Fiberglass & Resin Suitable for Steam Shower Wall Construction?

[JIMTMCDANIELS]

Hi,

Sorry I have an odd question/situation about fiberglass resin usage:

Remodeling our bathroom installing a steam shower.
To meet our artistic and unconventional desires, our handyman was certain he could create interior shower walls using plywood and the plywood covered with bondo fiberglass cloth coated with liquid polyester resin from home depot and silicone caulk the wall seams.

Additionally this would allow random single pages from a book to be placed on the wood under the cloth so it could be slightly visible through the resin for a unique look.

Our handyman created the shower wood walls but then his health declined and can no longer work.
I don’t remember what kind of plywood grade he used.
He did install plastic sheeting between the wall studs and the plywood.
The fiberglass and polyester resin has not been purchased yet.

We are talking to a new handyman about finishing the job and he is uncertain such a wall covering will be sound over the long run.
Before he attempts to finish he asked us to investigate this further.

So I know this may be unorthodox but Any input would be great please!
I’ve asked a shower forum with no response.

I see it appears this system is used on wooden boats, so very similar…..

Q’s that come to mind:

1. Might this wall design be reasonably sound for this application?

2. Should the wall design use the fiberglass cloth or the fiberglass matt or I see bondo has a fiberglass strands filler, or should no fiberglass reinforcement at all be used for these walls?

3. Is the polyester resin hard to apply on vertical walls, I see bondo has a jell formula for vertical surfaces, should we use that?

4. Will the random single pages from a book interfere with the adhesion?

5. At what stage should the single pages from a book be installed into the fiberglass & wall resin buildup?

6. Is there a better suited product than bondo from home depot?

7. Is there a better final finish coat to use?

8. Will the finished surface be smooth enough to resist mold, mildew, soap scum etc?

Thank-you for your time!

[forsailbyowner]

Ive been doing butcherblock for woodwork and coating it with polyester boatyard resin. After a year the places I started with are holding up well in hi use areas. It cleans easy, if you leave something wet on it it will cloud for a while then clear up when it dries out. The boatyard resin is the lowest grade of resin available and goes for around $20 a gallon locally. I havent been using any mat or cloth, On the first coat of resin I thin it with alcohol so it soaks into the wood. I dont like the idea of silicone for the seams.

Im planning on doing my head in a similiar fashion. I will be using pressmat and finish cloth there. Rounding the corners will be necessary using a thickened resin. I plan on this being a non trivial event and see a lot of fairing and nasty work before its complete.

[Delancey]

Sorry to hear about your contractors failing health. Sounds like a fun project. I say go for it! Shower enclosures are made from fiberglass with polyester resin all the time. Epoxy would be an alternative material but the type of resin your contractor suggested is acceptable and is less expensive with a shallower learning curve than epoxy.

I assume the original contractor had some idea of what he was doing. If you can see the exposed edge of the plywood, look for a dark purple glue line between the layers of wood. This will tell you if an exterior grade of plywood was used which features a waterproof glue.

Next you will want to soak the plywood with resin and apply a layer of chop mat fiberglass as a base layer and thoroughly wet it out. Once this dries and you sand it smooth you can begin applying the book pages with more resin. Once the application of the pages is complete you should cover the entire surface with a layer of very very light weight glass cloth. When this is properly wet out it will turn invisible and disappear.

The key to the successful completion of your project will be for you to complete a small scale mock-up which will allow you an opportunity to develop the required skills without having to risk screwing up your shower enclosure. Maybe mock-up is something useful you keep, or maybe it is something you toss in the bin. Regardless, you are doing something new so create a situation where you can make mistakes without consequences before you get to work where it matters.

Decoupage - Wikipedia, the free encyclopedia

[atoll]

i would just use west system epoxy to treat the plywood,and a collodial silicone epoxy fillet on corners and joins.
apply 2 coats,with the art work under the 2nd coat.

you could use a surface tissue on the 1st coat,but probably not nessacary with epoxy.

[Delancey]

Don't disagree. Epoxy requires careful measuring and mixing so for a first timer I figured poly would suffice. We have such **** plywood here in the states I recommended including glass because of footballs in the face veneer would be a path for water infiltration but really the decoupage should sort of seal over all of that. Prolly would be fine with a couple coats of epoxy.

One thing to mention with these different materials is that they have something called a "pot life" which means don't mix up more than you can use in a short period. Mixing the two parts produces a chemical reaction causing the liquid to gel then turn solid so you only have a limited amount of time to work with it.

[JIMTMCDANIELS]

Thank-you for your inputs!!

I also contacted bondo/3m to ask about their fiberglass - polyester resin products sold in home depot for use in this project.
Their website e-mail response gave me a phone number but the guy's answering machine picks up and he has never called back after 3 messages left to him.

I see bondo/3m has a gel formula for vertical surfaces, I wonder if that is what we should use..??

[Delancey]

Not sure what the gel product is, could just a have a thickener added to impart thixotropic properties to it. My concern would be the ability to wet out the surface and whether or not it would make the resin cloudy, which obscure the artwork. Usually polyester resin is pretty transparent.

[JIMTMCDANIELS]

Well is it difficult to keep polyester resin from running or sagging on a vertical surface before drying..?


Side note, it seems polyester resin may be the best thing for protecting exterior house surfaces that are problematic like window sills although they are already painted so it probably wouldn't stick well.

[Delancey]

In my experience controlling drips and sags is more about attentive and controlled application of a uniform coating thickness than the product itself.

If it were me I would probably expect to use a foam roller and an application of multiple thin coats of straight resin as the best strategy to avoid drips and sags while achieving the intended results.

Regarding the side note, it were the best thing for protecting window sills on your house everybody would be doing it. Polyester resin has been around for years. Most folks stick to paint.

[captain58sailin]

To keep the polyester resin from sagging, you need to mix it pretty warm and keep working it as it cures, and make several thin layers. If possible lay flat for the glassing portion of your program.

[JIMTMCDANIELS]

Thanks for the replies!

Can the wood be stained first before applying the resin, it appears boat wood is stained first or how do they obtain the rich colors you see in boat hulls?

---

3M did finally return my call today and they were great, really thorough about the process.
They said they have not had anyone use the product for this application but thought it would probably work fine.

Here's the steps they gave:

1. Sand the wood walls with 80 grit paper, then remove all dust.

2. Obtain throw away able paint: small rollers, roller pans and brushes, for batch applications.

3. Using the disappearing reinforcement fiberglass-mat, instead of the -cloth, is easier to work with.
4. Plan out and precut the fiberglass into workable panels, first cutting panels for only a 1" overlap over all wood wall joint seams.

5. The batch is very smelly until fully cured(several days), so vent the room well.
Mix in small batches of 1 quart resin, or less at a time to allow enough time to apply to the wall before hardening:
In a container of pre-measured resin, add exactly 12 drops of hardener Per ounce of resin.
Mix batch very quickly and thoroughly using a good paint mixing paddle, be sure to mix the hardener to the entire measured resin by scraping the sides and bottom of the container.
6. Pour the batch into the roller tray.
Keep in mind the batch left in large pools hardens faster so spread it out onto the wall soon.

Application to wall seams only:
7. Apply the batch to the wall seams working it well into the wall's cut edges with a brush, to help seal them(ideally the cut water-vulnrible edges would be sealed before assembly).
Apply the batch slightly wider than where the fiberglass panels will be applied over the wall seams.
Embed the fiberglass seam panels on the wet wall batch, then cover with more batch.
8. If there are bubbles under the fiberglass, use the paint brush with batch to release them.
9. If there are areas the fiberglass has not disappeared, it's still dry, so apply more batch on top. Work out any runs and gravity sagging of the batch.

10. If a batch coat dries, sand it with 220 grit before applying a new coat so the new coat sticks to the old.

Application to all wall surfaces including seams:
11. Then cut fiberglass panels to cover the entire walls in workable sections, including the seams(yes the seams get 2 fiberglass layers in the finished product).

12. Next, apply batch coats to the entire walls working in workable stages/sections, embedding the mat into the wet wall-batch, then covering with more batch, Then apply where desired, the artful book pages and cover them with more batch.
No further layers of batch are needed, the wall coating should be adequately strong and sealed.

13. Do not allow the walls to come into contact with water till full cured, at least several days.

14. If needed, silicone mildew resistant caulk-seal any fixture wall penetrations/concealing covers.

15. As an extra protection from stains, apply carnuba wax to the wall, let haze and cloth rubbed off.

15. The walls smell will dissipate as they age.

16. Over the years, if the walls loose their clarity, they can be sanded with 800 grit paper and then power buffed.

I didn't ask them about staining the walls and not sure if wall stain would be visible through the fiberglass mat?
If visible, a dark stain may make the double layer of fiberglass mat, over the wall seams, more obvious?

[JIMTMCDANIELS]

Regarding the side note, it were the best thing for protecting window sills on your house everybody would be doing it. Polyester resin has been around for years. Most folks stick to paint.[/QUOTE]

That's just the thing, the 2 year old paint on the window sills of the house are already cracking and flacking off..
I came across one article on the internet where a handyman prescribes resin as the only way to seal exterior wood surfaces.
Maybe he's right, cause paint just doesn't seem to hold up on window sills, and wood balcony's etc...

[mike d.]

If you feel that you/your handy man cannot get a/ the wall sections done in 1 shot you should consider non-waxed resin. This will allow you to continue working the next day with out having to sand as the resin stays tacky. once all sufaces are done you can put on a coat of waxed resin over the whole wall structure for the final coat! Also if you are going to do small sections make sure to start from the bottom, so your over lap is from the top. This will make it so there is no chance of seepage under the layer/s of glass. If you cut the cloth to fit the whole side at a time you can staple it at the top and then just roll the resin through it,when resin tacks pull staples and finish. Even better is to wet out ther wall, let the start to resin tack up, roll the cloth into it, then recoat with resin to seal, then do a waxed wet out roll you pages into the resin, let tack the reapply 1 coat of waxed and call it a day!. No seams to worry about, and you can do an inch lap at the corners! MAKE SURE YOU WHERE THE APPROPRIATE CHEMICAL MASK, WITH PLENTY OF FANS TO DRAW AIR OUT OF HOUSE!!!!!!