varnish on blade -suggestions?

[b.hennick]

Hello:

I have a wakizashi that has a pretty thick coat of varnish on the blade. Any suggestions for removal of the varnish that will not harm the blade would be appreciated. The tang fortunately was not varnished. The coat has a strong yellowish colour and is hard.

[Drago]

Hmm... Have you tried acetone or turpentine?

[ROKUJURO]

I had that too on my first blade that I bought some 35 years ago. My experience is that chemical solvents will not harm the blade, but sometimes you have to experiment a while. If it is nitro varnish it takes time.

 

I was anxious about my blade, but another collector told me: It's a hassle but better than deep rust! He was right!

[drdata]

2nd suggestion for isopropal alcohol, the 90% if available. I don't think acetone will harm, but a bit more aggressive.

 

Wipe clean and light coat of oil afterwards, of course.

 

Regards

[Ken-Hawaii]

Barry, you can use acetone safely on your blade, but I suggest that you not soak it; dipping & wiping several times should work. Pure acetone generally doesn't contain water, but can pick some up from the atmosphere, so please be sure to oil your blade once you have the varnish removed.

 

Ken

[Grey Doffin]

Hi Barry,

On the outside chance that this is shellac instead of varnish, see if a drop of alcohol somewhere on the blade dissolves it. Neither the alcohol nor acetone will damage the blade but acetone is more likely to do damage to you. If it is varnish, paint remover should be OK on the blade also.

Grey

[John A Stuart]

One of the best strippers of paints including varnish are those that contain methylene chloride. I have even used it on aluminum with no harm. It shouldn't harm your sword, but, test another bit of scrap to be confident. Poison, rubber gloves etc. http://www.homedepot.com/p/Klean-Strip- ... ifications John

[b.hennick]

Thanks for the suggestions. I am working slowly and patiently. I now see a nice suguha hamon. The hada is not clear yet. I will try to take some photos of the progress and document the outcome.

[b.hennick]

Here are a couple of shots before working on the blade.

After a little work..

[hxv]

Barry,

 

Off topic, but I see a very nice tsuba collection in the background.

 

Regards,

Hoanh

[ROKUJURO]

Yes, and these seem better focused than the blade itself! :D

[Stephen]

http://www.amazon.com/4-5-Oz-Oops-Clean ... ps+Cleaner

 

 

when i help the gold star museum this worked wonders on a tar like substandce id give it a try Barry.

 

local hardware shold have it.

[tesscoothome123]

Hi Barry, I have had a couple that were coated in varnish in the past couple years. There is a stripper called Citri_Strip that I have used. It does not harm the blade one bit like some chemical strippers if left on while being industrial strength, biodegradable, and you can use it indoors without a problem. Smell like oranges I think. Regards, John

[Ken-Hawaii]

Uh, John, ALL materials, including your stripper, are "chemical," by definition....

 

Ken

[drbvac]

Uh Ken - by definition not ALL strippers are chemical - have known some pretty nice biological ones as well

[Ken-Hawaii]

Brian, are you trying to tell me that biologicals, or ANY material, are not made up of chemicals??!! Don't want to hijack this thread, but saying that ANYTHING isn't chemical in nature is leading people astray!

 

Ken

[Alex A]

Hi Ken, i think maybe Brian was referring to strippers that dance

[Ken-Hawaii]

Still chemical!

 

Ken

[Brian]

Some more acidic than others.

Back to Nihonto please....

 

Brian

[Stephen]

Yea what the boss said....lol....Barry what did you try? pix?

[drdata]

Given iso alcohol is deemed safe, I wonder if these are a good option? Seems would not scratch and disposable so no cross contamination or concerns of a dirty cloth scratching.

 

Have seen at Costco and wall-mart, as well as online:

 

http://www.amazon.com/Zeiss-Pre-Moisten ... ords=zeiss

 

 

edit to add the mdss-seems iso only:

 

http://www.photodon.com/zeissMSDS.pdf

[benatthelake]

Barry: Is there a story behind this blade and how you came to possess it? What a lovely shade of yellow on this blade. :lol:

 

But seriously, did the seller think it was a loss?

 

Ben M.

[b.hennick]

The varnish is almost all gone. I am attaching jpgs of the blade. It will need polish, habaki and shirasaya. I used "Super remover" gel formula.

, ,

[b.hennick]

Here are images of the tang and mei:

[Lee Bray]

Mei doesn't look bad.

Possible nidai?

[Alex A]

Signed. Hizen Kuni Tadayoshi, if im not mistaken, stating whats obvious to some folk, i may add

[Darcy]

There is an extremely concentrated citric cleaner which will chew stuff up quite well.

*refers to citrus based strippers, and not citric acid itself, which should not be used on blades*

 

The alcohol based solvents sometimes proposed here will not affect varnish.

 

Varnish (mix of tung oil and polyurethane of some sort) cures and changes its molecular structure during curing. Once the solvent boils away the molecules in the varnish start to cross link and form strong bonds. This makes a more durable surface. It also makes it very difficult to break down. The tung oil also cross-links using oxygen and forms a different compound after the chemical reaction, like a plastic.

 

So generally you need to move up in your organic solvent grade.

 

Varnish: kerosene, gasoline, naptha, turpentine, mineral spirits will all do fine to thin your varnish but they will not do squat once it's cured.

 

After you need to use something like an acetone or this level of solvent to break this stuff down.

 

Alcohol based solvents are not recommended at all for varnish thinning nor will they do diddly squat in removing cured varnish.

 

...

 

Lacquer now, this doesn't change molecular structure but when we deal with lacquer in the west it's usually nitrocellulose lacquer. It should laugh off the thinners above and not worry about alcohol either. Lacquer thinner though will certainly attack cured lacquer because cured lacquer does not change its molecular form. The long tangled molecules just collapse down and attract each other as the solvent boils off. For this reason you can easily touch up lacquer by adding more on top. You can't do that with a varnish because the new varnish is a different chemical (pre-cured) than what is on the item (post cured) so you end up building up distinct layers like inside a tree. These layers do not like to adhere though so they peel off unless you create a rough physical surface which them can use to bond.

 

...

 

Shellac is the only thing you can use alcohol based stuff on to remove from an item. Also it will help with grease and oils etc. So basically 99% isopropyl alcohol from the drug store or else methyl alcohol from the hardware store will strip off any weak stuff that's on your sword and won't harm it at all.

 

...

 

None of the above will harm the blade any more than oil will, they are all organics and don't react with metal. They will react with you though so you really need gloves and plastic gloves will not help you with some of these things, the solvents will melt them. You end up in a new problem of matching gloves to solvents. For me I just used heavy leather gloves that couldn't be penetrated by any of them easily and aired them out after.

 

So in order of operation, if you want to do this right, use a meths or 99% isopropyl alcohol and strip any grease or shellac that's on the blade.

 

At that point all the mid level stuff is pretty useless. You can try rubbing it off with steel wool then which is safe but will abrade the blade. It's OK if your blade is already abraded.

 

Lastly take out the big gun and acetone that baby. Probably two wipes with a well soaked rag willl rip off anything that's on it. Do it with thick gloves, outside and you need to wear a proper mask with charcoal filters if you want to use acetone.

 

Otherwise steel wool or 600 grit sandpaper is ok.

 

After, your sword is completely naked to the world. So, oil it.

 

Don't bother with any of the thinners that come inbetween, as mentioned they are only for pre-cured varnishes that are in a different molecular state than finished varnishes. Finished and cured varnishes have incorporated oxygen into their structure and the evaporating thinner then allows them to cross-bond. Once that happens it's permanent and thinners do nothing.

[Darcy]

Oh and with the final note that lacquer thinner is going to be primarily acetone or something else extremely brutal so you need to treat that stuff with respect. It will shred anything you put it on. Cured varnish, shellac, etc.

 

In general just avoid all skin, lung, and eye contact with all organic solvents.

[ROKUJURO]

Darcy,

 

I would like to add some information to your overview:

 

Citric acid is a weak fruit acid which nevertheless attacks steel. It cannot be 'extremely concentrated', because it is a crystalline powder, when you buy it as 100% acid. It is soluble in water at a max. of 75% at 20°C.

 

A varnish of tung oil or linseed oil has no solvents. Also URUSHI does not need solvents. The change of the molecular structure during curing is called polymerization. The same goes for polyurethane, but here solvents may be added to lower the viscosity or as accelerators of the chemical reaction.

[Brian]

Thank you Darcy and Jean for that excellent info that I haven't seen posted anywhere else. I would like to shorten that into a brief article for the FAQ above, for those dealing with the same problem.

 

Brian