How much flex can Bondo take ?

14506 Views 16 Replies 6 Participants Last post by DJuanHouston, Oct 29, 2005

DJuanHouston

Discussion Starter · Oct 25, 2005

I used a bumper and masked it and made a fiberglass copy, came out really nice so far. Of course it needs smoothing and bondo etc... but right now its a little to flexable though I will use more resin and brace points the mold had, though I wonder how much flex can the bondo take?

On the Bondo I did for my glassed yamaha front it seems to bend a good amount for a solid though its not that thick. What is the point at which i can still have some fles for fit and car flex but not crack the bondo

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Flofocus

· #2 · Oct 25, 2005

I would say you wont have much room for flex with Bondo... Are you sing a bondo filler or a Bondo-hair type filler? I would guess the Bondo hair would let it flex a little since it has the strands of fiberglass hairs in it. But Im not sure, the only things I have done with Bondo/fiberglass is a guauge pod, grill & sub enclosures so they dont really get to experience any 'outdoor' abuse like a bumper would....

Majikal

· #3 · Oct 25, 2005

I wouldnt use bondo on a bumper. Bondo dries hard, like a sheet rock type texture almost. It cracks really easy, not to mention seperates from its mating surface easy when flexed. For a bumper, Id use some kind of plastic filler, like duraglass or something. It dries like silicon, and it can flex a little.

2xtremefocus

· #4 · Oct 25, 2005

A good filler to check out is Rage Gold made by Evercoat, it's what we use here in the shop at school, and it works good on plastics. Another filler to look into is Poly-Flex, which can be used alone or mixed with a normal filler, like Rage Gold for use on flexible plastics. I've used about a 75/25 mix of Rage and Poly-Flex on plastic parts here before, and have never had a problem with it.

I don't know about using duraglass on plastic, it dries super hard and may crack, I'd stick with Rage and Poly-Flex for plastics.

DJuanHouston

Discussion Starter · #5 · Oct 25, 2005

this is a complete new fiberglass bumper I made from another urethane bumper, Im looking at what to use to smooth and fill for sanding. There is no plastic in it just a fiberglass thats flexable because its not really thick.

Flofocus

· #6 · Oct 25, 2005

Apply more layers of glass and sand, sand, sand.

When your done, more sanding.

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DJuanHouston

Discussion Starter · #7 · Oct 26, 2005

true true and oh yeah true though i wanyed it to stay a little flexible it doesnt crack from a rock or something

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2xtremefocus

· #8 · Oct 26, 2005

More layers of fiberglass, more resin, sand it, then use a good filler like I talked about earlier, like Rage Gold by Evercoat. With auto body products, you get what you pay for, cheap Bondo brand filler is junk, pay a little more and get something good, you won't regret it.

midwestmuzikk

· #9 · Oct 26, 2005

If I was doing what you were doing, I would use a poly filler. aka polly putty, aka lightwieght poly glaze.

You won't need the "fill" that regular body filler does. You need a self leveling filler putty. It's not as thick as "bondo", a little bit runny.

Hope this helps.

Oh yea.. that Rage Gold is in my opinion about the best stuff out there. It even goes one step further with Rage Gold Extreme, wich is what I use.

midwestmuzikk

· #10 · Oct 26, 2005

Like 2xtremefocus said, use more 'glass and resin to make it stronger. Don't use the filler for strength, cuz it wont hold up.

DJuanHouston

Discussion Starter · #11 · Oct 26, 2005

cool ill look into the rage also. I has come out good byt it all comes down to the finish i guess!!

2xtremefocus

· #12 · Oct 26, 2005

Good to hear it's coming along good. The poly putty is a good choice as well.

We just did some crazy fiberglass work on the doors of our Ford 500 widebody drift car at school, and on the doors, we gave them a light skim coat of filler just so we could sand them nice and smooth. We also used a skim coat of filler over the rear quarters once we had them attached to the car and all the 'heavy' filling was done with Duraglass.

On your bumper, for a skim coat, you could probably go with a 75/25 mix of filler to flexible filler. (75% Rage to 25% Poly Flex is what I've used) Then sand smooth, and proceed to your primer, sealer, paint, clear. (if you're gonna basecoat/clearcoat, or single stage)

midwestmuzikk

· #13 · Oct 26, 2005

just a note. That Rage Gold is not a polly putty. It's more like the bondo stuff that a lot of people seam to use. It's great stuff, just not what I would personally use on your project, unless you want to do a 50/50 mix or something, if you need some more build.

2extreme...is there a site with some pics of your work? Sounds like you guys are doing some sweet things.

2xtremefocus

· #14 · Oct 26, 2005

just a note. That Rage Gold is not a polly putty. It's more like the bondo stuff that a lot of people seam to use. It's great stuff, just not what I would personally use on your project, unless you want to do a 50/50 mix or something, if you need some more build.

2extreme...is there a site with some pics of your work? Sounds like you guys are doing some sweet things.

Well, one of our cars, you can find by doing a Google search for 'purple rain dodge magnum.' That was last year's SEMA car. www.wccnet.edu has a couple pics of our Chevelle that was on Rides last tuesday. The Mustang will be on the site for Mustang Racing Technoligies soon (I hope) and our Ford 500, I'm not sure how soon I can get some pics of it.

I'm gonna talk to a couple of my classmates, and see if he can get some pics of the cars at SEMA for me when they go next week.

Also, the Purple Rain Magnum will be in the December issue of Speed, Style, and Sound magazine which should hit shelves early November according to the head guy at S3 Magazine I talked with a couple weeks ago.

I just wish I had a damn digital camera so I can document all these projects and create a web page of the builds.

If you're interested, check TLC's website, and see if they are gonna re-run the episode of Rides titled 'Summer School' to see our Chevelle.

I really have to get pics of our cars, it pisses me off even that I don't have pics of these things.

Oh, we also did paint and body on an Acura RSX for Car and Driver which will be at SEMA. We just found out they will have that car on display at the end of last week, so this year, barring a massive problem with the 500, Washtenaw Community College will have 4 cars represented at SEMA this year.

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midwestmuzikk

· #15 · Oct 28, 2005

Thats real tight man. Nice work. We have something in common, our 70 challenger will also be at the SEMA show this year.

Mr. Zetec

· #16 · Oct 29, 2005

4

i used alot of bondo and fiber glass on my car

The only prob is now i have a few hair line cracks but it was caused by a towing company, while on the flat bed the towing company stored two 2X6's under my side skirt, it actually cracked more side skirt then my fender flares.

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DJuanHouston

Discussion Starter · #17 · Oct 29, 2005

leave it to other people yea know!!

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