Molding plastic parts to metal - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Body - Exterior
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 02-29-2004, 06:17 PM
Registered User
 
Join Date: Feb 2004
Location: IL
Posts: 1
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Molding plastic parts to metal

I have a 1980 Trans Am and what I want to do is mold the back spoiler, which is plastic and mold the bottom fender flairs (rubber) flush with the car. I have seen it done and it looks sharp. My question is what should I use that will bond to both metal and rubber. The rubber fender flairs bolt on and the edge that runs along the quarter panel I plan to pop rivet then apply something over. I am afraid to use bondo or will it be OK. Something else I thought was lay a strip of fiberglass over the seem to add strenght. What do you think?

Thanks
Luke

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 03-01-2004, 09:46 AM
STUPID is as STUPID does...
 
Last wiki edit: Crankshaft Coalition Wiki Last photo:
Join Date: Nov 2003
Location: Stupidville, USA
Posts: 1,735
Wiki Edits: 1

Thanks: 11
Thanked 85 Times in 79 Posts
Don't do it... Metal and fiberglass have different expansion rates and the joint will fail in a short time. The urethane fender flares will be especially prone to flexing and cracking and there is no way to stabilize the joint because of this.
There are some urethane panel adhesives available that will glue the dissimilar materials together but I have no experience with blending them into a metal panel and how long the transition joint will last. My experience, everytime, has been bad when trying to mold dissimilar materials together. It will look good for a while then you will start to see the seam...
Mark
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 03-01-2004, 10:26 AM
willys36@aol.com's Avatar
Hotrodders.com Moderator
 
Last wiki edit: How to rebuild a Rochester Quadrajet 4MV carbureto...
Last journal entry: How to change auto shift timing on 200R4
Last photo:
Join Date: May 2002
Location: Bakersfield
Posts: 8,393
Wiki Edits: 21

Thanks: 1
Thanked 8 Times in 8 Posts
http://hotrodders.com/showthread.php...***+steel+bond
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 03-01-2004, 11:08 AM
Hoyt's Avatar
74 Nova SS
 
Last photo:
Join Date: Mar 2003
Location: Chattanooga, TN
Age: 43
Posts: 20
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
bonding

I just bought a rear bumper filler for my 74 Nova and other than the piece not fitting correctly, there was no way to attach the fiberglass piece to the rear of the car. I used the two part epoxy that you can buy at your local paint store, that is used to bond body parts together. I would suggest finding someone that has the equipment already because the gun that mixes the two tubes together is very expensive. I got lucky and the guy doing my painting had what I needed to attach the piece to the car. I'm hoping not to have any problems with doing this, the mixture dries like a hard rubber. It's flexible so I'm thinking that it won't fail with the difference of expansion, time will tell. This stuff wouldn't be good for making the part look seamless though I don't believe, but if bonds like you would not believe.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 03-01-2004, 12:06 PM
willys36@aol.com's Avatar
Hotrodders.com Moderator
 
Last wiki edit: How to rebuild a Rochester Quadrajet 4MV carbureto...
Last journal entry: How to change auto shift timing on 200R4
Last photo:
Join Date: May 2002
Location: Bakersfield
Posts: 8,393
Wiki Edits: 21

Thanks: 1
Thanked 8 Times in 8 Posts
No problem gluing parts to the car like you did Hoyt, as long as there is a margin seam. The problem arises when one tries to get the seamless look 'cause there is just enough movement in the margin to crack paint and filler if it is a rigid variety.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 03-01-2004, 12:13 PM
Hoyt's Avatar
74 Nova SS
 
Last photo:
Join Date: Mar 2003
Location: Chattanooga, TN
Age: 43
Posts: 20
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
rigid

I agree Willy, I don't know how workable this epoxy is as far as sanding goes but I see it a lot in truck beds so I know that you can paint it with no problems. But you would never get the seamless look from if I don't think. I'd probably just use body filler and hope it lasts until I'm ready for a new paint job. Otherwise someone has some metal fabrication work to do.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 03-03-2004, 12:51 AM
Hot Rod Hellion's Avatar
Member
 
Join Date: Feb 2004
Location: Little Rock
Age: 37
Posts: 81
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I once bought a 73 camaro where the previous owner did just that. The three piece duck tail spoiler was molded in. And the filler had cracked down the whole length of it.

There might be better products or better workmanship out there, but I would be afraid anyway.

also, the corner pieces of the spoiler are not hard fiberglass on the trans ams like they are on the camaros. They are urethane rubber.

Urethane parts require a flexable additive be added to the paint to prevent spiderweb cracking of the topcoat.
Reply With Quote Quick reply to this message

Recent Body - Exterior posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On



All times are GMT -6. The time now is 10:33 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.