metalwork

Makers Meet To Make A Mold, Second Part

The next morning I demolded the first half of the silicon rubber for MattC’s hammer head.  I cleaned all the surfaces of any residual clay from the embedding.  I spread a parting agent (petroleum jelly) over all of the silicon mold surfaces and reassembled the first half mold including the original wooden master pattern and the attendant elements.  [Sorry for the blurry pic — note to self, do not drop your camera on the concrete floor, it don’t work so good after that)

Reconstructing an identical plastic brick dam, I repeated the mixing and Matt poured the liquid silicon molding material and we let it sit again overnight to harden.

Once the entire rubber mold was separated and cleaned it was ready to go for making wax models for lost wax casting.  I did cast one wax pattern and saw that I needed to expand the sprues a little with a scalpel.  Had I used a larger piece of wire or tubing there would not have been a problem.

Just for the heck of it I walked him through the process for casting pewter directly into the mold, which requires depositing powdered graphite on all the cast surfaces to reduce the surface tension of the molten metal.  I mimicked the process with wax and he got a kick out of the metallic-looking wax pattern.

At this point I turned the mold over to Matt to proceed with the enterprise from his end.  My work was done.

Except for the second hammer head.  Stay tuned.

Maker 1 Meets With Maker 2 – First Part

I (a/k/a “Maker 1”) recently spent some time in the barn with my friend MattC, a tool enthusiast, collector, purveyor, and maker (a/k/a “Maker 2”).  Matt wanted to learn about making rubber molds from which wax patterns could be made for lost wax casting, so I demonstrated techniques for doing just that.  As a test exercise we used the wood pattern for a hammer he is hoping to produce.

Here’s a very brief report on that process.

First, I embedded the wooden master pattern in sulfur-free modeling clay, to an approximate halfway parting line (sorry for the blurry photo).  The “sulfur-free” descriptor is a critical one because silicon molding rubbers will not set in a sulfur-contaminated space.  Getting the contact margins with the master pattern is critical to getting a nice, clean two-part mold.

Once the embedding was complete I built a rectangular dam around the assemblage using my old favorite plastic toy bricks.  At this point I added a heavy wire sprue to the mold, along with the necessary gates to get the molten wax into the rubber mold.  In this case I constructed three funnel gates at the top of the mold and one through gate at the bottom, connecting the sprue and the master pattern.  All of these will be hollow voids in the end.

With everything ready to go I mixed up the silicone rubber molding material, using a disposable cup and my digital scale.  The rubber I chose for this project was Polytek 71-60, a fairly hard rubber that can accommodate low temp metal casting directly into the rubber mold.  I’ve used this product for decades and find it amenable to my work.  It is, of course, now discontinued.  I do believe that the Smooth-On company makes an analogous product although I have not yet tried it.

Ideally the container of mixed rubber would be placed in a vacuum chamber to draw out any air bubbles, but since I do not have one set up at the moment I just let it sit for a few minutes and popped all the bubbles rising to the surface, essentially reducing the overall vapor pressures within the liquid solution.

Additional methods of dealing with any remnant air bubbles include my holding the cup fairly high over the embedded master pattern and pouring a very thin stream of the liquid into the void.  The long, thin stream breaks up most of the remaining bubbles.  Furthermore, I always start pouring away from the pattern itself and allow the liquid rubber to flow over the surfaces on its own, which also reduces any bubble issues.

Finally, when the plastic toy brick flask is full, I spend a few minutes popping any bubbles that emerge on the surface, once again reducing the vapor pressure within the liquid and eliminating any risk of bubbles being permanent against the surface of the patter (the ultimate problem).

Depending on the temperature and freshness of the silicon rubber solution (there are definite shelf-life issues with these products), I return to de-mold the first half of the final mold in four to six hours.   Usually, I just wait overnight.

Next time – the second half of the mold.

Inspiring

My longtime pal Ripplin’John sent me photos of his latest project en route to an MFA (at our age John, what were you thinkin’?).  Seriously, I am immensely proud that we are friends, my circle of close friends is actually quite small, and of his artistic and technical accomplishments while exploring the realm of artistically integrating wood and metal.  Some time ago I gave him a copy of the Matthew Boulton book and is now going to town.

This “lunch box” employs classic boullework techniques, right down to the engraving.  In his own words,

I changed the normal procedure somewhat.   I printed the drawing on PNP paper and then transferred it to a brass blank slightly larger than the size of the sides.  After engraving the brass, I assembled the packet with shop-made veneer and cut out the pieces as needed.  Doing it this way meant that I was engraving much larger pieces of brass. Holding the very small pieces after cut out would have been pretty tough.
Each assembly was then glued to another piece of veneer before gluing to the box. This was done to ensure that a failure of the glue up on one side would not wreck the whole piece.
The corners, finial and cheese crackers are cast bronze.

 

Well done, sir.  You can tell him so in person at Handworks where he will be helping me in my booth.

Round Carving/Joinery Mallet

I’ve been hanging with my pal MikeM for a couple decades, and at least one of his consuming passions is rubbing off on me — hammers.  Many times a Christmas package would arrive from Mike, and on more than one occasion it was a hammer or mallet he had restored or made.  One of them, a polished vintage ball peen hammer head with a sublime curly maple handle, is in my personal tool pantheon and gets used every day I am in the barn (pic above).  Every day.

Well, as they say, “Bad company trumps good character,” and Mike’s “bad” influence on me over the years in the realm of hammers has taken hold.  (Just kidding folks, Mike’s friendship is a life treasure.)  I now find making hammers one of the many delightful undertakings in the studio.   I’m probably not approaching Mike Territory, but in response to a comment by a recent visitor in the studio, “No, I do not have a ‘hammer problem.’  I have a lot of hammers.  Big difference.”

Many years ago I picked up several steel pieces at a flea market.  These cylinders, which I naturally thought would make great mallets, were of unknown origin and a peculiar morphology.  The flat ends were easily drilled and tapped.  My original thought was this would be great for affixing faces to the striking surfaces.

The problem emerged when I tried to drill a hole on the cylinder surface for a handle.  It was hard.  I mean really, really hard.  Too hard for any drilling device I had, up to and including carbide and cobalt drill bits.  The rounded surface was so hard I could not even make a dimple with a machine punch and in fact the tip of the punch broke off when I tried.  I have never encountered something this hard, and scratch my head about the  manner of hardening this surface.  It was probably case hardened on a precision rolling mill, but what was its purpose?  I have no idea, but for several years its purpose was mainly to hold down the sill of one of the studio windows.  Occasionally it would be used as a dolly or backing anvil, but nothing more.

Recently, while in the tool-making “zone,” I decided to give up on the idea of creating a typical mallet configuration from the cylinder and exploit its differing hardness to create a joinery/carving mallet.  This began with drilling a hole in the flat face.

To match this I turned a white oak handle from some of my scraps, and drilled that as well.   The finish on the handle was Blend 31 wax melted into the surface while turning on the lathe, then burnished with a piece of coarse linen.  I like both the look and the feel of the handle, beautifully smooth but with just a hint of tack for gripping.

Inserting a threaded rod dowel with epoxy to assemble the two pieces completed the assembly process.   I didn’t clamp the assembly and let the hydraulic vacuum of the thick epoxy hold everything steady while it hardened.

It is now an intriguing addition to my inventory of homemade mallets.  I note that of these mallets there is a huge range of shape and weight. The tapered cylinder mallet on the left, made thirty-five years ago, weighs in with a lignum vitae head of a half pound, plus the handle.  The tulipwood mallet on the right, made 25+ years ago, weighs in with a head of 3/4 pound.  This new one with the steel cylinder has a head weight of two pounds.  It just might be a beast.  Because of its comparative diminutive size I was thinking of keeping it in my traveling tool kit.  With that weight I am reconsidering that decision as it is almost two full pounds more than the lignum vitae one

I will probably wrap the new steel cylinder with leather to diminish any strike damage inflicted onto anything I whack with it.

Stay tuned.

Fixing An Old Friend

My pal Long Tom generally prefers woodworking in a stylistically primitive form, even though his craftsmanship is sophisticated and exacting.  He just loves “woodland” woodworking, making rakes, walking sticks, stools, etc.  He generally keeps a nice inventory of walking sticks in the corner of his shop, and around the time we moved to Shangri-la he gave me a shoulder-height stick he had been saving “for something special.”  I am pretty sure it is some gnarly white oak he picked up during one of his walks through his woods.

For the first couple of years, it resided next to the cabin front door and received only occasional use as I traipsed through the woods or up the creek.  Later as I recovered from my broken hip it became a constant companion on my treks up and down the hill to the barn.  After I recovered fully from that injury the staff was used mostly during inclement weather, helping me to keep steady and upright on the steep driveway.

Then last summer after my knee surgery it became a constant companion once again, to the point where the tip was getting pretty beat up.  I love that stick and refused to let go of it.  So, I decided to make some modifications that will allow it to serve me until they scatter my ashes up on the mountain.

My initial thought was to fit the tip with a ferrule of brass or copper, but when scrounging through my scrap inventory I noticed some bronze bushings including sleeve bushings.  I found one of the perfect size and set to work.

I filed the tip of the stick to fit the inside of the sleeve bushing using an Ariou rasp, working my way slowly around the circumference until it got to the point where I could drive the new bronze ferrule onto it.

Once that was done I chamfered the adjacent wood to make the fit a bit more elegant, and now I do indeed have a faithful walking companion to last me the rest of my days.

All thanks to Long Tom’s friendship and passion for “found wood” woodcraft.

Some woodworking projects are hidden from others, some are fancy or extravagant, but this one was a simple task to guarantee this friend will remain a treasured gift and companion working for me for many more decades.

Reshaping A Petite Adz

Somewhere in the misty memories of the Mesozoic era I picked up a blacksmith-made petite curved adz head, probably at a PATINA tailgate tool swap.  At the time I fashioned a handle from a broken shovel and sharpened the head to a keen edge.

I used it from time to time but not as much as I thought I would.  Unfortunately, the tip was convex, rendering it almost useless for any task I might have.  So, I decided to reshape the tip into one that would be more useful to be, one that is at least flat, maybe even a bit concave.

In few minutes on the bench grinder the shape was established, but the ~1/8″ cross section at the new edge was presenting me with the potential of several hours hand grinding and beveling on the inside curve with round slips or sandpaper wrapped around a dowel.

Instead, I had a flash of inspiration and took the top shield off the belt sander in order to access the roller.  Miraculously the roller size was absolutely perfect for grinding the new in-cannel bevel.  That one thing cut the work time from several hours to several minutes.  I like innovations like that!

I reattached the handle to the head and gave it a test drive.

Me like.

Winter Project – Steampunk Weighted Infill Mallet

While watching a Bob Rozaieski video the other day my eye was drawn to the mallet he was using.  So I sez to myself, “Self, you gotta make yourself something like that!”

So I will.  Probably late next week.  Stay tuned.

Winter Projects (and well beyond) – Toolmaking

Since this list is already getting too long and I still have a large number of items yet to go, I decided to consolidate a half-dozen of my “winter projects (and well beyond)” into one with the identical theme for all the elements — making tools.  I have no doubt there will be other additions as time goes on, but these are the ones already on my “to do” list.

Copying (?) A Robert Towell (?) Infill Miter Plane

I do not own many truly “collectible” vintage tools, but this plane is one of them.  Perhaps made by London planemaker Robert Towell in the early 1800s, I bought this very-little-used plane at Martin Donnelly’s several years ago from one of the tailgate vendors.

Though the characteristics of the plane are consistent with Towell’s work, he was apparently somewhat cavalier about stamping his planes and this one is unmarked.  Had he stamped this one I would have certainly not been able to afford it.  So, thanks to his oversight I was able to become the owner of this superb beauty at a 90% discount (!) off an identical plane with his stamp.

In addition to this full-sized Towell miter plane, I have one of Raney Nelson’s early planes, a miniature scale but similar form.  I use it for trimming parquetry lozenges, one of a half-dozen planes I employ for that task (is that too many?).  Maybe I need to purge that inventory a bit.

Nah, I’ll wait until I finish and fill my new standing tool cabinet.  Check back with me then.

In the meantime, I’m thinking I need to make a third plane to complete this set, one halfway in between the sizes.

You (and I) might ask, “Don, do you really need it?”

And my reply would be, “Butt out of my bidnez.”

The project would give me a chance to invite over my new friend, an Amish blacksmith and newcomer to the county (heck, I’m a newcomer and we bought our cabin twenty years ago!  I expect my soon-grandson will be a “newcomer” also, but his grandkids maybe not), who is very interested in this kind of tool making.  It would also give me the opportunity to approach the local bladesmith/exotic dancer about fashioning a Damascus steel blade.

What, you think Austin TX is the only place with eccentric folks?  We might not be San Fransicko but we do have a lot of competing drummers.

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Triangle Squares for Parquetry

A couple years ago when I was making a set of Roubo-esque brass cabinetmakers’ squares I also wound up with a solid 30-60-90 triangle with a shoe on the short base that I have found exceedingly useful in the intervening period, especially for laying out Roubo bench dovetails and parquetry pinwheels.

As I am about to move even more into the work of parquetry I am thinking that I need a full set of 30-60-90 triangles; one with the shoe on the long base and one with the shoe on the hypotenuse.

In fact, I might need some additional ones as I move past my usual vocabulary of parquetry, including one dedicated to the 45-degree angle and another with a 22.5-degree feature, and perhaps even more.  I guess I could use my EDC pocket Delve square for the 45, but a full dedicated brass set would really be nice.

This is definitely one series of exercises drawing on the use of a micrometer caliper integrated with those 10th grade trigonometry sine-cosine-tangent tables I figured would NEVER come in handy.

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Japanese Joinery Hammer

Two years ago as I was constructing my Japanese tool box I also made a small Japanese-style (sorta) hammer for doing delicate work like driving small nails and pins and adjusting planes.  I recognized at the time the void in the kit of a beefier hammer for doing joinery.  It will be nearly identical to the smaller one except for the scale, being made from 1″ square bar stock rather than the 1/2″ bar stock of the previous one.

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Custom Stamps and Branding Iron Tips

I’ve always wanted a set of stamps/branding irons for marking my new work with my sign, the barn logo, and the date.  I would need three separate items, one to create an embossed presentation of my stylized initials, one for the simpler barn logo, and one would be a set of the letters “M, L, X, V, I” for the year/number stamp.  Hey, if you are going to live in the past, go way back.

I know there are companies out there who do that for a reasonable outlay, but I’d like to give it a try myself.   Actually, I might need two complete sets — small ones, for small objects, and large ones for larger objects such as Gragg chairs.  Since I keep plenty of raw metal bar stock on hand that would suit my needs for that undertaking, I’m going to give it a try.

I hope to start these sometime in the next couple weeks, so there may be some posts about that in a month or so.

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Finishing the Restoration of an Infill Smoother

Years ago, I bought an infill smoother and got part way through its restoration.  This is the year to finish it with fitting a new iron (already in hand from Josh) and a new wedge.  My only question at this point is, “How ‘over the top’ do I make the wedge?

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Expanding My Selection of Tools from Roubo’s Veneering Tool Kit

During the creation of the English translation of Roubo’s L’Art du Menuisier I made a number of tools for completing some of the accompanying photo essays in the books.  This did not satisfy my appetite for his tool kit but merely whetted my appetite.  The tools I make from the oeuvre will not be for curiosity-only purposes, these will be tools I expect to use in the shop regularly.  They worked in 1760, I expect they will work after the Zombie Apocalypse.

In some cases the tools will be even more of the iterations I already possess (bar clamps) and in other cases they will be new to my tool kit (veneerer’s hammer [as opposed to veneer hammer]), and some completely off the grid (oval cutter).

Winter Projects (and well beyond) – Foundrywork

 

Now that I have the foundry set up on the first floor, I really have no excuse to not start metal casting.  Well, except for the need to refabricate the large entryway, allowing me to roll out the smelting furnace from the interior space.

It might be just fine having a thousand degrees worth of hot indoors with a wooden floor above, but I would rather not test that hypothesis as a starting point.  Perhaps if there is a streak of ultra-mild days upcoming (it’s been unseasonably warm thus far this winter) I can get that task done.

To be sure the first project on the slate for the foundry is to move forward with replicating the infill mallet from the Studley Tool Collection.  Having that prototype in-hand would be a great excuse to revisit the collection itself, to compare my replica with the original.  Obviously, Mister Stewart gets the first unit off the non-assembly line, should he want it.

Right behind the Studley mallet in the queue is my finger plane project, with its thus-far three models underway.  I started working on these models 15 years ago if the date stamp on the images is correct.  I do not need these tools from a utilitarian perspective, but I do need them from a creative one.

Once I get the foundry humming along as a routine activity there is no telling what I can imagine making.

Clean-up “Christmas”

One of the aspects of having a humungous Fortress of Solitude like the barn, four stories of 40′ x 36′ space, is that there are a multitude of nooks and crannies into which things can be tucked, stuffed, crammed, lost, and re-discovered.  I call these instances my own “Clean Up Christmases,” when I come across treasures I had forgotten, or at least misremembered.

Such has been the case recently when prepping the classroom for this coming weekend workshop Historical Wood Finishing.  As the first class there in over two years, the space had, shall we say, devolved.  That pesky Second Law of Thermodynamics; they tried repealing it but it just didn’t take.  It has taken me over two weeks to get it ready for the group on Saturday.  The level of “rearrangeritis” (full credit to James “Stumpy Nubs” Hamilton for coining the phrase to describe an all-day travail when moving one thing in his crowded shop) has been monumental, and monumentally rewarding on several fronts.  It has also given me time for contemplation about future projects, a topic I will address in numerous upcoming posts.

At the moment I am mostly reveling the rediscovery of two caches that were set aside for some future completion.  The first is the two sets of brass Roubo-esque squares fabricated before and during that workshop more than two years ago; all it will take is a day or two with some files and Chris Vesper’s sublime reference square to get them up and running.

A second trove is the pile of French oak scraps from the multiple iterations of the FORP gatherings in southern Georgia.  I brought them home in order to turn them into veneers, probably oyster shell style, to use on some as-yet-unknown project.  That “unknown” identifier is becoming more “known” as the days go by.  Then, much like my shop being the only one in the county with two c. 1680 parquetry flooring panels from the Palais Royale in Paris, my tool cabinet will be the only one with veneers from some c.1775 oak trees from the forests surrounding Versailles.

Who knows what other “Christmas” presents I might find during the never ending effort to impose order on my space?  Stay tuned.