How to repair fibreglass fountain pot?

[macattack53]

We have a pond fountain that is based on a 4 foot tall fibreglass pot (brass tube up through centre, etc).  The original finish degraded so I sanded it back and painted on Zinsser sealer then a pool-rated top coat.  About 6 months later the top coat started to show small lumps of various sizes as the paint started to come free all over.  Have stripped this back, and realized that as the pot is fibreglass, maybe Zinsser not the right sealer / base product.  Need a fibreglass sealer (I guess) but not sure what is best.  Would paint it on, then aim to paint over it with the pool paint again.  Don't need fibreglass sheeting for repair - just the surface sealed as I hope this will act as a good base for the paint.

[EricL]

Hello @macattack53 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your fibreglass fountain.

I suggest having a quick look at this discussion - How do I waterproof a fibreglass pond? by @likepizza. In the discussion PVC pond liner and Crommelins pond sealer were mentioned as possible sealers for the fibreglass pond. I believe that these products will be suitable for your project as well. Please note that it was also mentioned that the fibreglass container must be bone dry to make sure that the sealer cures properly. Any moisture accidentally left in the fountain will result in the sealer not curing.

If you have any other questions we can help with, please let us know.

Eric

[macattack53]

Hi  Eric

Thanks for your reply.  Much appreciated.

However, your answer seems more for the inside of a pond/pool, whereas my question is about the outside of a large pot.  For instance, a PVC Pond Liner is good for a pool, but I can't wrap that around the outside of a curved pot.     I am not sure about CPS and will investigate whether it will adhere to fibreglass - their web site does not list fibreglass as a suitable base material.

Is there a Plan B?

thanks!

[JacobZ]

Hi @macattack53,

Do you have any photos of the set-up that you could share? This would certainly help. Let me know if you need a hand uploading images, I'm happy to assist if required.

The bubbling followed by the failure you've described makes me think the water was able to get in behind the paint and primer. 

I think there's a possibility that the water that got in behind the paint and caused the issues may have come from the inside of the pot. While fibreglass is waterproof when fully intact, if there is any cracking or delamination of layers, it's possible water can get through it.

If you can access the inside of the pot, check for any cracks or damage then use a Fibreglass Repair Kit to repair them. 

The Zinsser Bright White Bulls Eye 1-2-3 Undercoat Primer And Sealer Spray is the only primer I can find that specifically states it can be applied to fibreglass, however, it doesn't state it can be used in constantly wet environments.

It will likely be worthwhile to contact the manufacturer of the pool-rated topcoat for their advice on what preparation steps to take and a compatible primer for your specific purpose. 

Let me know what you think.

Jacob

[macattack53]

Hi  Jacob

You might have hit the proverbial nail on the head, thanks.

The pot was made in 2 halves and joined.  There is a vertical seam on both sides of the pot.  It may be that water is getting onto the inside surface from these, or through the top 'bowl' section where the tube comes out, which nowadays has some very fine 'spider web' cracks.  

I will use fibreglass repair (without the sheeting) across the top bowl and down the seams on both sides.  That will stop any water from getting onto the inside face and seeping through to the outside face which (now I think on it) is most probably the cause of the sealer and paint 'delamination'.

Thankyou again!

[macattack53]

Jacob!

Just a second thought / question:  I assume I can use the Protite resin (& hardener) you recommended above by itself and not have to use the matting as well?  I am assuming I can mix the resin and hardener, and just pint it on the surface of the pot where the seams are, etc....

[JacobZ]

Hi @macattack53,

It's not ideal to just put resin over the crack as the crack will still be there beneath the new layer of resin. Like concrete, the resin sets in one homogenous mass so if it is applied over old resin it will stick to it, but it will not form a singular mass, meaning the crack will still be there. It might work for some time, but the forces that created the initial cracking are likely still present and it may continue to widen underneath the new layer of resin.

Ideally, to stop further cracking, you'd widen the cracks slightly, apply resin to the cracks, apply matting over the top and coat the matting in further resin. The matting will give strength to the crack that resin alone won't.

You could certainly give it a try, but I imagine it wouldn't last as long as it would if the matting was used.

Let me know if you have any further questions.

Jacob