date: Mar 2004
Location: Oceanside, CA
Posts: 1,234
Received 0 Likes on 0 Posts
Default RE: Mold Considerations

ORIGINAL: CoosBayLumber

I don't even own a Dremel tool/set. However, would it be fair to state then to do the standard gel coat lay up.
I would highly recomend getting a dremel, or similar tool. I would go crazy without mine.
Old 04-05-2004, 09:23 PM
  #6  
Senior Member
Thread Starter
My Feedback: (1)
 
Join Date: Jan 2002
Location: San Bernardino Calif
Posts: 3,757
Likes: 0
Received 1 Like on 1 Post
Default RE: Mold Considerations

I haven't used a Dremel in years. Too delicate looking. Have a small air powered die grinder which gets used on occasion, and uses cheaper and easily available tooling.

I have a 2HP milling machine in the garage which seems to get the light cuts done accurately and quickly for me. Also can use a 7HP or a 15HP powered mill just down the street. Got more power than I need at present time.


Wm.

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
Trackbacks are Off
Pingbacks are Off
Refbacks are On


Thread Tools
Search this Thread

Contact Us - Manage Preferences Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.