Re: Re: anodizing, etc.
I wouldn't use a 4 1/2" grinder or the likes... too little finesse in removing metal...
I'd go with a plain jane 1/4" drill fitted with a small flap-disk to remove the previous damage, using repeated light pass overs until the divots are reduced to minimal impact... then use a larger flap-sander (Sears has them) or a 3M scotch sanding wheel to even out the luster, going slowly and taking long strokes, preferably the length of the faceplate, sorta like avoiding brush marks when painting... trying to feather the wheel at the end of the stroke.
When you get the right finish, you'll know... might try on some scraps till you get it right..
John L.
TomWaits said:
I wish I had a macro photo option on my camera, then I could give close ups. These blemishes are on the surface of the metal and there is one good scratch in there too...
I just rubbed it and took a good hard look at it, they are not chemical stains at all, they are divits in the metal by a drill or a grinder or some gouge marks that go perhaps .1mm under the top surface. It looks like someone sanded out the old scars before and after I stripped the paint, voila. I guess I understand what you were saying earlier.
I can fix it, I need to sand out those areas gently with something powerful. I have a hand held grinder but what attachment would be best?
Shawn.
I wouldn't use a 4 1/2" grinder or the likes... too little finesse in removing metal...
I'd go with a plain jane 1/4" drill fitted with a small flap-disk to remove the previous damage, using repeated light pass overs until the divots are reduced to minimal impact... then use a larger flap-sander (Sears has them) or a 3M scotch sanding wheel to even out the luster, going slowly and taking long strokes, preferably the length of the faceplate, sorta like avoiding brush marks when painting... trying to feather the wheel at the end of the stroke.
When you get the right finish, you'll know... might try on some scraps till you get it right..
John L.
Re: Re: Re: anodizing, etc.
I think the DC300A was scraps and I will get it right. auplater
Thanks,
Shawn.
auplater said:
I think the DC300A was scraps and I will get it right. auplater
Thanks,
Shawn.
Re: Re: Re: anodizing, etc.
You might want to do your sanding with a belt sander (Or other "In-Line" sander) like Peter Daniel (I think) showed in one of his "Building a case for your Gainclone" type of posts.
The sander running "In-line" will give you a more uniform & desirable finish.
Tall Shadow
auplater said:
You might want to do your sanding with a belt sander (Or other "In-Line" sander) like Peter Daniel (I think) showed in one of his "Building a case for your Gainclone" type of posts.
The sander running "In-line" will give you a more uniform & desirable finish.
Tall Shadow
Re: Re: Re: Re: anodizing, etc.
Actually I can get a great finish with a palm sander (worked great in the past) but these machines we speak of do not fit into the face of the amp. The plate has two sections horizontal across the front.
Shawn.
Tall Shadow said:
Actually I can get a great finish with a palm sander (worked great in the past) but these machines we speak of do not fit into the face of the amp. The plate has two sections horizontal across the front.
Shawn.
Hi,
the palm sander may be an orbital type.
It leaves circular scratches that show through a polished surface.
It's normal to polish before anodising to ensure it is smooth otherwise the blemishes show up after anodising.
the palm sander may be an orbital type.
It leaves circular scratches that show through a polished surface.
It's normal to polish before anodising to ensure it is smooth otherwise the blemishes show up after anodising.
AndrewT said:
Yes, the machines are for first pass. It's all hand finishing after that. 🙂
Shawn
End of Life
When did Crown stop manufacturing the DC300's?
I downloaded the orriginal service manual from their site and it is funny as heck. Some loose canon in the eng department wrote that cynical document but it was published. I love it.
Cheers,
Shawn.
When did Crown stop manufacturing the DC300's?
I downloaded the orriginal service manual from their site and it is funny as heck. Some loose canon in the eng department wrote that cynical document but it was published. I love it.
Cheers,
Shawn.
Re: Re: Re: Re: Re: anodizing, etc.
The best way (the way pros do it) is with a stationary wheel, holding the part FIRMLY (perhaps in a jig) and controlling the part against the (burnisher/flap sander/buffer/whatever)... but I'm hesitant to recommend this due to some safety issues if you're inexperienced with large moving wheels at high speed (as in flying parts!)
Flex wheels give the ability to finish intricate parts uniformly, and controlling the part rather than the tool allows for the "personal touch"
Been doing it for several decades....
John L.
TomWaits said:
The best way (the way pros do it) is with a stationary wheel, holding the part FIRMLY (perhaps in a jig) and controlling the part against the (burnisher/flap sander/buffer/whatever)... but I'm hesitant to recommend this due to some safety issues if you're inexperienced with large moving wheels at high speed (as in flying parts!)
Flex wheels give the ability to finish intricate parts uniformly, and controlling the part rather than the tool allows for the "personal touch"
Been doing it for several decades....
John L.
Re: Re: Re: Re: Re: Re: anodizing, etc.
John, I can handle a chainsaw like my grandmother handles a sewing needle! 😉 I need to take a little visit to Atlas Machinery and get a new attachment. 🙂
Shawn.
auplater said:
John, I can handle a chainsaw like my grandmother handles a sewing needle! 😉 I need to take a little visit to Atlas Machinery and get a new attachment. 🙂
Shawn.
Anything happening on the Crown Tom?
Please advise it has been one of the most enjoyable forums so far
regards Trev
Please advise it has been one of the most enjoyable forums so far
regards Trev
Shawn's adventure
I think Shawn is trying to avoid electrocution..... I hope!
or he got bogged down in the tool aisle at the local hardware outlet..
John L.😎
latala said:
I think Shawn is trying to avoid electrocution..... I hope!
or he got bogged down in the tool aisle at the local hardware outlet..
John L.😎
Re: Shawn's adventure
This particular store sells only machine tools and machinery and it hurts to go in there because you want to have everything.
It is a wonderful shop called Atlas and it is in an odd location down town in the heart of the city. I purchased a couple flap wheels but I have to take the stuff to my garage, which is not where I live, not to mention my tools are right now spread over three job locations.
I have not yet ordered the MJ21194 transistors
for the outputs of the Crown.
I have been thinking about switching careers and getting back into the electronics industry but having two diplomas and no degree means the money sucks.
I’ll have some more “entertainment” soon, I hope. 🙂
Shawn.
That is too funny. 😀 You can't be serious? I still have a Quasi in the oven and that project may finish first?latala said:
This particular store sells only machine tools and machinery and it hurts to go in there because you want to have everything.
It is a wonderful shop called Atlas and it is in an odd location down town in the heart of the city. I purchased a couple flap wheels but I have to take the stuff to my garage, which is not where I live, not to mention my tools are right now spread over three job locations.I have not yet ordered the MJ21194 transistors
for the outputs of the Crown.I have been thinking about switching careers and getting back into the electronics industry but having two diplomas and no degree means the money sucks.
I’ll have some more “entertainment” soon, I hope. 🙂
Shawn.
Tom
Dont bother getting back into electronics the "money sucks" as you would say !
I think you have to be into corrupt insurance or investments to make a few Quid (Moneys)
And I have a real interest in early transistor amplifiers, That means anything from the 1950 untill the 80,s
In these days of powerfets and super transistors its easy to forget how in awe we were at things like the Crown.
I used to work in a Hi Fi shop but as ever could never afford to buy any top ranking gear
My thoughts are that if you modify the amp what have you got ?ans= mongrel
But if you restore it people can hear the sounds of the seventies
Plus its not only the post but the way its presented I only do this for pleasure
regards Trev
Dont bother getting back into electronics the "money sucks" as you would say !
I think you have to be into corrupt insurance or investments to make a few Quid (Moneys)
And I have a real interest in early transistor amplifiers, That means anything from the 1950 untill the 80,s
In these days of powerfets and super transistors its easy to forget how in awe we were at things like the Crown.
I used to work in a Hi Fi shop but as ever could never afford to buy any top ranking gear
My thoughts are that if you modify the amp what have you got ?ans= mongrel
But if you restore it people can hear the sounds of the seventies
Plus its not only the post but the way its presented I only do this for pleasure
regards Trev
well guys!
say what you like about crown dc300a amplifiers, and yes your comments are amusing!
They always work fine for me, the only problem with dc300a amps are a few caps and transistors that do actually need replacing after 30 years or so.
Oh yeah almost forgot, probably the biggest problem is the people who just replace parts with (equivalents) or also known as , (cant be arsed getting the correct components, but im so bright any old transistor with three legs will fit).
All parts are available still, if you get out and look for them , i admit they can be slightly..........shall we say unpredictable.....
Flames smoke and burnt bits apart i dont think they are that bad when you consider how old they are....
PS does anyone want a **** load of dc300a amps, i cant give them away ........
dont breathe the lead solder boys!
say what you like about crown dc300a amplifiers, and yes your comments are amusing!
They always work fine for me, the only problem with dc300a amps are a few caps and transistors that do actually need replacing after 30 years or so.
Oh yeah almost forgot, probably the biggest problem is the people who just replace parts with (equivalents) or also known as , (cant be arsed getting the correct components, but im so bright any old transistor with three legs will fit).
All parts are available still, if you get out and look for them , i admit they can be slightly..........shall we say unpredictable.....
Flames smoke and burnt bits apart i dont think they are that bad when you consider how old they are....
PS does anyone want a **** load of dc300a amps, i cant give them away ........
dont breathe the lead solder boys!
Hi,
how much would it cost to send one up to Scotland.
After reading this thread it sounds like it might make an interesting refurb/upgrade project.
how much would it cost to send one up to Scotland.
After reading this thread it sounds like it might make an interesting refurb/upgrade project.
Hi krmaudio,
Andrew,
They would make an interesting project for sure. Keep you busy anyway. 😀
I have to agree with krmaudio. They were quickly superseded by better amplifiers in the late 70's. Touring companies don't want them these days even if they are perfect, just due to weight.
Given a choice, I'd rather have a BGW750C to work with.
-Chris
Sure you can. I'm on the wrong side of the pond though. With shipping I could buy a new - whatever -. 🙁
Andrew,
They would make an interesting project for sure. Keep you busy anyway. 😀
I have to agree with krmaudio. They were quickly superseded by better amplifiers in the late 70's. Touring companies don't want them these days even if they are perfect, just due to weight.
So true! They do seem to keep on going without major smoke.
Given a choice, I'd rather have a BGW750C to work with.
-Chris
thanks chris, sense in a mad world.....
I have never got my hands on any bgw gear..... although i understand its pretty good,
Are there any particular models to avoid???
I hade heard the early bose models were made by bgw?
I had a bose 1802 once that was a sponge for money, looking back it would have made a damn fine anchor for a nautical type!
cheers guys
I have never got my hands on any bgw gear..... although i understand its pretty good,
Are there any particular models to avoid???
I hade heard the early bose models were made by bgw?
I had a bose 1802 once that was a sponge for money, looking back it would have made a damn fine anchor for a nautical type!
cheers guys
Hi krmaudio,
I liked the 750C, the 750A was not as nice. Anything with Bose on the front panel is not worth looking at. I don't care who made it.
I would also stay away from Bryston. The 3B,4B especially. Of course the cheap and nasty "pro" models, but you know which ones they are.
I did really like the Yamaha stuff. Clean, quiet. If you didn't abuse them they were fine. I still remember getting P-2200's with the power transformer pushing the meters out after "the amp rack fell over". 😀 That happened a few times.
-Chris
I liked the 750C, the 750A was not as nice. Anything with Bose on the front panel is not worth looking at. I don't care who made it.
I would also stay away from Bryston. The 3B,4B especially. Of course the cheap and nasty "pro" models, but you know which ones they are.
I did really like the Yamaha stuff. Clean, quiet. If you didn't abuse them they were fine. I still remember getting P-2200's with the power transformer pushing the meters out after "the amp rack fell over". 😀 That happened a few times.
-Chris