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Hi

I just bent my fist side of Cherry, I sandwiched the side between some damp wrapping paper. What is all this black stuff ? It's not burnt.

Regards

John

I've had the same experience with blackwood. It's tannen. You can remove it with a mild solution of oxalic acid (available from a paint store). Just mix up a mild solution and wet the wood with it, brush with a stiff brush and rinse. That method worked great for me recentily. OR..you can lightly sand the wood and remove the stain. It's pretty much just on the surface (at least that was my experience)..
Jay

John: Looks like it is scorched to me. You should be able to sand or scrape to clean up the side.
Tom

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A person who has never made a mistake has never made anything!!!

Hi

Its not scorched, it is on the inside which was the furthest away from the blanket, the outside is not as bad however there is some staining which is quite deep - it won't sand or scrape so its a write off. Hopefully I can find out what it is on the second piece so when I order another set it won't happen again.

It has to be either my slats of the brown wrapping paper, my slats had a bit of rust on them, how do you keep them clean and stop them from getting rusty ?

John

I'll order some of the acid, but I think it is too deep. Its worth a try though.

Thanks

John

Cherry wood contains tannin. You probably used tap water that has iron in it for your bending. The iron reacts with the tannin causing the black stains. Next time use distilled water. Same thing can happen if you use tap water to mix hide glue. I keep a gallon of distilled water in the shop to use for that reason.

_________________
Steve Smith
"Music is what feelings sound like"

Sounds good to me, I have some distilled water I'll try it on the spare side that I have left

Thanks

John

I haven't found a way to keep the spring steel slats from rusting. I tried painting them with high heat enamel... Bad mistake. I don't recommend it.The paint softens up when it gets hot.
I use aluminum foil to protect the sides from iron staining.

Yep, tin foil as we call it here will be included on the next bend, I wonder if a thin coat of Camellia oil would be ok for the slats ?

John

it almost looks like rust stains to me (first time I used my new spring steel slats years back I only used parchment paper as the wrap, with maple .. had some nasty stains that looked kinda like yours) .... use foil to wrap the side, and almost no water (distilled) BTW - I never had this problem when bending cherry

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

I use AL house flashing for slats and have never had any problems like this. But then again I've never bent cherry.
Tom

_________________
A person who has never made a mistake has never made anything!!!

I've used both aluminum & galvanized flashing. Both work fine, but take on kinks after time. I do prefer the spring steel.
Aluminum will turn unprotected Koa sides a sickly shade of green.

Looks like the moisture leached some iron out of the slats and stained the wood. Definitely try aluminum foil. Any kind of paper will probably do the same thing.

Hi

I managed to bend side two last night, I used foil and distilled water. There is a significant difference in the outcome as you can see. Some slight tannin is showing in one area but I am confident that will clean. I think however these are for the scrap bin as number one is beyond cleanup.

Thanks

John

John,

Take Jay's advise and get the Oxcylic acid, you will be amazed at how well it works. I had worse staining than you show on a set of Red Oak sides. In less than three minutes after applying the oxcylic acid the black was completely removed.

Steve

Its on order via eBay, I'll let you know how I get on. Its not in trash yet

Thanks

John

I find that stainless Shim In a Can is fantastic for slats http://catalog.daemar.com/viewitems/shim-in-a-can/stainless-steel-shim-in-a-can? . Never a worry about staining with this stuff.

Bob

Hi Bob

Fantastic, I wonder if it is available in the UK ?

What thickness do you use ?

John

Are the slats blued spring steel or did the stainless turn black. If it is Stainless, you found some serious tannin , if you have Blued steel you may have a chemical reaction from the chlorine in your water with the blued steel or the tannin .
Don't use the paper . If you do need a barrier , use alum foil but do not wrap just fold in half and allow some open end for water vapor to escape . Also don't use a lot of water. Too much water is not a good thing. You are better to use just a small amount . I do most bending on the dry side.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Hi John

blued spring steel, the second side wasn't too bad. Another lesson learned I think.

John

I know a few people that painted the blued steel with grill paint. I think covering the wood with foil may help. As Todd Stock pointed out , it is a reaction not unlike letting a nail on somthing wet. The acid in the paper causes the reaction with the iron ions.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Bob's suggestion looks like an option for the future

http://catalog.daemar.com/viewitems/shi ... m-in-a-can?

John

I received my Oxalic Acid today, any idea what quantity of powder to water I should use ?

John

I use Bostik Top Coat for all of my machined surfaces - table saw, jointer tables, band saw table, etc. I also use it on my spring steel slats and no rust!

Chuck

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"To live a creative life, we must lose our fear of being wrong"
- Joseph Chilton Pearce

I thought of Top Coat but apparently its not available in the UK, and there are restrictions on shipping from the US.

Good idea though

John