Repair of a broken carriage casting - Photos

mickyd · Post by **mickyd** » Thu Mar 26, 2009 1:38 am

A design "oversight" on the old Greenie's lead many an owner to a broken carriage casting if the headstock was not tightly securely to the way tubes when put in a vertical position to do drilling. The headstock would drop down striking the carriage stop set screwin turn, fracturing the casting. When I got my Greenie, it was broken, but fortunately the guy saved the piece.

[ATTACH]3679[/ATTACH]

I was initially going to get the piece welded on but a mountain bike buddy of mine suggested using a cold weld product called “J-B Weld” available in the paint section of Home Depot, Lowe’s, Ace. It’s a 2 part material that you mix. After mixing, you have about 40 minutes to use it before it starts to set up too much. I actually liked the way it worked after about 25 minutes. It started acting more like a putty than the initial liquidy paste. Initially, it had a tendency to flow too much, which made filling a big gap at the top difficult.

The first step was to grind a hefty chamfer on ALL contact edges, including the backside.

[ATTACH]3680[/ATTACH]

The chamfer went about halfway through the material. This way here, when the cold weld material was applied, it would actually pass through to the backside, forming a kind of hourglass shape (if you looked at it in cross-section). This gave it maximum gripping area.

Probably the most critical step (from a cosmetic standpoint) is to make sure that the piece is properly clamped to the parent material before applying the cold weld. The piece should be flush on all edges. This can take some finagling with the clamping setup to get it right.

[ATTACH]3681[/ATTACH]

Once clamped, you apply the cold weld with any applicator you want to use. I used a bamboo BBQ skewer treating it like a small putty knife. Probably would have been neater if I used something flexible but since I planned on sanding it down after, it really didn’t matter.

[ATTACH]3682[/ATTACH]

It takes about a day to fully cure. The next day, I sanded the surface down flush with my dremel tool with a 150 sanding disk on it. I could have sanded by hand but after the time I’ve had the past few day with hand polishing, I decided to take the easy route.

This is how it finally came out.

[ATTACH]3683[/ATTACH]

You can see the finished work is nice and flush with the original cast surface and once painted, it won’t even be visible.

This was purely a cosmetic repair job. The carriage would have worked fine with the piece missing but I wanted to get it back to near original condition and I did NOT want to pay for a new casting.

Fun project. It was almost like doing body work with bondo.

Update 10-19-09 Final painted verison is in post #7

thainglo · Post by **thainglo** » Thu Mar 26, 2009 9:48 am

Mike - that turned out great, very impressed with the results. I had the exact same issue on the first SS I restored, couldn't figure out then what caused it. I went the easy (and more expensive route) by finding a replacement carriage on eBay. That JB Weld is great stuff, I've used it on several repair items before, just didn't cross my mind for that application.

Hit that with some hammered paint, you'll never know!

Matt

JPG · Post by **JPG** » Thu Mar 26, 2009 12:11 pm

Mike: If you have the stud and nut which were in that threaded hole originally, why not put in back in that hole, but backwards so that the 'battering ram' is INSIDE the carriage and the end of the stud even with the outside surface. That would retain all the 'original' hardware and NOT be a risk of repeating the damage. It would also make the hole SEEM to serve some purpose rather than an empty hole.

mickyd · Post by **mickyd** » Thu Mar 26, 2009 12:33 pm

JPG40504 wrote:Mike: If you have the stud and nut which were in that threaded hole originally, why not put in back in that hole, but backwards so that the 'battering ram' is INSIDE the carriage and the end of the stud even with the outside surface. That would retain all the 'original' hardware and NOT be a risk of repeating the damage. It would also make the hole SEEM to serve some purpose rather than an empty hole.

Ya jpg that was my plan. I am going to retrofit the Greenie with the carriage stop ring (ref. part 189) that was used on later models. Forum member SDSSmith has an extra that he offered to give me. Since he lives here in San Diego, that works out great. I get to meet him!! I am picking it up this weekend.

tom_k/mo · Post by **tom_k/mo** » Thu Mar 26, 2009 12:42 pm

Excellent repair job. JB Weld rocks... Thanks for sharing.

etc92guy · Post by **etc92guy** » Thu Mar 26, 2009 9:12 pm

I've used JB Weld to repair the mounting holes on the running boards of the conversion van. Has held up through 100 degree temperature change, snow, salt, and rain. Not to mention the strain of my 200+lbs. when I step on it. Great stuff. The product I use is a roll with 1 part wrapped around the other. You cut off a piece and need it to mix it. No dripping!!!!

mickyd · Post by **mickyd** » Sun Apr 05, 2009 11:44 pm

Here's the final painted piece. It's almost perfect. (If viewed under an electron beam microscope, you can see a slight depression...

) Driving by 60 mph you'll never know the difference!!!!

[ATTACH]3876[/ATTACH]

beeg · Post by **beeg** » Sun Apr 05, 2009 11:49 pm

GREAT job there Mike.

a1gutterman · Post by **a1gutterman** » Mon Apr 06, 2009 1:21 am

It looks fantastic, Mike!

thainglo · Post by **thainglo** » Mon Apr 06, 2009 8:21 am

Taping off all those holes in the carriage for painting is a great time! I was planning for the next one I strip and repaint to fab up a set of plugs that will snug into each size hole. Something like PVC pipe or wood dowels that can be turned down to fit...