Go Back  RCU Forums > RC Airplanes > Composites Fabrication And Repair
 Fiberglass Fuse to Plug help >

Fiberglass Fuse to Plug help

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

Fiberglass Fuse to Plug help

Old 03-28-2004, 10:37 AM
  #1  
Thread Starter
My Feedback: (8)
 
Deadstik's Avatar
 
Join Date: Mar 2002
Location: Rougemont, NC
Posts: 1,301
Likes: 0
Received 1 Like on 1 Post
Default Fiberglass Fuse to Plug help

I am getting ready to make a plug from a very old fiberglass fuselage. It is an old pattern ship and it is pretty flimsy. Nothing compared to the fuselages I make now, but.. this is what leads to my question. What can I do to reinforce this fuselage to use it as a plug? If anyone has done this, i would appreciate knowing what techniques they used. If it were very strong I don't think I would have to do much except fill and paint/polish... but.. this Fuselage is from the early 60's and would not take a direct layup.. heck I don't think it could take a strong sanding.. but.. I want to make a mold to make a really good fuselage of this plane and can certainly use the help. I have all the supplies for the mold, (tooling gel/glass/ect.) but have to buy the stuff to make a parting board. Any Suggestions? One other thing, anyone have a pet method to hold the plug while you place the parting board and then seal the gap around the plug? I've checked out most of the mold making sites and while they were very helpful... there always seems to be one picture/angle I need to see to "get it". Thanks for any help....

Dan

Carolina Custom Aircraft
Old 03-28-2004, 11:40 AM
  #2  
Senior Member
 
Join Date: Feb 2003
Location: Irvine, CA
Posts: 127
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fiberglass Fuse to Plug help

Hi Dan,

Whenever I need to reinforce a weak plug, I normally fill the cavity of the plug with plaster if it's a small project or use polyurethane high density pour foam if it's a larger piece. Both methods work well for me.

Evan
Old 03-28-2004, 11:52 AM
  #3  
Senior Member
 
Join Date: Jun 2003
Location: San Diego, CA
Posts: 691
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fiberglass Fuse to Plug help

To hold the plug in position, I use small balsa "bulkheads" which receive a "Bondo" layer to form a perfect fit to the plug. The same thing could be done with modeling clay, but the Bondo makes a rigid tool that can be re-used. I have pictures on my website, but it may be one of those cases where one angle/photo is missing.

-David

http://members.cox.net/davidfee/Fuselage_Molds.htm
Old 03-29-2004, 02:40 PM
  #4  
Thread Starter
My Feedback: (8)
 
Deadstik's Avatar
 
Join Date: Mar 2002
Location: Rougemont, NC
Posts: 1,301
Likes: 0
Received 1 Like on 1 Post
Default RE: Fiberglass Fuse to Plug help

Evan and David,

Thanks very much for your help. I've find that the hardest thing to do is to do something like this the first time.. you just have to DO IT !!! Evan, I don't think I can put the foam inside the fuse as I think it would really bulge it out and do terrible things to it. I am looking into an idea of using a hardening modeling clay so it will not distort. I was thinking about the plaster of paris trick but..I don't think that is a good idea on a part this big. I'm going to check out some type of hardening clay. David, I understand your technique on the bondo for the supports for the plug, but was wondering if you could clarify the "stiff paper tape" you use to suspend the plug exactly 1/2 way above the parting board?... As you said on your page, I NEED A PICTURE OF THAT !!

I really appreciate the help....


Dan
Carolina Custom Aircraft
aka deadstik.....[8D]
Old 03-29-2004, 03:05 PM
  #5  
Senior Member
 
Join Date: Jun 2003
Location: San Diego, CA
Posts: 691
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fiberglass Fuse to Plug help

How about tonight when I get home from the lab, I set that up and take a picture of it? Basically, the tape (masking tape or whatever) is cantilevered out over the splitter plate, suspending the plug at the right height. I'll take a pic though and get it done, once and for all!
Old 03-29-2004, 03:05 PM
  #6  
Senior Member
 
Join Date: Feb 2003
Location: Irvine, CA
Posts: 127
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fiberglass Fuse to Plug help

Hi Dan,

If there's airspace for the foam to expand then it won't push/deform your plug. What you could also do is line the plug with plastic wrap or something. That way it doesn't stick to the plug permanently. So if it does end up pushing your plug outward then you can just pull the foam out and try something else.

Evan
Old 03-29-2004, 03:30 PM
  #7  
Senior Member
 
Join Date: Jun 2003
Location: San Diego, CA
Posts: 691
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fiberglass Fuse to Plug help

BTW, on the tape method, there may be a better way (especially for large/heavy plugs) but this has worked for me so far. A picture will follow this evening.

-David
Old 03-29-2004, 03:31 PM
  #8  
 
Join Date: Dec 2001
Location: Beautiful Coastal Scarborough, ME
Posts: 820
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fiberglass Fuse to Plug help

Dan:

It sounds like you are willing to sacrifice the fuse/plug anyway, so why not reinforce the interior with layers of glass. This will make it nice and stiff for your mold layup.

Antony
Old 03-29-2004, 04:15 PM
  #9  
Senior Member
 
Join Date: Feb 2003
Location: Irvine, CA
Posts: 127
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fiberglass Fuse to Plug help

The drawback here is that the exotherm caused by the curing process of the reinforcement layers could cause the whole thing to warp. And if the plug is as flimsy as Dan has described then I'm sure that's going to be a problem.

ORIGINAL: aparchment

Dan:

It sounds like you are willing to sacrifice the fuse/plug anyway, so why not reinforce the interior with layers of glass. This will make it nice and stiff for your mold layup.

Antony
Old 03-29-2004, 05:09 PM
  #10  
Thread Starter
My Feedback: (8)
 
Deadstik's Avatar
 
Join Date: Mar 2002
Location: Rougemont, NC
Posts: 1,301
Likes: 0
Received 1 Like on 1 Post
Default RE: Fiberglass Fuse to Plug help

David, I really am looking forward to the pictures of that....a great mystery about to be solved !!

Evan, I like that idea about lining the fuse w/plastic wrap so if it screws up I can get it out. I think I am still suffering from the nightmares caused by blowing up Lanier Bronco fuses w/expanding foam..seemed like a good idea at the time, but now perhaps the foam is a bit kinder. You really think that it wouldn't distort the fuse Evan?... I may have to experiment.. after all, the stuff isn't that expensive and it would be better than stuffing modeling clay in it. Maybe I'll try it out on another fuse I don't care about... (like a couple made when I was learning to do this..!)

Antony, I appreciate the input, but Evan is right about the exotherm... it would probably turn that old fuse into spaghetti !!!.. but.. a good thought is better than no thought....

Guess I'll go to West marine and buy some expanding foam...... then when it EXPLODES one of my old fuses I can send pics to Evan...>LOL <G>

thanks all,

Dan
Old 03-30-2004, 12:59 AM
  #11  
Senior Member
 
Join Date: Jun 2003
Location: San Diego, CA
Posts: 691
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fiberglass Fuse to Plug help

Ok, here are some quick and dirty snapshots. I hope they make it more clear. The tape just forms little tabs which support the plug at the correct height by resting on the splitter plate.

Good luck,
-David
Attached Thumbnails Click image for larger version

Name:	Qn38123.jpg
Views:	19
Size:	74.3 KB
ID:	116826  
Old 03-30-2004, 12:09 PM
  #12  
Member
 
Join Date: Dec 2002
Location: Lebanon, IN
Posts: 39
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fiberglass Fuse to Plug help

I use 1/8" melamine from Menards or Home Depot for my parting boards and just glue the to the plug with a hot glue gun and popsicle sticks on an angle for supports. If the plug is waxed the hot glue will peel right off after you're finished. Also on the two part foam, pour it in multiple pours with time time cure between and you will be ok. Just remember,,,,, this stuff has incredible power to it and if it is trapped it WILL blow your fuselage up! Also, don't allow the mold to be post-cured with the plug in it or the foam will post-expand ruining your mold. This includes heat from curing too many plies in the mold at once.
Old 03-30-2004, 01:31 PM
  #13  
Senior Member
 
Join Date: Jun 2003
Location: San Diego, CA
Posts: 691
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fiberglass Fuse to Plug help

Good tips, Bruce!

Are you saying you use hot glue to fill the gap between the melamine and the plug, or just to tack-glue the popsicle sticks? Hot glue would be about the same speed as Bondo, but a whole lot less stinky!!! I think I'll have to try that next time!

Thanks!
-David
Old 03-30-2004, 01:41 PM
  #14  
Member
 
Join Date: Dec 2002
Location: Lebanon, IN
Posts: 39
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fiberglass Fuse to Plug help

David, I use the hot glue to hold everything in place and regular modeling clay to fill in the gap between plug and flange.
Old 03-30-2004, 01:46 PM
  #15  
Member
 
Join Date: Dec 2002
Location: Lebanon, IN
Posts: 39
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fiberglass Fuse to Plug help

I reread your post and want to add,,,, I run a continuous bead of glue on the back side of the flange. You then come back on the "good" side and clay in the gap. The hot glue in a continuous bead supplies enough holding power that you can brush the resin in the fabric without worry of the parting flange coming off. But the glue then just peels off the waxed surface when you're done.
Old 03-30-2004, 04:38 PM
  #16  
Senior Member
 
Join Date: Jun 2003
Location: San Diego, CA
Posts: 691
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fiberglass Fuse to Plug help

I see what you mean, Bruce. I've usually used masking tape along the backside but the hot-glue does the same thing, plus adds mechanical support. I like it. Do you use the low-temp hot-glue?

thanks,
David
Old 03-30-2004, 09:51 PM
  #17  
Thread Starter
My Feedback: (8)
 
Deadstik's Avatar
 
Join Date: Mar 2002
Location: Rougemont, NC
Posts: 1,301
Likes: 0
Received 1 Like on 1 Post
Default RE: Fiberglass Fuse to Plug help

David,

The light just clicked ON !!!! That Picture is exactly what I needed. I was trying to understand what "stiff tape" was... and obviously if you double the tape it will now be strong enough to hold the plug where you want it.

Bruce, I've got to try that..it does seem easier than mixing up the bondo and as Bruce said.. wouldn't smell as bad....I'll go pick up some melamine tomorrow...one other thing.. just how close a fit do I want to try for between the parting board and the plug? 1/16"1/8" 1/4" 1 /2"??

Thanks very much for the effort.. lots of work for me coming up.. I think I'll take some pics.. might help out somebody else...

Dan
Old 03-30-2004, 10:02 PM
  #18  
Senior Member
 
Join Date: Jun 2003
Location: San Diego, CA
Posts: 691
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Fiberglass Fuse to Plug help

Dan,
1/16"-1/8" is good. You want the gap to be as narrow as possible, but you still need to be able to work the clay (or Bondo... or whatever else) in there... so it can't be a press fit. Actually, if it were, then you wouldn't need to fill the gap.

good luck, and do take pictures...

-David
Old 03-31-2004, 08:22 AM
  #19  
Thread Starter
My Feedback: (8)
 
Deadstik's Avatar
 
Join Date: Mar 2002
Location: Rougemont, NC
Posts: 1,301
Likes: 0
Received 1 Like on 1 Post
Default RE: Fiberglass Fuse to Plug help

David,

Sounds good... I'll start rounding up the rest of the stuff I need and probably get started on Friday. I will do the picture thing....looks like a very promising project. I certainly appreciate the help from everyone.

Thanks ,

Dan

Carolina Custom Aircraft [8D]
Old 03-31-2004, 09:22 AM
  #20  
Senior Member
My Feedback: (1)
 
Join Date: Jan 2002
Location: San Bernardino Calif
Posts: 3,757
Likes: 0
Received 1 Like on 1 Post
Default RE: Fiberglass Fuse to Plug help

Deadstik:

Back when we wanted several copies of a vac-u-formed model boat. It too was rather weak, and had value, so did not want to ruin what we had.

Idea came to fill the whole cavity with wet sand. The whole desert is filled with fine blow sand, so our supply was endless. This system made it really firm, and then due to the weight would not roll around while we did the exterior copying. The surface of the sand was blanked over with about 1/4 inch of very wet plaster.

After we did three tries at a good mold, the plaster was broken up, and the sand flushed out. The flimsy plastic was then given back to the owner.


Wm.
Old 03-31-2004, 09:35 PM
  #21  
Thread Starter
My Feedback: (8)
 
Deadstik's Avatar
 
Join Date: Mar 2002
Location: Rougemont, NC
Posts: 1,301
Likes: 0
Received 1 Like on 1 Post
Default RE: Fiberglass Fuse to Plug help

Wm,

That is the most intreging idea I've ever heard...so simple, but would accomplish exactly what I want to do. I don't mess up the original... and I get a strong fuse to make the mold from. And besides, it gives me an excuse to go to Hatteras this weekend !!!!... Thanks very much.. As I said earlier... I'll get started next week.. so pics and progress will follow.


Dan

Carolina Custom Aircraft

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.