Using body filler.

[wbks]

One of my steel tanks has got a deep dent I need to patch up. I've never really used body filler before, so I'm not sure if you can put body filler over another (dried, sanded) layer of filler? It's impossible to spread this much filler at once without risking air bubbles. Would it adhere properly?

[The Stranger]

One of my steel tanks has got a deep dent I need to patch up. I've never really used body filler before, so I'm not sure if you can put body filler over another (dried, sanded) layer of filler? It's impossible to spread this much filler at once without risking air bubbles. Would it adhere properly?

Why not take some of the dent out?

[NDORFN]

Get some Nutech, I think that's what it's called. It's a 2 part filler with aluminium fibres. Been using it the past couple of days and it's the shit. It'll stick to anything, you can put it on as thick as you like, it's changes consistancy as it dries so you start out with a rough shape and as it hardens you fine tune it until it's like working with clay, and it's easy to sand. I'm pretty sure it's what panel-beaters use. I got it from Repco.

[wbks]

Why not take some of the dent out?I would but I can't bang it out myself and I'd rather use this old tin of body filler that's getting no use, than pay for someone with the tools to do it. I mean, even if I did push it out, wouldn't you still need to use a bit of filler to cover the creases?

[spookytooth]

I have filled some pretty big holes with bondy in cars,and it has stuck to itself ok.

[wbks]

Get some Nutech, I think that's what it's called. It's a 2 part filler with aluminium fibres. Been using it the past couple of days and it's the shit. It'll stick to anything, you can put it on as thick as you like, it's changes consistancy as it dries so you start out with a rough shape and as it hardens you fine tune it until it's like working with clay, and it's easy to sand. I'm pretty sure it's what panel-beaters use. I got it from Repco.If you put too much in one place don't you risk air bubbles?

[koba]

If you put too much in one place don't you risk air bubbles?

I think about 4mm is considered about the max for doing it right.
You CAN go much thicker, I've seen a few shockers BUT its best to pull the dent if you can and then use bog to finish it.
A Slide hammer can be useful here but if you do anything involving heat be sure to purge the tank fully!

I find the newtech good for the main bit of filling but I prefer to finish it off with good ol' pink stuff as it is much easier to work. (I don't have power tools.)

Make sure the surface is CLEAN, DRYand keyed well. rough it up with course sandpaper. You don't even want the natural grease of you fingers on the surface so wash it down with some prepsol or the like before you bog it.

EDIT: ahh the question! If I'm doing a bit and get air bubbles I just put a nice thin coat of pink stuff over it to fill the bubbles, its a bit fiddly.

[koba]

Practice lots and you will get good at it.

Just as a random bit of trivia a guy I knew dip stripped his rally car while rebuilding it. The car was a bit of a veteran being a factory car built for a jap hotshot. He worked out it had 25kg of bog in it!!!

[CookMySock]

Usually, big bog jobs look like big bog jobs. Ie, they look like shit. You will have fun anyway.

Steve

[wbks]

Well the dent was previously filled in (it has to be atleast 4 centermeters deep) with filler. Seeing as so many of you are suggesting that I bump the dent out, what is the proper way to purge the tank? I used to have mates that block one end of their two stroke expansion chamber, put pressurised air in the other and heat the dent gently with a blowtorch untill the dent pushes out. That's the only way I could think of doing the dent without proper tools.

[CookMySock]

I used to have mates that block one end of their two stroke expansion chamber, put pressurised air in the other and heat the dent gently with a blowtorch untill the dent pushes out. That's the only way I could think of doing the dent without proper tools.You used to have them? I can see why. Don't you even think of doing that with a fuel tank - you will blow yourself sky high.

Have a good search on KB and with google before you do anything.

Steve

[wbks]

Well of course I wasn't going to try it right now, but I figure there has to be some way of completely purging a steel fuel tank? I've tried pushing it out with a few spanners and anything else I can fit in and get to the dents with but I don't think it's going to work!

[FROSTY]

WBKS Look dude think this through--worst case senario is???
Reality in this case is the job you do looks like shit and youve gotta strip it back and start again--woopdee doo.
Its already a bog job so the dents a few layers down.
Get stuck in with some 40 grit sandpaper and rip into the old bog so youve got something for the new bog to bit into.
Heres a lil secret for ya. Cut a cardboard profile off of the UNDAMAGED side of the tank.
Now make up some new filler and lay it into the dent.
Your cardboard pofile will give you an idea if you are overthickness with the bog.
Let it go half off and you can shape it to close to the profile with a scaper (looks like a small cheese grater)
have fun dude

[wbks]

Just figured I should ask someone who would know before wasting all the filler! I'll have to wait untill tomorrow, anyway. Nah I took the bog off, it's bare metal all over, now. Might as well try it out and see if I can do it in one go, then...

[NDORFN]

I haven't had any air bubbles at all. It's not the kind of stuff that allows air into it in the first place. I filled a dent about 4cm deep and about 10cm in diameter in one go without any hassles. I doubt you could make air bubbles in this stuff if you tried.

[NDORFN]

It's called Newtech. Just checked.

[Owl]

It's called Newtech. Just checked.

Too bloody expensive to just fill dents. Newtech is for filling holes.

[Pussy]

Just figured I should ask someone who would know before wasting all the filler! I'll have to wait untill tomorrow, anyway. Nah I took the bog off, it's bare metal all over, now. Might as well try it out and see if I can do it in one go, then...

Get hold of Frenchy on kb.
He's a gun at this sort of thing

[motorbyclist]

I'm pretty sure it's what panel-beaters use. I got it from Repco.

my experience working with a panelbeater for 3 months over summer is that panelbeaters use good ol' bog and slide hammers (and weld up anything structural), but for tanks you either knock it out with a rod+hammer from the inside then bog the finish, or buy an extra big pot of bog


Newtech is for filling holes.

+1 I've used a pot of the carbon fibre stuff to hold together cracked fairings in lieu of a plastic weld and it worked well, but the finish was no too great due to the fibres - good thing it was inside the fairings.


put pressurised air in the other and heat the dent gently with a blowtorch untill the dent pushes out. That's the only way I could think of doing the dent without proper tools.

NOOOOOOOOOOOOOOOOOOOOOOOOOOOo!

assuming you fill the tank with water or something to prevent fire, and dont blow the tank apart at the seam with the explosion (from steam or fuel), that is just as likely to pop out the factory leg groove dents as anything else.

my experience is lots of bog and lots of patience wins the day. It comes out well and as said earlier be sure to have a good key and don't let greasy fingers in there.

Experiment (ie, cockup) tells me that if you lay it on far too thick it gets quite hot as it sets. the tank expands, bog peels off. do it in thin layers, and yes a cardboard profile helps, even if it's a guess cause there's no other crotch end of the tank to copy

oh, and get one of those soft foam sanding blocks if you haven't already

[nico]

use metal-tech it like 2 bucka from super cheep i filled some dents in a tank not to long ago and it came out mint just take ya time make sure you go down to bare metal ruf it up give it a good bace to build on then just small layers at a time and build it up, im not a expert this is just what ive always done think thers a pic in my profile of finshed tank


good luck and enjoy

[NDORFN]

There are some dickheads around here.

[ducatilover]

Get some Nutech, I think that's what it's called. It's a 2 part filler with aluminium fibres. Been using it the past couple of days and it's the shit. It'll stick to anything, you can put it on as thick as you like, it's changes consistancy as it dries so you start out with a rough shape and as it hardens you fine tune it until it's like working with clay, and it's easy to sand. I'm pretty sure it's what panel-beaters use. I got it from Repco. We have used that before, it's not too bad at all. Beter than stupid fiber glass filler :2guns::2guns:


I would but I can't bang it out myself and I'd rather use this old tin of body filler that's getting no use, than pay for someone with the tools to do it. I mean, even if I did push it out, wouldn't you still need to use a bit of filler to cover the creases?
Yeah you still want it smooth don't you?
Many bog jobs will get air bubbles in them, just mix a little more and go over it till they are filled and sand her back
I did this job on my cage yesterday, just normal CRC bog

[ducatilover]

Well of course I wasn't going to try it right now, but I figure there has to be some way of completely purging a steel fuel tank? I've tried pushing it out with a few spanners and anything else I can fit in and get to the dents with but I don't think it's going to work!

Slide hammer......:mellow:

[Ixion]

How to attach it ?

[ducatilover]

How to attach it ?

Grow some balls, a Mig and some decent steel pole, make a shape like a U bolt, weld it, get your slide hammer, whacky smacky and you are done. Just keep the tank sealed and full, it's the vapor that burns.

[Ixion]

And a lovely weldy lump on my nice tank!

If I wanted that sort of shit I could drill a little hole to attach the slidehammer with.

[motorbyclist]

Grow some balls, a Mig and some decent steel pole, make a shape like a U bolt, weld it, get your slide hammer, whacky smacky and you are done. Just keep the tank sealed and full, it's the vapor that burns.

dude, fill with water (or any other cheap, nonflammable substance) and leave it open. heating a sealed container is never wise.

the water won't be in there long enough to cause rust.


And a lovely weldy lump on my nice tank!

If I wanted that sort of shit I could drill a little hole to attach the slidehammer with.
and then have to weld the hole back up.....

either way you're using bog

[ducatilover]

And a lovely weldy lump on my nice tank!

If I wanted that sort of shit I could drill a little hole to attach the slidehammer with.

Then you have to weld the side of the tank up after you do your hole :mellow: ends up just the same, that's how we do it anyway :shifty:

[ducatilover]

dude, fill with water (or any other cheap, nonflammable substance) and leave it open. heating a sealed container is never wise.

the water won't be in there long enough to cause rust.



I have seen tanks left for weeks full with soapy water welded and explode. But I know of people who keep the tank full of gas [to the top] so there are no vapors and they still have their faces :shit:

[Ixion]

..

and then have to weld the hole back up.....

either way you're using bog

Precisely the problem. I want a way to boof the dent without having to weld things to the tank (especially if it's a chrome plated tank !)

There must be a better way.

[ducatilover]

Precisely the problem. I want a way to boof the dent without having to weld things to the tank (especially if it's a chrome plated tank !)

There must be a better way.

Magic wand? I don't think a suction cup would work well enough...How many PSI can you get from your compressor? [assuming you have one good sir Ixion] :innocent:

[motorbyclist]

I have seen tanks left for weeks full with soapy water welded and explode. But I know of people who keep the tank full of gas [to the top] so there are no vapors and they still have their faces :shit:

how can an open tank full of water possibly explode? this concerns me greatly.

if you empty it then of course it's going to explode as the vapours enter back in from the seam where the two halves are welded together


Precisely the problem. I want a way to boof the dent without having to weld things to the tank (especially if it's a chrome plated tank !)

There must be a better way.

giant magnets?

strong language? (we've all tried it)

[Ixion]

Yith I have a compressor which can easily enough reach 120psi. But that is no solution because it will certainly distort the tank in other areas. I want it still to be a petrol tank at the end, not a beach ball.

I think the answer is still to push it out from the inside. What is needed is some sort of hydraulic how's y' father that can be inserted into the fille oriface , positioned over the dent , clamped in place, with the tank also clamped, and then pumped to push the dent out.

Generally it doesn't need a lot of force to dedent a tank, it's not like straightening a car chassis. Just needs the force applied in the right place.

The principle's simple enough it just needs somebody like Sykes to develop the little hydraulic rammy thing.

Alternatively, a very small panel beater who can climb inside the tank and bsh the dent out with a little hammer.

[Ixion]

how can an open tank full of water possibly explode? this concerns me greatly.

..

Vapour lock. A "bubble" of petrolly air trapped inside in a crevice of the tank. Just think how hard it is to get all the air bubbles out of a hydraulic systenm when you bleed it. And a tank has lots more blind spots and dead ends than a brake system.

[ducatilover]

how can an open tank full of water possibly explode? this concerns me greatly.

if you empty it then of course it's going to explode as the vapours enter back in from the seam where the two halves are welded together



giant magnets?

strong language? (we've all tried it) See Ixions post below...


Vapour lock. A "bubble" of petrolly air trapped inside in a crevice of the tank. Just think how hard it is to get all the air bubbles out of a hydraulic systenm when you bleed it. And a tank has lots more blind spots and dead ends than a brake system.

I like your hydraulic ram idea, but, I think the steel will have stretched and you will still be left with minor ripples. [not nipples]

[Owl]

There are some dickheads around here.

That's not very nice!:no:

[wbks]

Vapour lock. A "bubble" of petrolly air trapped inside in a crevice of the tank. Just think how hard it is to get all the air bubbles out of a hydraulic systenm when you bleed it. And a tank has lots more blind spots and dead ends than a brake system.Yes, and what happens when explosions happen under under water?... Think I'll just fill the dent up in layers

[kevfromcoro]

Jesus.. dont put a flame near the tank. espesially if its empty.
If you can seal it off. get hold of a low pressure reg. stick about 3 0r 4 psi in it and you will find it will pop out.. doesnt take much..
just dont put to much pressure in it.... or you will end up with a fat tank

[LBD]

Beer and an office job....worked wonders for the ripples and dents I had around my tank...is now nice round and smooth.....

Crack open another 6 pack...?:yes::yes::yes:

[The Stranger]

A Slide hammer can be useful here but if you do anything involving heat be sure to purge the tank fully!



How do you "purge the tank fully"?
I have welded a used car fuel tank before, but it handn't been used for some time. I washed it out with water and (on the advice of a panelbeater) ran a car exhaust into it for a while before and whilst I welded.
I'm still alive, however that may just be luck.

[The Stranger]

I would but I can't bang it out myself and I'd rather use this old tin of body filler that's getting no use, than pay for someone with the tools to do it. I mean, even if I did push it out, wouldn't you still need to use a bit of filler to cover the creases?

Water expands about 5% when it freezes, but yes you will still have creases.

[LBD]

How do you "purge the tank fully"?
I have welded a used car fuel tank before, but it handn't been used for some time. I washed it out with water and (on the advice of a panelbeater) ran a car exhaust into it for a while before and whilst I welded.
I'm still alive, however that may just be luck.


Remove all fittings, valves fuel pulmps filler adapters etc, where fuel remenants may be lurking....wash out with warm water and detergent, when dry tape up openings and use an inert gas to purge the tank, and keep a slow flow of inert gas into the tank while the hot work is done....

[The Stranger]

Remove all fittings, valves fuel pulmps filler adapters etc, where fuel remenants may be lurking....wash out with warm water and detergent, when dry tape up openings and use an inert gas to purge the tank, and keep a slow flow of inert gas into the tank while the hot work is done....

Carbon monoxide will do it then?

[LBD]

Carbon monoxide will do it then?

CO would, if it was pure without any free oxygen....not sure if I would trust exhaust gas....Also may be from a rich running engine with some unburnt fuel in the exhaust gasses....

Argon, CO2 from an extingusher, nitrogen etc...

Done it many time but then I have always had welding gasses on hand....

[koba]

Carbon monoxide will do it then?


How do you "purge the tank fully"?
I have welded a used car fuel tank before, but it handn't been used for some time. I washed it out with water and (on the advice of a panelbeater) ran a car exhaust into it for a while before and whilst I welded.
I'm still alive, however that may just be luck.

I think there is a thread to two on this. I've sucessfully used exhaust gasses with a warm engine and the idle mix leaned out.

[CookMySock]

In the end there is no point in pulling the dent out, except to give you some more space for fuel, unless you are worried about the lump of bog falling out. The problem with polyester bog, is it shrinks when it cures. Epoxy is a lot better in this respect.

What we really need, is a large dildo-like thing, with a fat knob on the end that nods back and forth with some force, kinda a cross between a ladies toy and an air hammer. Poke it into the tank and nudge it against the dent and let it belt away at it for a while until the dent cums out, so to speak.

Steve

[hayd3n]

i also have a dent or 2 to remove ,one ive hit a few times with a rubber mellet as it is a inny/outie dent not much improvement yet:<
gotaa get rid of the outie one them ill just sand/newtech it

[motorbyclist]

Vapour lock. A "bubble" of petrolly air trapped inside in a crevice of the tank. Just think how hard it is to get all the air bubbles out of a hydraulic systenm when you bleed it. And a tank has lots more blind spots and dead ends than a brake system.

but how does that affect an open tank?! :(

idea behind water is not only denial of oxygen to the little fuel bubbles at the bottom, but it carries heat quite well too - fuel has a hard time igniting when it can't exceed 100 degrees. leave it open at the top (and brimming with water) and there's (surely) not much to go wrong...


either way, using argon from you welding gear is a pretty clever idea


and saves the hassle of getting all the water out too :laugh: