Pitted Aluminum

boddy

boddy

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I have some rather deep pitting in my sprocket cover case and was wondering what the best way would be to fix this. I intend to rattle can the cases but it has been suggested in other threads not to use primer so I don't think primer will work to fill in the holes.
case.jpg

What would be a good filler to smooth out the pitting and that would also stand up to a de-greaser such as acetone.
Thanks...Brad
 
I know it's going to sound like a lot of work but you could sand down the aluminum to get rid of the pits. Or, you could use JB Weld to fill them and sand it down to smooth before paint. That cover doesn't get quite as hot as the main engine covers where oil is present behind them, and JB Weld can stand the heat but either method is going to be some work. It might be simpler for you to look for a used cover, here are a few

https://www.ebay.com/sch/i.html?_fr...nkw=Honda+Cb450+front+Sprocket+Cover&_sacat=0
 
Acetone will eat most spray paints so be careful where you use it around painted parts.
I see 2 choices for you. 1) lots of sanding using a sanding block so you remove material evenly across the entire surface. 2) Fill the pits with a 2 part epoxy like JB Weld. Body filler like Bondo might work but I think the engine vibration combined with heat will lead to failure. If you do this then the cover and pits have to be degreased thoroughly with your favorite degreaser and a toothbrush in the pits. Apply just enough to fill the pits and scrape off any excess well before it sets up so there's minimal sanding to remove any excess.
If it were mine I would opt for #1 which is going to build up your arms and wrists.
 
I was considering sanding out the pitted areas but was worried that I would have to go fairly deep in some areas. At this point I don't have much to lose, so I will try sanding. If it doesn't turn out well, then there is always the option of a replacement from ebay.
Thanks for the replies!
 
That is encouraging. For me the difficulty would be keeping the surface from becoming wavy or having a noticeable indentation. So, remove a little at a time using a block sander and over a large area so no indentations form?
 
I use a @8" 1"x2" Oak block with sand paper stapled to each end. Hardwood is the best thing for sanding blocks IMO. Then with WD40 as a lubricant on the metal start working as large a section as you can so you don't create low spots. I'd start with 200 paper, coarser will leave too many scratches. Change directions as you work the metal also. You'll be removing a lot of material to bring everything down flush eliminating the pits.
 
I decided to tackle the pitted case today. I started sanding with 150 grit as this is what I had on hand. I soon realized it was going to take a long time so opted for a more aggressive removal method. I had a body filler file that I used on soft metals previously, so I decided to try it.
case2.jpg
Using the file and attacking from multiple directions as per LDR, the material was removed quickly and evenly.
case3.jpgcase4.jpg
This was followed up with the 150 grit emery stapled to a piece of hardwood and WD40 as a lubricant (thanks LDR, it works well!). I went to 320 then finished with 400 grit.
Here is the result.
case5.jpgcase6.jpg

It's not perfect but I'm very happy with the results since I will be painting the cases.
 
the good part was that it only took a couple of hours and I had everything on hand to do the job. Just gotta ask the questions wait for the replies and get on with it(y)

Thanks LDR and AD for the tips and nudge to try something new.
 
That came out well and the body file seems like a good option too. Can you post a picture of the file as I am always adding tools.

If your going to paint over the covers then an option I have used many times for scratched/gouged cases is Tech Steel, yet there are many iterations from JB Weld and others. It is a kneadable material that is chemical impervious once cured and easy to file and sand to shape once cured.
The Tech Steel is the best one I have found for my needs, as it has slightly different properties than say the JB stuff. It is set hard in 15 mins and can be shaped at that point and fully cured in 1 hr. It is also good for 500F temp wise.

I have rebuilt broken fins on barrels with it and it has held up over time and heat cycles on the motors.

Tech Steel:

P1060842.jpg
 
Flyin900 said:
That came out well and the body file seems like a good option too. Can you post a picture of the file as I am always adding tools.

If your going to paint over the covers then an option I have used many times for scratched/gouged cases is Tech Steel, yet there are many iterations from JB Weld and others. It is a kneadable material that is chemical impervious once cured and easy to file and sand to shape once cured.
The Tech Steel is the best one I have found for my needs, as it has slightly different properties than say the JB stuff. It is set hard in 15 mins and can be shaped at that point and fully cured in 1 hr. It is also good for 500F temp wise.

I have rebuilt broken fins on barrels with it and it has held up over time and heat cycles on the motors.

Tech Steel:

View attachment 11573
Click to expand...


Thanks for the tip, I will keep an eye out for this. Did you pick this up at Cdn Tire?
 
Boddy,

It is a NAPA item that they usually have to order depending on the store, although I did find it at Rona once. No Canadian Tire stock that I have seen so far.

It is from a Canadian importer and great stuff to work with and fast cure times.
 
Flyin900 said:
That's Hilarious,

I have a file that came from my dads tools and have never really used in 40+ years, yet have it ready in my file draw. LOL

Looks pretty familiar, just never knew what it was for work wise.
Click to expand...

If I'm not mistaken - and my father is no longer with us so I can't ask him - that file was originally intended for body solder prior to bondo becoming the replacement filler material. That would explain why it works so well on aluminum.
 
Flyin900 said:
That's Hilarious,

I have a file that came from my dads tools and have never really used in 40+ years, yet have it ready in my file draw. LOL

Looks pretty familiar, just never knew what it was for work wise.

View attachment 11582View attachment 11583
Click to expand...


Mine had a counter sunk hole at each end and I remember there used to be a handle that you could use with the file - kinda like a plane handle. I just wrap some tape or a rag around the blade to save my hands!
 
Flyin900 said:
Boddy,

It is a NAPA item that they usually have to order depending on the store, although I did find it at Rona once. No Canadian Tire stock that I have seen so far.

It is from a Canadian importer and great stuff to work with and fast cure times.
Click to expand...

I have a few NAPA stores in my area, I will check with them. Thanks
 
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