Repairing Forward Porthole

[Theis]

I'm looking for ideas regarding the repair of the screw mounts for the forward porthole covers. My repairs have failed twice.

Each screw used to tighten down the covers is connected to a pin that passes through two nubbins, one on each side of the screw part of the inside of the porthole mount casting. There are two screws and four nubbins on each side.

The two nubbins for one of the screws have broken off, and shattered. The casting, I guess, just got old. I need to replace the nubbins, and don't want to replace the entire inside casting.

I have tried epoxy paste (the stuff that comes in a tube) and aluminum weld stuff which is also an epoxy past. The molding is beautiful and works. However, after about two weeks, the new molding pulls away from the old casting. In other words, I can't get the epoxy to stick securely to the old aluminum casting.

Any ideas on rebuilding these nubbins so they stick and can withstand the pull from locking down the porthole covers?

[ebb]

G'mornin Theis,
You are talking ofcourse about our little delicate toy opening ports.
Ideas:
There is now low temperature welding (750 degrees) available for aluminum (Durafix?) Whether the process can weld ancient Almag your research will have to tell you. The cast cover is so fine it seems to me any heat would distort it.
The broken piece could be ground off and a stub shaped to the frame could be welded on in place. You know, this is almost jewelry work we're talking about.
If it can't be welded, let's see if a stub can be carved out of extruded 'billet' and attached with a couple machine screws to the frame. (I'm looking at the cover here and it seems improbable.) There is really no place for a machine screw to find 'meat' from the outside - except perhaps right in the middle of the curve where there is that ledge inside that the glass sits in.)

But if the stub has some thickness in section and covers more surface of the frame, it could be attached with blind machine screws from INSIDE. Just an idea, Right? If you could get two fasteners thru the frame from the inside it would work!

It is easier to imagine the fork(s) ground off and a replacement made that cups the curve of the frame and has material designed out from the sides that you could machine screw the fork to the frame with. But this is small stuff.

Even more radical would be to grind both sets of nubbins off on a side and create a long piece with both forks that would fit the curve and have more opportunities to be attached - maybe even glued, as there would be much more surface area.

A stainless steel prosthesis is more likely because it could readily be made out of thin tubing or curved stock and have appropriate standouts welded on for the hold downs, or the hinge. Again, if relatively wide surface area of the new piece is designed in maybe it could be glued on. It would take a certified genius to do this delicate work. Someone into small stuff.

The machine shop I've used in the past (called a 'design' shop) can't hardly drill holes in the right place and costs $250 just to walk in the door. A student at a trade school of college might have ideas and accept the challenge. Good luck.

Please post your solution as saving these really nice highly engineered ports is/has been of interest to many here. I don't think they could be made today in this country. Whenever I see a portrait of an Ariel I look first to see if the original distinctive 'eyes' are evident. Usually a disappointment to see a modern squared-off retro there. But you may have to go that way.

[Greg]

Cap. Peter,

I got some opening ports from Frank in TX a couple of months ago and took a few screws off which I needed for mine. Since I'm not watching the Packers in a playoff today, I went out to the garage and retrieved the remaining parts. The inside part of the ports with the nubbins (mostly) intact and in un-aesthetic condition is now lying on the desk in front of me. I'm thinkin' maybe they could find a new home down in Racine aboard Solsken. They might not last forever, but with a little care, might last a season or two.

Lemme know...I'm cheap.

Greg

[Theis]

Greg:

Yes, thank you, I would be interested. Send me a price at theis (A) owc.net. The Packers? I've heard of them but I can't recall where. Is that that group from up in the tundra somewhere that keeps pounding the living daylights out of that Chicago team?

EBB:

You are on to the problem - It is a jeweler type deal. The 750 degree weld, I suspect would melt the castings - a total disaster.

As for the old nubbins, they don't exist any more. The problem is that they cracked where the pin goes through them, and then cracked again, until there was nothing left to repair.

What I have managed to do is to successfully make replacement nubbins using tube epoxy. That works. The problem is that there is a traction force pulling the replacement pieces away from original frame. In other words, I am having an adhesion problem.

My homegrown solutions are (I'm looking for something better that is known to work):
a) put a small screw into the stationary frame as something for the epoxy to bind to (is there something better than a screw for this purpose?)
b) grinding down the aluminum casting so that I have very clean, but unfortunately smooth metal, and
c) routing 1/16" groves into the stationary fitting with a Dremel tool, perhaps at diverging angles to see if the epoxy would stick to the old aluminum.

I think all these alternatives would be easier, if successful, than replacing the inside casting - but then, replacing the inside casting would make it as good as new.

Obviously nothing is going to be tried again until we get out of the ice box up north.

[Tony G]

Theis,

It seems in the high tech society we live in today nobody want to hear stuff like this any more, but, have you tried JB Weld? I remember my dad using it on things he couldn't solder or weld. That's where I found out about cleaning things real good before you glue them. He reminded me of a surgeon scrubbing up before surgery. But he did successfully repair some things with it. Recently I have used it in my real world job. It's epoxy too.

Or take Greg's offer.

Tony G

[Theis]

Tony:

I've tried JB Weld but without successful results. But yet everyone swears by it. I figure I must be doing something wrong or it is lousy stuff to begin with. Anybody have any really good experience? Mind you, it would be the aluminum casting on one side, and an epoxy "piece" as the other component.

[Theis]

Reporting back. I think I have it.

I dremel tooled each side (top and bottom) of the two nubbins that holds the pin - to be sure I had clean aluminum. Fortunately, each side is big enough so that a hole for a #4-40 hold can be drilled and tapped. Using four #4-40 by 1/4 or 3/8 stainless pan head bolts (with anti corrosion goop on them because stainless and aluminum don't do well together), I was able to hold the pin in - securely - stronger than it was origingally. I then covered the entire assembly with epoxy stick, ground it down, painted it with aluminum paint, and it looks like new. And it is now stronger than new.

The key is that the base will support the #4-40, and the pan head overlaps the pin enough so that it is super snug.