That stuff creates a thin inert layer which should be left on the surface and then optionally painted over. As you've seen if you want the surface to look good you can't use it anywhere that will be seen as it looks worse than the rust. By wire brushing it you have re-exposed the rust/metal to the air and corrosion can continue. You might as well not have used it. I think the spot treatment you did on the underside is OK but no point wire brushing it afterwards. I've been through this process with various rust treatments but I'm yet to find anything I'm 100% happy with. I feel for you.
Honestly the best thing I could think to do at this point is hit it with a hand sander, polish it nicely and then go over it with a clear coat to keep the rust out. It's either that or re-plate it.
FYI, that rust converter is called MK-350 in it's 'commerical terms'. We use it on metal in the marine industry on capstans and hatches or anything where paint wears to expose metal to moisture. We don't actually remove it, we leave it on as if it were black paint. As you discovered, you don't want to get it on areas where there is no rust. Just wipe it off those areas fast. 👍
Agreed. Removing that black pretty much negates much of it’s purpose. It is meant to be either painted over or leave as is. You could have achieved that final result without the chemical treatment and just mechanically removing the rust. You may have neutralized any residual rust in the pitted spots but that’s about it. Really appreciate your videos!
The pink stain should wash off completely with clean water. Wire brushing now will just expose bare steel which will rust again. This stuff is intended for rusted areas on painted car bodywork or exterior ironwork like railings. It's a bit messy and mildly corrosive. I would.have carefully wire brushed the rust spots back to clean metal then use a mega soldering iron to flood solder the rust spots. Chris talk to a car body repair guy before rushing in with gallons too much Kurust and then wire brushing all the Kurust and the rust protective nickel plating away. Entertaining watching though.
Thanks Chris. Really enjoying the restoration series of vids. It reminds me that i have an old Bandmaster chassis knocking around somewhere that i should restore. Hope you're having a nice seasonal break. Looking forward to more videos soon. Cheers
As you probably figured out, you just need enough of the Kurust (cure rust) to cover the rusted spots to keep clean up to a minimum. I think it ment to be printed over, too. It reacts like the POR 15 I’ve used.
Hi Chris. I’m really enjoying this series. At the start I thought you were crazy to take it on, but now I can’t wait to see and hear the end result. It would be interesting to know how much it has all cost at the end.
Wear rubber gloves when using Kurust or it will stain your skin. Converts the rust to ferrous ferrocyanide which itself is then oxidised to a very dark blue compound (also used as a dye called Prussian Blue). You really wanted to know that I'm sure. It's not as toxic as it sounds though :-) The dark blue/black residue IS the protective layer so is left on after washing off the excess, but it is not very resistant to abrasion. Removing it is pointless, you may as well just take it back to bare metal to start with and paint it. It's a treatment for items that will be painted over or its cosmetic appearance doesn't matter.
Loving the long form and in-depth videos! Especially the recent one about the output transformers and winding ratios! Learning lots of great tips and affirming pieces of knowledge I have!
Further to my previous posting, now you have destroyed the Kurust with your wire brush, re-touch the Rusty bits with a Q-Tip and leave them at that; otherwise, the Rust will break out again.
@johnburns5783 they are called balance resistors because they make sure the two caps work equally. Usually it's 2 x 220k or even 100k in parallel with the caps but as chris said they are inside the chassis.
The recording output on these models is very usable. All the valve colouration and not just the preamp makes a difference sonically and you’ve done away with all the inherent problems with the noise of waxy boards and spaghetti wiring
Allright, I retract my vote to acid dip and re-plating the chassis. Preserving the patina and history is the right thing to do. Excellent video series!
It's a pre-painting treatment, if you're not going to paint it, then it looks like that, if you wire brush the black residue off (which protects the area that was rusty), then it'll go rusty again, won't it? As you've decided to treat it like some kind of historical object and you want to preserve its "patina" then I'm afraid you're stuck with it. Personally I'd have it blasted with something like walnut shells so the surface of the metal isn't damaged and then have it zinc plated.
I would also drill my (aluminum) chassises from blanks. I never had punches, so I would just use a cheap awful drill press. In doing this, the chassis would get all kinds of scratches and dings and just look horrible. Eventually, I got tired of this awful look and decided to start polishing my chassises. I would use a hook and loop pad attachment on my drill press or hand drill, and use WD40 or machine oil as a lubricant. I'd start from 40 grit or 60 grit, and work my way all the up to 3000 grit. Then wash everything off with soap and hot water, dry and apply metal polish or buffing polish. When done the chassis looked almost as good as a mirror. It never stayed that way, because aluminum oxidizes so fast, but it would still look rather handsome for a few years. I'm not sure which years Fender did it, but I believe most of the 60's and 70's Fender would apply a zinc layer on top of the steel chassis to prevent rust. Be very careful with zinc, it can become toxic, especially if heated and vaporized and you breathe in the air. I believe that's what the red color is. Some zinc compound that chemically mixed with that rust remover. Preventing rust on steel can be quite a chore. Cast iron pans burn a layer of oil on top until the oil becomes a polymer. Plating it with zinc, or chrome is a cheap option. Even paint or lacquer can be used. But if you leave it bare, the finer the scratches, the less deep the rust will be when it returns.
Hi Chris. What Kurust - and its predecessor, Trustan 23 - does, is to turn the Rust (Iron Oxide) into a Stable form of Iron Oxide, which doesn't rust. Don't scrape it off, or the rust will just return. From my own personal experience, Kurust isn't as good as Trustan 23, which is what the Royal Navy used on its Ships. I applied Trustan 23 to the rusty bits of my old Datsun and they were still Blue/Black five years later. Trouble is, it isn't made anymore, which is a damn shame. Russ. Hampshire.
I vote for keeping the transformers as they are. It's a tip of the hat to the original amp also I'm certain it'll add lots of cork sniffing imaginary mojo to the tone when you've finished...😂
That stuff creates a thin inert layer which should be left on the surface and then optionally painted over. As you've seen if you want the surface to look good you can't use it anywhere that will be seen as it looks worse than the rust. By wire brushing it you have re-exposed the rust/metal to the air and corrosion can continue. You might as well not have used it. I think the spot treatment you did on the underside is OK but no point wire brushing it afterwards. I've been through this process with various rust treatments but I'm yet to find anything I'm 100% happy with. I feel for you.
Thanks
Honestly the best thing I could think to do at this point is hit it with a hand sander, polish it nicely and then go over it with a clear coat to keep the rust out. It's either that or re-plate it.
FYI, that rust converter is called MK-350 in it's 'commerical terms'. We use it on metal in the marine industry on capstans and hatches or anything where paint wears to expose metal to moisture. We don't actually remove it, we leave it on as if it were black paint. As you discovered, you don't want to get it on areas where there is no rust. Just wipe it off those areas fast. 👍
Agreed. Removing that black pretty much negates much of it’s purpose. It is meant to be either painted over or leave as is. You could have achieved that final result without the chemical treatment and just mechanically removing the rust. You may have neutralized any residual rust in the pitted spots but that’s about it.
Really appreciate your videos!
There is a reason to pour out rather than use from the pot. If any ferrous metal gets back into the pot, it will all go pink. Guess how I know.
The pink stain should wash off completely with clean water. Wire brushing now will just expose bare steel which will rust again. This stuff is intended for rusted areas on painted car bodywork or exterior ironwork like railings. It's a bit messy and mildly corrosive.
I would.have carefully wire brushed the rust spots back to clean metal then use a mega soldering iron to flood solder the rust spots. Chris talk to a car body repair guy before rushing in with gallons too much Kurust and then wire brushing all the Kurust and the rust protective nickel plating away. Entertaining watching though.
You need a smaller brush for the Kurust. Excellent series Chris. 😂😂😂
I should have watched a YT video before!!
Thanks Chris. Really enjoying the restoration series of vids. It reminds me that i have an old Bandmaster chassis knocking around somewhere that i should restore. Hope you're having a nice seasonal break. Looking forward to more videos soon. Cheers
As you probably figured out, you just need enough of the Kurust (cure rust) to cover the rusted spots to keep clean up to a minimum. I think it ment to be printed over, too. It reacts like the POR 15 I’ve used.
I spoke too quickly. Your second application was better.
Hi Chris. I’m really enjoying this series.
At the start I thought you were crazy to take it on, but now I can’t wait to see and hear the end result.
It would be interesting to know how much it has all cost at the end.
Wear rubber gloves when using Kurust or it will stain your skin. Converts the rust to ferrous ferrocyanide which itself is then oxidised to a very dark blue compound (also used as a dye called Prussian Blue). You really wanted to know that I'm sure. It's not as toxic as it sounds though :-) The dark blue/black residue IS the protective layer so is left on after washing off the excess, but it is not very resistant to abrasion. Removing it is pointless, you may as well just take it back to bare metal to start with and paint it. It's a treatment for items that will be painted over or its cosmetic appearance doesn't matter.
Loving the long form and in-depth videos! Especially the recent one about the output transformers and winding ratios! Learning lots of great tips and affirming pieces of knowledge I have!
Further to my previous posting, now you have destroyed the Kurust with your wire brush, re-touch the Rusty bits with a Q-Tip and leave them at that; otherwise, the Rust will break out again.
Hi Chris. Love this bassman series. How about the 220uf balance resistors?
They’re inside the chassis, 2x 100k in this case
@bambule5268 First I've heard someone give a capacitor value for a resistor 😉😉
@johnburns5783 they are called balance resistors because they make sure the two caps work equally. Usually it's 2 x 220k or even 100k in parallel with the caps but as chris said they are inside the chassis.
The recording output on these models is very usable. All the valve colouration and not just the preamp makes a difference sonically and you’ve done away with all the inherent problems with the noise of waxy boards and spaghetti wiring
I would have rust treated and then painted over the doghouse area with aluminium paint
Chris, great video, but whats the lovely jazz track playing at around 18:00?
Allright, I retract my vote to acid dip and re-plating the chassis. Preserving the patina and history is the right thing to do. Excellent video series!
You’re spoiling us with all this content..loving the format of showing a project through various stages. 👍
Phosphoric Acid on the spots only and rinse with water after rust reacted
Moral of the story… a new chassis wouldn’t have been so expensive after all.
It's a pre-painting treatment, if you're not going to paint it, then it looks like that, if you wire brush the black residue off (which protects the area that was rusty), then it'll go rusty again, won't it? As you've decided to treat it like some kind of historical object and you want to preserve its "patina" then I'm afraid you're stuck with it. Personally I'd have it blasted with something like walnut shells so the surface of the metal isn't damaged and then have it zinc plated.
Enjoying the videos and nice to see clean holes.
There's a video title I can get on board with..... 😁
Hi again, Chris, and good tidings from Las Vegas! Quick question, where do you get your ceramic octal sockets?
Thx,
-Rick
What's the tool you're using with the drill press to fasten the eyelets? Tried to find something similar, but only ones to use by hand came up...
I would also drill my (aluminum) chassises from blanks. I never had punches, so I would just use a cheap awful drill press. In doing this, the chassis would get all kinds of scratches and dings and just look horrible. Eventually, I got tired of this awful look and decided to start polishing my chassises. I would use a hook and loop pad attachment on my drill press or hand drill, and use WD40 or machine oil as a lubricant. I'd start from 40 grit or 60 grit, and work my way all the up to 3000 grit. Then wash everything off with soap and hot water, dry and apply metal polish or buffing polish. When done the chassis looked almost as good as a mirror. It never stayed that way, because aluminum oxidizes so fast, but it would still look rather handsome for a few years.
I'm not sure which years Fender did it, but I believe most of the 60's and 70's Fender would apply a zinc layer on top of the steel chassis to prevent rust. Be very careful with zinc, it can become toxic, especially if heated and vaporized and you breathe in the air. I believe that's what the red color is. Some zinc compound that chemically mixed with that rust remover.
Preventing rust on steel can be quite a chore. Cast iron pans burn a layer of oil on top until the oil becomes a polymer. Plating it with zinc, or chrome is a cheap option. Even paint or lacquer can be used. But if you leave it bare, the finer the scratches, the less deep the rust will be when it returns.
Hi Chris, loving this rebuild. Does rust on the laminate stacks affect the magnetic performance of the transformers?
Really enjoying this project Chris
*Johnny cash voice* "I'm gonna break my rusty [...] ... And ruuunn"
Is that your guitar playing in that jazz tune?
Hi Chris. What Kurust - and its predecessor, Trustan 23 - does, is to turn the Rust (Iron Oxide) into a Stable form of Iron Oxide, which doesn't rust. Don't scrape it off, or the rust will just return. From my own personal experience, Kurust isn't as good as Trustan 23, which is what the Royal Navy used on its Ships. I applied Trustan 23 to the rusty bits of my old Datsun and they were still Blue/Black five years later. Trouble is, it isn't made anymore, which is a damn shame. Russ. Hampshire.
I vote for keeping the transformers as they are. It's a tip of the hat to the original amp also I'm certain it'll add lots of cork sniffing imaginary mojo to the tone when you've finished...😂
Guessing they want you to pronounce the name of their product "Cure-Rust"
Jenolite gel would be better. It's clear. Chromic acid I think.
Long-format++