Tag Archive: acrylic fading


To: Multi-Tech Products:
This repair (see pics) was done about 3 months ago and is now turning cloudy. What could be the cause ?
I’m thinking a reaction to spa chemicals?
Doug

IMG_1621 IMG_1622

To: Doug,
It is difficult to determine the exact cause of this problem without knowing some of the history and common water chemistry maintenance practices used on the spa. There are least two causes. Information on them follows.
Here is information on common chemical damage to acrylic spas. I don’t suspect this to be the cause, since issues would occur at other areas of the spa – not just at the repair.
https://multitechproducts.wordpress.com/2014/12/15/surface-discoloration-in-an-acrylic-spa/
The next article describes what can happen to our Clear Coat if it is exposed to moisture before complete curing – normally requiring 24 hours..
I think this is the most likely cause in your case. I am assuming you used the MTP Clear Coat to finish the repair, since we believe it is an absolute necessity to achieve a quality repair.
Three months is normally the time window that post cure repair issues show up.
https://multitechproducts.wordpress.com/2012/06/
The repair could certainly be damaged by strong oxidizing chemicals (e.g. tri-chlor). However, Tri-Chlor would also cause fading in the acrylic in other areas of the surface. So, I don’t believe tri-chlor exposure is the culprit.
If the problem is simply premature exposure to water, it is an easy fix. You just need to remove the repair coating, and respray.
I would recommend sanding with 400 grit sand paper to remove the top coating. Light sanding can remove the damaged Clear Coat while preserving the Color Coat. At least, it could limit the need to spray more of the Color Coat.
After completing the repair, it is very important to keep the repair zone dry for a sufficient time to allow the coatings to completely cure.  Exposure to any form of water may effect the coatings.   If the repair was below the water line, wait for at least 24 hours before refilling the spa.
This communication addresses the post-repair cure procedure, and how to place the cover to protect against water getting on the repair zone.
https://multitechproducts.wordpress.com/2012/07/02/118/
Hope this helps,
Rob

To: Multi-Tech Products

I own a spa service company, and I have a customer with a unique problem. He owns a large yacht, which had a spa installed several years ago.  It has been abused by failing to keep it covered when not being used. Also, it may have been exposed to the wrong water maintenance chemicals over the years. It is extremely faded, and has crazing and cracking in some areas of the acrylic surface. Since it is still functional, and would be expensive to remove and replace, the customer is inquiring if there is a simple way to renew the surface color and fix the cracks. He is asking about painting with a pool paint or Zolatone® to match the granite appearance. There are a lot of jets in the spa, and some would be very difficult to remove, if a spraying operation was required. What do you think?

Thanks,
Bill

IMG_3257

TO: Bill

I agree with you. The spa is crazed and cracked mainly due to over exposure to the sunlight (i.e. no cover in use).  Also, the use of strong water chemicals like Tri-Chlor was probably the major factor in the fading, although the excessive UV exposure contributed.  Acrylic sheet manufacturers have confirmed that Tri-Chlor will fade the pigments in acrylic spas and should be avoided for use in maintaining hot tub water chemistry.  Tri-Chlor is intended for use in swimming pools.
First, Zolatone® is a brand of hybrid lacquer paint, and will peel from a wet environment surface rather quickly.  This product, although speckled in color, is intended for top-side and non-wet areas in marine, auto, and industrial applications. It should not be used below a spa water-line, in tank or wet bilge areas. Even clear coated, Zolatone® will delaminate when painted onto constantly wet and high moisture environments.
So, a spa/hot tub refinish is out of the question. In fact, there is not a coating available that would provide a “quick” fix to renew a crazed/cracked acrylic hot tub surface long term. This even includes swimming pool and bathtub coatings, as well as marine finishes, and let’s not forget gel coat as paint. The reason is that the acrylic surface will continue to crack, craze, expand and contract under the applied painted coating. The cracks will simply come through, along with rapid delamination (peeling) of the coatings. These paints are just not made to withstand heated water, constant moisture exposure or chemicals.  These factors will cause  bubbling and peeling of the coating.  However, they do work well when the surface stays dry.  Moisture must dry quickly from these coatings in order to stay pristine, and adhered to the resurfaced substrate. They work well for resurfacing bathtubs. The tub is filled (gets wet), drains (dries) and the surface will continue adhered to the substrate.  Overuse, or a dripping shower head or fixture will result in constant wetness and the paint will fail.  Furthermore, pool coatings or marine anti-foul paints have an application life of only about 3 years. Therefore, these coatings would have a short life expectancy on a spa in a spa application.  Under spa conditions, we have seen these types of coatings fail within a few months from application.

Since there was no commercially available means to meet this need, we developed a process that works, and performs well under normal spa and wet conditions.  It is a special resin embedded with glass fiber reinforcement. The reinforcement along with the high performance resin adheres to the original spa structure, and creates a barrier surface with minimal expansion and contraction. The system is laid-up by hand and will give an expected life of 15 to 20 years. We developed this system specifically for spas, tanks and challenging wet areas as a economical method to extend their life.  It is our FiberGlass Reinforced Lining (FRL) system. It adds a new reinforced, white colored layer on top of the existing surface or prepared structure. You can see the system components and procedure at the following link. It is contained under the Technical tab in our website.
http://www.multitechproducts.com/content/Procedures/FRL%20PROCEDURE%20Final%20Draft.pdf

Your application doesn’t require removal of the jets or other fixtures, since the crazed areas on the subject spa do not appear to be causing severe peeling or delamination of the acrylic layer.  It would not be necessary to remove the acrylic or repair the areas before applying the FRL system.  The finished FRL layer will be about 1/8” thick, so it will contribute some additional strength.  In other words, it is a structural finish.  Since the FRL final color coat is white, it will provide an attractive textured finish and appearance that hides the underlying fiberglass throughout the FRL application.  It is easy to clean, and is resistant to fading by sunlight.    With proper water chemistry maintenance, it will retain its gloss.  It has proven to add long term life to spas in these high end settings where replacement was not an easy option.

I hope this helps. Our Customer Service Department will help you in ordering the proper kits and materials to do the job.

You can see the FRL components at:

http://multitechproducts.com/resin-fiberglass-resurfacing-kit

Thanks,
Rob Clos