Sealing HF for containing water

[Eric Holmquist]

Is it practical to use some sort of epoxy to seal the inside of hollow forms in case someone puts water in them? I just started making hollow forms, and the first question anyone ever asks me is if they can fill it with water to use it as a vase.

I am considering picking up the small System 3 Clear Coat kit at my local Woodcraft, but was not sure if something like that would be helpfull if poured inside and swished around before being put on the lathe at low speed to keep it spinning until cured.

Epoxy seems to be fairly pricey stuff, no idea if there is a reasonably well performing lower cost option of barrier coating hidden surfaces like this.

[Doug Herzberg]

I'm very interested in whatever responses you get, Eric. My wife wants to put cut flowers into most everything I turn. She already has several "weed pots." I've started combing thrift stores for glass vases which will fit inside my wooden ones. Won't work for a hollow form, though, unless you make it in pieces like a segmenter might.

I've also considered that thick, clear acrylic you sometimes see on restaurant tables or pored into molds to preserve insect specimens or whatever. Also expensive and I haven't tried it yet. Wood moves, not sure this stuff does.

I think I saw a video with Cindy Drozda talking about a form with a frog in it for cut flowers. No mention of how she protected the wood from the water.

[John Keeton]

Eric, while there may be some short term solutions, I think if one looks at the various cabinetry applications, etc., one can see that eventually, the finish will fail and moisture makes it past the barrier. Once that happens, the finish will degrade quickly. I think the reality is that wood movement prohibits a long term solution. Perhaps one just needs to look at these pieces as relatively short term functional items, and in that case, the epoxy idea seems to be the best one. Perhaps the bar table finishes would be a very good start. Check out this link.

(http://bartopepoxy.com/)Note it is water resistant - not water proof.

[Jason Ritchie]

My idea would be to maybe try the bar top epoxy then melt layer after layer of paraffin wax into the form after the epoxy has cured. Melt the wax in a double boiler until very runny then pour into the form and rotate it all around until the inside gets covered really well. Do this repeatedly until you have enough thickness inside. Paraffin wax is somewhat flexible with wood movement and is water proof. It will have a very delicate and vulnerable surface because of the softness of the wax but I would think this would not be an issues on the inside of a form. I have never tried this but I'm an engineer by trade and my mind is always working on solutions to problems.

[Faust M. Ruggiero]

Eric,
I never tried this but I have a thought. I was watching TV one night and a product was advertised to spray a sealant inside a rain gutter. I don't recall the name. I am sure it was a rubber or vinyl product so it will expand and contract. I might consider trying some on a test piece to see if it works in the long term. John is spot on with wood movement. However, consider that mahogany boats are finished with marine varnish and last very well. There is a company named Epafane (I may have misspelled that). They specialize in marine finishes. Maybe they have conquered the expansion and contraction issue. Their products can be found on line at Jamestown Distributors or any other company specializing in marine finishes. Sit when you look at the price.
faust

[Brian Brown]

I've been thinking about the same idea lately. I have never found an epoxy that didn't allow water to get through after a short time. I would also worry about the movement of wood. Unlike a side grain table top that moves only 2 directions, a HF moves 3 ways, longitudinal Circumferential, and radial. Longitudinal movement is negligible in both, but radial and circumferential are a big deal. Whatever you use on the inside would have to have some flexibility. I saw some stuff at Bed Bath and Beyond the other day that they are claiming will permanently water seal anything. It is a synthetic rubber based product, and from the looks of it it is about the same stuff used to coat pickup beds; similar to a Rhino lining. I think it was about $12 a can. It appears to be flexible to some degree, and I have been thinking that maybe it would move with the wood. I worry that it will also allow water through, but maybe not. I'm not sure exactly how you will get it evenly inside a HF , but it would be nice to know how it worked. Fiberglass resin for boats maybe another answer, but speaking of expensive! Let us know what you try, and the results.

[Jason Ritchie]

That stuff on TV is nothing more than rubberized undercoating you can get at the auto parts store. It does seal and water proof but it's black and very messy to spray out. It also stinks terribly. I have used it before to seal the inside of speaker enclosures.

[Bernie Weishapl]

Eric I agree with John and others. Most any finish you put inside epoxy, etc. will fail. I tried two different types of epoxy to no avail. Wax will not help IMHO. It just won't last. This is what I now use if they want to put real flowers in vases. http://www.woodturnerscatalog.com/store/Projects___Flower_Display___Flare_Top_Flower_Vase_ __flare_top_flower?Args= and this one http://www.woodturnerscatalog.com/store/Projects___Flower_Display___Flower_Vase___flower_v ase?Args= I make sure they fit snugly and then use flexiable silicone adhesive on the bottom to hold it in place and is flexible when the wood wants to expand and contract without breaking the glass.

[David DeCristoforo]

I can only think of one word.... fugedaboudit! Short of totally impregnating the wood with resin, there is no way you are going to make this happen. Eventually the wood movement will cause the "lining" to fail. You may have some short term success with epoxy or something like a rubberized coating which might be OK as long as you can leave town before the waterproof coating on your customer's vase fails.

[Sam Murdoch]

Here is a product that might have merit in this case http://www.jamestowndistributors.com/userportal/show_product.do?pid=1268&familyName=Smiths+Warm+CPES+Epoxy#pr-header-1268 I HAVE NOT used it yet, but it seems that it would be worth a shot - just haven't had the need. I agree with Bernie that wax or paraffin as a liner would eventually fail - you just poke at it long enough with flower stems and you will penetrate the wax. The clear penetrating epoxy on the other hand - if it really does penetrate - would become part of the piece and not just a surface. Worth a try?

I'm not a turner so you can ignore this post without hurting my feelings as I will never try this solution myself :D.

Sam

[Jim Burr]

This is a sticky one Eric! I'd stick with inserts. Some examples can be found at CSUSA. Some cigars come in glass tubes. There are also laboratory supply places that sell test tubes and beakers in a crazy range of sizes.

[Prashun Patel]

Why dont you just make a bladder for the inside out of a plastic bag. Since it's inside, nobody will see it.

If that's too low tech, then I have to believe there is some kind of durable liner that can be applied to the interior. In my work, our 55gal steel drums are lined to withstand a lot more aggressive chemicals than water, and they do a darn good job of not leaking. But yr probably looking as some kind of 2part urethane or commercial grade finish. I am sure it exists.

[Eric Holmquist]

Thanks for the feedback, I guess hollow forms are more purely decorative than functional. I'll just have fun making them and not worry about them being practical.

[Harry Robinette]

I was told or read somewhere that the stuff you dip tool handles in is a rubber coating that unless cut will not loosen or deteriorate from water and that a turner somewhere is using it in vases.I can't remember were I heard or read it but I have a can of the tool handle stuff and was going to try it but haven't yet. My next oops that is still a shape that will hold water I'll try it on. I know this stuff stinks cause I put it on some tool handles for my uncle a couple years ago and it's sill there.

[Paul Williams]

I think your best bet would be a glass or copper pipe liner, however I do think it could be done with epoxy or a rubber coating.

We built a foam and glass airplane in 1982. It has had avgas in the tanks for 30 years with no leakage. The difference would be the epoxy is used to saturate fiberglass cloth and not as a paint. You could achieve the same effect by mixing chopped fiberglass or cotton floss in the second coat of your epoxy.

Another product I have had good luck with is "Leak Stopper" by Gardner. It is a rubberized roof patch sold by Ace Hardware. I used it to make nylon cloth airtight. It is holding up well so far dispite lots of movement. It is clear when dry.

Good Luck, but if this is for a client I would still try to find a glass or copper container that fits inside.

[Jeffrey J Smith]

Having spent many hours working on a wooden boat for the past 11 years trying to keep it on top of the water, I can verify that a good epoxy coating like West System products will permanently seal the wood against water. In an application like this, no need to use saturated fiber glass. But, while West System will make the wood impervious to water, it is subject to degradation by UV. You've got to overcoat it anywhere it will be exposed to light (even flourescent lights are high in UV output). A coating of a good marine grade varnish with UV inhibitors like Epifanes or a marine enamel does the job.

By the time you've assembled all that's required, getting a readily available glass or metal liner will look like a bargain in both time and dollars.

[robert raess]

Urushi, Japanese makes functional bowls and cups with it .To my knowledge, it is quite hard to get here in the states, and once you get it, you almost have to serve an apprenticeship to go thru all the steps.Having said that, i believe that Permatex is or was made out of black shellac to seal gaskets in cars. Rob

[Eric Holmquist]

Having spent many hours working on a wooden boat for the past 11 years trying to keep it on top of the water, I can verify that a good epoxy coating like West System products will permanently seal the wood against water. In an application like this, no need to use saturated fiber glass. But, while West System will make the wood impervious to water, it is subject to degradation by UV. You've got to overcoat it anywhere it will be exposed to light (even flourescent lights are high in UV output). A coating of a good marine grade varnish with UV inhibitors like Epifanes or a marine enamel does the job.

By the time you've assembled all that's required, getting a readily available glass or metal liner will look like a bargain in both time and dollars.

Well if I am using it on the inside of a hollow form it will always be dark in there, so UV issues will not be a problem! I would use more traditional wood finishes on the outside

[Doug Reesor]

One of the techniques in metal and ceramic casting is to fill your mold with metal or ceramic and after some period of time, depending on the wall thickness you want, pouring out the liquid in the middle. Has anyone ever tried doing this with epoxy in a hollow form?

Doug

[Dick Strauss]

I made a staved mug for a picnic that holds a quart. The staves are ash, the bottom is wild cherry, and the handle is willow burl. The staves were glued using TB2 and the bottom and handle were attached using using the 20 min epoxy full strength. I used the two part epoxy from Klingspor (no longer available through them but is available through Highland and others) thinned about 1:1 with DNA IIRC for the finish. The mug has had water and beer in it with no issues over the last year or so. Beyond a year, I don't know what to expect but so far so good.

FYI-An experiment by a friend showed xylol works best for wood penetration (about 1/32-1/16") but I didn't have xylol/xylene on hand when applying the epoxy finish.

Here is a link to the epoxy I used: http://www.highlandwoodworking.com/stickfast20-minuteepoxykit9oz.aspx I used the 20 minute version of the StickFast epoxy rather than the 5 minute version for extra working time to spread it as a finish.

Your mileage may vary,
Dick

[Jon McElwain]

Having spent many hours working on a wooden boat for the past 11 years trying to keep it on top of the water, I can verify that a good epoxy coating like West System products will permanently seal the wood against water. In an application like this, no need to use saturated fiber glass. But, while West System will make the wood impervious to water, it is subject to degradation by UV. You've got to overcoat it anywhere it will be exposed to light (even flourescent lights are high in UV output). A coating of a good marine grade varnish with UV inhibitors like Epifanes or a marine enamel does the job.

By the time you've assembled all that's required, getting a readily available glass or metal liner will look like a bargain in both time and dollars.


I second Jeffery's comments on West Systems epoxy. It is a different animal than the stuff you pick up at a hardware store. I spent several years working in a boat yard in Portland, Oregon (60 ton dry dock) and have applied many many 5 gallon West Systems epoxy kits to wooden boats. The stuff is expensive, but applied correctly it will provide years of water proof coverage. We applied west systems to every wooden surface that was not a railing, deck, or cabinet (finish woodwork in the boats). Applied as the straight 2 part mixture with no additives, it penetrates the wood and seals it. Wash with alcohol between coats and build up a finish. While it is not a "flexible" finish, it does maintain a small amount of elasticity, so it will withstand some wood movement without cracking. The other epoxies I have used become brittle quickly - especially those little 5 minute kits from the hardware store.

Of course, after all of that, I still agree with Jefferey - the time and money may not be worth it. The available glass liners are a sure bet and are cheap.

[Doug Herzberg]

I've been following, as I indicated I would. For those of you with experience with West Systems, do you need anything other than the resin and the hardener? For what we're talking about, would the fast hardener or the slow hardener be best? Looks like you could get a quart of resin and a quart of hardener for well under $100. What about shelf life?

[Jeffrey J Smith]

Doug:
It's been a while since I've worked with the West System, but there's a separate hardener for finish coats. Can't remember the number, but, if my memory serves, the mixture seemed less viscous and hardened a little clearer. I wouldn't think you'd need anything other than resin and hardener, but don't forget the gloves - the stuff can be messy.
If you use multiple coats, it is very important to clean the surface before recoating. All it takes is a rinse with water and a quick scrub with a scothbrite pad. The reaction produces a waxy coating that will not allow the next coat to adhere called a blush.