Thread: Choice of finish for Saw Handles.

Originally Posted by rob streeper

Hi Ian,

I don't usually get wound up about safety but in this case, since I know from my work what the risks of these compounds are or may be, I'll give my perspective.
....

Rob, I also have a bit of experience in pathology & toxicology & I don't disagree with anything you've said. I did advise prudence!

A wise man once said something like: "All things are poison and nothing is without poison, only the dose permits something not to be poisonous."
Every day of our lives we are exposed to potential toxins, from those with a straight pharmacological action to potential carcinogens. Fortunately, our bodies have evolved some petty sophisticated mechanisms to deal with most of it, so as long as we are only exposed to levels that can be handled by the system, or any damage repaired (& we have a pretty good DNA repair toolkit, too!), all is well. This is not to say we shouldn't exercise due care at all times, just making the point that a single or occasional exposure to even known carcinogens doesn't necessarily condemn you to death.

So I've been comfortable enough using the cross-linking shellac where it is appropriate (with gloves!) but I agree with you & Stewie that you probably don't need it on saw handles....

Cheers,

Hi Ian, I agree. I see problems like this as being perhaps more serious than the average person does. In the case of Zama7, the aziridine group is the reactive center. For those who don't know the aziridine groups are the triangles with N in them at the ends of the arms of the molecule.Zama 7.JPG

There is a cancer drug that also has aziridine groups, it's called thio-tepa.thio tepa.JPG

Thio-tepa is a nasty critter. I'd be very afraid of using any Zama7 containing product.
I'm posting all of this as a warning to the less chemically inclined. Those of you who know my postings here also know that I will do and work with things that others consider dangerous. Zama7 is, for me, way too dangerous. I wouldn't even let it in my house.

Pharmacologists divide the things in the world into three basic categories food, drugs and poison. Anything that isn't food is poison depending on the dosage.
Cheers,
Rob

I think that Ian made good points in:

1. Advising caution and prudence in dealing with all these things

2. Ensuring our levels of exposure are minimal, which in a hobbiest arena is quite likely.

3. Adding the rider of providing you are not allergic or super sensitive to anything in particular.

Of course if you are allergic to peanuts, they are toxic, although not carcinogenic.

I recall a debate at work with our chemist who proudly claimed we do not have any carcinogenic substances on site.

One of mu colleagues immediately said "Yes we do!" Immediate and predictable reaction was "Oh no we don't."
"Yes we do."
"OK what is it."
"Petroleum products. Look up the MSD." Chemist looked it up and then no more was said ."

Any of you good folks ever put petrol (gasoline, essence etc) in your motor vehicle?

My colleague was at a considerable advantage over our poor chemist as he had worked as an operator at an oil refinery before working for us.

My point is that we are constantly subjected to potentially toxic substances in our every day lives. The question is whether that is enough to kill us or make us sick. Another classic example is flouride in toothpaste (a controversial issue, which I am not going into) which in sufficient dosage would be lethal.

Regards
Paul

Originally Posted by planemaker

http://www.woodsolutions.com.au/Articles/Resources/Timber-Finishes-Interior

Wax and oils are much easier to apply, but they offer little protection over the surface of the handle wood.

As such, my personal preference is to use a shellac finish.

Stewie;

I have quite a dilemma over finishing handles. In the past I have stated that I have used varnish, but I have gone away from that in recent times.

I have done the oil and shellac (hard) road, the oil and wax road. I have tried Ubeaut's new rubbing oil, and I am about to try the Shellawax technique.

I suspect I will go back to oil and hard shellac, but am trying to keep an open mind. One point that I think Derek made is that some processes do darken the timber. With apple wood and old handles, I am quite happy for that to happen, but other timbers I wish to retain something close to original colouring.

In days gone by the saw makers seemed to use varnish quite extensively.

Regards
Paul

Originally Posted by Bushmiller

I think that Ian made good points in:

1. Advising caution and prudence in dealing with all these things

2. Ensuring our levels of exposure are minimal, which in a hobbiest arena is quite likely.

3. Adding the rider of providing you are not allergic or super sensitive to anything in particular.

Of course if you are allergic to peanuts, they are toxic, although not carcinogenic.

I recall a debate at work with our chemist who proudly claimed we do not have any carcinogenic substances on site.

One of mu colleagues immediately said "Yes we do!" Immediate and predictable reaction was "Oh no we don't."
"Yes we do."
"OK what is it."
"Petroleum products. Look up the MSD." Chemist looked it up and then no more was said ."

Any of you good folks ever put petrol (gasoline, essence etc) in your motor vehicle?

My colleague was at a considerable advantage over our poor chemist as he had worked as an operator at an oil refinery before working for us.

My point is that we are constantly subjected to potentially toxic substances in our every day lives. The question is whether that is enough to kill us or make us sick. Another classic example is flouride in toothpaste (a controversial issue, which I am not going into) which in sufficient dosage would be lethal.

Regards
Paul

Hi Paul,

I'm criticizing neither you nor Ian. My purpose is to point out to the non-specialists on the board that these compounds are special hazards and that relying on MSDS's can be dangerous as they contain at best only known and well proven hazards.
PPE is extremely important but it is not a panacea. Early in my career I thought that gloves, lab-coat, apron and eye protection were entirely sufficient to protect me from the dangerous chemicals I routinely handled until I started working with radioactive chemicals. These experiences opened my eyes to the fact that despite the best protection and most cautious handling chemicals manage to spread themselves far and wide.
The chemicals referred to above are, in my professional opinion, quite dangerous. I'm not trying to scold, only to warn.

Cheers,
Rob

Getting back to finishing, I think it's really a matter of personal taste. I should have stated that I only use Shellawax on new handles, and I carefully select woods that I think will respond to it in the way I like to see. For restoring old handles, I might go after an 'original' look, or something that would give the handle a bit of an aged look, depending on what I thought appropriate. My own 'user' (pre-WW2) Disston handles got 'cleaned' by rubbing them down with 0000 steel wool soaked in some dilute 'Scandinavian' oil. They were already darkened with age, so I wasn't worried that the linseed base of the stuff I used would change them noticeably. After they dried, I buffed them up with more 0000 steel wool & wax, and they looked like nice & clean, but well-used handles, complete with a few stains..

Though speaking of 'original' finishes, I'm not sure I could bring myself to dip handles in thick goop the way many seem to have been done from the 1950's on.. I guess I simply wouldn't bother with the horrible things, anyway, they have no redeeming features. I would just replace them with something I could imagine holding in my hand. Paul, I think you are quite right, there seems to have been a variety of techniques used over the years, which I'll bet were dictated as much by cost, & how easily & quickly they could be applied by semi-skilled workers, as any other criteria such as archival-standard durability.....

Cheers,

Originally Posted by IanW

Getting back to finishing, I think it's really a matter of personal taste. I should have stated that I only use Shellawax on new handles, and I carefully select woods that I think will respond to it in the way I like to see. For restoring old handles, I might go after an 'original' look, or something that would give the handle a bit of an aged look, depending on what I thought appropriate. My own 'user' (pre-WW2) Disston handles got 'cleaned' by rubbing them down with 0000 steel wool soaked in some dilute 'Scandinavian' oil. They were already darkened with age, so I wasn't worried that the linseed base of the stuff I used would change them noticeably. After they dried, I buffed them up with more 0000 steel wool & wax, and they looked like nice & clean, but well-used handles, complete with a few stains..

Though speaking of 'original' finishes, I'm not sure I could bring myself to dip handles in thick goop the way many seem to have been done from the 1950's on.. I guess I simply wouldn't bother with the horrible things, anyway, they have no redeeming features. I would just replace them with something I could imagine holding in my hand. Paul, I think you are quite right, there seems to have been a variety of techniques used over the years, which I'll bet were dictated as much by cost, & how easily & quickly they could be applied by semi-skilled workers, as any other criteria such as archival-standard durability.....

Cheers,

What is the orange varnish used on Disston handles, anybody know? It crackles in a way reminiscent of nitrocellulose / cellulose acetate but I've never read anything concerning it's composition.

Originally Posted by rob streeper

What is the orange varnish used on Disston handles, anybody know? It crackles in a way reminiscent of nitrocellulose / cellulose acetate but I've never read anything concerning it's composition.

That would be my guess (nitro lacquer). Anything else that would've tolerated some exposure to moisture probably would've taken too long to dry.

Originally Posted by IanW

Rob, I also have a bit of experience in pathology & toxicology & I don't disagree with anything you've said. I did advise prudence!

A wise man once said something like: "All things are poison and nothing is without poison, only the dose permits something not to be poisonous."
Every day of our lives we are exposed to potential toxins, from those with a straight pharmacological action to potential carcinogens. Fortunately, our bodies have evolved some petty sophisticated mechanisms to deal with most of it, so as long as we are only exposed to levels that can be handled by the system, or any damage repaired (& we have a pretty good DNA repair toolkit, too!), all is well. This is not to say we shouldn't exercise due care at all times, just making the point that a single or occasional exposure to even known carcinogens doesn't necessarily condemn you to death.

So I've been comfortable enough using the cross-linking shellac where it is appropriate (with gloves!) but I agree with you & Stewie that you probably don't need it on saw handles....

Cheers,

I like to tell my wife (as an actuary) that the probability is very low that she is going to correctly worry about the factors that cause her demise. The probability is, however, very high that she will spend a lot of time worrying and cause a negative impact on her life and interactions with people if she worries that everything is deadly or at least a cause for morbidity. (needless to say, she doesn't like to hear that).

Especially annoying when the topic of worry changes several times a year (she and her mother put a lot of stake in the quacky stuff that Dr. Oz peddles, which is puzzling given that his conventional medical practice is apparently stellar).

I go so far as ian does, if my exposure is not a regular basis and significant amount, I'm satisfied with gloves. (if something really stinks or I'm spraying finish, I do wear an OV respirator).

One of my other favorite things to say to my wife since DNA damage is such a hot topic is that she's aiming to keep her DNA from every taking any damage, but it's likely the things she's doing to prevent it are making a small fraction of difference vs. the things that she can't do or doesn't know about. (she doesn't like to hear that either).

Both MIL and FIL have had Cancer, but MIL is still more worried about the bugaboos that Dr. Oz talks about.

(I have two definite rules, though. The latter is that I will absolutely not eat plutonium no matter what - the first is that I won't take opiates by prescription, or any illegal hard drugs for that matter. I guess I have a third one, and that is I refuse to worry about mortality or morbidity, but I do plan for it financially - it's guaranteed to happen sooner or later, but worrying has no effect on that).

Genomic damage is actually the lesser of the two evils I described above. Much more problematic is the perturbation of immunological functions.
Cancers that arise from genomic damage or mutations constitute the minority of cases. Well known examples include the Philadelphia chromosome and BRCA1/2. Much more problematic are the adult onset cancers that are associated with systemic immunological derangements. Dioxin, for instance, doesn't cause much in the way of genetic mutation but it is a potent carcinogen acting both through the aryl hydrocarbon receptor and by altering immune functions. One outcome of dioxin exposure is diabetes, an immunological problem.
Thus it pays to be very careful with so-called 'safe' materials.

Originally Posted by D.W.

That would be my guess (nitro lacquer). Anything else that would've tolerated some exposure to moisture probably would've taken too long to dry.

I'm going to put an FTIR analysis of some scrapings on my long-term to-do list.

Originally Posted by D.W.

That would be my guess (nitro lacquer). Anything else that would've tolerated some exposure to moisture probably would've taken too long to dry.

Over here: https://www.woodworkforums.com/showth...25#post1878925 is a posting that has a Spear & Jackson catalog and reference is made in the Spearior 88 item description to 'cellulosed' finish. Nitrocellulose lacquers are available, though not very cheap but not too expensive. It seems that they're used in finishing musical instruments.

Originally Posted by rob streeper

Over here: https://www.woodworkforums.com/showth...25#post1878925 is a posting that has a Spear & Jackson catalog and reference is made in the Spearior 88 item description to 'cellulosed' finish. Nitrocellulose lacquers are available, though not very cheap. It seems that they're used in finishing musical instruments.

Yes, still common in musical instruments, especially guitars and banjos. I have some on hand, but haven't sprayed it yet, but I also have a couple of stringed instruments with it. Some of the smaller makers who have been making instruments for a long time won't move to the new plastic water based finishes (or whatever you'd call all of those various acrylic finishes).

In guitars, it gets that same crazing over time - or if a guitar gets really really cold, it can craze like that all in a day.

I'm sure someone good with modern finishes could tone a finish to look like nitro, and I have some well made guitars that have acrylic on them that don't have coldness, but that look is standard with nitro without any additional work. It burns together well, builds well and rubs out with no witness lines.

Not sure when instruments switched from varnish to lacquer, but I don't have any instruments old enough to know because old instruments require care and repair, even if you don't play them. ultimately all acoustic instruments do, I guess.

Anyway, nitro is nice. the crazing on the saw handles looks familiar, though a little more severe on some handles, probably because of their exposure to changing temperatures.

(I've never heard of any way to apply it other than spray it, though google could prove otherwise if anyone has successfully done anything else with it).

https://www.youtube.com/watch?v=3olCH1mbsGg