Fibreglassing Pool Question??

[Chase]

With the collective knowledge herein someone might be able to answer this question for me.. I've got an old concrete (with fibreglass overlay) spa attached to the pool and internally it's pretty fkd. The original fibreglass coating has cracked so I've had to rip it out.

Anyone ever had to reline a pool or spa with fibreglass and if so is there any particular type of glass to get or just the old trusty we do the bikes with? Any info here would be great.

[pav69]

ill ask a mate of mine steve and let you know

[Chase]

Cheers Pav.

[Redmohawk]

Yep done 2 , got to use a special resin is chlorine resistant (not cheap if you buy it in a small 20l drum better bought by the 220l drum) but its not much better than run of the mill shit we use for general stuff to be honast when layed over concreat.

If your going to re do it , I'd just use the run of the mill stuff make sure to use a wax in the top coat. And use plenty of mat as the vibration can make the fiberglass seperate from the concreat with vibration due to blowers etc.

[336LJ]

I used to do this for a living. but we used to do it in reverse, gel coat layer on the moulds, then the vinyl ester(greeny clear stuff, dont quote me its been years) from a chopper gun mixing the glass in with it, works out to be about 3 layers of matting glass at a time, 1 shift would do 2 of those layers, then the white stuff. fuckin things were thick as. I did once do a babtist tank at a church that we built out of wood first, then layed the fibreglass down, 1 layer of the green shit, then 2 layers of the clear sanded it back and sprayed a rubber lining over the top so it was non slip.also waiting to hear back from the dude that helped me, its easy but make sure you wear a mask the fumes are awesome enough to make your eyes water when the resin is going off in ur littl hidy hole

[Chase]

quote:Originally posted by Redmohawk

.. And use plenty of mat as the vibration can make the fiberglass seperate from the concreat with vibration due to blowers etc.


Good point about the vibration stuff Red, hadn't thought about that.


quote:Originally posted by 336LJ

I used to do this for a living. but we used to do it in reverse, gel coat layer on the moulds, then the vinyl ester(greeny clear stuff, dont quote me its been years) from a chopper gun mixing the glass in with it, works out to be about 3 layers of matting glass at a time, 1 shift would do 2 of those layers, then the white stuff. fuckin things were thick as. I did once do a babtist tank at a church that we built out of wood first, then layed the fibreglass down, 1 layer of the green shit, then 2 layers of the clear sanded it back and sprayed a rubber lining over the top so it was non slip.also waiting to hear back from the dude that helped me, its easy but make sure you wear a mask the fumes are awesome enough to make your eyes water when the resin is going off in ur littl hidy hole


Cheers LJ, you mean the gelcoat was sprayed onto the inside first, to use like a waterproofer?

[Redmohawk]

Moulds would have been positive formers , so first layer put on is inside (water side) of spa. Positive formers (molds) are easyer to work with in volume production.

A gel coat can be layed on over your job , on the horozontal surfaces you can pour it on and work it about with a broad scraper and let gravity smooth it a little for you (it will be thick though) , on the vertical's brush is prob the easyest.

If your planning on doing a gel coat no wax in mat layers (not needed). Or you can add pigment to the final layer of a glass coat (with wax) to save cash and avoid doing a gel coat.

[Chase]

Ah yeah... don't really get most of that.. just trying to work out wht stuff is best to put in the concrete spa.

[Redmohawk]

A gel coat is basicly just a layer of specific resin (thicker than usual stuff and has a pigment in it to colour it) more for looks than anything, has no fiber in it to give a smooth coat.

It can separate from fiberglass layer if put over a top coat. A top coat is a layer of glass with wax in it (wax is added in final layer ,stops resin from setting with a sticky residue , generally used on top coat only to make finished product better for skin contact)

I'd wash your concete with sugar soap then with just water , finish off your prep with a wipe down with some acetone. Give the whole thing a thin coat of resin with a paint roller to give it a slightly ruff stipelled effect (helps to key second layer).

Glass layers (depending on what you mat you use) prob 3 layers of chopped strand mat in 180 gsm would be about right. Should work out to be about 4 or 5 mm thick when all layed up. Use a metal roller to work all the air out of the mat with every layer.

Last a top coat of resin with some wax in it (get the wax from same resin supplyer and a pigment if you want) or use a gel coat instead just pick your colour use the same supplyer for the lot and you should be fine. A Light sand of the final glass coat before a wax top or gel coat can aid in adhesion of final layer but isn't really nessasary if you get it on right after final glass layer has just cured. If you have to wait more than a day give it a lite scuff with some wet n dry and a wipe down with some acetone.

[Chase]

Ahhh... (light bulb goes go) brilliant Red. Thanks Mate :D

[Redmohawk]

stay away from dark pigments in the final layer , if the fiberglass top coat does start to break down the darker pigments will taint your skin and light coloured hair (blue turns blonde hair green etc) stick to light colours and theres no issue.

[336LJ]

If you can grind off all the ratty fibreglass thats there, not sure how bad it is. But if its not too bad you can skip the priming/VE-waterproofing layer and go straight to layin down the white stuff (still cannot remember what its called).

If your starting from bare concrete, dilute some resin (VE, greeny purple stuff) with acetone, add your catalyst and slop it onto the concrete or the first layer of glass might not stick as good. Let that go off, then chuck down a layer or 2 of the glass with VE, i think we used to sand with 50grit on the orbital sander between layers. When you get to the white stuff dont be shy with the resin pour it all over the joint even if it looks like too much. Make it sloppy. Ends up much smoother and the matting/glass texture goes away
Sand good enough to get rid of all the loose strands cause they suck when they bite once hard. You can usually get away with just sanding the last layer and making it pretty but im sure ud be best using some kind of sealer. We used rhino lining. Like a spray on rubber. There should be plenty of options.

Dont mix your resin too hot. It can get so hot shit catches fire i was told but i onoy.ever saw smoke, but also will blister and bubble up on your job, we used about 15mL of catalyst (methyl ethyl ketone peroxide???) In a milkshake sized cup each time. Big industry uses $40k chopper guns with catalyst mixed in automatically.

[Chase]

Prob 90% of the fiberglass has come off now, so it's pretty much just the concrete shell. I ordered some vandex grey - which is a render that has crystals in it to fill in the cracks in the concrete and be putting that in this weekend weather permitting, and hopefully getting on with the fiberglass the following weekend - should be fun [xx(]

Thanks for the advise guys, much appreciated.