# What is the best way to finish a spalted maple burl slab?



## ModCo Design (Oct 17, 2011)

Hey I really don't have much experience with finishing burl, I'm not looking for something like bar top pour over, I really want it to look as refined as possible. So far I have it sanded down all the way with 4000 grit ( which has given it a very slight sheen) but I would like to keep it from getting damaged from spills. This piece is roughly 62" X 52" and I would hate to start all over with another piece.


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## woodtick greg (Sep 12, 2011)

wow, no takers on this one? I guess I'll give my 2 cents worth so everyone can disagree with me and get this thread started and give you some options. That's a beautiful slab by the way and it deserves to be massaged with the best finish you can give it! I for one like the long, slow, multiple coats, hand rubbed finish. I like the sam maloof blend of 1/3 pure tung oil, 1/3 boiled linseed oil, 1/3 oil based polyurethane, thined with mineral spirits for wipeing. I like to start with a first coat of pure tung oil only applied liberally, as it will really make the grain and features pop, the first coat of pure tung oil is just magical! allow it to soak in for 24 hrs. and then wipe off any excess that may be on the surface. then start applying the maloof finish, how many coats is up to what you see and like. A dry wipe with a fresh clean cotton rag is recomended between coats. for a little more durability and protection from spills and uv rays a thined out 50/50 mix of spar polyurethane and mineral spirits could be applied. I like a gloss finish, rather than a satin with flatening agents, In my opinion they look muddy, and then rub with liberon 0000 steel wool to a satin finish. When useing this finish it helps greatly to keep the finish room warm, this oil based finish is slooow to cure! but it provides a depth and warmth like no other.......ok guys what say you?
P.S. Do not wad the rags up and put in the garbage, they will spontainiosly cumbust!!! lay rags on a flat surface or drying rack spread out till dry. or better yet dispose in a can of water. whew!


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## chemmy (Dec 13, 2011)

Firstly, I would concern myself more with the treatment of the figure to bring out as much dimensionality as possible. I will leave the subject of the finish to others, unless you post more info on exactly what your hoping to produce as the end product. There is to much to take into consideration on something of this nature, like will it be used as an actual everyday table? Or more of a conversation piece. Depending on the wear and tear or accident, this has more to do with what should be used to coat the burl. 

As to bringing out the most depth possible on maple, i would suggest you purchase some Tannic acid and put that down firstly and then come over that with a solution of 1/32th of an oz. Ferrous sulfate to 1 quart of distilled water as the chemical ground before spraying ok?

If you nee more info, just ask. 

PS: Woodtick's answer is an option as to one type of finish.


Sincerely,

Chemmy


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## ModCo Design (Oct 17, 2011)

Wow, thank you for the repossess, I had started to lose hope for an answer. A good question about the final look, I'd really like to bring out as much of the grain as possible. Here is a better picture so you can see what I have to deal with. It will be a conversation piece but will also have some minor dinner use.


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## chemmy (Dec 13, 2011)

Looks beautiful, better lighting conditions. 

As i say if you add the T A and follow with the FS you will get the most pronounced depth and figure possible. if you want or need formulas or directions then just ask OK?

we can discuss in depth any finishing you then need, since now i know it's more of a conversation piece with "only" occasional use as a dining table. :thumbsup:

Then you can pick or choose to use any other suggestions that may be posted. But i will make a strong case for mine and the reasons why lol.


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## Carlo Bartolini (Aug 30, 2011)

Grat info Chemmy - saved to my files, is the tannic acid in very strong "undrinkable" black tea enough for that? (it does contain some oxalic acid)


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## aardvark (Sep 29, 2011)

When dampened down you can see how just a clear coating might effect it.
Fears to me in staining is evenness, on burl. If you get one area soaking in faster deeper than another, you have a problem.
In voids, I was instructed to use epoxy and sand it smooth. Same with bug eaten portions to give it strength. I'm due to cut some oak burl with similar graining. Drying is near done.

Love that piece.
What are your future plans for it?


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## chemmy (Dec 13, 2011)

Carlo Bartolini said:


> Grat info Chemmy - saved to my files, is the tannic acid in very strong "undrinkable" black tea enough for that? (it does contain some oxalic acid)


 
My dear Friend Carlo, nice to hear from you again. Actually Black Chinese tea [in it's original blocked form as shipped from China, has the strongest amount of tannin on the market. [easily found in china town, not sure about on the high seas lol.] and if you add a pinch of sodium hydroxide to it instead of oxalic, it will help the penetration even more so. but for the best affects, other chemicals will be needed for color or dimensional changing.

"Pure" tannic acid, or pyrogallic acid from the gall nut of oaks, are the 2 best sources for it though. It is a very strong liquor and has been used in wood finishing in formulas to treat woods such as and mainly on figured maple, but will work to readily to prepare any wood that will be receiving other chemical coloring upon it such as ferrous sulfate, in this instance. . It gained great strides by the wood dyers in England when they produced the still popular "Hare-wood" Finish. One that was a light to medium grey, struck fully through the dyed veneers of curly Sycamore. 

It was found later that a saturated solution of TA followed by very weak solution of the FS in hot water [120-140 degrees] could bring out the figure in maple in a most excellent way, just as Potassium dichromate does with figured mahogany, in it's own way. 

The Real "trick" is to not get it concentrated enough to turn the wood grey as it would for the hare-wood finish color. At the very most you would want it to be ever so slightly grey, no more than the natural occurring grey or less, in this case, as the burl itself has, which in some areas is pretty grey already. And less in other figures. It's a fine line of mixing and testing, that's why i always start out weak so as to not have to keep adjusting much as my trials continue. Always easier to add, than to take away lol.

Oxalic acid, my friend, is only really used in our trade as chelating agent, it has the ability to grab on and hold metal oxides as iron and thus is used to remove any type of iron stains including old iron-gall inks etc. It also has a light bleaching action which may be useful, but seldom is really necessary, as the surface, once stripped and treated and sanded to any degree, removes the thin layer of this. 

Never use in shellac as you already know my friend.

Sincerely, 
Chemmy / sam:thumbsup:


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## chemmy (Dec 13, 2011)

aardvark said:


> When dampened down you can see how just a clear coating might effect it.
> Fears to me in staining is evenness, on burl. If you get one area soaking in faster deeper than another, you have a problem.
> In voids, I was instructed to use epoxy and sand it smooth. Same with bug eaten portions to give it strength. I'm due to cut some oak burl with similar graining. Drying is near done.
> 
> ...


The idea with FS Aardvark, is to work upon the different normal grain and burl and every other area to make a very noticeably difference in the areas as to perception of varying depths. this is what causes the magnificent optical results obtained . In the case of burl, you want those areas that absorb and ones that don't, to do just that, which, in turn, increase the effect. 

If our poster decides to go this route I'm sure you will in time, [ if he hopefully post finished pics], see and be amazed at the difference in this and or just the use of other or nothing at all ok?:thumbsup:

Sincerely,

chemmy


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## aardvark (Sep 29, 2011)

It can also backfire with the wrong stains and absorb near black in coarse graining, leaving other area's hardly tainted. It depends on the cut of course and how porous it is, as well as the stain type. The safe method is clear. Otherwise you better know about what will happen. I haven't been that lucky in my attempts.


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## Carlo Bartolini (Aug 30, 2011)

chemmy said:


> Oxalic acid, my friend, is only really used in our trade as chelating agent, it has the ability to grab on and hold metal oxides as iron and thus is used to remove any type of iron stains including old iron-gall inks etc. It also has a light bleaching action which may be useful, but seldom is really necessary, as the surface, once stripped and treated and sanded to any degree, removes the thin layer of this.


Sorry Chemmy, did not explain myself well, I meat that black tea contains oxalic acid naturally, as tannic acid, but I did not know if the oxalic in it would act i a contrary manner.

Anyway your answer is even more complete now, added to my files, thanks again.:thumbsup:


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## chemmy (Dec 13, 2011)

aardvark said:


> It can also backfire with the wrong stains and absorb near black in coarse graining, leaving other area's hardly tainted. It depends on the cut of course and how porous it is, as well as the stain type. The safe method is clear. Otherwise you better know about what will happen. I haven't been that lucky in my attempts.


I'm very sorry to hear of your misfortunes with what ever you have attempted to use in the past. But you have to understand that a chemical stain is or can be different than one which produces a strong color such as dye or pigment, when necessarily used weakly. For example the tannin that is naturally present in all woods to varying degrees is not seen and even when a saturated solution of additional tannin is applied - once dry, it will still not be evident to the viewer. Therefore, by itself, it has no color or darkning affect at all. 

When a chemical stain of weak consistency is then applied, your are producing a look that will be permanent, it will, in this case, effect every area that it's applied to in it's own way, Meaning, where interlocking grain is readily apparent, it will act to darken this affect, where burls exist it will act to possibly brown or redden or darken those, where flame exist it will affect it [or not affect it] in other ways which all add up to a depth that can not be achieved any other way. The secret is the action of the FS on the tannin principal within the wood itself. This is also magnified when a saturated coat of tannic acid is further introduced to assure the ultimate gain of the FS affects on the dimensional look to the piece once cleared. and here again the coating is of most importance, to insure that the refractive index of the film is in very close relation to the RI of the wood applied on. so it is like a 1,2,3, punch, in lay mans term, that this produces what so many search for and never achieve, As i say, the final pics will prove the point and no more discussion will be needed afterwords ok? Again, that is if the poster decides to go this route over some other. If not you are more than welcome to try this your self i will reply for any help you might need ok? :thumbsup:


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## chemmy (Dec 13, 2011)

Carlo Bartolini said:


> Sorry Chemmy, did not explain myself well, I meat that black tea contains oxalic acid naturally, as tannic acid, but I did not know if the oxalic in it would act i a contrary manner.
> 
> Anyway your answer is even more complete now, added to my files, thanks again.:thumbsup:


Ahh i see now Carlo, actually i did not understand because i know of no such tea, tell me more about this tannin/oxalic if you would please and what you know of it's use?


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## Carlo Bartolini (Aug 30, 2011)

Wow, than there is something in chemistry that I know and you don't???...hahahaha:laughing: huh: well not for long, should have kept my mouth shut:blink

Of all the tea types, black and black decaffeinated teas contain the most oxalic acid, typically ranging from 12 to 30 mg per cup. Green, green decaffeinated and white teas typically contain 6 to 18 mg oxalic acid per cup. However test results tend to vary cup-to-cup and some of our independent laboratory testing of oxalic acid content has resulted in quantities too small to be measured or to contain none at all. 
Herbal teas typically contain only 0 to 2 mg oxalic acid per cup.


from


http://www.bigelowtea.com/faqs/tea-...lic-acid-and-how-much-is-in-a-cup-of-tea.aspx

But I was wrong about the tannic acid

While 'tannic acid' is a specific type of 'tannin' (plant polyphenol), the two terms are sometimes (incorrectly) used interchangeably. The long standing misuse of the terms, and its inclusion in scholarly articles have compounded the confusion. This is particularly widespread in relation to green tea and black tea. Although tea contains tannin and various types of polyphenols, "contrary to widespread belief, tea does not contain tannic acid." 

http://en.wikipedia.org/wiki/Tannic_acid


The use, I've read for darkening maple.


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## chemmy (Dec 13, 2011)

Carlo Bartolini said:


> Wow, than there is something in chemistry that I know and you don't???...hahahaha:laughing: huh: well not for long, should have kept my mouth shut:blink
> 
> Of all the tea types, black and black decaffeinated teas contain the most oxalic acid, typically ranging from 12 to 30 mg per cup. Green, green decaffeinated and white teas typically contain 6 to 18 mg oxalic acid per cup. However test results tend to vary cup-to-cup and some of our independent laboratory testing of oxalic acid content has resulted in quantities too small to be measured or to contain none at all.
> Herbal teas typically contain only 0 to 2 mg oxalic acid per cup.
> ...


Very interesting my friend, no i do not use tea as a stain, so i never looked into it past noting that it had been used as such just as coffee has also. back in the seventies i had tried both but was not fond of the results, and if adding additional color was necessary, back then, i would just use dyes instead that gave me what i wanted much quicker. also i used different types of flowers/ tobacco/ and anything else i read of - just like you are now, lol. 

I find the only way to know for sure yourself is to try everything for yourself and note the results. Knowledge is not in the "knowing" it's in the doing. And that has served me well all my career. 

Thanks for your reply my friend, 

Chemmy


PS: jusr re-read again and overlooked responding to the Tannin verses Tannic acid, yes that is correct, though i seldom bring the point up to those i tell to use, simply because it is not necessary for our purposes. "tea" would never be used in chemical stain as a pre mordant to achieve what i talk of here or elsewhere.


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## Dominick (May 2, 2011)

It's just a piece of wood for the love of god
:laughing: slap some BLO on it and be done with it. This isn't science fair. :laughing:


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## chemmy (Dec 13, 2011)

Dominick said:


> It's just a piece of wood for the love of god
> :laughing: slap some BLO on it and be done with it. This isn't science fair. :laughing:



Your correct, it is not science fair, but it should be lol. Or at least i wish it was. I see your no lover of naturally occuring figure and how to bring out all of it's character evidentally, shame, but to each his own. :no:


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## Dominick (May 2, 2011)

chemmy said:


> Your correct, it is not science fair, but it should be lol. Or at least i wish it was. I see your no lover of naturally occuring figure and how to bring out all of it's character evidentally, shame, but to each his own. :no:


I'm a lover not a fighter. I'm just messing with you hahaha. No I don't know all the technical stuff. But I find it very interesting.


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## mdntrdr (Dec 22, 2009)

Chemmy,

I find your posts very informative and am always looking for new/other methods of finishing.

Please keep posting. :thumbsup:


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## ModCo Design (Oct 17, 2011)

Thanks for all the posts everyone, believe it or not I have over 5000bf of this material from this 10' diameter tree I had cut down, chemmy I feel like we need to sit down and have a beer, I could listen to this type of stuff all day long....... I'll be trying a few different things over the next few months on different pieces, this is just my first


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## aardvark (Sep 29, 2011)

GNARLY !
Nice Find!


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## chemmy (Dec 13, 2011)

:thumbsup:


ModCo Design said:


> Thanks for all the posts everyone, believe it or not I have over 5000bf of this material from this 10' diameter tree I had cut down, chemmy I feel like we need to sit down and have a beer, I could listen to this type of stuff all day long....... I'll be trying a few different things over the next few months on different pieces, this is just my first


 
Thanks for getting back ModCo, well I'm glad to hear your at least experimenting young man. If and when you get around to what i suggest to you, let me know OK? There are certain things you will need to know specifically at the time of your experimentation OK? It also would be nice to know what other choices you have made so far also, is that possible?

As to the tree, is that on your property? If you would care to send me a slice, i would be happy to do what i have written to show you in advance how it will appear with my methods so you could know first hand what and how it compares with other thought and methods you may be thinking of using, just a thought.:thumbsup:

Sorry ModCo, i only drink beer standing up while juggling several objects and a mouthful of pretzels, lol.

Sincerely,

chemmy


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## ModCo Design (Oct 17, 2011)

Chemmy, I really haven't tried anything yet, I was going to use BLO but thought I should ask others before I did. About the wood, send me a pm with your address and we can work something out  the tree was on someone's property, I saw it driving by and asked them about it, it was going to be firewood and horse bedding, so I bought it to keep that from happening

Woodtic, thanks for the finishing recipe, I'll be trying that out after I've given it the chemmy treatment


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## chemmy (Dec 13, 2011)

ModCo Design said:


> Chemmy, I really haven't tried anything yet, I was going to use BLO but thought I should ask others before I did. About the wood, send me a pm with your address and we can work something out  the tree was on someone's property, I saw it driving by and asked them about it, it was going to be firewood and horse bedding, so I bought it to keep that from happening
> 
> Woodtic, thanks for the finishing recipe, I'll be trying that out after I've given it the chemmy treatment


Just sent you my info just pm back when you read ok?:thumbsup:


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## ModCo Design (Oct 17, 2011)

Sounds good chemmy, we'll keep in touch


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## woodtick greg (Sep 12, 2011)

[QUOTE the tree was on someone's property, I saw it driving by and asked them about it, it was going to be firewood and horse bedding, so I bought it to keep that from happening

Woodtic, thanks for the finishing recipe, I'll be trying that out after I've given it the chemmy treatment[/QUOTE]

Outstanding save! Great find! Many beautiful projects will come of this and the trees time on earth will live on and be honored. I am glad this thread has opened up and other options have become available to all. Chemmy and Carlo bring alot to the table and have much experiance. I am more traditional with my finishing and like the old methods for their warmth and feel, but that's just me. Their is no 1 perfect method and we should always try new and different techniques to achieve what our eye likes. Practice with a piece of scrap from this tree to hone your method before you decide which to use and to see if it makes the figure pop the way you envision. Keep us posted and show us how things are going.:thumbsup:


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## ModCo Design (Oct 17, 2011)

I agree Woodtick, Chemmy and Carlo bring a great deal of experience and know how to the table, and I'm always one to try out new things in my projects, one reason, you will never know it all, and second it sometimes leads to discovering something else whether that be about design, finish, joinery, technique, or whatever thanks again guys!!


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## Carlo Bartolini (Aug 30, 2011)

Thank you, very nice of you, but I am only an apprentice here, chemmy is a true maestro, thank you MadCo Design for the thread, very useful to me, I'll be finishing some maple in the near future with what I've learned here (after samples of course), thank you once again chemmy!!!


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