finishing an ipe bathtub.......can I do this?

[Redonebyme]

I am currently fabricating a bathtub out of ipe.
I guess it would be best discribed a a strip planked hull 1 3/8 x 1 3/8 strips 29" tall, with tapers at the corners to achieve curves. It will end up being a 57" x 32" japanese soaking tub. Each 'plank' is secured to the ajacent 'plank' with 2 3/4" s.s. screws at 6" centers. It also has 1/8" threaded rod 8" from the top and 5" from the bottom. On the exterior the top rail will be laminated from 26 strips of 1/16" x 1 1/2" stock.
The finishing is my consern.
That being said, I was considering CPES followed by two coats of epoxy followed by three coats of varnish.
Will this work?? Can I apply epoxy directly onto the CPES'ed surface without the aplication of any fiberglass cloth. Will it crack??? If so, any reccomendations for what type of epoxy. Heat is also a consern, but I do have a temp control fill that won't go over 110 f.

Comments.............please....????

[Mrleft8]

What do the Japanese use?
The only tubs like what you are describing that I have seen have been Redwood, or Cedar, and are left unfinished.

[Ian McColgin]

I don't know if they still do it this way but back in the '70's when I built a few hot tubs, the cost-effective way was essentially barrel construction with untreated unfinished (in the sense of paint or varnish, but very finished in the shaping and smoothing) wood.

If you've not started at all, check out the method as it's much more durable, better use of materials, and pretty near fool proof.

If you must go with a rectangular shape, I've seen some nifty yacht installations where the "hull planks" were essentially over sized layers glued up in a stack and then carved out rather like a log canoe except that much of the center was already hollow. This resulted in a thicker wall than you describe. They were not reinforced by any mechanical fastenings. I don't know but what the drifts you describe could actually weaken the wood and I don't know if the construction you describe will move a bit with changes in moisture content - both possible problems.

They were CPES'd and then varnished. This was thought better than adding a thick layer of epoxy over the CPES as that would be prone to cracking. It was also thought that a glass layer would only foster rot if there were any secondary failings while CPES/varnish made for a surface both readily inspectable and readily repairable.

So, with the caveat that the construction I witnessed is different enough that the finish I know of might not be so relevant to your plan, I'd still just go CPES (maybe) and over a dozen coats of high quality high gloss varnish.

G'luck

[Redonebyme]

Currently I have fabricated the corners and milled the material to size, but I havent drilled the stock for the threaded rod. I also considered using a pieces of 1 1/2 " x 1/8 S.s strapping on the exterior kind of like a squarish flared barrell.

I am using ipe because I ended up with 170 cut of's from a job where I built a deck. they started out as 1 1/2 x 1 1/2 but with rounded corners, so they had to be resquared.

Ipe end grain and run out is not moisture friendly so sealing it is a must.

[formerlyknownasprince]

I seem to recall a finished wooden bathtub in one of the boats in the Gougeon Bros book - the 92' Whitehawk - but I must have seen the photos in Woodenboat or elsewhere.

Ian

[TimothyB]

That being said, I was considering CPES followed by two coats of epoxy followed by three coats of varnish.
Will this work?? Hey guys, this is a tub! The environment it will be in is not that harsh, really and most of the time it will be empty of water.

YES it will work, assuming you are careful about making sure all surfaces are well coated. If the epoxy is industrial grade high temp epoxy, it should work well. This is very similar to a strip plank hull, and those are done with this sort of treatment (sans varnish) and work well. I am assuming though that there are NO gaps!!


Can I apply epoxy directly onto the CPES'ed surface without the aplication of any fiberglass cloth. Will it crack??? YES you can do this, CPES is an epoxy and as long as you rough up the surface before application, the barrier epoxy will stick. No it won't crack, again, assuming you have NO gaps.

As far as high temperature epoxies, and considering the temperature of the water, you may want to look in an industrial catalog for those. They do require high heat to cure though.

I would ask Paul Oman if you want authoritative advice, he knows quite a bit about this stuff and is a member of our esteemed forum:

http://www.epoxyproducts.com/

[StevenBauer]

George has much more experience with Ipe than me but I have used it a little. I seal endgrain with Anchor Seal but I've always just left it bare other than that. Nothing sticks to it anyway. I'd experiment with scraps and various glues and finishes before I'd settle on what to do. What are you using to glue the strips together. And are you wiping down the faying surfaces with, some sort of solvent? And will you post some pictures? Please. smile.gif

Steven

[Figment]

My boat's brightwork is varnish over epoxy over CPES. Going on three years with absolute minimal maintenance. My canoe is varnish over epoxy. Four years (outside never covered) zero maintenance and still going strong.

My father and a buddy of his did it the CPES before varnish thing last year and the year before. They both had varnish-popping issues in a few months.

We've narrowed their problems to two possibilities.
1) It's possible that they didn't allow sufficient cure time on the epoxy. I've since read that amines can still work their way to the surface days beyond the published cure time.
2) I used system three varnish. Epoxy-friendly by necessity. They used whatever oil-based varnishes they've been using for years. The epoxy doesn't allow the oil to get into the wood, and the adhesion problems are the result.

I assume you're talking about the exterior of the tub. Finishing the interior of the tub in this way seems like a slip&fall injury waiting to happen.

[Stiletto]

eons ago WB had an article about a boat built by a woman as I recall, that had a strip timber bath in it. It looked like an epoxy-varnish finish, definitely not bare wood.

[Figment]

Might that have been Lin Pardey and Taliesin?

[Pernicious Atavist]

i used ipe to replace the wood on my thistle. i used good quality varnish, first few coats were thinned and subsequent coats were not, just like reccomened. it's not doing all that well and has flaked off in many places. other than seal the edge grain, why coat it at all?

[Adamant]

If your worried about an apoxy coating failing, why not add a layer of angel hair glass like they do on canoes and kyaks?

[woodtubsnet]

Hi there.

You can use epoxy on your tub, although I would highly recommend fiberglass cloth.

If this is a bathtub and not a hot tub, you can use a good admiral's varnish over the epoxy. We found that prolonged exposure to hot water (2-3 days at 105 degrees) totally degraded varnish (We tried all kinds) and made it peel off.

[jverl]

Hi All,
The WB issue in question is #120 and the lady is Linda Smith who built a Lyle Hess Falmouth cutter. She states that she used epoxy with varnish over the spruce bathtub.
http://im1.shutterfly.com/procgserv/47b7df30b3127cce98548a7d234600000015100KYtGbRyyYy