Chris Schwarz's Blog

Black Ooze and a Waiting Game

I went looking during lunchtime for stuff to make my epoxy black. I struck out trying to find lamp black and black food coloring in our neighborhood. I guess our neighborhood just isn’t chi-chi enough to support people who make their own tires or bake high-end cakes.

However, at our local art supply store, I found Gamblin “Mars Black” powder, a synthetic black iron oxide used to color both paint and construction materials. And I found some India ink.

I mixed my epoxy product from Advanced Repair Technology, which was recommended by several readers who restore rotted wood (this is the stuff they use at Colonial Williamsburg). It is structural and has a 30-45 minute open time.

Then I colored it. I started with one drop of India ink. Then two. Then three. It stopped getting blacker after two drops. It looked good, but the epoxy retained some of its yellowness and translucence.

Then I sprinkled a wee bit of the “Mars Black” on a second glop of epoxy. It instantly turned jet, tar, coal, pit-of-Kurt-Cobain’s-soul black. And it was dark, too.

I went with the “Mars Black.”

I forced the epoxy into the cracks with my putty knife. It wasn’t difficult at all. The stuff is just a little thinner than peanut butter. Then I scraped off the excess. Now I have to wait for 24 hours. Then I’ll finish planing the top and see what it looks like.

– Christopher Schwarz

17 thoughts on “Black Ooze and a Waiting Game

  1. Josh

    Nice work, very interesting.

    If you didn’t want to dull your planes, you could just use an orbital sander. I mean, you already sacrificed the "hand tool only" production of this bench earlier with the use of that band saw. Heck, I’m surprised you didn’t spread the epoxy around with an electric putty knife.

    πŸ™‚

    Josh

  2. Thom

    This is all good information. As a wooden boat builder, I keep the finest saw/sanding dust from my current project in large plastic jar. When I mix a batch of WEST System epoxy, I blend in the sawdust that acts as a filler and is an great bonding agent. I mix in the dust to create the consistancy that is best suited to the job at hand. I haven’t played much with colorings but I will keep these suggestions in mind.
    Thanks.

  3. Derek Cohen

    Hi Chris

    Next time you want to colour epoxy, try using the tints made for cement. They come in powder form and are concentrated so you only need a little. I mix it into one part of the epoxy (it does not matter which), then add the second epoxy part.

    The advantage of these cement tints is that you can get a very wide range of colours, plus you are able to custom mix your own shades.

    I have been using these for years with good results – reliable and colourfast.

    Regards from Perth

    Derek

  4. Larry Arnold

    Chris,
    I use ebony sawdust mixed with 5 minute exoxy to fill small cracks and voids around knots. Works great and the finished product looks good.
    Larry Arnold

  5. Kevin Haffey

    Chris, I’m going to bet that the Mars Black plays the devil with your plane blades. I’m a metallurgist that works for a company that produces iron powder – our first step is to produce a water atomized black powder by blasting molten steel with high pressure water – the resulting black powder is very abrasive to our transport equipment until we anneal it in an nitrogen/hydrogen atmosphere to get a silvery iron powder. After the anneal, it’s still abrasive but not nearly as bad as the black powder.

  6. Brian Ogilvie

    Hi Chris,

    Glad you tried the India ink–that is what worked for me. India ink is lampblack (carbon) suspended in a solvent with a binder (shellac).

    The yellow and translucent black epoxy looks very natural when troweled onto cherry, in my experience. It is not going to absorb any oil finish so some amount of shiny translucence is helpful to make it look right.

    I will have to get some Mars Black and try it too!

    By the way, India ink also dyes veneer very black, very quickly. You have to be quick because it is fast drying, but it worked great for me.

    Great post!

    –Brian

  7. Brian S

    The black epoxy is gonna look wicked. Nice choice. I think i might steal the idea for my bench. I’ve got mild checking on the fir beams i’m using (6x material). I’m not sure how’d it’ll look on fir though.

    So, you’re waiting 24 hours for this to dry. I hope you’re not drinkin yet, what about the base!? Have you already started gluing them up yet or are they still drying?

    Brian S.

  8. Christopher Schwarz

    Matthew,

    Every substance wears out a plane iron. I have found that epoxy is much nicer on blades compared to purpleheart, for example.

    Plus, sharpening a plane iron is easy!

  9. Tony Z

    Next time you need some filler material, shoot me off an email and I send some iron or bronze powder.

  10. Matt Cianci

    Chris,
    Are you worried about the dried epoxy wearing on your planes irons when you true the top of the bench?

  11. Christopher Schwarz

    Flex-Tec HV.

    The site is a bit confusing. There actually are only two epoxy products on that page. One is a pre-treater (a very thin epoxy) and the other stuff, which is available in a variety of sizes. I bought a starter kit. It’s way more product than I need, but epoxy always gets used.

    Chris

Comments are closed.