Fibreglassing/flowcoat waterfall problem, advice please

[kernowkoi]

Hi All,

I have a waterfall to my pond that has two pools which I plant up as a veggie filter.
This was fibre glassed in 2007 when it was built; I applied another coat of flow coat last year after a rebuild (details below).
This went wrong and I have had to rub down to the original flow coat.

Questions:

1. Can you actually put a new flow coat on top of a well keyed previous flow coat?

2. Could I seal it 1st say with G4 or similar. Or is there some other preparation I should/could apply?

3. I notice there are few pin holes from which moisture is beading through from below.
So I am inclined to apply another coat of matting before the flow coat. If I did the same two questions 1 & 2 would also apply?

Any thoughts comments please? I’m loathed to rip the whole thing up!

Regards
Steve


Below is a picture of the waterfall as built in 2007.

Original waterfall

WF_original.JPG (92.67 KiB) Viewed 28721 times

Last year (2009) I added additional filtration to the head of the water fall. See next pictures

New Waterfall

New WF.JPG (100.57 KiB) Viewed 28721 times

New waterfall filter bays, outlet

New WF Filter.JPG (76.52 KiB) Viewed 28722 times

I fibre glassed the interior of the new filter bays with no problems. As I had to build up the side walls of the water fall and seal it into the new filter outflow. I keyed the original flow coat and reapplied a new flow coat.

Now here's where I went wrong (I know I did )

1. The day I applied the flow coat it was VERY hot so I cut down the catalyst to 1% instead of 2%

2. I roller’d the flow coat on too thin and I don’t think I keyed the old well enough.
Where as in the new filter bays it was brushed on thick over fresh fibreglass.

3. I let it 'bake' in direct sunlight. The filter bays where naturally shaded.

Every thing looked OK so some weeks later when I put water in the filter to start flushed this ‘new’ fibreglass out before use. The filter bays where ok. But in the waterfall although it felt and looked ok, the flow coat developed patchy white areas and underwater it became soft and easy to scrape off.

So now we have some decent weather at last I’m back on this project to at last (I hope) finish it off.

[Bob Hart]

Steve,

As long as the waterfall fibreglass has now dried out, you should have no problems. If it has plenty of matting in there, just ensure the flow coat is well rubbed down with some very rough sandpaper (60/80 grit) and then apply another coat of resin first. This will seal any holes in it and you can go up to 4% catalyst if you want it to go off quickly. Just roller it on as thick as you can. One trick if you want a thick coat on it, is to wait until it is just starting to go off in the bucket and then get it on there quickly and it will be slightly thicker.
Then rub out any lumps and bumps and flowcoat it again. Always do this out of direct sunlight as it will go off too quickly, a tarpaulin usually dos the job well. In hot weather you can go down to 1% and it will still cure OK, otherwise just keep it to the standard 2%

[kernowkoi]

Hi Bob,

Thanks for the reply. Sounds good. I'm half way through rubbing back the rubbish flow coat I put on last year.
I'll finish up and take some more pics so you can tell be if you think I've done a good enough job.

The matting is good just as I say a few pin holes so just resin over that. That will bond ok to remaining original flowcoat?

Just don't rain please

Rgs
Steve

[kernowkoi]

Hi Bob,

Here are some pictures now I've rubbed down to the original flow coat.

What do you think?

For comparison, the first two shows some partially rubbed down flow coat. The last two show each pool rubbed down.

Water Fall rubdown compare.JPG (75.83 KiB) Viewed 28609 times

WF closeup before rubdown.JPG (81.42 KiB) Viewed 28606 times

WF closeup after rubdown.JPG (64.58 KiB) Viewed 28606 times

WF closeup after rubdown2.JPG (80.61 KiB) Viewed 28607 times

In the last picture I have marked the pin holes. I'm finding that the heat of the day is drawing moisture from below, that bead up. How will I prevent this from potentially ruining the new resin you suggest putting on?

Rgs
Steve

[Bob Hart]

Problems like this are fun to resolve!

What I would do is this:
1. Mix up some very strong resin/catalyst mix, something like 10%. You wont need much though, just enough to paint onto the affected area.
2. Get a hot air paint stipper gun, or if you dont have one just use a hot hair dryer. Heat the area with the pin holes, while keeping an eye on the resin.
3. Get the area quite hot, then paint on some of the resin. This will go off pretty quickly now, keep an eye on it. Paint on more resin as you can, especially as it starts to go off in the bucket.
4. What you are trying to achieve is to seal the area with resin that has gone off hard

Once this is done, then you can resin the whole area, once dried, do the flowcoat.

Have fun!!!!!

[kernowkoi]

Thanks Bob,

Sound like a good plan. I'll let you know how I get on

Rgs
Steve

[Matthew]

Pointing heat at uncured resin/flocoat?

You could set yourself on fire doing that! Take a look at the hazard warning labels on the resins, even better look at the flash points in the data sheets for the materials.

Waiting for flocoat to thicken up to get it on thick? Bob, I'm sorry fella but this is plain and simple bad advice to the guy.

The entire water fall needs re glassing by a very experienced grp specialist who knows how to deal with this kind of situation.

This is a classic case for re glassing the entire waterfall.

Kernowkoi, please be very very careful as you are dealing with some highly volatile materials here and I'd hate to see you get hurt or end up with dead fish.

[Bob Hart]

Hi Matt,

Please read what I've written again if you dont mind.

I've not advised him to heat uncured resin, or advised to wait until flocoat has nearly hardedned.

What I have advised him to do is to warm the area before applying resin. And also to wait for the resin to start to harden off before applying it. In this was it will cure quickly from application and therefore seal the area's with issues. Once cured off apply the flocoat as usual.

Many people are practical people but who cannot afford to pay someone to do it for them and therefore need a little advice in how to cure the issues they have.

Hope you agree Matt, nice to see you on the forum. You gonna be working in Kent at all soon?

[Matthew]

Yep, read it again Bob, and I'll put my hands up to misreading what you put.

Good luck to the guy with the problem in any case.

[kernowkoi]

Hi Bob,

Thought I'd post up a couple of pics of how I'm getting on.

1st Pic shows about 3 weeks after I'd finished as per your sugestions. Little bit of rain water had got in, but looks promising

flowcoat1.JPG (80.24 KiB) Viewed 28196 times

2nd/3rd Pics show the water fall course full of rain after the downpoor we have had the last week or so. No sign of the white blooms and softening of the flowcoat I had previously

flowcoat2.JPG (107.88 KiB) Viewed 28197 times

flowcoat3.JPG (103.23 KiB) Viewed 28194 times

I'm keeping it a bit pumped out so as to not let any thing nasty wash into the pond. I have had this whole filter/water fall system full of water and flushed twice.
Once more tommorow I think and then the middle of next week I'll get the media in the filter and get it running. will post some more pics then.

Thanks for your help Bob.

Rgs
Steve

[Bob Hart]

Brilliant Steve, glad it all went well and has cured the problem for you

[kernowkoi]

Hi Bob,

Read Duncan's excellent post on the 'correct' way to configure jap mat, exactly what I intend to do.

Hears a question I'm sure you will be able to answer. What's the best tool to cut jap mat with

Else where I read an angle grinder is the best thing, if so what type of blade should I use I've got nearly every type!

Other suggestions are heated Stanley knife, ouch

Saws are just going to make a horrible mess I think

Rgs
Steve

[Bob Hart]

The missus electric carving knife is supposed to do a great job - just dont tell her what you've been cutting it with - LOL

[vippymini]

if you have not got an elec carving knife the either a jig-saw or a circular saw does the job. just mark the lines with a marker pen and chop away

[kernowkoi]

Hi Bob (and All),

So finaly got water fall running here's the pics i promissed.

Once again thanks for your help Bob.

Rgs
Steve