Go Back  RCU Forums > RC Airplanes > Composites Fabrication And Repair
 Help Required for Vacum Bagging Fuselages!!! >

Help Required for Vacum Bagging Fuselages!!!

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

Help Required for Vacum Bagging Fuselages!!!

Old 06-29-2004, 06:18 AM
  #1  
CZM
Banned
Thread Starter
 
Join Date: Dec 2003
Location: Calcutta, INDIA
Posts: 18
Likes: 0
Received 0 Likes on 0 Posts
Default Help Required for Vacum Bagging Fuselages!!!

I want to vacum bag my fuselage after laying up. Molds are in two halves, left and right. I have a couple of questions on which I require some help.

When should I release the vacum and remove the bagging materials from the molds ? Also when should I trim the excess cloth around the seam ?

I am also used to baking the molds for 20 minutes after laying up. Can I bake it after adding vacum to the molds. I plan to hold the nylong bagging film on the mold flange with sealent tape. Any help or step by step photos on laying up a fuselage and vacum bagging it would be welcome.

Thanks.

CZ
Old 06-29-2004, 09:59 AM
  #2  
Senior Member
 
Join Date: Feb 2003
Location: Irvine, CA
Posts: 127
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

Once the resin has completely gelled up you can turn off the vacuum and remove the bag. I like to remove the bagging materials at this time because the peel ply comes off easier. You can bake it after adding vacuum without a problem. As far as trimming goes you can also trim it after it is gelled. It should cut like cheese with a box cutter. I like to use the hook blade so that I can trim without pulling the laminate off of the mold prematurely.

HTH
Evan
Old 06-30-2004, 12:38 AM
  #3  
CZM
Banned
Thread Starter
 
Join Date: Dec 2003
Location: Calcutta, INDIA
Posts: 18
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

Thanks Evan...one more question...the seam joint is always a problem and requires a lot of work after the fuselage is out of the mold. While joining the mold halves together would it be a good idea to line up the joint with a mixture of epoxy and cabasol in addition to the joining tape which goes from the inside. Also, would it be a good idea to vacum bag the entire mold after the joining tape has been put in place..

CZ
Old 06-30-2004, 01:06 AM
  #4  
Senior Member
 
Join Date: Feb 2003
Location: Irvine, CA
Posts: 127
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

Bagging it again is probably too much for too little. I'd mask tape the outside part of the fuselage so it doesn't get messy, then join the two halves using what you had there (tape & resin+cabosil). What you can do is mask tape the two halves together on the outside. Insert a baloon or inflatable bag of some sort to press the tape up against the part for better bond. I know it's too late now but the next time you build the toolings, build one half that goes beyond the joint line with a recess. That way it makes it much easier to bond afterward. Here's a quick drawing of what I'm talking about. Good luck,

Evan
Attached Images  
Old 06-30-2004, 01:48 AM
  #5  
CZM
Banned
Thread Starter
 
Join Date: Dec 2003
Location: Calcutta, INDIA
Posts: 18
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

Evan,

I could try and have a recess in the next mold I make. Presently, I am joing the fuselage halves while they are in the mold. Maybe. I should put in some sort of inflattable bag inside the molds for the tape to adhere better to the surface.

Also, how would a recess in the tooling be built in. I generally build my plugs in one piece and then have a parting board in the centre for making molds.

CZ
Old 06-30-2004, 04:38 AM
  #6  
Senior Member
 
Join Date: Jun 2003
Location: San Diego, CA
Posts: 691
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

You can make the little steps in the fuselage side using removable mold pieces (you can still use the mold you have). You screw the removable sections to the flange and then bag the side. When it is cured, you remove these mold pieces which leave the "bonding ledges." I'll attach a bad sketch... hope it makes sense. Basically, you would put your plug back into your mold and make 2 more small mold pieces.

-David
Attached Thumbnails Click image for larger version

Name:	Hf99207.jpg
Views:	44
Size:	19.9 KB
ID:	148888  
Old 06-30-2004, 05:45 AM
  #7  
CZM
Banned
Thread Starter
 
Join Date: Dec 2003
Location: Calcutta, INDIA
Posts: 18
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

David,

Good idea but excuse my ignorance..after I put the plug back in the mold the plug would be flush. How do I get the step in place. Is it that I make two small mold pieces for the part of the fuselage which would be the step and then after taking out the plug, position the small molds a 1/16 inside the main mold to create the step.

CZ
Old 06-30-2004, 11:57 AM
  #8  
Senior Member
 
Join Date: Jun 2003
Location: San Diego, CA
Posts: 691
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

Yes, that works just fine. You can also leave the small mold pieces flush, but use layers of tape to build up the thickness of offset you need (then wax the tape). But yes, I think the best permanent solution is to reposition the small molds to provide the offset. You can make them screw in place so it's the same each time.

-David
Old 06-30-2004, 09:17 PM
  #9  
Senior Member
My Feedback: (4)
 
Goggles's Avatar
 
Join Date: Dec 2001
Location: Abbotsford, BC, CANADA
Posts: 1,026
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

After reading this a light bulb just went off.....after you make your small mold piece, roughen up the surface a little then do a small layup of the thickness of the opposite part, only let it stick to the surface of the small mold piece. Then use a final layer of 3/4oz or so and make that nice and smooth. This way you have a flange that is the exact thickness of the piece you want it to fit into.

Just a thought.
Old 07-01-2004, 01:31 AM
  #10  
Senior Member
 
Join Date: Jun 2003
Location: San Diego, CA
Posts: 691
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

Yup, that should work. I think I'll try it, in fact. It may be prone to peeling off, but there's on;y one way to find out for sure.

-David
Old 07-01-2004, 04:08 AM
  #11  
CZM
Banned
Thread Starter
 
Join Date: Dec 2003
Location: Calcutta, INDIA
Posts: 18
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

Ill try it myself and post results. Also, how can I use my existing paint air compressor as a vacum pump..any way to do it other than buy the gadgets sold by ACP or Fibreglast...to convert the compressor to a vacum pump..
Old 07-01-2004, 08:35 AM
  #12  
CZM
Banned
Thread Starter
 
Join Date: Dec 2003
Location: Calcutta, INDIA
Posts: 18
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

Got a great thread on RC Groups which describes the process very well with good sketches..

http://www.rcgroups.com/forums/showt...5&page=2&pp=15

CZ
Old 07-01-2004, 09:13 PM
  #13  
Senior Member
My Feedback: (4)
 
Goggles's Avatar
 
Join Date: Dec 2001
Location: Abbotsford, BC, CANADA
Posts: 1,026
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

How much vacuum should you use?

I'm building a pump system soon to get my fuses that "little bit" lighter. But I've read different #'s so, what a good starting value?

Thanks.

Kelvin
Old 07-01-2004, 10:50 PM
  #14  
Senior Member
 
Join Date: Feb 2003
Location: Irvine, CA
Posts: 127
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

You don't need any more than 25 inches of merc for regular vacuum bagging.

Evan
Old 08-19-2004, 08:38 PM
  #15  
My Feedback: (5)
 
heli001's Avatar
 
Join Date: Apr 2002
Location: Charlotte, NC
Posts: 1,146
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

This is a response to CZM's post on rcgroups.com, and here.

CZ, aka Avdesh Khaitan ( http://kadetmodels.com ), (Kolkata, India)

We have NOT heard from you in recent history....... It seems a bit strange that you are on the internet, seeking information on VACUUM bagging, when WE were led to believe that the 50 models, that we paid for and have not received, were a part of your famous manufacturing process that included VACUUM bagging along with CNC foam cutting capabilities.

You led us to believe that, you had the manufacturing facilities to produce "World Class" fiberglass molds, and models, when in reality, your shop turned out to be a small concrete shed in your back yard....The samples that you sent me, were of such LOW quality, that we have had a hard time, even giving them away. The "Qualified" pattern professionals that have seen your samples, have essentially said, that they were S**T, and would NEVER sell in THIS or any OTHER country. They're twice as heavy as they should be, they are weak structurally, (no spars in the wings!!!!) they (models) use inferior materials in all respects, they are assembled sloppily, finished poorly, and are not even good enough to be called third rate. Your fiberglass work is horrible, the seams are sloppy and show visable seperation, and when you pull the parts out of the box, they are dirty, and the cheap, sloppy packaging can barely make it across town.

Every aspect of your "manufacturing" is grossly inferior and OVERSTATED. Your landing gear, which serves as the wing "spar", was sheared in such a way that it leaves sharp dangerous edges at the axle, the cheap wheels were drilled sloppily and wobble, the heat shrink film was done with the skill of a young, inexperienced child. There is a gaping hole in the firewall, covering up another error in your design process, which allows fuel to leak inside the plane. The control surfaces were beveled and hinged poorly, with insufficient throw to be effective, and your control linkages, with the cheap hardware, were binding. Not only were they binding, they were unmovable , because of the poor use of CA on the inferiorior hinge material (Tyvek....?) The only accolade on YOUR website, about your models, is from your DAD....Go Figure.....! and, BTW, when can I expect a FULL refund, of the monies paid to you, for the "50 Models" and Distributorship fee.......?

Avdesh Khaitan ("A.K." ), we look forward to your response to the above post.

If there are any questions about the above post, or if you want the FULL story about this venture, PLEASE feel free to contact me at,

http://www.panacea-engineering.com

OR

W.C. Fischer
Panacea Engineering Company
408 Roundtree Road
Charlotte, N.C. 28217

Office :704-523-1881
Nextel: 980-721-6567
Old 08-20-2004, 07:42 PM
  #16  
Member
 
Join Date: Jul 2004
Location: Issaquah, WA
Posts: 37
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

Vacuum Bagging, the more pressure the better, if you can get 29inches go for it. You will have a stronger part. For normal layup you can make do with 18inches if that is all you can do with a leaky bag cuz like me you are trying to use the bag for the umteenth time to save a $. [:'(][:-] If on foam and you are baking it, it depends on the temperature and foam type.

Brian
Old 08-26-2004, 10:48 AM
  #17  
Senior Member
My Feedback: (4)
 
Goggles's Avatar
 
Join Date: Dec 2001
Location: Abbotsford, BC, CANADA
Posts: 1,026
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help Required for Vacum Bagging Fuselages!!!

Here's my follow up to making a flange:

- I put the plug back in the mold then made a ring a couple inches high all the way around the plug. I figured it would be a little flimsy so I shot some foam around it for strength (I'm going to use this technique on the next mold instead of endless layers of cloth).
- I pulled the plug out then did a normal layup with the same layers of cloth that I would use on the cowl top except on the inside I added another layer of .75.
- When dried and trimmed I ran a coat of bondo on the surface then sanded smooth. Primed and waxed it was ready to use.
- I then clamped it to the mold, used a mixture of resin and cabosil to fill in the flange corner and layed up the rest of the cowl.
- It came out perfect and the top cowl fits nice and snug.
Attached Thumbnails Click image for larger version

Name:	Jh15129.jpg
Views:	49
Size:	144.7 KB
ID:	167667   Click image for larger version

Name:	To45643.jpg
Views:	64
Size:	134.8 KB
ID:	167668   Click image for larger version

Name:	Rx60363.jpg
Views:	47
Size:	137.5 KB
ID:	167669  
Old 11-22-2004, 07:49 AM
  #18  
My Feedback: (41)
 
Join Date: Dec 2001
Location: WEST PALM BEACH, FL
Posts: 1,773
Received 1 Like on 1 Post
Default RE: Help Required for Vacum Bagging Fuselages!!!

[]HI I HAVE TRIED THE LAP JOINT SYSTEM.. FOUND THAT IF YOU LET THE GLASS FUSE COME LOOSE FROM THE MOLD,THE RESIN GOES ON THE OUT SIDE.. THIS HAPPENS WHEN TO TRIM IT IN THE CHEESE STATE.. ALSO THERE IS NO WAY TO PUSH THE OUTER HALF OF FUSE AGAINST THE FLANGE.. ANY ONE HAD THIS PROBLEM ??

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.