Pot metal repair

[Chips_Mahoy]

I dont know what the correct name is but I have always called it "pot metal"....

The headlight housing for my Schwinn B6 is cracked/broken where the front screw holds it down. Is there something I can do or use to repair it and still be able to prep it for paint or am I just better off replacing it? I like to use the original parts as much as possible. I was thinking of using some kind of epoxy but I'm not sure if it would hold and/or be able to be sanded for primer/paint. Thoughts?

 

[ozzmonaut]

As long as you're painting and not chroming, jb weld putty works great for that stuff. It even looks like pot metal when it dries, but maybe a little darker. Once it is sanded, primed and painted you won't know it's there, and it holds some pretty crazy stuff. Supposedly you can fill cracks in an engine block with it , but I wouldn't. Anyways, you can get it at autoparts stores. It comes in a tube. You tear off a chunk and it's like 50/50 base and hardener. You just knead it in your fingers until it's consistent and heats up. Then apply it into the crack until you get good hold or the area filled. Then let it cure for a couple hours and sand. Don't apply too excessively because it is very hard and takes a while to sand down.

 

[scrumblero]

PC-7 works good too, if the hardware is closer than the auto supply..

 

[Chips_Mahoy]

That's good to hear. I don't like buying replacement parts if the orig can still be used, even if it needs a little work. Thanks for your help!

 

[B607]

I think the housing on original B6's was aluminum. Ever seen one that's rusty? :wink: Gary

 

[enbro]

I agree with PC-7 or JB Weld. Most people don't know but you CAN weld pot-metal. It's a high zinc content. I can't do it, but I know a guy that can. He's welded some things for me including a very rare pot-metal grill for my old car. You just gotta find the right guy.

 

[Chips_Mahoy]

I think the housing on original B6's was aluminum. Ever seen one that's rusty? :wink: Gary

Mine is too heavy to be aluminum.

What's the best way to strip the chrome off it to be painted?

 

[NewOrleansFlyer]

I've never used JB Weld, so when I got to the hardware store, I bought a knock off brand with the "Ace Hardware" name on it. I took it home, and followed the instructions and used a hunk to repair my kickstand bracket. 2 days later, the first time I opened up the kickstand, the forward motion of the leg broke the chunk of the material clean off the repaired spot :x I haven't gone back to get the "real" JB Weld, but I will...

 

[ozzmonaut]

I tried the off brand from walmart. It was "liquid metal filler and repair". Did not work in the least. I'm not sure about a kickstand bracket though. Those take some abuse and hold some weight. I'd just weld that back on. I use the putty for smaller stuff myself. Cosmetic stuff or a chainguard bracket or filling frame dents, attaching fender stays is ok too.

 

[ozzmonaut]

I used it to repair an oil cooler stud on a vw engine though. Ground the end of the stud to make some clearance, then put the putty in the stripped hole and put the stud in and let it cure for a full day. It held fine, but an oil cooler stud doesn't get torqued like a case stud.

 

[Chips_Mahoy]

I'll try to take a picture of what I need to repair and see if you think an epoxy will still work.

 

[c.p.odom]

What is know as "Pot Metal" is Die Cast Zinc.
A lot of different repairs can be made, just be sure to cut out all of the corrosion. Zinc gets a type of corrosion similar to a rot. A zinc die cast part repaired with epoxy can be re-plated, this just depends on the type of substrates applied first. Ultimately this is a question of how much do you want to spend?

 

[Chips_Mahoy]

Here's a pic of the break....... Fixable or better off replacing? The light cover will be completely painted to match the bike when it's done.

 

[c.p.odom]

30 years ago I would have fixed it, but this part has since been reproduced in quality and quantity. Buy a new one and save this for the future.

 

[ozzmonaut]

Assuming that you decide to fix that one, here's how I'd do it. I would remove it and rubber band the front so that it holds the part you need to repair together. Then, in the interest of strength, I would use jb weld or similar epoxy. I would apply some between the breaks and allow the rubber band to hold that together. I would also epoxy all around the breaks and even fill the screw hole. When you are done applying the epoxy, take a nail or punch and put a small indent in the very center of the hole. This will make it easier to redrill and keep the hole that you drill centered once the epoxy is cured. I would probably drill the hole a little smaller than the original to give the epoxy more holding surface. Then you can sand around the repaired area to bring the shape back. I don't know if this is the BEST method, but it's probably the route I'd go since I have to stay on a pretty tight budget.

 

[Chips_Mahoy]

Assuming that you decide to fix that one, here's how I'd do it. I would remove it and rubber band the front so that it holds the part you need to repair together. Then, in the interest of strength, I would use jb weld or similar epoxy. I would apply some between the breaks and allow the rubber band to hold that together. I would also epoxy all around the breaks and even fill the screw hole. When you are done applying the epoxy, take a nail or punch and put a small indent in the very center of the hole. This will make it easier to redrill and keep the hole that you drill centered once the epoxy is cured. I would probably drill the hole a little smaller than the original to give the epoxy more holding surface. Then you can sand around the repaired area to bring the shape back. I don't know if this is the BEST method, but it's probably the route I'd go since I have to stay on a pretty tight budget.

Thats what I was thinking of doing for the most part except for filling the screw hole. But I like that idea! I can at least give this a try to see if its going to work before I buy a replacement. My budget it tight too especially after what I've spent on just a few parts already !! :shock:

 

[ozzmonaut]

Just placing epoxy between the separated area may not be enough, which is why I suggest filling the screw hole. Luckily those things aren't under any kind of load.

 

[ozzmonaut]

Then again I guess the screw will go into one of those clips in the fender, so it may need to be the same sized screw.

 

[Chips_Mahoy]

I knew what you meant....... :wink: I figure I'll bevel the edges to help make more contact area for the epoxy.