Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Replicating (dogbone) resistors what method have you used ?
#16

Richard,
This Alumilite appears to be similar to (maybe supplied by?) the product and process sold by Dow Corning. About fifteen years ago I tried the D-C molding materials and had very good success with them. The give clean smooth surfaces, flow well into details and if you use the correct compatible products as per the instructions, they perform as advertised.

One note :: when I was trying it, the Dow product I was using recommended a vacuum evacuation of air just prior to pouring. It increased the density and strength without compromising the flexibility. I don't see that (unless I missed it) in the Alumilite instructions or spec's.

cheers, good luck and have fun !!

EDIT :: the shelf life on the D-C raw product was very short (a year or so as I recall), so buy the smallest amounts that are economical for your purpose, and be ready to use it.
#17

hello Everyone,
Well it is time to start making some resistors !
My latest Philco 38-10T needs some made one is a 3 watt 10 k power resistor .

Sincerely Richard
#18

Hello Guys,
Well this year is time to final make these resistors because I also have to make some for my Philco 38-10T they are easier then the Zenith !

Sincerely Richard
P.S. I have a week off of work during the week of thanksgiving so in the next few days I will be ordering molding supplies .
#19

Hello Everyone ,
Rockler had a sale on Amazing mold maker and Amazing Casting resin
By Alumilite So I ordered those two items to see how they work .
there is also a knob for my 1950s GE clock radio I want to try casting too.

The Resin says it's good for 185 Degrees

Sincerely Richard
#20

Hello guys,
I have a question has anyone tried using off the shelf Pematex sensor save RTV to make a mold like the one Russ posted to make my dog bone resistors ?

Sincerely Richard


Attached Files Image(s)
   
#21

RTV is flexible. For dog bone replacements you want a rigid material such as epoxy.

Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA
https://plymouthcolony.net/starcity/radios/
#22

Richard,

The RTV might work for the molds, but it might be too soft, I haven't worked with gasket maker in a few years. The newest idea I have run across is making the shells on a 3D printer. Below is the work of someone else, not myself:

   
   
   
   
   

I believe he made his on a resin printer. I printed some off with plain old PLA filament, but for heat resistance PETG or maybe ABS would probably be best. I have some STL files if you're interested. The third picture is an enlargement I made in TinkerCad.

John KK4ZLF
Lexington, KY
"illegitimis non carborundum"
#23

Hello Dale,
I am talking about using the RTV as the mold.
Well John, yes, I have seen that design I think it was one of the ARF forum members he sent me that file.
I really want a 3D printer to use at my home and found one that I really want Prusa MK4S but it's over a grand see I want fully enclosed one we use a Flasforge brand in the classroom at the school I have been using one for over 5 years .
John did you see the domino style capacitors that he made too.
Sincerely Richard
#24

Quote:John did you see the domino style capacitors that he made too.

No, I did not see those Richard. I'll have to try and find it over there.

John KK4ZLF
Lexington, KY
"illegitimis non carborundum"
#25

Hello John,
I can look for the file and email it to you too.

Sincerely Richard
#26

Hello Guys,
I can't wait to try printing some of these I might go ahead and order some from PCB way !

Sincerely Richard




Users browsing this thread:
[-]
Recent Posts
Philco Model 38-7: what caps & resistors do fail typically?
Hello Martin, Welcome aboard our little community what great Model 38-7 Sincerely Richardradiorich — 12:30 AM
Philco Model 38-7: what caps & resistors do fail typically?
Welcome to the Phorum Martin. I count about 9 paper caps, the 3 electrolytic caps and 2-Y2 safety caps to replace th...RodB — 09:44 PM
Part numbers to model cross
Jim, We have this index put together by Dale Cook but I don't think that is quite what you are looking for. The Parts...klondike98 — 09:37 PM
Philco Model 38-7: what caps & resistors do fail typically?
Yep the dim bulb test is OK but I'd definitely replace all those electrolytics before I did it. Since those #47 conden...klondike98 — 09:18 PM
Philco 42-345 Restoration/Repair
The resistor is a 2.2 Meg, it was the last one I hadn't replaced. The broadcast is coming in after replacing it.osanders0311 — 09:09 PM
Philco 42-345 Restoration/Repair
What does the resistor measure? I think it should be 3.3 Meg. If the oscillator coil has continuity and the resistanc...RodB — 09:03 PM
Philco Model 38-7: what caps & resistors do fail typically?
Good idea to check the coils... then I'll get hold of an incadescent light bulb and see what happens when the unit is sw...Musaeum — 08:49 PM
Philco 42-345 Restoration/Repair
I have that same set, ain't too much shortwave I like anyway.....it is a good AM DX set. PaulPaul Philco322 — 08:32 PM
Philco Model 38-7: what caps & resistors do fail typically?
Welcome to the Phorum, Martin! Open a new thread in Philco Electronic Restoration when you begin working on your 38-7. ...GarySP — 08:28 PM
Philco Model 38-7: what caps & resistors do fail typically?
Welcome to the Phorum! :wave: Here's the schematic for that radio from our digital library: Something to do bef...klondike98 — 08:05 PM

[-]
Who's Online
There are currently no members online.

>