best way to bleach old dirty cracks?

[geigen]

Hi,

what are your experiences with bleaching old dirty cracks?

Do you clean them with water and with xylole? What would be the best concentration of H2O2 to use? Has anybody tested different concentrations?

thank you for sharing your experiences with us.

Anne

[FiddleDoug]

I was taught to use alternating applications of bleach (sodium hypochlorite) and hydrogen peroxide, applied with a fine tipped applicator. 30% Hydrogen peroxide is what was recommended, but it's difficult and expensive to get. I use the strongest peroxide that's available in beauty supply stores (50 volume?). Use alternating applications and you will see bubbling along the crack, which both bleaches, and helps lift dirt out of the crack. DO NOT mix bleach and peroxide together in bulk as it would create a hazardous situation.

[Oded Kishony]

one of the safest and best ways to clean old cracks is to use deionized water. It's a surprisingly strong chemical but doesn't leave a residue or cause any damage, if used with the appropriate care.

If you cannot obtain deionized water then simple distilled water works well too. Steam distilled water is available at most supermarkets. (in the USA)

Oded

[Jeffrey Holmes]

What works best depends on what you're trying to clean out of the crack. My standard procedure is to lift everything I can out mechanically (dry) before resorting to bleaching cleaners or solvents. In doing so, if you save a number of little bits of dry crud to test, often you may be able to determine "where to go" (by figuring out the least invasive solvent the crud dissolves in). For example: Simple glue/dirt may come away easily with distilled water, but if it's orange shellac, glue and dirt, water won't do it.

[IBK]

I use the strongest peroxide that's available in beauty supply stores (50 volume?).

You want to be very careful about buying Hydrogen Peroxide at beauty supply stores. A guy just got into a lot of trouble for doing that. Presently he is being charged with terroism. :)

[FiddleDoug]

I did think about the terrorism aspect as I was writing it, but figured that my 4 oz. bottle wouldn't be a problem. Bleached blonds are probably more dangerous!

[geigen]

I did think about the terrorism aspect as I was writing it, but figured that my 4 oz. bottle wouldn't be a problem. Bleached blonds are probably more dangerous!

Thank you so much, and guys, I love your humor ;-)

Anne

[IBK]

I did think about the terrorism aspect as I was writing it, but figured that my 4 oz. bottle wouldn't be a problem. Bleached blonds are probably more dangerous!

Yes, I don't think that 4 oz of hydrogen peroxide would qualify you to be a maker of WMD's

[MANFIO]

Wow, now I know why they are called suicide blondes!!!

[Stephen Shepherd]

Before you try and bleach the dirty cracks, you might want to clean them. Apply some cornstarch to the crack and allow it to absorb the oil and grease from the crack. You can repeat this as necessary and it often does a great job at sucking out the dirt from cracks.

[Brad Dorsey]

Apply some cornstarch to the crack

Dry?

[Michael_Molnar]

Stay away from buying Beauty Shop peroxide. The latest terrorist flap in NY and Denver involved a guy doing that!

Mike

[Stephen Shepherd]

Dry?

Yes just sprinkle it on dry. Corn meal works on larger stains and is used by museums to clean textiles. Corn starch is much finer and goes down into small cracks to absorb the oil and grease.

[Michael Richwine]

Yes just sprinkle it on dry. Corn meal works on larger stains and is used by museums to clean textiles. Corn starch is much finer and goes down into small cracks to absorb the oil and grease.

I always used diatomaceous earth for that with woods and fabrics and even leather, since it absorbs everything - oils & grease, water, solvents - pretty well. Also used it as a poultice with various solvents. I wonder how that would work? I've got a once-good 1906 Heberlein with a long, black crack in it, so I may be finding out. I was just going to use the "normal" methods, but I can see the possible advantages of a good absorbent. If it doesn't work, it won't make things any worse.

I wouldn't think you could use corn starch with anything aqueous, since it makes a pretty good thickener for sauces?

[geigen]

I believe that we would make a mess with the corn starch here. But its worth a try!

When it absorbs the dirt, does it not become sticky inside the crack?

[Bruce Carlson]

Hi,

what are your experiences with bleaching old dirty cracks?

Do you clean them with water and with xylole? What would be the best concentration of H2O2 to use? Has anybody tested different concentrations?

thank you for sharing your experiences with us.

Anne

In agreement with Jeffrey Holmes, always start with the weakest and least damaging solvents. Distilled water and if you want you can add a small amount of a wetting agent which breaks down the surface tension of the water making it even more effective for loosening dirt. I use the same wetting agent that is used for the final rinse in photographic film developing so you don't get spots on you negatives. A 2% solution is adequate. Water is often enough.

Gentle mechanical coaxing is effective on more stubborn dirt.

Bleaching with oxalic acid solution, hydrogen peroxide and other chemical treatments should be avoided if possible.

Bruce

[Stephen Shepherd]

I always used diatomaceous earth for that with woods and fabrics and even leather, since it absorbs everything - oils & grease, water, solvents - pretty well. Also used it as a poultice with various solvents. I wonder how that would work? I've got a once-good 1906 Heberlein with a long, black crack in it, so I may be finding out. I was just going to use the "normal" methods, but I can see the possible advantages of a good absorbent. If it doesn't work, it won't make things any worse.

I wouldn't think you could use corn starch with anything aqueous, since it makes a pretty good thickener for sauces?

Fuller's earth is an excellent desiccant. You can also use attapulgus clay which is used to clean marble, it will suck the oil out of tar sand.

[luthierwannabe]

Hi,

I know this is a little bit off topic but once you have cleaned and glued the crack, what is the best method of sealing the crack before staining or varnishing? I ask because I am at that stage on a practice repair instrument (no value).

Thanks..Tony

[Jerry Lynn]

It depends on the crack. Generally, I use a fill varnish that is allowed to fully cure before being trimmed flush (or just slightly under flush) before retouching. If you do a search on "fill varnish" you should be able to find more info.

[luthierwannabe]

It depends on the crack. Generally, I use a fill varnish that is allowed to fully cure before being trimmed flush (or just slightly under flush) before retouching. If you do a search on "fill varnish" you should be able to find more info.

Will do Thanks...Tony