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Old 10-31-2019, 09:07 PM   #1
memosub
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oil finish on mahogany guns

Hi friends, someone has good results with oil finish on mahogany guns? some tricks or tips please
thanks
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Old 10-31-2019, 11:10 PM   #2
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Re: oil finish on mahogany guns

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Hi friends, someone has good results with oil finish on mahogany guns? some tricks or tips please
thanks
tung oil : coups:: coups: 5 layers minimum
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Old 11-01-2019, 05:09 AM   #3
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Re: oil finish on mahogany guns

The old way or the new way.
Old way, it lots of coats, hand rubbed, tung oil.
New way, build a vacuum chamber ( PVC pipe works well) insert wood and oil and pull a vacuum. The oil will really penetrate deep, remove and polish off the excess.
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Old 11-01-2019, 06:10 AM   #4
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Re: oil finish on mahogany guns

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The old way or the new way.
Old way, it lots of coats, hand rubbed, tung oil.
New way, build a vacuum chamber ( PVC pipe works well) insert wood and oil and pull a vacuum. The oil will really penetrate deep, remove and polish off the excess.
Sorry,
I do not know the new method :rouler des yeux:
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Old 11-01-2019, 07:42 AM   #5
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Re: oil finish on mahogany guns

If your only doing one gun, the old way is the most reasonable way. The cost to set up and do a vacuum chamber for one gun would be a big deterrent, not to mention space to store it all.
Doing it the old way, strip the gun to bare wood (no parts on it). Sand kinda smooth, apply a thick wet coat, let set and soak in BUT DO NOT LET IT DRY wipe off till polished. If you let the thick coat dry it will turn gummy/tacky/shitty and cause you lots of extra work. Let the polished wood dry over night and repeat the process, again and again, till it no longer takes the new oil.
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Old 11-01-2019, 10:49 PM   #6
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Re: oil finish on mahogany guns

I like the new way. Yes. Positive results Mahogany.
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Old 11-02-2019, 12:09 AM   #7
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Re: oil finish on mahogany guns

I think you guys might have to explain the new way more, it sounds really interesting

Thing is, if you pull vacuum too long, you can end up impregnating so much oil into the wood, you risk ending up with a negative gun, right?
So, how do you do it? You still use an oil bath fully covering the blank, right? And then just give it a few mins under vacuum?

What do you use for the chamber? I guess PVC pipe would be a cheap, easy way to do it. You can even get screw-in caps for them.

I guess the only downside is that you would need quite a bit of oil to make a full bath, instead of just a small bottle, but if you are a gun builder that's not an issue.

I've talked elsewhere about how an old discarded fridge compressor makes one hell of a vacuum pump and so does the small, cheap, Chinese HVAC pumps for anyone wanting to get started with vacuum bagging (or as here, wood impregnation) on the cheap. Also, for you US based folks, Gast vac pumps often come up second hand on Ebay and I think most (all?) of them are still supported in terms of getting replacement seals for them.

Last edited by Diving Gecko; 11-02-2019 at 12:24 AM.
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Old 11-02-2019, 01:12 AM   #8
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Re: oil finish on mahogany guns

Somehow a brush seems much easier and use repeat applications. I had some timber infused with resin in a pressure chamber in a commercial process and that turned it into a heavy object that would not float, but being a grip handle that did not matter so much. As mahogany tends to dent I would rather paint it with marine varnish rather than oil it. Marine spar varnish that stays flexible, but is dry to the touch (eventually).
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Old 11-02-2019, 09:33 AM   #9
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Re: oil finish on mahogany guns

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Originally Posted by Diving Gecko View Post
I think you guys might have to explain the new way more, it sounds really interesting

Thing is, if you pull vacuum too long, you can end up impregnating so much oil into the wood, you risk ending up with a negative gun, right?
So, how do you do it? You still use an oil bath fully covering the blank, right? And then just give it a few mins under vacuum?

What do you use for the chamber? I guess PVC pipe would be a cheap, easy way to do it. You can even get screw-in caps for them.

I guess the only downside is that you would need quite a bit of oil to make a full bath, instead of just a small bottle, but if you are a gun builder that's not an issue.

I've talked elsewhere about how an old discarded fridge compressor makes one hell of a vacuum pump and so does the small, cheap, Chinese HVAC pumps for anyone wanting to get started with vacuum bagging (or as here, wood impregnation) on the cheap. Also, for you US based folks, Gast vac pumps often come up second hand on Ebay and I think most (all?) of them are still supported in terms of getting replacement seals for them.
You can't pull too much vacuum and get too much oil in the gun. When you pull the vacuum, air is pulled out of the space between the fibers in the gun. When the vacuum is released, oil replaces the air. Further attempts at vacuuming more air out won't be very successful since you just pull the oil out, not more air, and longer times with the vacuum on the gun won't matter either since the pressure inside the gun and outside (but inside the vacuum chamber) reach equilibrium within a few minutes.

If you only plan on doing one gun, building a vacuum chamber is a lot of effort and some unnecessary cost for just one gun, and wiping with oil will do just as good, but the oil won't penetrate as deep. Either way, the oil won't go very deep (like 1/8" or less, depending on the wood). The small vacuum pumps used for evacuating auto and home ac units work great, and I've used the kind that pull a vacuum by using compressed air to educt- they work, but not as well, and are cheap.

To do a typical gun, you will need about 1.5- 2 gallons of oil, and tung oil is expensive, so that's a big downside to using a vacuum system. You won't consume very much oil (a couple of ounces), so the oil would last a long time, but if you're only doing one gun... By the way, whichever method you use, only use 100% tung oil, with no additives. Otherwise you have no way of knowing what is in the oil, or even what the oil is. Some mixes have wax, or even varnish, which will seal the pores of the gun on the first coat and prevent any further penetration from additional coats.

If you are going to oil a lot of guns, a vacuum chamber is great because in 30 minutes or so you are done. If you're only oiling one or two, all you need is about a 1/2 pint can of 100% Tung oil and some soft rags and you're good to go.

An old refrigeration compressor is probably not a good idea. The system will have lubricating oil in it, which is hard to get out, and could contaminate your tung oil. Tung oil isn't a very good lubricant so the longevity of the compressor without lubricant would be an issue.

However you decide to finish the gun, prep is important. An oiled gun will only have that beautiful deep lustre if it' pre-sanded very smooth with 325 or even 400 grit sand paper.

If you decide to build a vacuum chamber. I'll be happy to share the specs on the one I built.
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Old 11-02-2019, 09:40 AM   #10
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Re: oil finish on mahogany guns

Thanks so much for elaborating.
But... I may have to disagree on the "not possible to get too much oil into the blank" thing;-). At least in theory, as granted, I have never done wood impregnation but I have seen some guys online impregnate a wooden mallet and then cutting it apart afterwards and it looked impregnated to the core - and thus, heavy. Maybe their wood was more porous, the resin way thinner and possibly they pulled vacuum for a whole lot longer than you do. Also, Pete just mentioned that the one time he had it done, his wooden part was a sinker after the impregnation which leads me to believe you may have to limit how long you pull the vacuum. Then again, perhaps tungoil is so thick there's it seals itself off before it gets too deep into the part.

As for the oil in the compressor you are absolutely right that there is a risk of contamination. But with one added valve and some discipline in the order you turn the pump and valve on/off and bleed the system, you can avoid the oil being sucked back into the chamber (or vac bag). That said, you are totally right - the risk is there. Same with the HVAC pumps, they are not oilless, either. And def something to keep in mind if people wanna do this on the very cheap. I should perhaps have mentioned that, so great you brought it up. One more reason to go look for a good secondhand Gast as they are often (or always?) oilless.

Last edited by Diving Gecko; 11-02-2019 at 10:50 AM.
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Old 11-02-2019, 11:44 AM   #11
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Re: oil finish on mahogany guns

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Originally Posted by Diving Gecko View Post
Thanks so much for elaborating.
But... I may have to disagree on the "not possible to get too much oil into the blank" thing;-). At least in theory, as granted, I have never done wood impregnation but I have seen some guys online impregnate a wooden mallet and then cutting it apart afterwards and it looked impregnated to the core - and thus, heavy. Maybe their wood was more porous, the resin way thinner and possibly they pulled vacuum for a whole lot longer than you do. Also, Pete just mentioned that the one time he had it done, his wooden part was a sinker after the impregnation which leads me to believe you may have to limit how long you pull the vacuum. Then again, perhaps tungoil is so thick there's it seals itself off before it gets too deep into the part.

As for the oil in the compressor you are absolutely right that there is a risk of contamination. But with one added valve and some discipline in the order you turn the pump and valve on/off and bleed the system, you can avoid the oil being sucked back into the chamber (or vac bag). That said, you are totally right - the risk is there. Same with the HVAC pumps, they are not oilless, either. And def something to keep in mind if people wanna do this on the very cheap. I should perhaps have mentioned that, so great you brought it up. One more reason to go look for a good secondhand Gast as they are often (or always?) oilless.
I've only done a half dozen guns with the vacuum system, so not a lot of experience, I admit. I am curious, however, as to what "theory" you are using that indicates you can impregnate a gun (or mallet) to it's core. The vacuum pump I use pulls pretty close to a perfect vacuum, and I've held the vacuum for as much as 45 minutes. You can actually hear the air coming out of the wood since it comes out into the oil as bubbles. I'm sure the density (porosity, actually) of the wood makes a difference- all the guns I've done were teak. The bubbles quit after about 20 minutes. I haven't figured out a way to tell how long it takes for the oil to soak into the gun, but I'm assuming that since the differential pressure is the driving force for the oil, it's pretty much over a few minutes after the pressure in the chamber returns to atmospheric. I use the tung oil at full strength, so I can see how it would go further into the wood if thinned with a solvent such as mineral spirits, but then you'd be dealing with what happens to the solvent that has been impregnated into the wood with the oil.

I've measured the amount of oil used, and it was 1.5-2.0 ounces for each gun, and that included the amount wiped off the wet gun. At a density of .93g/ml, that's not a lot of weight . If that makes a gun a sinker, it was pretty close to neutral to begin with.

Maybe some others who have used the vacuum method have some info they would be willing to share.
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Old 11-02-2019, 11:54 AM   #12
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Re: oil finish on mahogany guns

Could very well be that the viscosity has a lot to say and that the two examples I referred to were done with a much thinner resin. So, not referring to a "theory" (that was a figure of speach - I am not a native English speaker) but only to two examples that had stuck in my memory. Also, not mahogany or teak in the first one though I don’t know what wood Pete’s gun part was made out of.
Seems like it’s safe to say that with your experience of pulling a long vacuum it’s not an issue with the types of wood and tung oil used in spearguns. Sorry for the false alarm but thanks for allowing me to voice the concern.


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Old 11-07-2019, 04:36 AM   #13
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Re: oil finish on mahogany guns

A cheap, easy, and durable finish is beeswax. I coated a mahogany gun with beeswax in 2010 as an experiment and have been pleased with the outcome. It does require periodic re-application on a similar interval to re-oiling a teak gun, maybe every 10 dives or so. I picked up a 1 pound block of beeswax in a thrift store for $1. Cut the top half off an aluminum can and shave off pieces of the beeswax and put them in the can. Put the can in a pot of boiling water and when liquid, paint on the gun with a chip brush. After the gun is fully coated and has a thick film on it, move the pot and turn the burner up to high. Slowly pass the gun over the burner and the heat will re-melt the wax and draw it into the gun. Repeat the process 2-3 times rubbing with a cotton rag.
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Old 11-07-2019, 03:24 PM   #14
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Re: oil finish on mahogany guns

Interesting facts about Tung oil, https://en.wikipedia.org/wiki/Tung_oil
Never thought about it originating in China.
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Old 11-08-2019, 10:00 PM   #15
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Re: oil finish on mahogany guns

Teak oil does a fantastic job. Just follow the instructions on whatever can you buy, they can be a little different. I do multiple coats then start dipping 600 grit sandpaper in the oil and brushing on the last thin coat or two. Does great.
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