adhesives

Restocking

Decades ago I discovered the benefits of keeping a stash of emory boards at-hand in the shop.  Bought at the local pharmacy I found these little tools to be a magnificent solution to any number ot abrading and shaping problems.  Unfortunately, like a great many products over the years these have become too cheezy to really be the workhorses they used to be.

So, as I have posted previously, I make my own.  One of my beginning-of-year habits is to make a new set of abrasive sticks, gluing sheets of sandpaper to tongue depressors with a spray adhesive and then cutting them apart into a pile of useful tools.  (I really don’t need any posts about my New Year’s regimen of sharpening routine edge tools, do I?)

This year I did something a little different and expanded the variety of sticks.  In addition to the typical pairing I’ve been using for a long time, a coarse side and a medium side of aluminum oxide abrasive, I added finer stearated silicon carbide papers into the mix.  These options created their own issues, as I found the adhesion to be not as robust as with the AlOx paper.  Using a small roller, made by and given to me many years ago by my pal MikeM, I found that pressing the edges worked well, plus I discovered the need to embed the sticks while the spray adhesive was still soaking wet.

I wound up making three different sets of abrasive sticks.  The specs for each was detrmined by the abrasive sheets I had on the shelf.

The first set was pretty similar to ones I’ve made  the past, this time with 60-grit and 100-grit sandpaper.  I think that the 60-grit side will be less useful than I originally thought, but that could be because the product itself is pretty cheap and the abrasive particles spall off with first contact to the substrate.  Next time I will aim for 80 and 120-grits.

Next up are the sticks using SiC papers, 150-grit and 220-grit papers.  I’ve not made this combination before and think it will be a very satisfactory one.

Finally I went utra fine, with 400-grit and 600-grit together.  We’ll see how useful these are in the coming days.

I’m now set up with this year’s inventory of abrasive sticks.  Well, we’ll see if this lasts my usual full year since there are now so many different options.

 

 

Inside The Guts of the Long Rifle

Once Tim got all the metal parts removed from the rifle I was able to take a good look at what was inside.  It was pretty much what I expected, based on my observations from the outside.  The narrowest part of the rifle stock is also the region of the greatest stress from the explosion and reaction of the gunpowder igniting and expulsion of the heavy lead bullet.  And when the material used for said stock is curly or highly figured there is a lot of end grain/short grain structure, so failure is a given.

I could see immediately that the break was all the way through the narrow neck, and the only thing even holding it halfway was the inlet repair from days gone past (this picture was taken prior to the removal of the barrel).  Even this repair was loose and shattered.  At the very least, “the structural integrity was compromised,” as we say in our reports.  As a matter of fact there were pieces already so loose that they were coming off n my bare hands.

There was no doubt that a complete disassembly was called for.

The initial “disassembly” was auto-started as one major piece came off without any help from me.  It popped off when the barrel was detached in the initial disassembly.

My first step was to remove the inset repair that was the last thing holding the rifle together.  I poultice the area with water and 1% surfactant to soften the glue holding it all together.

No sooner was that accomplished than the entire thing came apart.  I now had direct access to all the gluing margins (and the glued that had been slathered/poured on in a previous restoration campaign).

I poulticed and cleaned every surface I could get to, softening the glue and scraping it off with one of my home-made ivory tools, followed by swabbing with distilled water to get them squeaky clean.

I let eveything sit for a couple weeks to reach moisture equilibrium before beginning the reconstruction.

Talkin’ Hide Glue Magic

Recently I spoke to both the Washington Woodworker’s Guild and the Professional Refinisher’s Group, a/k/a “Groop,” on the topic “Decoding Hide Glue.”  This marked 33 years since my first talk to WWG, and I have spoken many times at previous Groop gatherings over the past two decades.  (Anyone even marginally interested in the art, technology, and craft of wood finishing should belong the the Groop forum where finishing problems and techniques are the coin of the realm.)

This presentation was — for me — a delightful romp through the materials science of protein polymers, including their description and derivation and the many routes of modifying them that can directly influence practices at the workbench.

The presentation began with a description of the term “gram weight strength” which in turn begins with the rendering of the animal parts, then walking through the use implications of the different grades.

 

I covered the basics of how glue works, and how the components of adhesion contribute to the success or failure of the system.

I discussed in some detail the modifiers used with glue, including plasticizers, gel suppressants, crosslinkers, and preservatives, wrapping up with moldmaking and casting.

Fortunately thanks to my friend JohnH the Groop presentation was recorded almost in its entirety (~99%) and I will work on getting it posted on line.  I did not get the camera settings perfect but the information is all there.

Stay tuned.

Flexible Gap Filling Adhesives (video)

Recently I was making a presentation to a group and afterwards one o the attendees approached me and told me that he enjoyed my youtube video,   As he described the video I was perplexed until I realized it was not my video, it was from The Getty Conservation Institute, a video of a presentation I made almost a decade ago.

I do not recall ever posting it here before, and if I did this already I apologize for the redundancy.  I hope you laugh in all the right places,