Acrylic stabilation of pernambuo or bow repairs


Recommended Posts

In the early 1970's luthiers, knife makers, pen turners, and craftsman of all sort began experimenting with stabilizing wood that was either rotten, pithy, or unable to be used. This began mostly because a lot of the "unusable" wood or bacteria ridden species are nice to look at. most of this had to do with two part polyester urethanes. (fiberglass resin)

Fast forward 20 years to the 90's when the chemistry behind acrylics/plastics had come a long way. substances became available that will transform a flawed piece of wood into a stable, flexible, and resilient top grade choice.

In the 90's my father did his research and began making a synthetic (acrylic) ivory, pearl, and bone for the gun, knife, and guitar industries. (among others)...

The resin itself is purchased in 55 gallon drums, and poured into 3x3 foot molds ranging from .25-1.0" thick. Once hardened... It can be cut easily, milled, and made into one of millions of products. Its been used in many areas, ranging from Gibson guitar inlay, to colt factory 1911 grips.

I grew up around all of this, and began working wood at an early age. I began buying woods from all over the world using ebay, and noticed quickly that a lot of the nicest burls and spalts were too light and unstable. So I discovered and began buying "Stabilized" woods from knife suppliers. This did OK... but you never knew what you would get. So I began experimenting and asking around.
I tried several types of acrylic, and developed a very successful process.

It wasn't until I found THE acrylic (still used today) that I was totally satisfied.

The process, basically goes like this......

 

-Cut lumber to desired dimensions. (no more than 2" THICK)

-Submerge in acrylic inside of a vacuum/pressure pot

-Pull vacuum on wood and release several times.

-Put pressure on wood to finish saturation process.

-Remove from pot, wipe excess, and bake at 150 degrees for 35min

 

This gives a very stable, lightfast, UV protected, and FLEXIBLE final product.

I tested a lot of acrylics. This particular acrylic will allow several inches of deflection on cross grained Engelmann spruce.  It will transform a fragile piece into a flexible and unbreakable final product.

 

I have several very high end bows that I have collected over the past 12 years, that had BAD tips. Though "some" of the originality is in the tips... they have been repaired, pinned, splined, and re-broken several times.
if stabilized they would gain almost NO weight, and the broken pieces would join together as one. It took me a long time to figure out how to stabilize un-porous and oily woods like pernambuco.... but IT IS possible.

 

This would also allow you to craft a bow out of softer and lighter woods, then stabilize them with acrylic.

No reason to attack me for a "crazy"..... Its just a thought and I wanted to take the time to write it down, and figured I might as well share.

 

50 years ago if you were to waltz into an instrument shop with a carbon fiber bow and told them what it was made from they would have laughed you out of the building.

 

Link to post
Share on other sites

Ummm, nowhere in your description do I see either "THE acrylic" (as well as its source) specifically identified or "how to stabilize un-porous and oily woods like pernambuco" explained.  Was that an oversight?  :) 

Link to post
Share on other sites

I have not done any further testing on speed of sound or dampening.

 

In response to THE acrylic, and the process to stabilize oily and un-pours wood.... I would rather not post the type of resin, simply because I still provide a lot of stabilized woods for the gun, knife, and pen industries.  And the chemistry is 90% of the work figuring out how to make the best product and at a profitable margin. I literally tried over 20 different resins to find something with the flex, UV protection, stability, and heat cure that I was looking for. This company makes over 5000 resins all VERY similar.... but giving very different results. It costs between $50 and $200 a gallon considering which one you choose, and I normally purchase it 55 gallon drums. So I like to see a return on my investment.

 

I will be glad to share the resin privately you or anyone else would like to know you can PM me.  

 

On the topic of stabilizing oily and difficult woods. Lets just say it has to do with heating, and vacuuming the woods with solvents, so that they release most of their oils and are in need of some type of bonding agent.

Link to post
Share on other sites

"if stabilized they would gain almost NO weight"

 

What do you consider "almost no weight"? Bows are very sensitive to added tip weight. If you're not adding weight, you're not adding plastic. Pernambuco is quite dense, and you may not be able to actually get any plastic to where it's needed. I don't know what this would do for the value of an already severely damaged, and devalued bow (might actually improve it). As for making new bows out of acrylic impregnated wood- It would depend on whether you could get the weight and flex correct. Ability to work it with hand tools would also be very important! I think that most pens and gunstocks are almost all worked with power tools (lathes, drills, routers, mills).

 

Keep us informed!

Link to post
Share on other sites

I have not done any further testing on speed of sound or dampening.

 

In response to THE acrylic, and the process to stabilize oily and un-pours wood.... I would rather not post the type of resin, simply because I still provide a lot of stabilized woods for the gun, knife, and pen industries.  And the chemistry is 90% of the work figuring out how to make the best product and at a profitable margin. I literally tried over 20 different resins to find something with the flex, UV protection, stability, and heat cure that I was looking for. This company makes over 5000 resins all VERY similar.... but giving very different results. It costs between $50 and $200 a gallon considering which one you choose, and I normally purchase it 55 gallon drums. So I like to see a return on my investment.

 

I will be glad to share the resin privately you or anyone else would like to know you can PM me.  

 

On the topic of stabilizing oily and difficult woods. Lets just say it has to do with heating, and vacuuming the woods with solvents, so that they release most of their oils and are in need of some type of bonding agent.

 

Thank you for your answer.  It appears to me that your process is producing an engineered composite material of naturally aligned wood fibers in an acrylic matrix rather than "treating wood", not necessarily a bad thing at all. The engineering homework needs to be done, however, so that the properties (which will depend hugely on both the woods used as well as the process parameters) may be known and published as applications documentation.  A violin or bow, unlike a knife grip, is a dynamic system.  :)

Link to post
Share on other sites

I can easily dye the acrylic a matte black and stabilize basswood... It would transform into something harder than ebony, but easier to work with hand tools. Imagine how easy it would be to carve a fingerboard out of basswood before it was stabilized, and then stabilize and touch it up with abrasives

Link to post
Share on other sites

I can easily dye the acrylic a matte black and stabilize basswood... It would transform into something harder than ebony, but easier to work with hand tools. Imagine how easy it would be to carve a fingerboard out of basswood before it was stabilized, and then stabilize and touch it up with abrasives

Several things:

I don't think it would need to be matte. Some good quality ebony will polish up quite nicely.

Most of us would like it best if it will cut well with a plane. Abrasives are quite cumbersome for some of the shaping and fitting we do.

Would it be porous at all? If so, that might increase the likelihood that we could use customary adhesives.

Link to post
Share on other sites

Hull is blowing some smoke.  Big secret--hush, hush.  Can't reveal anything, but Hull has discovered a miracle product.

 

Here is reality:  Minwax makes a wood hardener for sale--can you believe it?!  It is actually for sale!   I think it is an acrylic dissolved in ketones.  Good luck with that idea that there is no increase in density or final weight after using this stuff. 

 

Anything to that warning on the can that continued use will result in brain damage? 

 

Mike D

Link to post
Share on other sites

Some people have been using phenolic resin for finger boards, pegs and frogs rather than ebony. You may be familiar with the counter tops form back in the days of high school chemistry class. It absolutely destroys your tools. 

 

I think one of the reasons that ebony has been a popular wood is because of it's consistently small pores. We are lucky enough to live near Keim Lumber in Amish Town, Ohio which is essentially like a Cabela's for wood workers. They have a great exotic wood section there that we browse, we're always looking for alternatives to ebony and pernambuco. We might pick up a piece here and there but it always seems like it is too weak, or the pores are too big or the sound just doesn't travel through the wood very well. There are a couple woods that we have found that work well as substitutes but they don't have a standard name and when we ask for this specific kind of wood there may be 3 or 4 different types that come up with the same name. 

 

Anyway, what I'm trying to get at is that with a wood that is as dense as pernambuco how would you laminate (which is what it sounds like you're doing) it and be able to assure the customer that it is going to stay in one piece over time? My dad made a laminate bow (with a 4g thumb drive in the frog) out of thin laminated pieces of wood, he has gotten several inquiries about having another made or selling his but he won't because he can't guarantee that it will stay in one piece. 

 

What kind of long term testing has been done with this type of material? Do you think it will stand the test of time or should we just hope it holds up until after we've retired?

Link to post
Share on other sites

Very interesting thoughts everyone. It isn't pourus at all after the stabilization is complete. And I'm fairly certain that the "minwax" off the shelf product is not a two part... neither is it heat activated. If your counting on something to cure correctly, and most importantly.... ALL THE WAY THROUGH evenly and thoroughly.... then it needs to be two part chemically activated BY HEAT.

This is based on chemistry and chemical makeup. I am no chemist..... but I can tell you that if it were available off the shelf, or the "minwax" product was even remotely similar to what is used in the actual procedure..... more people would know about it.

Some people....

Link to post
Share on other sites

Hull is blowing some smoke.  Big secret--hush, hush.  Can't reveal anything, but Hull has discovered a miracle product.

 

Here is reality:  Minwax makes a wood hardener for sale--can you believe it?!  It is actually for sale!   I think it is an acrylic dissolved in ketones.  Good luck with that idea that there is no increase in density or final weight after using this stuff. 

 

I can understand if he has a lot of time and money wrapped up in testing different resins and methods, and would like to be able to recover some of this. And I think a solvent-borne resin is quite different from what he's describing. Besides, I'd much rather buy a viable finished blank, than have a vacuum/pressure chamber (or soak wood in a solvent-based hardener) and go through the process myself. I don't have the time or the space.

 

What I would care about is having a viable product which can be used and tooled in a manner close to what we're accustomed to.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Recently Browsing   0 members

    No registered users viewing this page.