Need quick help with epoxy/welding problem:

speeder · speeder's Garage

I'm at yet another impasse with the 356, the engine is now ready to go in save for this little problem with the heater boxes. I've let this one go until now because I was busy with other things but now I need to solve it or install them with no working heat and deal w/ it later. (They were not previously working).

Basically, I need to attach this shaft to its flap/valve while it's installed in the HB. I took it to my welder and he could not assure me that his MIG welder would not warp/melt the flap even with a small/quick tack weld. The factory somehow crimped these on with a tiny weld, you can see the marks on the shaft and flap.

I either need to drill tiny holes in both parts and find small screws and/or use some super-duper epoxy that is heat-resistent to attach the parts together. I don't know my epoxy products and this would be a 1-shot deal, ie. if it does not work, the part would be really mucked-up.

New heater boxes are available for ~$300 each but need to be shipped. I need to install the motor today and would love to fix this box cheaply. Thanks in advance as always.

Here is the offending part:

gtc · gtc's Garage

Know anyone with a spot welder?

Hugh R · 02-11-2011, 09:54 AM

If you won't be able to get at it again easily, I'd drill, tap and machine screw with lock washer and high tensile strength (2 hour) epoxy.

Shaun @ Tru6 · 02-11-2011, 09:56 AM

JB Weld will work, as with all epoxy, surface prep is everything.

Seahawk · 02-11-2011, 09:57 AM

If it has to go today, JB Weld is fine...how hard is it to get to later?

speeder · speeder's Garage

Is JB weld really heat-resistent? (Never used it).

speeder · speeder's Garage

Quote:

Originally Posted by Seahawk

If it has to go today, JB Weld is fine...how hard is it to get to later?

Any work involving heat exchangers is an engine drop + exhaust removal. Which is not the end of the world on these cars but it would be nice to fix this one before installing. The HE on the other side is junk so the engine is coming out again either way but I could at least have heat on one side.

speeder · speeder's Garage

Quote:

Originally Posted by Hugh R

If you won't be able to get at it again easily, I'd drill, tap and machine screw with lock washer and high tensile strength (2 hour) epoxy.

That would be a great repair but for time reasons it's dead. Thanks just the same.

Tobra · 02-11-2011, 10:08 AM

what about drilling through it and rivet together, or grind a flat spot on shaft and use a punch to get flap in close approximation to flat spot

How different is that piece from a bug of similar vintage?

Eric 951 · 02-11-2011, 10:08 AM

What about drilling a hole through the shaft/flap and using a cotter pin?

Tim Hancock · 02-11-2011, 10:11 AM

If you need to weld the flap to the shaft, I would simply drill a couple small holes in the flap where the original crimp indentations are and then I would simply rosette weld them with the tig welder..... Very simple IMO...

Hugh R · 02-11-2011, 10:20 AM

Drill and cotter pin then, don't trust the epoxy in torsion.

Superman · 02-11-2011, 10:23 AM

Sure sounds possible. Maybe I'm missing something. Most if not all the above suggestions are excellent. What's so hard about drilling through both pieces and driving an interference-fit pin in there? Or as Tim says, open a couple of little ports in the sheet metal, and weld there. If the engine and exhaust will need to come out eventually, then you lose nothing with the gamble. Worst case scenario: The sheet metal gets a bit warped.

Aerkuld · Aerkuld's Garage

I'd drill a small hole through the flap and the shaft and pin the two together. Possibly two small holes, one on each of the flats. Alternatively, do as Graham suggested and find someone with a spot welder.

wdfifteen · wdfifteen's Garage

Quote:

Originally Posted by Tim Hancock

If you need to weld the flap to the shaft, I would simply drill a couple small holes in the flap where the original crimp indentations are and then I would simply rosette weld them with the tig welder..... Very simple IMO...

THIS IS THE WAY TO DO IT. There won't be any warping problems.

Short of this, epoxy the shaft to the flap. The problem with that is getting enough epoxy between the sheet metal and the shaft.

Tim Hancock · 02-11-2011, 10:33 AM

Rosette weld..... I promise it will work perfectly and is the easiest/quickest way to get the job done right. (unless of course you have a specially configured tongs for your spot welder that can fit inside the heat exchanger opening and still squeeze/weld the parts together)

Joeaksa · 02-11-2011, 10:39 AM

Quote:

Originally Posted by gtc

Know anyone with a spot welder?

Spot welding is what I would use. Gotta be someone around with one. I have a small one from HF that I use...

wdfifteen · wdfifteen's Garage

Quote:

Originally Posted by Joeaksa

Spot welding is what I would use. Gotta be someone around with one. I have a small one from HF that I use...

Maybe there is an issue of semantics here. I don't see how anyone would get a spot welder down in there.
It was swedged on to begin with. That might be an option, just deform the hole in the plate so badly that you have to hammer the shaft through it. Inelegant, yes, but it would work just fine. I would probably do just that if it was mine, but Tim's suggestion is the best permanent, fool proof solution.

Jared at Pelican Parts · 02-11-2011, 10:52 AM

Quote:

Originally Posted by speeder

Is JB weld really heat-resistent? (Never used it).

I've used it to fix rusted out holes in mufflers. Surface prep is everything.

Seahawk · 02-11-2011, 11:26 AM

Quote:

Originally Posted by Tim Hancock

Rosette weld..... I promise it will work perfectly and is the easiest/quickest way to get the job done right. (unless of course you have a specially configured tongs for your spot welder that can fit inside the heat exchanger opening and still squeeze/weld the parts together)

Honestly, Tim, WTF do you know...I mean, really