Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Colas LeGrippa on September 13, 2022, 05:58:09 pm
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Hi amigos,
I removed the short tranny from its black cover
(Old Ampeg ) and I am ready to put a new in.
My question is: what kind of stuff should I use to replace the black tar that holding the old one inside ?
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it should've been epoxy resin, or potting compound.
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I was going to use silicone, just to hold the new tranny in the cover of that B15N. I had to use a propane torch to melt that black stuff in order to remove the damaged tranny from the black box. In doing so, I burnt the black coating so I had to sand it entirely to metal before priming it ( automotive grey primer). I was really excited to fit the new tranny in but Linda just called me for supper and the evening took another path....
This morning, after 3 expressos to help swallow
my half inch peanut butter spreaded on 2 full grain toasts, I went down to my shop and.realized the new tranny wouldn t fit in the newly painted enclosure......gee whizzz
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now I know how to easily remove a b15n tranny from its enclosure but I have to check the measurements BEFORE ordering the new transformer. I had a transformer in stock that would fit in but with plate supply of only 300V.
Colas
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it should've been epoxy resin, or potting compound.
Epoxy in transformers is rare or never. The unyielding fill tends to break fine wire.
Roofing tar is readily available and appropriate. Heat it up, don't start a fire. Solvent thinner is probably a bad idea unless you know all the varnish and plastic in the transformer can stand it. If you can get it thin enough to stir, clean coarse sand in large quantity improves the heat transfer. (See and open UK job-site 110VAC yellow transformers.)
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I'll avoid the use of epoxy (near impossible to go back if you put It on), also silicon will be really difficult to manage if there are problems
Obviously the better will be to don't use any material, however PRR Is absolutely right, roofing tar will be the right way to do It, in the future, if you have any problem you'll be glad you followed his council
Franco
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If it would fit iin I would jam it in place with.copper pipes or any heat proof material.
Anyway the enclosure is screwed on the chassis , the tranny can t go away
My Linda can go away though she promised to stay with me. I could put her in a box , no ?
I stop right here. She.might read this.post...
Hey honey, I love you don t go away !!!
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it should've been epoxy resin, or potting compound.
Epoxy in transformers is rare or never. The unyielding fill tends to break fine wire.
We used it all the time for low voltage applications. Fully encapsulated transformers are common. Usually we put a silica mix with the epoxy for heat dissipation.