molding and casting

Rethinking, or, “State of the Barn Address”

 

It’s been almost thirteen years since the skeleton of the barn was erected, nine years since it was outfitted with the first of more than a dozen workbenches, and over six years since the first blog post.  Now safely ensconced in my 65th year, lately I’ve been contemplating the entire enterprise, reflecting on how blessed I have been and continue to be.  Whether it is good news or bad news, after serious consideration I have no plans to change the fundamental structure of activity on the homestead for several more years, but at some point life in the mountains will simply become too physically taxing and the barn and cabin will be in my rear-view mirror.  Until then, however, it is still full(?) speed ahead with a big smile on my face, albeit not necessarily in the exact same direction nor the exact same speed.  I’m working just as hard as I did when I was 30, but the output is demonstrably less.   My Mom is 102 and lucid so I’ve got to think about another forty years of engagement and productivity.

Here is a sketch of what future activities might look like.  No telling if it is accurate.

Conservation Projects

Early on I maintained a fairly vibrant furniture and decorative arts conservation practice but have no plans to continue much of that except for specific projects and clients.  Yes, I will continue to work with the private collection of tortoiseshell boxes that I’ve been working on for more than a decade.  Recently I was approached to collaborate on a couple high profile on-site projects and if those move forward, fine. I love it but at this point I’ve got other things I want to do on the priority list.  And I want to truly perfect my artificial tortoisehell.  And I want to explore new uses of materials in furniture preservation.  And invent new materials, or novel uses of existing materials.   And, and, and…

Making Furniture

I make no claim as a furniture maker of any note, but I hope to concentrate on making more in the future.  I would love to maintain a small output of Gragg chairs every year, and even modify them and take them in directions Samuel Gragg never went.  I also have enough vintage mahogany for eight more Daniel Webster Desks, so perhaps there are some clients who might want one.  Only time will tell.  I’ve always had a hankering to make some furniture in the milieu of Charles Rennie Mackintosh or Alar Aalto, so maybe that becomes part of the equation.  And I have these sketches for pieces representing a collision of Roubo and Krenov while they are sitting on the porch of a Japanese temple.  And Mrs. Barn has a list of things she would like for the cabin.  And exploring parquetry more intensely.   And finally get pretty good at woodworking in general.  And, and, and…

Metal Work

I’ve always had a interest in metalworking since my boyhood when I would spend time with my Dad in his shed, melting lead weights and doing a little brazing and welding.  Many of those skills have grown fallow but I am trying to get them back and take them to new places.  My love of tool making has been rearing its lovely head in recent times and I have every intention of bringing that focus closer to the bullseye.  And part of that has to include getting my foundry back on-line.  And tuning up all my machine tools like my machinists’ lathes and mill.  And getting really good at brazing and silver soldering, maybe even welding.  And, and, and…

Finishing Adventures

I remain committed to looking both backwards and forwards into the realm of finishing materials, ancient and super modern.  I truly believe Mel’s Wax to be a transformative furniture care and preservation product for which I have not yet discovered the key to marketing.  But I will keep at it because of my knowledge of its performance and my commitment to Mel’s vision for it.  And as for beeswax and shellac wax? Finishing with them may be among the oldest and simplest methods, but they can be extremely difficult and I cannot pretend to have mastered them.  And what about my fascination with urushi and its non-allergenic analogs and the beautiful things I want to make from them?  And what about the fifty bazillion things I do not know about shellac?And, and and…

Writing

My plate of writing projects is full to overflowing, building on a strong foundation of completed works.  Notwithstanding my current struggles with the manuscript for A Period Finisher’s Manual, due entirely to my having too much esoteric material to include in a reasonably consumable book (really, how much solvent thermodynamics does the typical woodworker need to know?), I enjoy every minute I am writing even when it is driving me crazy.  I’d better because my collaborator Michele Pagan is one full book ahead of me in the Roubo Series.  And there are two or three more volumes after that one.  And some day I need to finish the almost-completed manuscript for A Furniture Conservation Primer created with a colleague while at the SI and thus will be necessarily distributed for free via the web site.  And what about my treatise on the technology and preservation of ivory and tortoiseshell?  And the dozen mystery/thriller novels I have already plotted out?  And who knows how many short stories about the life of First Century craftsman Joshua BarJoseph?  And, and, and…

Web

My first of almost 1,200 web posts went up six-and-a-half years ago, which I understand in the world of hobbyist blogging, where blogs come and go like the tides, puts me as some sort of  Methuselah.  But certainly not in the same class as The Accidental Woodworker, who has been blogging daily for even longer IIRC.  Ralph, I tip my hat to you, sir.

I once thought the web site/blog would be a useful portal for soliloquies about my projects and things I’ve learned over a long and rewarding career, but now I am not so sure.  A while back I decided to make a concerted effort to blog at least five times a week for a year, and I think I came pretty close.  Surely this would increase my web traffic!  Well, not so much.  At the end of this effort my web traffic was 2% lower than when it began.  Despite fairly consistent blogging my visitorship has dropped by almost half over the past four-plus years.    So I just scratch my head.  I’m not whining, but instead recognizing that the flock who is interested in my musings is shrinking, not growing.  Oh well.  This is not a good or bad thing, it is just a thing, helpful in me making decisions about priorities.  I have no plans to really change anything about the blog, we’ll just wait and see where it goes.  When I am not somewhere else, with someone else, or doing something else, I will blog.

Recently I was chatting with someone who informed me that web sites and blogs are now passe and the currency du jour is the unholy trio of Instagram, Facebook, and Twitter.  Given that and my antipathy towards the latter two it is likely that I will undertake the former at some near date (yes, I know the relationship between Instagram and Stalkerbook) .  Something inside me rebels at the notion of validating the post-literate world, however.  Still, the economic treatise presented by Larry the Liquidator is not only dramatic but accurate.  Even the Professional Refinisher’s Group is moving forward, transitioning from a moderated email forum to a private Facebook Group, which will leave me behind.  But they will survive without me and I intend to maintain contact with that circle of fellowship regardless.

Trouble is, I am by temperament a bizarre mélange of buggy whip maker and hardline “emergent order” Hayekian.  Hmmm.  Not really sure how that works out.

Workshops

Integral to my vision for the barn was to have it be a place of learning.  As the facility was coming together, whenever I spoke to any kind of woodworking gathering the verbal response was overwhelmingly enthusiastic.  The reality that unfolded was anything but.  I now realize that my vision was a faulty one and the enthusiasm was superficial.  Quite bluntly, almost no one wants to come to such an isolated location where local amenities are practically nonexistent, to spend a few days engaging in subjects I want to teach.  Fair enough, the barn is too remote and my topics are too arcane.  Like I said before, this is not a good thing or a bad thing, but just an instructive  thing to add to the equation.

As a result and in recognition of reality I plan to deemphasize workshops at the barn, perhaps even eliminating them altogether, notwithstanding that I created dedicated spaces for the undertaking.  Should a small group of enthusiasts approach me with the request to teach them, I will do so.  That is precisely what a quartet of guys have done for next June.  And, I might do an occasional blockbuster-type workshop (a Gragg chair class would be such an example, if that ever occurs; I had thought a ripple molding machine class might be such an event, but with zero response…), or I might travel a bit to teach but otherwise that part of the portfolio is likely to close.  Not definitely, but likely.

Videos

Hence my transition to teaching via video.  If I cannot get folks to come here perhaps my best strategy is to go to them.  I have a multitude of ideas (more than twenty full-length [>30 mins.]video concepts on the list) and a brilliant local collaborator to work with.  I am committed to this path to the degree that I have the time, energy, and resources.

Further I have decided that making shorter, self-produced and thus less polished “shop technique videos” might be a useful undertaking to post on donsbarn.com, youtube or Vimeo.  I will explore this avenue in the coming weeks and months.

The Homestead

With several buildings, several gardens, and a power system to maintain and improve there is never a shortage of things to do here on the homestead.  I want to build/expand more garden capacity for Mrs. Barn to spend time doing the thing she loves best.  And fruit and nut orchards.  And I want to finish creating a rifle scope for shooters like me who have lost most of the vision in their dominant eye.  And another hydro turbine downstream from the current one.

And, and, and that’s all I’ve got to say on the subject.

That is The State of the Barn Address, 2019.  To quote one of Mel’s favorite songs, “The future’s so bright I gotta wear shades.”  Yes it is.  I am living the dream.

A Reader’s Adventures With Gelatin Molds

I got this note recently, and it encouraged me immensely. This is the fellow who planted the seed in the first place in some correspondence going back to last autumn. We have continued to communicate with our respective tinkering with the process.

Hi Don,

I’ve been meaning to follow up with you on my experimentation with the gelatin molds.

In short, at least for now, I’ve changed my expectations for the gelatin mold. I have had excellent results but have changed my goal of utilizing the gelatin mold for “mass” production. Rather, I think these molds work well for making a few casts.

While the gelatin may not last for years like a silicone or urethane rubber mold, it’s key advantage is that it can be melted down after use and reused. Given the cost of quality silicon and urethane this is noteworthy.

I ended up with a basic formula of 2 parts liquid hide glue to 1 part glycerin (by volume). I bought some hardener but haven’t used it.

I enlisted the help of my 6 year old daughter. We started with making a mold of a quarter and then making a cast in chocolate.

Then during Valentine’s Day she made a clay sculpture and then we made another chocolate cast

Then I moved on to a simple wood carving. The gelatin mold worked well here. Unfortunately I seem to have deleted the picture of the cast. Detail replication still very high.

I have kept my recycled gelatin mold material in my refrigerator for about 3-4 months and there has been no sign of spoilage.

More experimentation to come. I’ll keep you posted on the results.

J

Salvaging A Gelatin Mold. Not!

I mentioned earlier the failure of a plaster casting in a gelatin mold when I had to step back from work in the shop for a couple weeks during my vertigo incident (very much improved, only an occasional moment of lightheadedness), and my desire to try to salvage the warped, shrunken and hardened mold.

To manipulate and try to regain the utility of the mold I immersed it in hot water to see if that would do the trick. The experiment was both a complete failure and an enlightening success. Yes, the mold being manipulated started dissolving and slumping immediately, with, um, some loss of definition, resulting in it becoming a useless blob of goo.

That said it was elucidative of a correct direction in the overall enterprise, and enlightening to the future modifications. The fact that the mold could be manipulated by the hot water was instructive in confirming this strategy for a dried mold. That said it was immediately clear that the proportion of crosslinker in the original formulation was too low, so I will make a new mold with twice as much crosslinking additive. The mold had very little fungal attack so I know I am about at the right place for that additive.

So, sometimes ven failures keep you moving in the right direction.

Stay tuned.

When A Gelatin Mold Meets Vertigo

A couple months ago I made another gelatin mold and plaster casting in my efforts to refine that process, and test the proportions of preservatives for the gelatin.  At primary issue was keeping a mold viable for the longest period possible, to see how long the mold could be kept in a sealed container for future use.

The initial steps went perfectly.  Then my vertigo attack became manifest and I did not get back into the shop for more than two weeks.

Unfortunately for the mold and the plaster cast in it, it was just sitting on my bench and became desiccated and warped in the intervening fortnight.  Not good.  The mold became hardened and crushed the casting as it warped.

My next step is to see if the damaged mold can be resurrected with hot water or steam.  I’ll let you know what I find.

PS – Vertigo per se is gone, but I’ve had lingering dizziness which I describe as “being fuzzy around the edges.”  As long as there is no excess motion around me or I do not have to turn my head quickly I can manage.  Extensive and thorough medical examinations have yielded nothing yet.  I’m hoping it all goes away on its own.

Casting A Hairy Paw Foot

 

 

 

I have been doing molding and casting for almost four decades, and for the most part it has become a routine and enjoyable aspect of work in the studio.  But as with anything involving technology, technique, and “touch” there is room for it to go south, and I am in the midst of one such project.

Several weeks ago I was contacted by a blog reader asking me to cast a replica of a carved hairy paw foot he saw in an image I posted.  “Sure,” I said, and the misadventure was inaugurated.

My first step of creating a silicon mold was so straightforward I did not even bother to take pictures.  I figured I had just enough of the RTV rubber to make the mold and could cast it in plaster as requested.

Eeezy peeezy.

Only it turned out I had mis-estimated and I did not have enough of the molding rubber for the task, the liquid rubber barely covered the top knuckles of the foot, and was not thick enough for me to demold the foot without destroying the mold.  So, that time and material was down the crapper as a wasted effort.

Not to be dissuaded I turned to other mold-making options and struck on another molding material, Gelflex, a rubbery PVC molding material that is poured as a molten mass.  I’ve used it before with fairly good success, in fact one of the benefits of Gelflex is that is reusable.   When you are done with one application, you can just cut up and remelt the rubber for a subsequent use.  As long as you do not char the material it seems to have a near-infinite utility.

I set up the molding operation with my typical Lego box dam around the carved foot, which was anchored to a base board with sculpting clay.

I set up a Pyrex sauce pan on the hot plate and began to melt the material.  This was considerably more mass of Gelflex than I had tried using before (I had used it for replicating metal hardware in the past) and balancing the temperature so that it was hot enough to become liquid but not so hot as to char was a challenge.  It literally took three hours for me to get the temp/viscosity correct.

Even then I managed to chat some of the medium.

Then I poured the molten vinyl into the Lego box holding the carved leg in place with sculpting clay.

What could go wrong?

More Improvements to Gelatin Molds For Plaster Casting II

Armed with the knowledge and experience of recent attempts at making gelatin molds for plaster castings I charged forward with some new modifications to the formulation of the gelatin.

In this iteration I used the following recipe:

1 part 135 gws glue (dry granules)

1 part water, soaked overnight and cooked twice

3% glycerin

3% gelatin hardener

0.5% borate preservative

*Note: it is important to actually record the weight of the dry glue granules as the other additives are based on that number.*

Once the glue was well-cooked I added 3% glycerin and 35 of the hardener.  These numbers were based on the dry weight of the granules, in other words for 200 grams of glue granules I added ex poste 6 grams of glycerin and 6 grams of hardener.  I then added 1 gram (0.5%) of borate complex powder as a fungicide to extend the lifespan of the mold itself (not borax from the hardware store).

The working properties of the gelatin mold were excellent, although the time required for it to lose the requisite moisture  to become robust enough to use as a mold took longer than I expected.  I waiting a day before demolding from the pattern, two days would have been better.  But the resulting mold was extremely tough and utilitarian.

I cast plaster into the mold and demolded that the following day. Like the original demolding, longer would have been better.  Next time I will try 36 hours rather than~20.

The plaster casting was still pretty green since it took so long to slough off the water, so I placed it into a desiccation chamber to draw out the water.

The mold itself was placed into a sealed kitchen container with a damp sponge to maintain the water content of the mold, and thus its viability as a flexible and functioning plaster mold.

After three weeks I checked the mold and found a little bit of surface mold.  This was a useful observation.  The initial mold from many moons ago was a lump of goo after two weeks, this was still sort of viable after three.  I think next time I will jump the borate salt content to 0.75% or even 1.0% to see the result.

All in all I was very pleased with the progress being made, both conceptually and practically.

Stay tuned.

Where Did I Put That Stinking Knife Handle?

Recently I was sitting down ready to incise the pattern into the block that would become the pattern for the mold for making my soon-to-be-available Blend 31 block wax.  It was at that moment that I realized I had put the handles for my detail knives someplace for some reason I could not remember.  It was not that I had misplaced one of my handles, I could not find any of them, suggesting I had collected them for some purpose that I could no recall.  Fortunately they will be found as soon as my task is completed.

In the mean time, I needed a handle for the knife blades I needed to use.  So I made one.

Taking a piece of dowel stock from inventory I sawed a small slot with a fine Japanese back saw, inserted the blade into that and bound it with twisted copper wire, much in the same manner as quill brushes.  It worked just fine for the carving of the mat board that was the detailed surface of the block pattern.

An hour later I had the design incised into the surface and the block was ready for making the rubber mold.

 

And sure enough, the box with my micro tools was found right after this was finished.  Sigh.

More Improvements to Gelatin Molds For Plaster Casting I

Last month I brought together all the new information I had derived from the initial gelatin molds exercises to see if I could nail it on a more complex application.  For this project I used a pattern derived from a cast pot-metal satyr’s head mount from a 19th century pastiche of a 17th century French desk.  The hardware on the desk was cheezy and poorly finished (I was only interested in the desk itself as it was the earliest intact example of “mastic tortoiseshell”; another tale for another time).  This was probably a poor choice for a pattern because its level of “finishing” made it difficult to ascertain the ultimate success of the new mold and casting.

Just before this endeavor I was doing some winterizing and had a bolt-of-lightening stroke of inspiration.  As I was affixing the shroud around the window air conditioner with rope caulk I suddenly noticed the similarity of the rope caulk to the gaskets I made from modeling clay for my molding and casting.  Could it work the same way, but without the time involved in making the the initial gaskets?

I could hardly wait to get back home to try it out.

Fabulous!

I built the form-fitted Lego casting dam for the pattern/mold and quickly laid in a bead  of the rope caulk as the gasket on the inner edge of the underside, and pressed the assembly together.  The adhesion and squeeze-out was basically perfect.  Rope caulk is formulated to stick just enough to make it through the winter and then be peeled off with no residue in the spring.  Cleaning off the squeeze-out required only a pass with a boxwood sculpting tool configured  with a knife edge.

Suddenly I was in possession of a new technique to cut many minutes out of my pattern/casting dam set-up for the remainder of my working life.

It was now time to move forward with the modifications to the gelatin formulation and make the mold.

 

All A-buzz

Many times in the studio I need to shake something, just a teeny bit.

For example, when casting plaster or plaster like materials, such as ceramic media for lost-wax casting investment, it is sometimes necessary to tap on the mold container to dislodge air bubbles that all too often get lodged against the surface.  If they remain there the casting will be diminished, even ruined.  Many years ago I looked into getting a vibration table for buzzing the molds while the medium was still liquid, loosening the bubbles to rise to the surface.  After pricing the available devices I decided to go another route.

What could I use to cut the cost of a vibrating table down to near-zero?

Hearkening back 55 years to my times with Stan the Barber I recalled two things — Stan always had the latest comic books for the boys to read, a real treat for me because we were too poor to get them, and the tickle of the vibrating electric clippers on my neck when he was trimming up.  Could electric hair clippers be part of the answer?

The next time I ran across some clippers at the thrift store I decided to roll the dice with a buck-and-a-half for the clipper.  I combined the tool with some scraps of wood, two pieces of plumbing strap and a few screws.

Viola’.  A vibrating table for a couple bucks and a couple minutes.

Gelatin Molds For Plaster Casts III

With a number of data points in my hand it was time to give this  gelatin mold thing a trial run.  For the master pattern I selected one from my inventory of such things, an epoxy replica of a carved element.

I first affixed the pattern to a flat board using sulfur-free modeling clay as my gasket and adhesive.  I have used this method as a rock-solid tried-and-true technique for decades, the sulfur-free aspect is critical whenever the mold-making material is silicon rubber (sulfur inhibits the silicon rubber from setting), and I just use this as my default for every similar application.  I cleaned off the excess and brushed the thinnest possible coating of petroleum jelly onto the pattern to assure perfect separation, then dammed the pattern with a rectangle of Lego blocks.

For the gelatin mold material I used 192gws Standard glue, soaked overnight with the water level equal to the height of the glue in the glass jar.  I wanted the gelatin to be on the viscous side, remembering that all the water going in has to come out and there are shrinkage issues to consider with that.

Once the glue was cooked and ready, I added 3% of glycerin to it to serve as a plasticizer  followed by 2% protein hardener to crosslink the glue (both additions were by weight in proportion to the dry glue granules).  I had already learned to allow the glue to cool a bit before adding the hardener as higher temps make the crosslinking go too fast, turning the glue into an heterogeneous lumpy mixture.

Once everything was ready I simply poured the glue over the pattern until it stood proud of the surface by about 3/8″ and set it aside overnight.

The next day I dismantled the Lego dam and the rubbery block was just what I wanted, it peeled away from the pattern easily.  Clearly the hardener was imparting toughness from the git-go and the glycerin enhanced the flexibility of the still-swollen block.

 

I whipped up a batch of plaster and poured it into the gelatin mold with outstanding results.  Well, as outstanding as I could have expected given my impatience, which caused me to de-mold the casting too soon.  I should have waited 36 hours instead of 12; the high moisture content remaining in the gelatin mold retarded the setting of the plaster.

I immediately double bagged the gelatin mold to keep it from drying out, thinking the crosslinker would inhibit mold growth.

Not so much.  Two weeks later when I opened it to use it again it was something akin to a slimy special effect for a space alien movie.

Still more territory for improvement on the next try.