I’m intrigued by metal body filler. What are the benefits over the ‘bondo’ stuff?
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- Thread starter Bewarethemoon
- Start date
I’m intrigued by metal body filler. What are the benefits over the ‘bondo’ stuff?
I'm currently working on one I found in a scrap metal yard years ago. As I was working there at the time the boss let me have it for free. It looked as if someone had taken an axe to it. Truth be told I could have bought a new aftermarket tank for less than what I'll have in this one by the time I'm done but then I wouldn't get to practice with the plasma cutter I just traded a guy out of and practice my horrid welding and metal working skills.
And yes, there are plenty of pin holes but when all is done, before I paint I'll use the rest of that Red Kote I have left from the last tank I sealed just in case I missed any.
After all, it's not a frame so even my welds aren't too likely to break.
And yes, there are plenty of pin holes but when all is done, before I paint I'll use the rest of that Red Kote I have left from the last tank I sealed just in case I missed any.
After all, it's not a frame so even my welds aren't too likely to break.
I used metal body filler for the soul purpose of hardness and chemical resistance. I had holes all the way thru. After I had my dents pulled, i taped over holes with duct tape really well. Then I used this kit
Motorcycle gas tanks expand and contract with temperature changes more than body panels seem to, and ordinary polymer fillers like Bondo do not. It may take a few seasons, but eventually you'll see a line at the edge of the repair where the Bondo is starting to crack out. Because aluminum-bearing fillers respond to temp changes, they're much more resistant to cracking out. The repairs are still invisible on one tank that I filled with Metal-2-Metal over 10 years ago.
Very good point. I tried metal filler at first for the soul purpose of powder coating. Can't powder coat over bondo. Even powder coating over metal filler didn't look so good. It expands and contracts with the powder curing process and comes out wavy.
While I've never used the metal fillers myself I do know that Bondo is notorious for shrinking over time. That's why I was taught to use brazing and welding, lots of grinding, and then finish up with glazing putty making every effort not to use Bondo. But then again, the guy who taught me preferred working with lead right up until the government told him he couldn't.
Of course it was lead, exposure to fumes, dust, etc, etc that has him wearing an oxygen mask now. But once in a while when he's feeling good, we go riding together.
I was watching a documentary once on how cars were made by Rolls Royce and this guy was filling roof panel seams with lead, man he made it look as easy as spreading butter! It really does a nice job.
Well, I'm gonna be (respectfully) disagreeable here. As someone who's worked with bondo since the seventies, I'll offer that, done correctly, bondo doesn't get wavy or fall out over time. I've seen some of my work 10-15 yrs after that's just as good as the day I did it. Consider this; 99.9% of all body shops use bondo. Are their repairs falling out after a few yrs? No, they wouldn't stay in business long if that were the case.
Bondo uses a polyester resin as a binder. The aluminum stuff uses a polystyrene binder. The two chemicals are so closely related they even use the same keytone based hardener. Very similar properties except for the actual filler. And the filler isn't what's important, it's the binder that determines whether or not it stays affixed.
A few yrs ago I was involved in repainting a Cessna 310. Part of that process is going through the logbooks and finding out when and what paint has been used in the past so you know how much stripper to have on hand. As we stripped the tip tanks, we found lots of pink bondo on them. I don't recall the exact number, but it was something like 15 yrs prior when the paint was applied. The bondo repairs were not visible until we stripped the paint. And those were fuel tanks exposed to sub-zero temps at altitude and 100+ deg days sittin' on the ramp. The stuff works. It's all in the preparation.
Bondo uses a polyester resin as a binder. The aluminum stuff uses a polystyrene binder. The two chemicals are so closely related they even use the same keytone based hardener. Very similar properties except for the actual filler. And the filler isn't what's important, it's the binder that determines whether or not it stays affixed.
A few yrs ago I was involved in repainting a Cessna 310. Part of that process is going through the logbooks and finding out when and what paint has been used in the past so you know how much stripper to have on hand. As we stripped the tip tanks, we found lots of pink bondo on them. I don't recall the exact number, but it was something like 15 yrs prior when the paint was applied. The bondo repairs were not visible until we stripped the paint. And those were fuel tanks exposed to sub-zero temps at altitude and 100+ deg days sittin' on the ramp. The stuff works. It's all in the preparation.
While I never did it I saw him do it. If you don't mind the heat and the risks lead is a great material to work with. Just remember, there's a reason the hot rods of my Daddy's days were called Lead Sleds. Nobody used fillers in real racing machines.
Anyone remember Black Knight body filler? It was hard to work with, dried hard as a rock. But once it set up it could not be removed without tearing up the metal it was bonded to.
Agree with Jim; logged a lot of miles on bondo/paint jobs I did so even with my crap prep it sticks around pretty good.
There was a CB750 chooper with a heavily "frenched" hardtail frame that REALLY got exercised, that bondo all stayed put, wish I still had a pic.
There was a CB750 chooper with a heavily "frenched" hardtail frame that REALLY got exercised, that bondo all stayed put, wish I still had a pic.
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I wrecked my XS650 in 1985. The tank was damaged. The repair was made with plastic (or whatever) body filler. There has been no change in 35 years. The paint is now dead, so I'll do it again, just as before. I'm not disagreeing as much as stating my personal experience. The lack of response to temp change did not affect my repair.
Haven't seen a Bondo tank repair actually fall out, but I've seen plenty that developed edge cracks over time, and the guys who do P&B work at local shops blame expansion and contraction and won't use Bondo on a gas tank. Maybe the cause is bad prep after all, and not the compound. Thanks, guys--live and learn.
My first job out of school was in a body shop. I did it all, building metal quarter panels, filling, shaping, primer and paint. I was formally trained before that with the RM method.
While the boss was away I repainted his old Chrysler Imperial with the octagon steering wheel. The former lead repairs were in awesome shape and worked real well with some touchup of plastic filler.
https://www.zoro.com/bondo-fiberglass-reinforced-voc-24624-1-qt-272/i/G1403543/?msclkid=a786b77c7f0d1b2d309ee96fba557aff&utm_source=bing&utm_medium=cpc&utm_campaign=PLA_US_L1 Adhesives & Sealants&utm_term=4586200438774309&utm_content=All Products&gclid=CNH1__qS8OYCFbeTxQIdvbwJ6g&gclsrc=ds
If I am bringing something up to shape I use chopped fiberglass filler first, the Bondo can right next to the plastic filler, then a rough grinding disc, then 60 grit paper strips on a sanding block. When the shape is there I put on a coat of plastic filler about 1/4" above the surface contour, then rough grinding disc on the plastic filler high spots, then 60 grit paper again. Repeat with a skim coat of plastic filler and sanded again with 60 grit, I don't make it super smooth, I rely on sandable primer to fill in the 60 grit scratches. Three coats of primer sanded with 220 dry grit, no block. Then 2 or 3 coats of primer sanded with 400 paper dry, no block. I don't go any smoother than that, paint does the rest of the smoothing.
So, my repairs are mostly fiberglass filler and very little plastic filler. The fiberglass filler can even be exposed in some places if the pin holes have been blown out and filled with plastic filler.
That spot putty stuff was hardly ever used and was frowned on. Maybe on a Friday before a break when the boss was busy, and only used on pinholes, before the first primer is sanded.
Scott
While the boss was away I repainted his old Chrysler Imperial with the octagon steering wheel. The former lead repairs were in awesome shape and worked real well with some touchup of plastic filler.
https://www.zoro.com/bondo-fiberglass-reinforced-voc-24624-1-qt-272/i/G1403543/?msclkid=a786b77c7f0d1b2d309ee96fba557aff&utm_source=bing&utm_medium=cpc&utm_campaign=PLA_US_L1 Adhesives & Sealants&utm_term=4586200438774309&utm_content=All Products&gclid=CNH1__qS8OYCFbeTxQIdvbwJ6g&gclsrc=ds
If I am bringing something up to shape I use chopped fiberglass filler first, the Bondo can right next to the plastic filler, then a rough grinding disc, then 60 grit paper strips on a sanding block. When the shape is there I put on a coat of plastic filler about 1/4" above the surface contour, then rough grinding disc on the plastic filler high spots, then 60 grit paper again. Repeat with a skim coat of plastic filler and sanded again with 60 grit, I don't make it super smooth, I rely on sandable primer to fill in the 60 grit scratches. Three coats of primer sanded with 220 dry grit, no block. Then 2 or 3 coats of primer sanded with 400 paper dry, no block. I don't go any smoother than that, paint does the rest of the smoothing.
So, my repairs are mostly fiberglass filler and very little plastic filler. The fiberglass filler can even be exposed in some places if the pin holes have been blown out and filled with plastic filler.
That spot putty stuff was hardly ever used and was frowned on. Maybe on a Friday before a break when the boss was busy, and only used on pinholes, before the first primer is sanded.
Scott
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Contour sanding...………………….An EX girlfriend said that I would disturb her Wah sometimes. So, when contour sanding you must enter your Wah first, start sanding instinctively and before you know it you will be surprised with a perfect shape.
Damn, I feel like Michael Angelo
Damn, I feel like Michael Angelo
It's not intentional by any means, but I usually wind up feeling like Jackson Pollock. My Wah is usually entered when I'm sanding out the orange peel that I've shot into the top coat and realize that I've gone through to primer: "Wah! Wah! Wah!" I might start a paint job in a spirit of equanimity, but it never holds for long.
I'm not using Bondo to fill holes in the bottom of a gas tank. I'd lose sleep over that. Haha. Bondo as a filler anywhere else? Sure but only on a wet paint job. Everything services a purpose. A lap dance isn't sex tho.... Haha!
You can use it to GLUE custom filler necks on gas tanks!
Was wondering why this tank on madness when I got her had some "bubbles" starting.
