Right Carb Cover - Fixable?

[moonpup]

Just noticed that my spare cover that I thought was in great shape with the exception of some corrosion, was actually in not so great shape. 

Luckily there was no hole punched through it but there is a dented area with some small cracks. I'm pretty sure there is no way that this can just be hammered back but can the area be heated and pressed back into shape? Are there other ways to tackle this and if so, can you share them with us/me? 

[Sno Jet]

Take it to a welder/fabricator.  They will be able to weld a little aluminum to it and grind it down.  That is nothing compared to mine.  It should come out fine.

I just had some work done to mine and I will have to wait and see how it comes out.  Scary looking.

If it does not work out for you, put your order in with Richard.  NEVER KNOW WHEN YOUR GOING TO NEED ONE!!

[moonpup]

Thanks Harry,

What about the "new" aluminum matching the rest of the cover? Didn't I read something here about that being a problem. Is it that off?

I thought if I could just get the dent out, the amount of aluminum needed for the crack would be so small, it'd be hardly noticable.

[Bikenstein]

It's beyond hope, might as well send it to me. lol You should see the ugly welding on the one I bought. I think a weld would be difficult to polish out to match depending on the welder. I'm a welder by trade and an ex welding instructor. I would first try putting it on a piece of wood and try cold hammering with a ballpeen hammer, tapping only in the center. Then back fill it for a seal with jbweld. Heating it will make it more malleable but aluminum will oxidize very easily. If you do weld it, I would suggest tig welding only. It is the only way to control the heat and keep from damaging the aluminum further. Otherwise, as in the case of the cover I bought, which was apparently stick welded or migged, you end up with a big funky glob to grind down.

[Bikenstein]

Perhaps a safer way would be doing it in a press with proper support around the hole. Otherwise I don't know. But I have fixed a couple with a hammer without adding any more damage.

[moonpup]

Bikenstein,

I saw that cover you got on eBay..... I definitely don't want that welder touching this one!     

Just some followup questions for you, I thought cast aluminum like this would be too brittle to be hammered, is that not correct? Also, what did you mean when you said "but aluminum will oxidize very easily"? More so than it already does? I'm not sure how heating would have any affect on future oxidation. 

Thanks for the tig welding tip.

Mike

[Bikenstein]

I've managed to remove dents from a Honda 450 cover after my brake pedal ruptured it. It took the hammer quite well without cracking or breaking as some cast iron would. But different castings can react differently. Pressing on it with a vertical press would be safer. Heating aluminum can be tricky because it doesn't turn red when at the melting point it just turns shiny. It wouldn' be necessary to get it near the melting point to make it bend easier but because it transfers heat so rapidly to the surrounding area it would be difficult to isolate one spot with heat. That's why I feel better with cold bending. It was damaged cold and didn't shatter. And if you did cause further damage, weld it at that point. I'm not a metallurgist but enough heat will cause oxidation. Oxy-acetylene cutting is in effect rapid oxidation or rapid rusting of metal and then you blow it out with the oxygen stream. I'm not sure about the future effects of the finish after welding but there will be a heat effected zone around the edge of the weld that may react different than the base metal. And if the welder gets it too hot, even though it's repaired, it can become very brittle. It really doesn't look that bad.

[Sno Jet]

Not my field here but I believe the aluminum will blend in well.  The question is can the welder add the minimum amount of new metal in and then grind out the excess smoothly.  Find the best welder you can.  This is not bridge work.

I don't think you are going to have a problem, as your damage is minimal.  I was told that it is when you start filling in voids that it gets trickier.

[Bikenstein]

You're right it is not bridge work. Even very experienced welders cannot perform this seemingly simple task. The main problem with welding cast aluminum,  I've found, is porosity. Welding aluminum requires much higher heat than steel because of its high conductivity and the more heat you apply the more hydrogen is absorbed into the weld area which causes porosity in the weld and the metal surrounding it. Hydrogen will dissolve easily in molten aluminum but will not blend in when it solidifies. This is the major cause of porosity in aluminum welding. Also oxidation plays a major factor because aluminum oxide has a higher melting temperature than the base metal itself. Therefore the more heat applied the more oxide forms and requires even more heat to melt . That's why you can't cut aluminum with a torch, you can only apply heat until it falls out in a bubbling glob. That's also why T.I.G. welding works best but only on a.c. with a round tip and high frequency. In the positive cycle half the oxide is cleaned from the surface and the negative half you get penetration. So in effect you are cleaning then welding 100's of times per second. I even clean the filler rod of its oxide with steel wool just before welding. Also the filler you use is determined by the base metal alloy type which could include copper, magnesium, zinc, or silicon. Then if you do make a successful weld there is still the heat affected zone at the edge of the weld that is going to be much weaker than before because its crystal structure has changed and probably its polishing characteristics.  If a welder has 50 years experience, but little or none welding cast aluminum (especially side covers), I highly doubt that he will do much better than the guy who welded my cover. Mine probably started out with a relatively small dent and a leaking crack  but after the guy chased it around and tried to fill the porosity as it formed he ended up giving up with what is left and then still applied jbweld inside to keep it from leaking. If it was as simple as taking it to the welding shop and gettin a little weld on it and just grind sand and polish it out like new, we would have been doin it since back in the day and there would be no question about how to fix one now. I have many years experience in job shop welding and fabrication, pipe welding, tube welding, stainless, aluminum,  magnesium, cast iron, brass even plastic. You can check out my old website (cambarfitness.com) and see my line of fitness equipment that I designed and marketed for a few years. I don't claim to know it all, but I would try cold bending first and welding as a last resort. That little dent could end up looking like mine. If you find someone else more knowledgeable or has successfully welded a cover where it can be polished out like new please let me know. When I get my shop set up I'm gonna do some experimentation myself.

[moonpup]

WOW! Very informative Bikenstein, I really appreciate you taking the time to explain this in such detail. I know it's a small boo-boo per se, but being as picky as I am, I'm after "looks" as well as functionality.

I may have to wait till I get back up to Houston to find someone with that kind of knowledge and experience. This small border town I'm in now seems to only excel in wrought iron gates and burglar bars!  

[Sno Jet]

Glad you joined the site and are enjoying it.   Thanks for the insight.  As I was reading your last post and looking at the cover that was welded for me, it made sense.  We will have to wait and see what is under those lumps.

I will let you guys know.   Hoping for the best but expecting the worse.  Hopefully it turns out better than what I had!

[Jeff Bar]

Bikenstein, Great information, happy you took the time to type it all out.  Yes I do think we need some 350 covers made, please HELP RICHARD!  ;DJeff Bar

[moonpup]

Ok Bikenstein, good news, the dent is gone. I got the ol' hammer out and started pounding away and what ya know, it worked!  

At the right angle & light, you can still see the hairline crack but I'm hoping that once it's polished up, it'll hardly be noticeable.

[Mike Anderson]

Hey Pup,
Good job, what is your plan for the corrosion? I have a pretty badly corroded one myself. Not sure how to attack it, let us know if you come up with any good solutions.
Thanks Mike

[moonpup]

Mike, If you look at the pic of the cover in the beginning of this thread, you'll see all the corrosion that was on the same side as the dent.

In the past, I've used a sanding block and worked it till my hand & fingers gave out.  This time I used an electric palm sander and it worked great. Took me about an hour to get the side with the dent to look that good. (that includes rounding up all the supplies and setting up)

I used 220 grit wet/dry with a spray bottle of soapy water to keep everything lubed up. I'll probably start the other half of the cover using 200 grit first. It should make the job go a little quicker. After I get all the corrosion out, I'll work it down using a progressively finer grit and finish with a 1500 or1600. Might even go to 2000 or 2500 depending on how it looks.

I was a little concerned using an electric sander since this is a "wet operation", but there was very little splash or flinging of water with the palm sander. To err on the side of safety however, I did wear a pair of rubber gloves... just in case! 

The smaller tight areas and curved sections will need to be done by hand.

[Mike Anderson]

Moonpup,
I see what you mean, hadn't looked back at the beginning of the post. Looks like you have made good progress. That should work for mine also, thanks. I will probably use air tools, don't need any surprises.
Later Mike

[moonpup]

Air tools would definitely be the safer way to go for sure, however since I haven't had the time yet to get a 220v line hooked up in the garage for my compressor, I had to go with what was available. For anybody else going the electric route, take precautions and be safe!

[Bikenstein]

Ok Bikenstein, good news, the dent is gone. I got the ol' hammer out and started pounding away and what ya know, it worked!  




Nice job. Better'n tryin to weld it. When I get hold of a Hi-freek welder I'm gonna try repairin one. Post a picture after polishin it.

[reed]

Moonpup,
I have put some casings in the bead blast cabinet, and then i wet and dry and then polish.
And i have got dents out by heating the casing then putting in my press and very carefully
Pressing the dent out bit by bit, i put with different Pisces of steel between the casing to
Form the original shape back it takes time but it works.
Thanks.
Steve.
PS at sometime i will post a picture to show what i am talking about.

[disc_valve]

I just thought I'd throw in my two cents' worth on the subject of bending aluminium. You're right that you need to be careful heating alluminium, as it melts at a low temperature and when it does so it goes very quickly indeed.

The method I use is to cover the offending item with soap lather, then heat it gently in a flame until the soap lather dries out and the residue turns black, then quench the item in a bucket of cold water. The ally will now bend quite easily, but the metal will work harden as you bend the component. If the component begins to need more force to bend it before it's back to the correct shape, get the soap lather out again and repeat from stage 1.

I've successfully used this technique many times to straighten cylinder and barrel fins and handlebar levers. I've even straightened a bent choke/starter lever, wich is quite thin and delicate. If you try cold bending, though, the chances are that the item will crack or break. It's amazing but true - A minor spill can easily bend a brake lever into a with breaking it, but as soon you apply force to the cold lever to straighten it,.... SSSNAPPPP!!

Graham