Help with Repairing Crack in Hot Tub Shell

[BauerN]

Contacted Aristech last week - would have posted sooner but have been in the field and out of state.  

My e-mail:

Hello,
 
I run a service and install department at a Bullfrog Spas dealership in Montana.  I also spend time (when I can), researching and writing in online spa forums.
 
During a recent discussion, there was a claim made that once an acrylic shell is heated and vacuum formed from its original sheet, it becomes very porous/permeable.  A further statement was made that, because of this, the fiberglass layer actually holds the water (as opposed to the acrylic layer).
 
I have been attempting to research this myself, to little avail.  If at all possible, I would greatly appreciate if someone at Aristech could e-mail a response back to me.  No great explanation necessary, would just like to confirm or deny.
 
Thanks in advance.
 
Sincerely,
 
Michael

The response:

Dear Michael,

 

The claim made below is absolutely false.  The fiberglass is used to rigidize and strengthen the acrylic shell.  In fact, if you cut a cross section of a fiberglassed acrylic shell you will find porosity in the fiberglass where air gets trapped between the layers as the fiberglass is sprayed and rolled.  Therefore, the acrylic shell is a nonporous material.  Please let me know if I can help you with any other questions or concerns.

 

Best regards,

 

Todd Whitney

Global Acrylics Market Manager

 

Aristech Acrylics,LLC

7350 Empire Drive

Florence, KY 41042


Not trying to ruffle feathers, I just have a thing about accurate technical data.

I have seen enough cross sections (various fiberglass and others) to back up Mr. Whitney's statements.

I think we're headed for BADH -  

[Mr._Bubbles]

Popcorn anyone?

[Chas]

OK. I guess I stand corrected. All of those tubs I have seen with obvious porosity and leaks must have been non-porous. I have been wrong before. Of course, these would be older tubs going to the landfill, or tubs I have been called in to repair over the past twenty-plus years - from any number of tub makers. The problem had to be something else then.

I am always ready to learn new things. I would, however, like to ask how many of the over 100 manufacturer's production lines this gentleman has inspected? I have no trouble agreeing that in sheet form the product is non-porous exactly as he says. If the tub is built correctly, I'm sure the sheet could still be perfectly water tight. I also agree that the fiberglass can be porous due to air entrapment. Sometimes I do repairs with thickened epoxy resins and I lay them up too thick. The heat generated makes them boil, and they become riddled with air bubbles.

I would be very impressed if he actually will vouch for every tub maker that they do not under any circumstances exceed the elastic or plastic limits of the product as they form it? Will he vouch that the temperature of the ovens is not only correct, but perfectly even, and if it has designed-in variations in heating that those variations are perfect for the mold in use?

I guess I don't see the big deal - he says his product is non-porous, I say I have seen tubs with porosity.  There are a boatload of possible variables and even changes between the sheet as it goes out the door of the plastic plant and when I see it as a repairman, in use. I think we can both be right.

 8-)

[BauerN]

I would be very impressed if he actually will vouch for every tub maker that they do not under any circumstances exceed the elastic or plastic limits of the product as they form it? Will he vouch that the temperature of the ovens is not only correct, but perfectly even, and if it has designed-in variations in heating that those variations are perfect for the mold in use?

That's a great point - I feel a bit silly for overlooking that.

There are a boatload of possible variables and even changes between the sheet as it goes out the door of the plastic plant and when I see it as a repairman, in use. I think we can both be right.

 8-)

Agreed.  Ultimately, it can go either way, depending on the variables.

 

[stuart]

I'm really thrilled that someone proved Chas wrong 8-).....but, can we get back on subject.

What's going on with the Crack?

[Hillbilly Hot Tub]

When we worked for a spas manufacture, the sheets of acrylic (lucite) had to be stored where there was no humidity per instruction of lucite. We were told they would absorb moisture and when put into the ovens, it would raise he**. This was before they went in the oven....very interesting.....

There is a stuff called pool fis that will fix up to a 1/4 inch hole or crack. It works really well.

Is the crack somewher that when you add water/weight it is going to cause it to spread open, ie the footwell?

[knightcap]

Hi, OP here.  My crack is fixed.  The crack was located on one of the seats, just where it starts to go vertical and run down into the footwell.  From under the tub, I peeled away the insulation and could see the water coming through.  There is a two-by-four brace under the seat, and when the tub is empty I can see about 1/8 inch gap between the shell and the 2x4.  So I assume it wasn't supported properly.  I hammered a shim into the gap.

For the crack, I called a company called Surface Specialists.  They are a franchise, and have an office in St. Louis.  They were recommended to me by several others, including Prestige Pools and Henry Plumbing.  The basically followed the method above -- drilled holes, used a dremel tool, and added some type of acrylic repair compound.  It looks great!  Best of all, it hasn't leaked again.  You need to search hard to find the crack.

I'd recommend these guys, you can find them on the Web.

They charged $177 for a one hour appointment.  Seemed pretty high to me.  Prestige Pools, who sold me the tub, gave me a $100 gift certificate to their store to help cover it -- since I also have a pool, I'll use this for chemicals, pool toys, etc.

So, a happy ending, but I'm down $77.

[gwstudios]

100% clear silicone will work pretty good but it will get yellow or cloudy and start to come apart over time from the chemicals and the heat of the water. I would suggest fiberglass resin, it cures fairly quicky and you can use a flexible soft plastic squeegee to force it into the crack. let it cure, then do it one more time.

You can get fiberglass resin at any auto parts store or home improvement center. I've used for many fixes in the past.

[James_Outlaw]

Hi,

I asked them why they names their spas "Outback Spas", they replied that it is because most dealers kept them "OUTBACK"

LOL!!

[HandyAndy]

When I had a crack in my fiberglass shell I used a shell repair kit that worked very well. It has been a year now and still no leaks It is very important that when you go to use a repair kit that you make sure that you clean the area and be sure that the area is also dry.