Bondo experts please read

[Darianis]

I recently laid down my bike and as a result I have a dent in my tank. it's about 1.5 inches wide and 4 inckes long, something like .75 to 1.25 inches deep. the dent is along a complex curve of the tank.

Now I want to repair it, and thought that bondo filler would be the best option, but I have no experience with it. as I understand it you sand the area to be repaired doen to bare metal, clean it throughly then apply bondo and sand smoth and then paint. The filler is the consistance of penut butter? or more like paydogh.

is there any more to it than that or are there any pitfalls I need to be aware of before I start. I don't want to get half way through and realise I should have done something differant and then have to start over heh.

Thanks

Tony

[Miranda]

Hi

I hate to bondo....

expect to do two layers

sand the area with rough sandpaper like 60 grit

fill the area

wait about an hour and rough shape with a surform (looks like a cheese grater)

look over your work.

then If you are like me, sand it and paint it

and then see the flaws and lumps.

sand the paint down, and add more bondo, and sand and paint.

I have never done the last step more than once.

good paint work is harder to do than the bondo.

miranda

[bgary]

To whatever extent you can, get the metal back out close to its original shape, first. Bondo is good for making things smooth. However, Bondo doesn't like to be too thick - if it is laid on more than 1/4" thick or so, you run the risk of it cracking (it expands and contracts with temperature, but at a different rate than the underlying metal, so... if it is too thick it can't flex enough, and will separate)

The other thought, depending on application, is that Bondo is very porous and depends on a paint surface to seal it. If there's any chance that Bondo is going to be left exposed, better to use an epoxy filler (can get good ones at a marine hardware store). Much more tolerant of water and weather.

$.02

[Darianis]

Yea that's basically waht iwas thinking... I'm not really looking to make it show quality or anything heh... hell I'm just gonna rattle can paint it and prolly let the hids do some silly graphics or sometihng. haven't really decided.

Thanks for the info

Is bondo the best material for this type of repair. I only ask cause I have never done it and have no information heh just only heard of bondo heh.

Edited September 4, 2008 by Darianis

[Joe4d]

many moons ago I had the same situation I bought filler, a spray gun etc etc etc and got done and it looked like crap, took it to an automotive body shop and they made it look great for less than I spent on the bondo, sand paper, paint, etc.

[HSMITH]

That dent is WAY too deep to fill with Bondo. Get it ironed out close, then go in with plastic filler. No more than 1/4" thick and that is pushing it.

[GTOSHootr]

I'm no expert but I watch the guys in our shop often. Like HSMITH said, they would iron or pull it out to minimize the amount of filler needed. We have a gun that tack welds pulling studs to metal that you later break and grind off. They use DuraGlass body filler, never Bondo. I think it is stronger, adheres better, and handles moisture better. That only gets it so smooth though. They use another finer filler they refer to as "icing" that comes in a tube sands out smoother, and even then they follow up with a high build primer. The idea is to not only fill the dents but the sanding scratches you are putting into the layers of filler. In a crappy job a wavy surface and sanding scratches are really visible even through a few layers of paint.

A lot of guys at body shops seem to do tanks on the side. Some guys can bang a job like that out in no time.

[Darianis]

Hmm I don't wanna spend too much getting it fixed heh as I'm still paying to get me fixed Also I kinda like to do my own work when I can. Anyone have any specific products taht ishould ask about or try?

Thanks again

Tony

[SiG Lady]

I had to laff when I finally dove into this thread and saw that it was a gas tank he was talking about..... and not

1. A tank (like, where do you manage to PARK it???)

2. A fish tank (do you also need hardwood floor repair now as well?)

3. A scuba tank (you survived.)

[Darianis]

LOL Siggy you made me laugh that time. and I and now you owe me one cause it still hurts when I laugh heh.

I had to laff when I finally dove into this thread and saw that it was a gas tank he was talking about..... and not

1. A tank (like, where do you manage to PARK it???)

2. A fish tank (do you also need hardwood floor repair now as well?)

3. A scuba tank (you survived.)

[AlamoShooter]

The Bondo shrinks as it drys = that is one reason why you don't want it too thick .

Sanding the old paint off and putting scratches in the metal so the bondo has something to grab to

Waring Power sanders make sparks and I can tell by your post you are not into removing the tank and filling it with water before you work on it. So Watch out for sparks Fire BOOM

A bad Bondo job looks LOTS worst than most any dent.

[earplug]

Don't forget to buy a decent Tank Bag to help hide the ding.

They work real good for hauling stuff to and from the range.

[JimmyZip]

I'm no expert but I watch the guys in our shop often. Like HSMITH said, they would iron or pull it out to minimize the amount of filler needed. We have a gun that tack welds pulling studs to metal that you later break and grind off. They use DuraGlass body filler, never Bondo. I think it is stronger, adheres better, and handles moisture better. That only gets it so smooth though. They use another finer filler they refer to as "icing" that comes in a tube sands out smoother, and even then they follow up with a high build primer. The idea is to not only fill the dents but the sanding scratches you are putting into the layers of filler. In a crappy job a wavy surface and sanding scratches are really visible even through a few layers of paint.

A lot of guys at body shops seem to do tanks on the side. Some guys can bang a job like that out in no time.

This is exactly what I would reccomend from experience with this stuff at some friends shop who liked my table finish work and had me help him get out some isurance work before a deadline.

The Bondo shrinks as it drys = that is one reason why you don't want it too thick .

Sanding the old paint off and putting scratches in the metal so the bondo has something to grab to

Waring Power sanders make sparks and I can tell by your post you are not into removing the tank and filling it with water before you work on it. So Watch out for sparks Fire BOOM

A bad Bondo job looks LOTS worst than most any dent.

The old gas vapors and spark trick , " Works every time" (Maxwell Smart Voice off)

Edited September 5, 2008 by JimmyZip

[JKSNIPER]

Body shop relatives......

Recommendations:

1. Have it done by a pro.

You'll save time money and aggravation.

Also you can get a really cool design painted over it since it has to be painted anyway and will probably not match the other stuff (Fenders, covers , etc...) you might as well use this as an excuse to get that really nifty USMC emblem you've always wanted on there.

2. If no to#1 then empty the tank and fill with CO2.

Inert gas filled tank can't go BOOM!

Nice and safe.

If no to that

3. Fill the tank with gas all the way up.

Explosions are more likely with an empty tank from the vapors.

Sand to bare metal.

Rust can form on the bare metal so this should be done when you can at least devote the day to it without interruptions.

Fill the void with bondo.

Let it cure.

Sand it smooth using pnumatic sanders or a random orbit sander.

Since you're not experienced doing it use a smaller grit paper. Not an 80 grit but more like a 100 or even 120 grit.

It will take you longer but you're less likey to gouge it or over sand it with a finer grit paper.

Change the paper frequently. Don't try to use it until it fals off or is shredded to save $.

Be aware of heat build up from friction and stop if its getting too hot under the sanding.

Remember you're working on a GAS TANK not a water tank.

Get the "icing" from your local body shop supply. It comes in a huge toothpaste type tube and it may be blue in color and called "glaze coat" or some other name.

Spread this on using small plastic spreaders taking care to not lump it up or have it spread over a void without filling it.

Press it in using mild/moderate amount of force and feather/blend the edges.

Kind of like spackling drywall.

Sand this down smooth.

Repeat.

Once its smooth (feel it with your hands. I've found spots that I could not see using hand touch.) sand it to at least 400 grit.

Then you can tape off the areas to not be painted and hit it with primer and then paint it.

Good luck with it.

JK

[Darianis]

Body shop relatives......

Recommendations:

1. Have it done by a pro.

You'll save time money and aggravation.

Also you can get a really cool design painted over it since it has to be painted anyway and will probably not match the other stuff (Fenders, covers , etc...) you might as well use this as an excuse to get that really nifty USMC emblem you've always wanted on there.

2. If no to#1 then empty the tank and fill with CO2.

Inert gas filled tank can't go BOOM!

Nice and safe.

If no to that

3. Fill the tank with gas all the way up.

Explosions are more likely with an empty tank from the vapors.

Sand to bare metal.

Rust can form on the bare metal so this should be done when you can at least devote the day to it without interruptions.

Fill the void with bondo.

Let it cure.

Sand it smooth using pnumatic sanders or a random orbit sander.

Since you're not experienced doing it use a smaller grit paper. Not an 80 grit but more like a 100 or even 120 grit.

It will take you longer but you're less likey to gouge it or over sand it with a finer grit paper.

Change the paper frequently. Don't try to use it until it fals off or is shredded to save $.

Be aware of heat build up from friction and stop if its getting too hot under the sanding.

Remember you're working on a GAS TANK not a water tank.

Get the "icing" from your local body shop supply. It comes in a huge toothpaste type tube and it may be blue in color and called "glaze coat" or some other name.

Spread this on using small plastic spreaders taking care to not lump it up or have it spread over a void without filling it.

Press it in using mild/moderate amount of force and feather/blend the edges.

Kind of like spackling drywall.

Sand this down smooth.

Repeat.

Once its smooth (feel it with your hands. I've found spots that I could not see using hand touch.) sand it to at least 400 grit.

Then you can tape off the areas to not be painted and hit it with primer and then paint it.

Good luck with it.

JK

Wow that's exactly what I needed heh I don't think it will look professionally done, but as I was the one who painted in in the 1st place heh that's not a real problem. I think for the time being I'm just gonna spray some rustolium on it to prevent rust and leve it be till I get healed enough to get all the work done.

Getting more strength in my arm everyday. I should only have to miss one match and then I'll be good as new.

Thanks for all the info guys I think this will be a fun project. I love to tinker with the bike. I can't wait till I replace the headlight assemble with a custom piece heh. Fun Fun Fun.

[Neomet]

I'll pile on to the "See what it actually costs to have a pro fix it" sentiment. I've seen very few homedone bondo work that made the damaged metal look better than it did before the repair. Most looked like refugees from a Mad Max film. Doing bondo well is sort of like mudding drywall. It takes a certain amount of skill/proficiency to do well. Also as others have said your damage is really too deep and my bet is you will wind up pretty quickly with cracks showing.

There are also paintless dent removal places, some of which work on gas tanks that you might check out.

[GTOSHootr]

I just poked around our body shop supply closet and got more info on the fillers we use. Duraglas is strong and waterproof but doesn't shape the best, Evercoat Chromo-a-lite is a general filler, and the fine sanding stuff is USC Icing polyester filler.

[SiG Lady]

Darianis, when I posted that list I didn't realize you were injured! Sorry. But, remember: Laughter is healing, so the pain is well-intentioned. Or something.

Take care of yourself and forget the Bondo. It tends to pop off the surface (once it's shrunken a bit) and land embarrassingly at your feet in front of your friends. Not good.

[-JQ-]

I had to laff when I finally dove into this thread and saw that it was a gas tank he was talking about..... and not

1. A tank (like, where do you manage to PARK it???)

2. A fish tank (do you also need hardwood floor repair now as well?)

3. A scuba tank (you survived.)

I too was a bit disappointed...I was hoping for at least a classic M60...where you park it? Anywhere you like! There is a great video somewhere of a guy who stole one...that thing will rip through a motorhome like plasma through AL foil.

[Ming the Merciless]

As others have said, the dent is too deep for just bondo or fillers. Pick up one of these when Harbor Freight has them on sale for $89.00 and you can pull most of the dent out.

http://www.harborfreight.com/cpi/ctaf/disp...Itemnumber=3223

Here are some general instructions on it's use.

http://books.google.com/books?id=zh94U0W_h...esult#PPA304,M1

[TMC]

If you take this on yourself he's a bit of advice from a shadetree body guy,

Plastic fillers, if mixed right, are only workable for about 5 minutes. If you don't apply it really smooth (which takes lots of practice) then you'll want to start sanding the high spots off just after is gets stiff. The longer you wait the harder it gets so use 80-60 grit and get it close within 15-20 miuntes of mixing. After that use finer paper and a block to get it to the final shape.

Filers need a mechanical bond so the surface needs to be clean and rough, 60 grit.

Don't try to get the final shape when appling, use more and sand it to shape, otherwise you'll be putting more on later.

"Icing" or glazing putty can fill pin holes but nothing bigger, its basically thick uncatalized primer and takes a long time to dry

When you get the filler taken care of use a sealer before primer.

Heavy coats of primer are ok becuase most will end up on the floor, like filler.

When you get to sanding the primer, wet it down once in a while and look it over, at the right angle it will look like glossy paint and you'll get an idea of how smooth the area is and what the final finish will look like.

Paint the whole tank rather than trying to blend it, it will be easier, the edges won't show and it will look better.

Automotive supplies aren't cheap these days and once you've bought filler, putty, sealer, primer, sand paper and paint it may be cheaper and you'll get a better result taking it to a pro.

Have fun!

[3GunF1Guy]

Having been a bodyman in a previous life. LEAD IS THE BEST filler there is. You can put it on thick or thin never shrinks, comes off and is 100% waterproof. Its just a little hard to work with. Next is the aluminum fill waterproof filler. Its really just waterproof bondo with aluminum in it. It works good but is more expensive than bondo. I hate bondo.

I would alway laugh and feel bad for the clients of American Hot Rod, they would spend a lot of money to have a car built, then they would cover it in bondo before finishing it. The proper way is to straighten the metal and "pick and file" it to make it straight. If you needed filler then use lead.

But I have used a lot of bondo in my life though. We had a saying "A little putty and a little paint makes it look like what it aint."

Good Luck

Scott

[sfinney]

Its very very hard to get good results with body filler, unless you get some practice in. Biggest misconception is the imperfections of your work will covered over by paint, and go away. Reality is the paint magnifies every little ripple, pore, rough mark.... once you get the bondo to where it is perfectly shaped to the tank dent, you'll still need several coatss of primer/filler to make it smooth. The putty in a tube helps lots too. After all that you need a good paintjob. Again, spray cans will not get you the result you want. By the time you pay to have the tank repainted by a pro, they probably would have fixed the dent for free more or less. Just my 2 cents.