Author Topic: Oil Impregnation  (Read 6914 times)

Offline LagrueCustomCalls

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Oil Impregnation
« on: February 16, 2017, 06:01:45 PM »
Had a fun conversation with Ryan Roosa at Reelfoot about oil impregnation in certain kinds of wood. To that end, I've been working on that process in my shop.

I have a vacuum rig that I built many years ago for laying up composite parts. Unfortunately, the setup does not quite pull as much vacuum as I'd like right now, however it is fully automated. It uses an industrial Gast vacuum pump, along with a Dwyer photohelic vacuum switch to control things. Set the vacuum that you want and walk away. As the vacuum bleeds off, it will hit a point I set and then kick on the point until it hits the vacuum level I set and the pump turns off.

My container right now is a glass jar. Have been impregnating certain woods with teak oil. Even with the lower vacuum, I'm getting a lot of penetration by keeping the vacuum on for a good while.

I'm pretty happy with the results so far. I tested calls done with this process this winter and liked what it did for the interior of the barrels of oil finished calls.

« Last Edit: February 16, 2017, 06:05:47 PM by LagrueCustomCalls »
There's a duck call in that block of wood. I just have to find it!

Offline Jeff @ Mutt Calls

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Re: Oil Impregnation
« Reply #1 on: February 17, 2017, 08:50:58 AM »
There was a conversation in the Turkey Call section recently where this was discussed.  Vacuum impregnation a call with oil.  I think it was Mr. Fred that mentioned a concern with the impregnated oil not drying completely after the exterior of the call dries?  What is your experience with this issue, if any?

Jeff
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Offline LagrueCustomCalls

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Re: Oil Impregnation
« Reply #2 on: February 17, 2017, 10:37:39 AM »
I think it is a valid concern, but i have not had any issues thusfar. I should read that thread.
There's a duck call in that block of wood. I just have to find it!

Offline BigB

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Re: Oil Impregnation
« Reply #3 on: February 19, 2017, 09:07:16 PM »

I do this on all of my wood calls, but I use Velvet oil.

Brian
You won't get money rich in this hobby.  The richness is in the culture, the craft, the friends you meet along the way, and being able to call in a wary game animal with a call that you made with your own hands.

 

Offline LagrueCustomCalls

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Re: Oil Impregnation
« Reply #4 on: February 19, 2017, 10:15:27 PM »
Thanks for the input Brian!

Good to see you this weekend too!
There's a duck call in that block of wood. I just have to find it!

Offline MadTrapper

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Re: Oil Impregnation
« Reply #5 on: February 20, 2017, 02:09:50 PM »
I'm curious, what are the advantages (besides time I presume) of this method over submersing a call in oil for a week or two?  At some point can it be assumed that a call will naturally absorb the same amount of oil simply by submersion? 
"The power of accurate observation is commonly called cynicism by those who have not got it". - George Bernard Shaw

Offline Jeff @ Mutt Calls

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Re: Oil Impregnation
« Reply #6 on: February 20, 2017, 02:48:56 PM »
I assume the removal of entrapped air via the vacuuming process would allow a deeper penetration of oil vice just soaking.  Soaking for a while would surely allow more penetration than a few coats of "wiping on" but not nearly as much as extracting air under vacuum and allowing to soak/penetrate?  I have no data to back up my theory, but I imagine similar results if you were to "just soak" a piece of wood in "Brand X" stabilizing resin.  You could soak it, but not get the same penetrating results as you would pulling a vacuum first? 

Thoughts?
For it is in the Woods, Fields, & Marshes that Retrievers make thier own legends... and become our heroes!

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B Hoover

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Re: Oil Impregnation
« Reply #7 on: February 20, 2017, 10:43:45 PM »
Could be an interesting test there.  Soak a 1" thick piece of wood and vacuum another from the same blank; then cut them a week later to see what the difference is between the two.  Not too many calls out there have that much meat in them, but it would give you an idea of its potential.

Offline LagrueCustomCalls

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Re: Oil Impregnation
« Reply #8 on: February 20, 2017, 10:47:41 PM »
Jeff's description is pretty much spot on. By creating a vacuum in the piece, i.e. removing the air, the oil tries to fill the void. As a result, it goes very deely into the wood.

Could you get the same penetration using purely time and soaking? Depending on the wood, I bet you could get close, but it would be more than weeks to even get close. The process also would not be as repeatable/consistent.

Brent's suggestion is a good way to test it. I was thinking earlier if a way to measure penetration without cutting and considered doing a weight before and after. In this case, the weight delta would be the amount absorbed, and the difference between the two samples would tell the story.

There's a duck call in that block of wood. I just have to find it!

Offline Jeff @ Mutt Calls

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Re: Oil Impregnation
« Reply #9 on: February 22, 2017, 07:34:47 AM »
Go to the "Stabilizing Your Own Blanks" section.  Page 2, bottom of the page, "Discussion on vacuum pumps for stabilization" created  by Stelz on MAR 12, 2012. 

Curtis @ Turn Tex breaks it down with graphs/charts on this very discussion we are having here.  Excellent analogy based off professional experience.

Interesting read!

Jeff
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Offline gooseforsupper

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Re: Oil Impregnation
« Reply #10 on: February 25, 2017, 06:09:29 AM »
Hi gang!
Finding what I would call the best finish for a call has been a research project of mine for over a year now.  I am not interested in a fast finish, just the best possible waterproof durable finish to make a call last for generations.  Any of you following my outdoor finish test on Facebook "Call Nutz" are seeing the results.
First of all I am completely sold on pure tung oil.  Not the stuff you buy at the hardware store that is actually cut with petroleum distillates and is more of a varnish than an oil finish.  Pure tung oil has been used to waterproof wooden boats in China going back 2000 years.  Old school...  :yes:
The process is tedious to do it correctly, but the results are worth the effort.  Not for the production guys.
I have to get after Velvit Oil just a bit, as I see many people soaking calls in it, and my outdoor test shows it fails miserably. I once saw an MSDS sheet on it.  Almost 50% vegetable oil, actually I hear soy oil, and the rest petroleum distillates.  The distillates thin it enough for the soy oil to get into the pores and polymerize and seal the wood.  Only water resistant.

That said, let's talk penetration of the tung oil into the wood.  I do not sand past 400 grit so the pores in the wood remain open.  I want it to penetrate deep down.  To get that, I start with a 50/50 mix of pure tung oil and citrus solvent.  Non toxic, food safe, smells great, and boy does it penetrate.  Not unusual for it to bleed all the way through a call from the inside where the wood is just under 1/4 inch thick.  Here is what I am using:  Not cheap, but a little goes a LONG way.  I have done about 30 calls with this 16 oz. bottle.  That's with around 7 coats per call.
So, I brush the call inside and out.  You can see the wood soaking it up as you go, and the first coat really sucks it up. It will drip so you have to keep paper towels handy and catch them as it drips out.  TAKE THE TOWELS OUT OF YOUR SHOP IMMEDIATELY AND DISPOSE OF EITHER BY BURNING THEM, OR PUTTING IN AN AIR TIGHT METAL CANISTER DESIGNED FOR OILY RAGS.  YOU DON'T WANT TO BURN YOUR SHOP DOWN!!  Please remember that these oil soaked rags are very combustible if left out in the air.
After 45 minutes or so, I come back and completely wipe the call down inside and out with old t-shirt rags. THEN I GO BURN THOSE RAGS IMMEDIATELY.  Wait 24 hours and repeat the process.  and again and again and again until the wood will no longer soak up any more.  The wood will tell you as it will no longer have any dry spots when you come back to wipe it down.

Once I see the wood is completely saturated with the 50/50 mix, then I switch to the PURE tung oil.  It is best applied by hand rubbing it in, and heating up the oil to thin it works best.  I boil water on my stove, put it in a thermos bottle and head to the shop.  Then I take a cool whip plastic container, and pour in about a half inch of super hot water.  I put the tung oil in a baby food jar and set that in the water.  Kind of like a double boiler.  When the oil is almost too hot to touch, I brush it inside the call and then go back and dip my finger in the oil and hand rub it on the outside.  It's actually kind of fun and smells good too.  Same procedure, catch the drips, burn the rags, wait 45 minutes to wipe it down and burn the rags again.  You can rub as many coats as you like until you are satisfied with the finish.
Then you set the call aside for a 30 day cure.  The tung oil air cures and take 30 days to solidify.  Note, you will get a little bleed out especially with burl wood, and you MUST go back daily and hand rub in any bleed out you see.  if you do not, it will solidify on the outside of the call and leave a shiny spot that will stand out after curing.  I learned this the hard way... :eek:
Once cured, the tung oil dries to a completely flat finish, so I go back and wax the call with this:  It has a great color to it, is inexpensive and available at Woodcraft. 
Buff the call and enjoy.
It would be very interesting to see how far the 50/50 mix would penetrate in a vacuum chamber... ???
I hope this adds to the discussion, as I don't mind sharing what I am learning with all you call making buddies.  :punk:

B Hoover

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Re: Oil Impregnation
« Reply #11 on: February 25, 2017, 08:05:17 AM »
Wow, Doug!  I remember your post a while back about a new finish you liked, but now I see why you stated it was an exercise in patience.  Thanks for taking the time to post this.

Could we make this a sticky?  Lots of good info from Lagrue and Brian all the way to Doug.

Offline gooseforsupper

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Re: Oil Impregnation
« Reply #12 on: February 25, 2017, 09:50:39 AM »
Thanks!
I have been doing a batch of 10 calls for over a week now, so the process is fresh in my brain.  My neighbors must think I am some kind of pyromaniac because I am starting little fires twice every evening...  :whistling:

Offline LagrueCustomCalls

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Re: Oil Impregnation
« Reply #13 on: February 25, 2017, 10:48:17 PM »
Too funny! Doug, my I was in the backyard burning a couple rags in the fire pit and all of a sudden I hear the next door neighbor yell my name and ask if I knew there was a fire in my yard!  :rofl: Had to explain what I was doing...
There's a duck call in that block of wood. I just have to find it!

Offline MadTrapper

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Re: Oil Impregnation
« Reply #14 on: February 26, 2017, 12:07:09 PM »
Interesting stuff here...  I too like a traditional, non-glossy finish on my calls.  I too believe wholeheartedly in 100% pure Tung Oil.  (I've never used Velvet Oil so I don't know anything about it.)  I've not went to nearly the effort that gooseforsupper has but I very much like my finishing recipe.  It's simple and effective and doesn't involve burning nearly as many rags!

I mix 100% pure Tung Oil, (not the diluted or misrepresented garbage sold at the big box stores) along with 100% pure Gum Spirits of Turpentine and McCloskey's Gloss Spar Varnish.  1/3 (equal parts) of each ingredient mixed together in a jar.  Don't worry, the Gloss Spar doesn't produce a gloss finish with this mixture.  I only use McCloskey's Gloss because I've found it to be the best.  Why, I don't know, it just is.  For some reason, again I don't why, Gloss works better than Satin.   

I soak my calls in this for up to a week or so and then pull them out, wipe them off, and hang em for a couple more weeks.  In about 30 days or so the turpentine odor fades away.  The end result is a gorgeous traditional looking, water resistant finish that will last a very long time.   

I use a jar a bit larger than my largest call.  I take a piece of copper wire and bend it into a "V".  The point of the V goes into the call opening and the tips of the V push up against the top of the closed jar lid, effectively keeping the call submerged in the mixture.  The finish lasts a long time in the jar and is used over and over until it needs to be replenished.  Incidentally, it stays mixed and does not separate or settle out like varnish or stain does.

I wish I could take credit for coming up with this recipe but I can't.  I picked it up from someone much more knowledgeable than I am.  It was explained to me that with this recipe the turpentine becomes part of the finish so should not be substituted for Mineral Spirits.  Since Turpentine is made from tree resin, this tends to make sense, at least to me.  That is why using only 100% pure Gum Spirits of Turpentine is necessary.

Very simple and very effective. 
"The power of accurate observation is commonly called cynicism by those who have not got it". - George Bernard Shaw