Can you fiberglass over epoxy primer? - Hot Rod Forum : Hotrodders Bulletin Board -- Hot Rod Forum

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

LinkBack Thread Tools
  #1 (permalink)  
Old 09-05-2019, 07:17 PM
Registered User
Join Date: Sep 2019
Posts: 1
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Can you fiberglass over epoxy primer?

My vehicle is unique, I don't plan on making it showroom floor worthy or anyting, but I won't get too much into that..I had to remove some fiberglass in order to then remove some rusty areas in the floor of the interior. I then coated it with epoxy primer in hopes that it would be the final coat considering it's in an inconspicuous area. That way I can get some other work done and keep the floor from rusting before the fiberglass stage. But I'm now learning that I may not be able to fiberglass over epoxy primer, though I've heard that you can scuff the primer with 80 grit and fiberglass over it depending on the fiberglass. I have Bondo fiberglass resin which I hope to put over the Raptor epoxy primer. Is there any way I can make this work? Thanks!

Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 09-06-2019, 06:43 AM
Excellenceautosoluti's Avatar
Registered User
Join Date: Nov 2016
Location: Pinehurst North Carolina
Posts: 136
Wiki Edits: 0

Thanks: 73
Thanked 24 Times in 22 Posts
You can put fiberglass filler such as Dynaglass, Kitty Hair, Tiger Hair, Etc.. over bare metal prepped with 24 or 36 grit Roloc Grinding Disc. You Cannot put fiberglass mat or resin over metal with, or without Epoxy coating. It will pop off.
I have seen guys install fiberglass hood scoops on a metal hood, and it NEVER works. Please let us know what you are trying to accomplish and someone here will have a solution that will work.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 09-06-2019, 06:59 AM
Molon Labe's Avatar
Registered User

Last journal entry: Floors
Join Date: Sep 2017
Location: Hoosick Falls, NY
Age: 70
Posts: 160
Wiki Edits: 0

Thanks: 70
Thanked 29 Times in 19 Posts
Aaron, I don't know the answer to your question but Southern Polyurethanes (SPI) is a smaller paint company that is outstandingly focused on customer service. They have a forum on their website that is very active and this question would be perfect for them. The forums are broken down by subject and there's even one for fiberglass and plastic. You might want to try posting this question there.

Fiberglass & Plastics | Southern Polyurethanes Forum
Reply With Quote Quick reply to this message
The Following User Says Thank You to Molon Labe For This Useful Post:
55 Tony (09-11-2019)
  #4 (permalink)  
Old 09-06-2019, 08:58 AM
Registered User
Join Date: Jan 2018
Location: Laurel, De.
Posts: 417
Wiki Edits: 0

Thanks: 213
Thanked 165 Times in 123 Posts
As said, fiberglass mat and resin doesn't stay attached to metal very long. Using epoxy resin such as West Systems might do better but if you have rusted/ perforated metal welding in new metal is the better way. A lot of repair type resins contain wax so they cure properly. Laminating resins are better for layups but they need a topcoat to cure properly. Epoxy resins have the best adhesion but they need prep between layups.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 09-06-2019, 02:18 PM
Registered User
Join Date: Jan 2012
Location: Grand Rapids, MI
Posts: 1,910
Wiki Edits: 0

Thanks: 213
Thanked 393 Times in 320 Posts
Not sure why your putting glass down on an interior floor.

Weld in panels, grind them down, then lay down matt, or undercoating. If you want to change something it is easy enough to cut out later.

If you want a exposed area such a hump you can simply undercoat the high traffic areas. Or install an aluminium in place of steel by panel bolding(permanent)or rivets(temporary) to a recessed area so the aluminum is flush.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 09-10-2019, 07:38 AM
Brian Martin,Freelance adviser
Join Date: Jun 2004
Location: San francisco bay area
Age: 60
Posts: 16,146
Wiki Edits: 0

Thanks: 6,239
Thanked 6,695 Times in 4,305 Posts
I did a fiberglass patch on the floor of my Rambler. The car was all together and I just figured I would do a little test to see how it would work. I spot blasted the metal and laid fiberglass mat over it. I then brushed epoxy primer on over that. I drove the car for 7-8 years every single day after that, it never saw a garage once, and it lasted fine. I would check on it every year when I did a brake check and adjustment being the master cyl was right there, I had to pull up the carpet to get to it. And that fiberglass looked like the day I did it every year.

I have to believe that if you sand the epoxy primer the fiberglass would adhere to it. The bummer is with pitted metal the epoxy can't all be sanded, I don't know, post that question on the SPI forum and see.

Reply With Quote Quick reply to this message

Recent General Rodding Tech posts with photos

Quick Reply

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:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


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 07:17 AM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.