a Special Guest Chat with
with Host Ellis Walentine

Sunday, May 1, 2007

Topic: "General Wood Finishing"

    Mark Chaimberg is Vice-President of Swing Paints Limited, makers of Circa 1850 products. Mark holds a PhD in Chemical Engineering from UCLA and has been formulating finishes for 20 years. He has authored articles for several magazines, most recently Woodworking for Women. He is also a familiar lecturer and exhibitor at various consumer and industrial woodworking shows, as well as an amateur woodworker. Here is the edited transcript of that chat. Enjoy!

Ellis Good evening everyone. I am pleased to have as my guest tonight Mark Chaimberg, Vice President and chief formulator for Swing Paints Limited, makers of the Circa 1850 line of finishes, strippers and finishing accessories. Welcome, Mark!
JohnP Welcome Mark.
JL Mark, to start things off with a question, what do you think of mixing BLO and polyurethane?
Mark Chaimberg If BLO and polyu works for you, go for it. It seems to be a favourite of many finishers
Ellis Does the addition of oil change the chemistry of the polyurethane?
JohnP Wouldn't that be a soft finish, and not suitable for everything?
Mark Chaimberg I prefer to use tung oil instead of BLO, but that is my preference.
JL Why tung instead?
Mark Chaimberg It all depends on the ratio of oil and varnish (or polyu). At low % oil, the finish is actually harder.
JohnP hmmm, very interesting
CW How long should you wait to buff and wax after appling Tung oil
Mark Chaimberg Tung oil dries nicer and does not require the chemical driers that linseed oil does. The driers can alter the colour of the finish
Mark Chaimberg Just tung oil?
Ellis What is the reason to add tung oil to a varnish?
Charles is water base paint a good finish?
Mark Chaimberg Tung Oil needs to have the right temp, humidity, air flow and especially light to dry quickly. If not, it can take several days to weeks to completely cure. I like to add tung oil to varnish in order to make a wipe on finish. Wipe on finishes have less problems due to brush marks, dust, etc.
Ellis I had always thought that finishes, as formulated, were fait accompli, and that adding other stuff would affect them adversely.
Mark Chaimberg Adding "stuff" to finishes is like adding seasoning to prepared foods. Sometimes it works and sometimes not.....
Stephen I heard there were problems with tung oil in contact with the human body, hands, etc?
Ellis Aha. So you add a little 100% tung oil to a regular oil-based varnish or poly to extend its working time and make it a wiping finish?
Mark Chaimberg Experimenting is good, but never experiment on something you care about.
Ellis "Finish firewood first," in other words.
JL There's alway pine :)
Ellis Great advice, Mark. What role does light play in the curing of tung oil?
Mark Chaimberg I once read about Epstein Barr as it relates to tung oil. I don't know if it was every proven.
Mark Chaimberg Tung oil contains many unstaturated bonds. The UV light cleaves those bonds, thereby allowing the tung oil to form a polymer.
e in the early days, i used to make my own finish: 1/2 MCloskey Spar Varnish 1/2 tung oil and a splash of turpintine -- came from maloof student
Stephen the AIC mentioned in their journal in the 80's about tung oil and skin cancer
JL Nitrile gloves - mid elbow length.
Mark Chaimberg If you have every put linseed oil or tung oil on the inside of a drawer and come back to smell it months later, you will appreciate the fact that UV light is important
Mark Chaimberg AIC?
Stephen American Institute of Conservation (of Historic and Artistic Works)
Ellis Here's a quote I dug up about tung oil and Epstein-Barr: "During the screening of plant oils for their Epstein-Barr virus (EBV)-activating potency, we found that tung oil possesses an activity comparable to croton oil. Tung oil from various sources and the extracts from its parental plant Aleurites fordii (Chinese tung oil tree), when used in combination with n-butyrate, were shown to efficiently activate EBV persisting in human lymphoblastoid Raji cells (non-producer). The major diterpene ester in the plant extract, 12-O-hexadecanoyl-16-hydroxyphorbol-13-acetate (HHPA), also exerted a similar activity. In producer P3HR-1 cells, both tung oil and HHPA increased the yield of infectious EBV by approximately five-fold. Since tung oil is used for the manufacture of oil paints, varnishes, waterproof substance, anticorrosives and other products, the implication of using such an agent with EBV-activating potency in our daily life is assessed and discussed."
Stephen wow you type fast Ellis, I am impressed, do you get paid by the word?
Ellis Sorry, I wanted to read that into the record, in case anyone wanted a quick rundown on this particular facet of tung oil.
CW wow
Ellis I only wish, Stephen :-)
Stephen will there be a log?
Ellis Yes
Ellis Circa 1850 is widely known for its variety of strippers. What are the main differences between the different kinds of strippers and removers you offer?
Mark Chaimberg Never heard of any link to skin cancer.
Mark Chaimberg We have different removers for different applications.
e ellis-what was the conclusion from the article you cited?
Ellis I didn't get that far, e. Google epstein-barr and tung oil. There is quite a bit of information about the connection
Mark Chaimberg Some work very fast, some a bit slower
Mark Chaimberg Some even work on milk paints, which are very hard to remove with most strippers
Ellis Wow, I didn't realize that, Mark. Which is the milk paint stripper?
JL Mark - some of the unsaturated oils have been found to have carcinogenic effects.
Stephen wow milk paint
Mark Chaimberg The original is from 1983 - not much work has been done since.
e since fingernails are an immediate pathway into the blood-stream, i try to keep all solvent-based liquids from contact with my hands
Ellis Stephen would like to get rid of all milk paint. :-)
Stephen milk paint is a myth
Ellis Is that so, e? I am guilty of using my hands to apply varnish.
Stephen nothing wrong with whitewash Ellis
e mark -- i've been trying to remove some thick epoxy from some redwood slabs. any EASY method for removing this?
Ellis Sandblasting comes to mind, e. :-)
Mark Chaimberg Epoxies are succeptible to acid cleavage
e yep, ellis -- pretty scary isn't it
e sandblasting might be too hard on the soft redwood
Ellis So you can use acidic strippers to remove it, Mark?
Mark Chaimberg So, take a good quality paint remover (Circa 1850 comes to mind) and add about 5% of a small molecule acid
Mark Chaimberg The best is formic acid, but that really stinks.
e the normal off-the-hardware-store-shelf remover did nothing
JL Glacial acetic acid then?
Mark Chaimberg You can also use maleic acid
Mark Chaimberg Glacial acetic acid is pretty nasty stuff also.
e is this a commonly found acid?
Stephen no that really stinks JL
Mark Chaimberg The smaller the acid, the better.
Ellis This is all very interesting. Acids and paint removers.
JL Is HCl too harsh?
Mark Chaimberg It works in conjuction with the dichlormethane. You can strip epoxies in under 30 seconds.
Stephen Nitric acid will discolor the wood won't it?
Mark Chaimberg HCL is great, but it is hard to find high molal HCl
Ellis How come nobody ever talks about this? Is it dangerous?
Mark Chaimberg The water content reduces the effectiveness.
JL Nitric is too oxidizing.
Stephen oh yes Ellis, it is very dangerous
Stephen if you put water into acid it will Explode!
e so ... outside ...respirator ... glasses and acid-gloves
JL Face shield also.
JL And an acid proof apron.
JohnP sounds like stuff that the average person just shouldn't even think about.
Ellis Yeah, JP, it sounds like we need a disclaimer. Acids are dangerous. Don't try this at home.
e is the acid/remover/epoxy deactivated upon drying? ie-how to discard waste?
Ellis Mark, were you suggesting adding the acid to your heavy-body remover?
JL e - neutralize with baking soda to get rid of the acid part.
Mark Chaimberg We generally sell the components separately and have the end user mix them up.
Ellis I used to use acids all the time in the shop. For catalyzing finishes, staining maple and cherry, etc. You need to stay away from the fumes.
Ellis I can only imagine the liability issues.
Mark Chaimberg The formic acid will eventually lose its effectively when stored with the remover.
Mark Chaimberg These are professionals
Mark Chaimberg I would not sell this to the average joe on the street
e i'm just wondering how to discard the waste? let it dry and put in garbage or something else
Ellis Thirty seconds, though. I can't imagine epoxy melting away that quickly.
Mark Chaimberg The dichloromethane will evaporate and cause the acid to do the same. You are left with a dry paint product.
e thanks
Ellis So, it's like most other finishing waste. Let it dry and throw it out.
Mark Chaimberg We sell a different version for contractors that need to remove epoxy bathtub coating prior to applying new epoxy
Mark Chaimberg it is a more stable acid and does not have any odour.
Charles hi Ken
Ellis With the acid mixed in?
Mark Chaimberg Yes, the acid is premixed.
Ellis It must be tricky to formulate things for the general market.
Mark Chaimberg Since the acid is not in water, it is more stable. For the general market there are a lot of different factors that must be considered.
Ellis Speaking of which, can you tell us what is involved in formulating a finish? Can you describe the process?
Ellis I assume you start with a perceived need.
Mark Chaimberg We had a letter from a lady that decided to pour her left over stripper down her drain. Unfortunately, the drain pipes were PVC>>>>>>>>
Ellis Um, I hope you had adequate warnings on the label? :-)
e no accounting for ignorance
Mark Chaimberg Ya - don't be a fool is right on the can
Ellis Never underestimate.
e my city sewer people would be hunting me down if i did something like that
Mark Chaimberg Formulating generally begins from one of two avenues. Either a new resin that a supplier has made, or a problem that an end user needs resolved.
Ellis What about speculative formulations based on perceived market needs?
Mark Chaimberg Those are the fun ones. Right now we are working to develop a brush-on epoxy for marine applications.
Ellis So resins are key players in this. How is resin chemistry coming along? Anything new and exciting on the horizon?
Ellis Brush-on epoxy sounds great. I used to make driveway gates. There was not a single acceptable exterior clear finish on the market.
Mark Chaimberg We already have a pour on ANTI-UV finish, but that does not work very well on vertical surfaces.
Ellis Is that a linear polyurethane?
Mark Chaimberg The key is to reduce the viscosity and increase the rate of cure. At the same time it needs to be brushable, UV resistant and clear.
JL Mark - with the push for "sustainability" and "green" ingredients - ya'll working with any of the corn based resins?
Mark Chaimberg Actually, resins from plants have been available for many many years
Stephen take linseed oil
Stephen turpentine
Mark Chaimberg The key is trying to find suitable solvents that are not from petroleum
Mark Chaimberg such as turpentine
Mark Chaimberg thanks
Stephen alcohol
Mark Chaimberg No thanks - too late in the evening for me.
Stephen lol
Mark Chaimberg The big issue these days is the VOCs
Stephen not me, a little barley wine in my tankard
JL Especially in the big cities.
JL What's your opinion of the "water based" polyurethanes.
Mark Chaimberg Trying to formulate finishes with low VOCs is very big in Canada now (where we manufacture) as they are instituting the CA regs in a couple years.
Mark Chaimberg Water based polyus have come a long way
Ellis That was one of my next questions.
Mark Chaimberg They are easy to apply, very clear and fairly durable.
Mark Chaimberg There are still a few issues that remain
Ellis When can we expect a new WB polyurethane from you folks?
Ellis I know you already have one (or more).
Mark Chaimberg Most woods could do with a good coat of tung oil to bring out the grain prior to applying the polyu
JL and then put the WB polyu on?
Mark Chaimberg The second issue is the dry time. They are just too quick for most large application
Mark Chaimberg The slow drying ones tend to be less scratch resistant
Mark Chaimberg Yes, JL
Ellis How long would you let the tung oil dry before proceeding with the WB finish?
Mark Chaimberg The final issue, and one that affects us all, is the in-can stabilty.
Mark Chaimberg These products will not stay fresh for more than about 1 year
JL Reaction with the metal of the can?
Ellis Can you make them two-part, with catalysts that you add when you're ready to use the finish?
Mark Chaimberg Since I put my tung oil in the sun, 24 hours
Ellis Before or after you put it on the wood? :-)
Mark Chaimberg No, even in plastic cans they do not last. The problem is that water-based polyu -- real ones -- are not actually water-based
Ellis Please go on...
Mark Chaimberg In order to make a real water-based polyu, you first make an oil-based polyu
Mark Chaimberg Then, you add an eye of newt and a hair of dog, and mix this all up with water.
Ellis Ah, trade secrets. :-)
Mark Chaimberg You now have very small droplets of oil-based polyu in a water bath
Ellis Emulsions?
Mark Chaimberg That is why the finish looks WHITE in the cans
Mark Chaimberg Emulsions
Mark Chaimberg Emulsions are unstable.
Ellis Right, so when the water evaporates then the oil finish cures down to a film. Is that the way existing WB formulations work?
Mark Chaimberg Once the particles decide to come together, the whole thing is ruined. Ellis, you da man
Ellis I just stumble onto facts, Mark. :-)
Mark Chaimberg So finding the right stabilizer for the emulsions is the key to long term in-can stability
Ellis And I assume you spend some part of your time working on these issues?
JL So you really have to look for an expiration date?
Mark Chaimberg I'd rather be playing hockey
JohnP this suggests that once a WB poly has cured the film finish is the same as an oil poly that has cured. and I don't think that is the case.
Mark Chaimberg JP - never assume anything
Ellis So, what is the case?
JohnP which of my assumptions is wrong? lol
Bob_in_NJ obviously there are trade offs in the water oil mix and the resulting finish durability?
Mark Chaimberg If you could use the EXACT same resins in an oil-based as a water emulsion, the end results would be pretty close.
Mark Chaimberg But that is not really the case.
Ellis Why is is, for example that WB varnishes are more abrasion resistant than oil-based ones?
Mark Chaimberg Also, when the WB cures, it does not have a chance to form the same sort of network as the OB does, because the particles are separated.
Ellis Is that a function of the resins?
Ellis So would thinner formulations put the resin molecules in closer proximity?
Mark Chaimberg Therefore, WB tends to be a softer finish. Just like 200 thread count sheets will tear more easily than will 600
Ellis What's the future hold for WB finishes?
Ellis Will they ever have the look of saturated color that the oil-based products do?
Mark Chaimberg Think of polyu as long strands of noodles. The more you can tangle them up , the harder they will be to pull apart
Mark Chaimberg That is a very good question
JohnP this has been a great discussion, but I must run. Thanks for coming Mark.
Walnutty They've improved greatly over the past 3-4 years, the chemical cocktail is improving, getting closer.
Mark Chaimberg There is some new work on WB linseed oil
Mark Chaimberg Adding that to finish may enhance the colour depth of the finish.
Mark Chaimberg We have been experimenting with this new product in WB stains.
pam WB linseed oil? Would that be oil molecules suspended/mixed in water?
Ellis Does it bode well for Circa 1850? Is everyone going to jump on this bandwagon?
JL So I could still have my BLO and polyu :)?
Walnutty It's generally a good coalescer if you break it at the correct titration and temperature.
Mark Chaimberg Anything for you JL
Ellis Finish junkie. :-)
Mark Chaimberg Pam - this is a different method
pam ?
Mark Chaimberg What they do is modify part of the oil chain so that is is hydrophilic
Mark Chaimberg similiar to making soap from fats or oils
JL PEG based?
Mark Chaimberg No, the linseed oil can be dispersed in water
pam Thanks, Mark, I thought soap ingredients were emulsified.
Mark Chaimberg But the oil now has some water-loving groups.
Mark Chaimberg Pam - soap IS an emulsifier
JL Will it still polymerize in a similar fashion?
Mark Chaimberg It has one end that loves water and the other that loves oil.
pam yeah, i know that. :)
Mark Chaimberg JL - If it still has the same unsaturated groups it should be able to polymerize.
Mark Chaimberg I have not seen the chemistry of it yet
Mark Chaimberg But I would love to give it a try in some forulations
JL Will the hydrophylic groups cause water molecules to get into the mix?
Mark Chaimberg I would think you would want to have the water. It will decrease the viscosity and allow for better penetration.
Mark Chaimberg No VOCS
JL When will it be available to test?
Mark Chaimberg I am hoping to get my hands on some this summer.
Mark Chaimberg I really want to try adding it to our WB stains to see it I can get the grain to pop.
JL That's you - I'm talking about us "finish junkies" :).
Mark Chaimberg It can take many months to come up with something that will work.
Mark Chaimberg When we do get new products, we usually make them available on our web site before they get to stores.
JL Well - if you want some "testers" - you know where to find us :).
Mark Chaimberg We like to get feedback.
Bob_in_NJ Mark, whats the URL?
Mark Chaimberg
Bob_in_NJ tnx
Mark Chaimberg Ok - guys and gals. It's been a load of fun. I have to get up real early to get up to Montreal and make some finishes. Any other questions before I go?
Walnutty Look forward to your formulations.
Ellis Thanks, Mark, for an enlightening chat.
Ellis Yep, my satellite connection got wiped by the T-storm. I'm on dialup now.
Mark Chaimberg My pleasure. Hope to be invited back again sometime
Bob_in_NJ Thanks Mark
Mark Chaimberg dial-up what's that?
Ellis We'll see what we can do. You were excellent.
Ellis I only keep it for thunderstorms.
Stephen great chat
Mark Chaimberg Good night everyone.
Ellis Night, Mark.