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epoxy question

john lucas

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a friend gave me this piece of wood along with a lot of other great wood. I want to make an ornament out of it. I'm thinking of filling all tge voids with epoxy. I'm not an epoxy guy. I've filled a lot of cracks but usually on flat wood. I don't have a pressure pot. can I fill all these voids without one. I will be using West system 195 with their 205 clear hardener. it's pretty thin and very slow drying. all tips and suggestions welcome.
 

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The answer is yes you can. I use epoxy and mica quite often, not the west system epoxy though. My method for something that looks like yours would be to clean out any junk (dirt), use a hot melt flue to build up a dam around the area to be filled so the post fill area will be flat, mix up about one ounce of epoxy, SLOWLY fill the void. After the epoxy solidifies, rinse and repeat for all the voids you need filled.
 
Vacuum or pressure pot are used to get the bubbles out of the resins or make them so small they can’t be seen.
If you don’t mixi in bubbles you won’t need a pressure pot.

If you are worried about bubbles you could probably rig a vacuum chamber easily from a big pot and a wooden lid.
Probably 5-10 minutes of vacuum to pull the bubbles out.

You do need to research how thick various resins can be poured.
 
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John, if you use a dye to color the epoxy then you don’t need to worry about bubbles. I would go with a fast setting epoxy. I recommend TransFast black powder dye. You could also use TransTint liquid dye, but only a small amount. Rockler Hardware has a new product that I haven’t tried, Mixol concentrated liquid dye that they claim can be mixed with anything.
 
a friend gave me this piece of wood along with a lot of other great wood. I want to make an ornament out of it. I'm thinking of filling all tge voids with epoxy. I'm not an epoxy guy. I've filled a lot of cracks but usually on flat wood. I don't have a pressure pot. can I fill all these voids without one. I will be using West system 195 with their 205 clear hardener. it's pretty thin and very slow drying. all tips and suggestions welcome.
Hi John
I do this kind of thing all day everyday. That piece is a great candidate for epoxy. Sorry to say it will be difficult to do cleanly without a pressure pot. Those cracks go very deep and probably all the way through the diameter of the piece in many spots.

If you can find a similar sized container to use as a form, that’s your best bet for getting most of the voids filled with west systems. Maybe a tennis ball can, or pringles can? Without pressure, there’s a 98% chance you’ll find unfilled voids once you turn it. These can be filled one at a time but it’s a major time suck.

Without pressure, depending on your design idea, I’d be more inclined to turn the piece to close to its final shape and then use a putty type of epoxy (milliput eg) crammed into the cracks then final turned.

If you’re looking for the piece to be hollow and allow light to go through the translucent epoxy, try to find a fellow turner with a pressure pot. If you want it to be a solid piece, epoxy putty is probably the way to go.
 
John, if you use a dye to color the epoxy then you don’t need to worry about bubbles. I would go with a fast setting epoxy. I recommend TransFast black powder dye. You could also use TransTint liquid dye, but only a small amount. Rockler Hardware has a new product that I haven’t tried, Mixol concentrated liquid dye that they claim can be mixed with anything.
Hi Bill
You are correct that the visual effect of bubbles can be fairly well mitigated by dark, opaque coloring, but in this specific piece of wood, the challenge will be getting the resin into the deepest parts of the cracks. There will be large voids that the resin won’t reach that will be exposed once the turning commences.

If interested in a review, Mixol is a very good coloring agent but it isn’t particularly translucent like trans-tint brand. There’s a lot of colors available and is a worthwhile product.
 

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If interested in a review, Mixol is a very good coloring agent but it isn’t particularly translucent like trans-tint brand. There’s a lot of colors available and is a worthwhile product.

After some searching, I discovered that Mixol is a pigment, so it is best used as a stain. You also have to buy a set of 12 colors for $75.
 
I like to use the bag and duct tape method for pieces that are round. Put it in a bag and add a little resin in the bottom. Start wrapping the bag with duct tape from the bottom up and add more resin as needed. This works great for hollow vessels to just put a second bag inside and pack it with sand or marbles.
 
Great tips, thanks. I was planning to color it with TransTint dyes. I do have Milliput epoxy putty left over from my article on making a zig-zag ornament, so I might consider that option.
 
A thrift store pressure cooker can make a useful vacuum or pressure vessel. Only problem is you can't see inside to monitor.
 
A vacuum bag might help to remove the air bubbles. I've only used them for applying pressure but I think removing air bubbles is a side effect. The guy who posts the Blacktail studios videos uses a propane torch to remove air bubbles but the voids in his tables are bigger than the voids in the blank in the photo.
 
I use West System epoxies a lot for pieces like these. The advice to use hot melt glue to form a dam is good - but be prepared for many leaks. It’s a long process, so plan for a couple of days - the low viscosity of West Sys allows it to penetrate fully, but it also finds any openings you may not see. I spend some time closing up anything suspicious before the pour. And top off the pour as needed until the epoxy starts to gel.

There’s always a few small voids that need attention once turning starts, but easily handled with ca or epoxy. I usually use System Three coloring additive (black)
 
Coloring the resin won't eliminate the bubbling issue. A pressure vessel seems to be favored for small pieces, compressing and entrapping the bubbles in the cured resin. Vacuum is worth a try but you will probably use a lot of expensive resin. Maybe you could put your workpiece in a slightly oversize plastic bag inside a vacuum bag or chamber., if so experiment with a small piece first. I used to fill voids in turnings with marine epoxy and ambient air pressure but gave up due to bubbling and leaking. I have used epoxy extensively for filling voids in flatwork and found that with sufficient overfilling the bubbles would migrate upwards and could be planed off above the wood surface. With turnings that would require multiple filling sessions. If you do wind up with small voids in the epoxy fill it is tedious and almost impossible to get rid of them, at least in my experience. Secondary CA fills don't quite blend in and trowelling on more epoxy never quite works for me. Maybe it will for you. Now I just accept the natural voids as they are, but I am not really into working with plastic.
 
a friend gave me this piece of wood along with a lot of other great wood. I want to make an ornament out of it. I'm thinking of filling all tge voids with epoxy. I'm not an epoxy guy. I've filled a lot of cracks but usually on flat wood. I don't have a pressure pot. can I fill all these voids without one. I will be using West system 195 with their 205 clear hardener. it's pretty thin and very slow drying. all tips and suggestions welcome.
John, off-topic, did you rebuild some of the dog holes in your bench? I see a dog hole in the photo that looks like it has been enlarged and fitted with an insert. There are a few dog holes in my bench that don't like to grab holdfasts anymore so I wonder if you have any tips about the repair.
 
John, off-topic, did you rebuild some of the dog holes in your bench? I see a dog hole in the photo that looks like it has been enlarged and fitted with an insert. There are a few dog holes in my bench that don't like to grab holdfasts anymore so I wonder if you have any tips about the repair.
Yes, I did. This workbench is forty years old. It was an outdoor door to a photo processing lab I worked in. The place burned and the owner closed the business. He said I could have the door. I cut off the vent that was on the bottom. Several holes were elongated after all these years of using Holdfasts. Maybe that's not a word but you know what I mean. I have one of those drill guides that uses a hand drill. I plugged the holes with a ¾" dowel. Then I put a Forstner bit larger than the final hole in and drilled through. Then plugged it with a turned plug of that diameter. I think it was 1¼" Then drilled again with the ¾" drill to fit my holdfasts. Without that drill guide, it would have been difficult. you can buy those at flea markets if you keep your eyes open.
 
Yes I did. This workbench is 40 years old. It was an outdoor door to a photo processing lab I worked in. The place burned and the owner closed the business. He said I could have the door. I cut off the vent that was on the bottom. After all these years and using Hold fasts several of the holes were allongated. Maybe that's not a word but you know what I mean. I have one of those drill guides that uses a hand drill. I plugged the holes witha 3/4" dowel. Then I put a forsetner bit larger than the final hole in and drilled through. Then plugged it with a turned plug of that diameter. I think it was 1 1/4" Then drilled again with the 3/4" drill to fit my holdfasts. Without that drill guide it would have been difficult. you can buy those at flea mkts if you keep your eyes open.
Ok, so the sacrificial dowel keeps the bit centered and the turned plug is probably cross-grain so that it matches up with the bench. I hadn't thought of the dowel. I have a drill guide but it doesn't work as well as I hoped so I use a plunge router to start the dogholes. I was wondering whether it would be easier to drill out the turned plug on the lathe or in the bench. Sounds like you did it in the bench. Thank you for the advice.
 
Coloring the resin won't eliminate the bubbling issue.
Didn’t mean to suggest that it would. I use colored (black or brown) epoxy because it looks better (to my eye) than natural or near clear color that most epoxies cure to. Any bubbles within the epoxy are not an issue if it is opaque. Only those that rise to the surface and leave a crater behind are problematic, but easily fixed with another application before finish sanding is done.
 
How long does the epoxy bond last in contact with wood? Anybody have pieces done many years ago that still look as good as on day one? Wood moves seasonally, how does that affect the resin bonding? What about UV exposure? I have the same concerns about the longevity of CA glues.
 
How long does the epoxy bond last in contact with wood? Anybody have pieces done many years ago that still look as good as on day one? Wood moves seasonally, how does that affect the resin bonding? What about UV exposure? I have the same concerns about the longevity of CA glues.
I have seen and "felt" depressing discontinuities between various fillers (epoxy, metal powder, etc) in older pieces done by others. Sometimes the wood appeared to have shrunk and I could feel the filler "proud" of the surface suggesting a separation, sometimes there was even a visible gap. That's one reason I prefer to not fill voids, unless they are small.
(I've filled narrow groves with things like brass powder held with CA glue and they have held up so far. I've also filled small, stable cracks by wet sanding with fine CA glue, but that fills the gap with a lot of wood particles.)

I suspect the answer depends on several things: the type of epoxy or filler, the type and thickness of wood, the starting and storage moisture content, the environment where the piece has been kept, etc. Perhaps some epoxies are more flexible than others.

The piece, of course, should be "well dried" before filled but at what EMC?

JKJ
 
How long does the epoxy bond last in contact with wood? Anybody have pieces done many years ago that still look as good as on day one? Wood moves seasonally, how does that affect the resin bonding? What about UV exposure? I have the same concerns about the longevity of CA glues.
As long as the wood is dry when bonded to epoxy and doesn't undergo a huge change in moisture content in service the bond is quite stable over time. Of course marine epoxies like West System have not been around forever, but there are many cold-molded boats still in service after decades of use. I have built scores of doors joined with epoxy and filled many a knot and taphole that are in fine shape after decades. With a piece like John's most of the wood fiber is encapsulated in epoxy which is a very effective moisture barrier. UV is a real issue for work exposed to the weather, much less so for interior work, and a UV resistant coating is recommended for work that sees much sunlight.
 
The piece, of course, should be "well dried" before filled but at what EMC?

JKJ
The moisture content should be compatible with the environment expected in service. Around here EMC in an unheated shed may be 12-15% whereas in a (non-AC) residence it might run 5-10% over the course of a year. I try to work with material around 7-8%. The bigger the discrepancy the more likely problems will ensue.
 
suspect the answer depends on several things: the type of epoxy or filler, the type and thickness of wood, the starting and storage moisture content, the environment where the piece has been kept, etc.

The bigger the discrepancy the more likely problems will ensue.

Yes, that's the answer to the big question about the effect of moisture. Difficult or impossible to predict or control if or when the piece leaves the shop.

JKJ
 
How long does the epoxy bond last in contact with wood? Anybody have pieces done many years ago that still look as good as on day one? Wood moves seasonally, how does that affect the resin bonding? What about UV exposure? I have the same concerns about the longevity of CA glues.
So far, forever… in 15 years I’ve ever only had one come apart. That failure was an experiment on my part to see if this particular design I had in my head would actually work. It did stay together for about nine months and then popped off…. Epoxy is just flexible enough to move with the wood as it moves. I exclusively use boat making epoxies.

I made a 9’ long kitchen island a full 4” thick and the bond is exactly the same as when I built it. (5 years ago)

I’m convinced that preparing the wood area that is to be in contact with the epoxy is the key for me and my work.

Once the epoxy is in/on the piece, that part of the wood is entombed and basically impervious to any moisture content changes and therefore exceptionally stable.

UV light changes the color of the epoxy over time (yellowing) and probably does weaken the epoxy over time but we’d be talking about a decade or more of being outside all the time. The sun always wins.IMG_1932.jpeg
 
How long does the epoxy bond last in contact with wood? Anybody have pieces done many years ago that still look as good as on day one? Wood moves seasonally, how does that affect the resin bonding? What about UV exposure? I have the same concerns about the longevity of CA glues.
resin filled gaps hold up well. I have done inlayed rings and did a platter with an epoxy outer ring. both came loose within about 10 years. wood movement is of course the culprit.
 
Epoxy likes rough surfaces. I had some epoxy bonding failures in flat work until I wised up. Sawn or 80# abraded joint surfaces promote a strong grip.
 
Epoxy likes rough surfaces. I had some epoxy bonding failures in flat work until I wised up. Sawn or 80# abraded joint surfaces promote a strong grip.
That's an excellent point to remember. I rough up almost everything I glue with epoxy - sometimes with coarse paper, sometimes with a scratch awl, and sometimes with a small file or dremel (for example when epoxying metal to wood.)

JKJ
 
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