[morzh]

This 20 was gifted upon me by Tom. A few years ago, may be 5 or so.
I was supposed to buy it off of him, he brought it to Kutztown but then left it with someone for me, so I did not have a chance to pay.
And then when I reminded him of it, he said I could consider it a gift.
Mighty generous gift, Tom; thanks again!

So here it is.

   
   
   
   
   

It is in a pretty good shape; I think I will not be touching the cabinet at all. Let it bear the imprints of history.

I have taken it apart.
Amazingly the speaker seems to be all good. Both the field coil and the transformer. And the bent part with the plug even though it is a bit rubbed through, it is  in good enough shape to be left alone. Maybe one turn of a tape, just in case.

[morzh]

It is obvious the radio was repaired one or more times. But it was a repair: the old caps are not disconnected, nor are they re-stuffed.
Plus a new electrolytic one is there, and a couple of newer carbon composite resistors.

   
   
   

It seems that the volume pot is good.
I will have to check the dogbones, restuff the backelites, the tin-cans, and see if I do want to take upon that big can filter. (I hate that one).

[Phlogiston]

When a cabinet is that nice, it only makes sense to keep the chassis as original looking as you can. It is a classic, probably more so than the "Deluxe" version.

[morzh]

Russ


>>It is a classic, probably more so than the "Deluxe" version.


This was the reason I had been hunting a plain 20 for a few years to that point.
I intend to gut and re-stuff the backelites; I am not sure I want (did it twice on the other two 20s I have) to restuff the can; I heard on a good authority the big caps in it stay quite OK. I will test them and see how much they have migrated. If too much then....well, I will gut it.
The dogbones is a separate issue. I know they are almost universally go way up, especially the older style, with large metal solder ends.
But then I am a bit leery of the idea of using the plastic-covered ones. At least in places where there is power dissipation.

[Phlogiston]

I have a mold set up for that kind of dog-bone. If you need one, let me know.

[morzh]

I might. This was my first one to check: it is 250K and they in my experience get really way off.
Well, this one is simply open. All the way.

Russ, could you point me to the molding process description? I want to see how involved that is. Have never molded them before. And as I said, I want to try that way.

[Phlogiston]

This post is for grills, but the materials to make the mold(s) is the same:

https://www.russoldradios.com/blog/grilling-my-saba

Russ

[morzh]

Russ

Since I am not familiar with the hi-temp silicon at all....

So, OK, you make a mold for the resistor; I take it, two halves, right?
Then, for the resistors, do you add some binder-filler into the epoxy so it would become more ceramic-like?
Also, considering the resistor is a cylinder, I take it, the epoxy should be mixed in such a way that it becomes packable and not really liquid, so then if you press the second half, it would squeeze out the excess epoxy and form the resistor shape around the regular one?

How do you make the terminals? Do you simply save them off of the original one and then re-use them?

[Phlogiston]

   

Yes - 2 halves.

See the little holes in the left half? They extend through the mold. You bend the leads from your replacement resistor (as large a wattage as will fit in the mold) so that they extend out of the mold.  The leads are left exposed as you remove the mold halves.

Yes. The easiest material to make the replacement from is vinyl - Bondo is a convenient source.

If you have the original resistor, removing the lead (metal) ends and replacing the ceramic center with glass (also a ceramic) is the best method if you think that the resistor will get (very) hot. The tiny resistive element in the originals was not capable of dealing with much heat - so your replacement probably does not need to (either).

   

[Phlogiston]

It just occurred to me that if you were to buy a bucket of the red stuff (red matter - ask Spock), you could take some to Kutztown, in jars (2-parts) to sell or share with others. this could spread the cost around. I would only trust this stuff being good for 6 months - year max.

[morzh]

I found this:

https://www.ortechceramics.com/products/...both-ends/

I am yet to look at the quote, but they could provide 0.25"/0.188" OD/ID ceramic tubes of the requited length (1.4" in my case).
I can put the resistor inside, re-use the ends and paint it .

What do you think?`

Got the quote for 100pcs: $4.99 apiece.
Getting a smaller (10pcs quote)

OK. They have $375 minium order which is 60pcs at $6.25 apiece.

I was wondering. ...

[Phlogiston]

You can get lab-grade Pyrex (kits) with a cutter for ~ $25 or less.

I would like to see that stuff. You know the tubes are about 3 different sizes. I always have a hard time getting the replacement in the smallest size.

If the ceramic tubes are the right sizes, I would go in on it with you. Maybe we can find one or two other people that might want some.

Russ

[morzh]

Russ

I was only looking for the one for that size; I am sure the others (the smaller dogbone) could be found too; however this being the different size it might trigger another minimum purchase, even though it might be the total for them and two part numbers could make up for that amount.

In the "Old Ron's" I started the thread on it; I found the other company with a bit larger minimum but 1/3 the price per piece.


PS. I was looking for the right size Pyrex too, have not found the size needed.
PPS. Even at $5 per piece, let alone $1.60 apiece, I think that beats the heck off the red stuff molding process. If, of course, it works.
PPS. They do have exact size for the smaller dog-bone size - 0.188x0.12. It will need to be about 0.75" long. I called them to see if the order could be split between the two parts.

I suggest we discuss that in the separate thread I opened.

[Eliot Ness]

It is a classic, probably more so than the "Deluxe" version

I'd have to agree with that.  I picked up a pretty clean Deluxe because my friend had it marked down so low, and I will restore it, but ultimately I'd like to find a clean classic model 20.

Mike as far as that metal can goes, years ago I stuck one in my vise with a metal can under it and when heated the guts just plopped right out.

[morzh]

John

I might try.....I gutted two of these. The first was the learning experience, but then the second still was a messy thing. I had to resort to the screwdriver and a bolt. That cardboard somehow holds on to it.

I will try that heating. I have the vice. Or the vices both kinds