Tank Dent removal - Other than cutting and welding

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Stanm
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Tank Dent removal - Other than cutting and welding

Postby Stanm » Sat May 07, 2016 9:39 am

Hi Folks
There was a bit of interest in this topic that came up in a different Topic so I thought you may give me some ideas before I resort to cutting my tank apart. My tank is a ty250 aluminium tank which I think is quite thick and fairly tough compared to the A steel one.

Some people will say that's odd Stan rides around with a pretty battered tank anyway. But this dent was to Ugly to ride with.
This tank is a spare tank now so i muck about with it as I get a bit of time and the urge.
There is a topic in Trials Australia Steel tank dent removal that talks about importance of cleaning out old petrol and rust.

This tank was bogged up where the dent is and I dropped it on a hard clump of dirt in a strategic spot that collapsed the dent really well. It was probably twice as deep so i have had some success. From the photo you will can see the difficult bit is the decreased radius at the bottom of the dent.

1/So i have tried pumping up to 40 psi with some strategic tapping. Some success
2/ Poking metal objects inside the tank. I probable need a better poking object design
3/ Gluing a puller stud on with fiberglass reinforced resin. Left the resin to dry for a week - This had some success
4/ Lastly i tried hot melt with a slide hammer.( as suggested by Pop) First attempt the stud cam off first pull - the tank was cold. Then I heated the tank up with a heat gun to get the melt to stick better. It took about 6 pulls to break the bond. No noticable dent improvement. So I need help with this method.
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second attempt hot melt
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For all the above it would be good to get move details and just build a good forum topic on good dent removal methods.

For example the blood pressure cuff method may have some merit for really easy dents. And I guess you should probably only pump it using it's bulb pump that it comes with otherwise BOOM!!


Cheers


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Hot melt slide hammer
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second attempt hot melt
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David Lahey
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Re: Tank Dent removal - Other than cutting and welding

Postby David Lahey » Sat May 07, 2016 10:02 pm

I think you are trying to pull out too much of the dent in one go with that. I've done a (steel) KT tank successfully by welding on some steel nuts and pulling on them one at a time while heating the steel where I want it to move.
Pulling on a large area in one go like in your photos, no matter what you attach the pulling medium with, makes for a very hard pull.
Photos of KT250 tank dent removal attached
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relax, nothing is under control

David Lahey
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Re: Tank Dent removal - Other than cutting and welding

Postby David Lahey » Sat May 07, 2016 10:27 pm

If you don't mind taking a bit of a risk, try using less pressure, say 10 psi, and gently heating the aluminium where you want it to move. I did a steel TY175 tank that way and it went very well, but i don't know if I am good enough with managing the process to do an aluminium tank that way. Steel is much easier to see how close the metal is to melting
To avoid causing the TY175 tank inflating like water wings or balooning inwards into the tunnel when it was pressurised, the TY175 tank was fitted into a purpose-made steel jig that held the sides together via the bottom seams and filled the tunnel gap. Photos attached
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relax, nothing is under control

Stanm
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Re: Tank Dent removal - Other than cutting and welding

Postby Stanm » Sun May 08, 2016 10:28 am

Hi David
Man that TY175 tank was battered about but the end job looks great.
I like your steel jug and the idea of lower pressure and heat. However the aluminium tank has a chunkier bottom seam I tried clamping on the seam and the softer aluminium distorted and I was afraid it was going to let go or damage the seem welds. The aluminium tank may need an additional bracket that goes over the top help hold it in the vice. I will also think about how to monitor the temperature if I use heat. An infrared temperature sensor would be really handy.

I want to experiment with Hot melt a bit more.
I am scratching up the surface and cleaning it with prepsol, Then heating up both the stud and tank with a heat gun. Applying melt to both the tank and the stud. Mixing the melt a bit to ensure the surfaces are covered. Then applying the stud to the tank. Allowing an hour or so to cool.
This morning I rehot melted the puller stud to the side of the dent. Trying to reduce the amount of the dent as you have pointed out.
I will let you know how it goes.

Thanks



Stanm
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Re: Tank Dent removal - Other than cutting and welding

Postby Stanm » Sat May 14, 2016 12:02 pm

Reposted with photos below. Sorry.



Stanm
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Re: Tank Dent removal - Other than cutting and welding

Postby Stanm » Sat May 14, 2016 12:05 pm

Hi Folks
I have had quite a bit of success with Hot melt glue method and learnt a bit. I am making most of this up from so I could be doing this wrong but anyway this is what i have found.

1/ This method takes time so lucky I am not in a hurry.
2/ I have stuck the puller stud on about 10 times and are nearly there with the one big dent. I used a heat gun to heat the tank and stud so you can recycle some glue by scraping it up and relocating.
3/ It seems that the bond is better if you do the pull in about an hour rather than letting it cool overnight where it appeared the glue got a bit more brittle and bond snapped. So about 1 hour to cool is enough.
4/ The previous photo showed the glue just coming through the holes. I have attached another photo showing much more glue and it overlapping the puller head.
5/ When pulling the bond will generally come off the tank, So scratching it up with a razor knife will help if you need and extra strong bond. I got such a strong bond several times i got tired of using the slid hammer! Then you can use the blocks and puller method as David showed in his photo if you need more movement.
6/ I mainly only used a puller stud diameter 50mm,

So with hot melt glue and easy dents I would use this straight over the paint and hopefully not damage the paint to much.

Hope this helps others
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David Lahey
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Re: Tank Dent removal - Other than cutting and welding

Postby David Lahey » Sat May 14, 2016 1:29 pm

Excellent stuff. I reckon I will try it out. I've got just the tank to do it on


relax, nothing is under control

S.E.Lucas
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Re: Tank Dent removal - Other than cutting and welding

Postby S.E.Lucas » Thu Jun 02, 2016 4:13 pm

fill it with water and put it in the freezer



David Lahey
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Re: Tank Dent removal - Other than cutting and welding

Postby David Lahey » Thu Jun 02, 2016 9:59 pm

S.E.Lucas wrote:fill it with water and put it in the freezer

You have enough space in your freezer for a fuel tank?


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TerrY
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Re: Tank Dent removal - Other than cutting and welding

Postby TerrY » Fri Jun 03, 2016 7:23 am

Come on David. You know how there is always room in the shed for another bike. So, there is always room in the freezer for a fuel tank if it needs freezing to sort out a dent. Always room in the oven to dry out paint properly. Always room in the bath to clean up those wheels and frames. Etc etc.




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