Results 1 to 20 of 41
Thread: Topcoat Questions
-
25-06-2020, 04:16 PM #1
Topcoat Questions
Hi Folks,
Yes, another thread on Topcoat woes but thought I'd ask the question in public as thats how we can all learn hopefully.
Firstly, I've done quite a bit of glassing over the years, from ponds to hospital tanks and apart from the usual learning curve mistakes, all has gone fairly well.
I'm just on with a new pond extension which will more than double the size, with a 1000l filter pit on one end which will become a moving bed.
All the building work is done and 2 weeks ago I finished the glassing, 2x450gsm & tissue. I'm really pleased with the finish so last week I decided to give it a topcoat.
Thank God I started with the filter pit as I've got the nightmare problem of a tacky finish!
I've got a sneaky feeling I know what has gone wrong but would like some second opinions if possible please.
The air temperature was about 18 degrees with a slight breeze.
Topcoat was mixed for over 20 minutes before decanting 2Kg at a time to smaller bucket.
Catalyzed at bang on 2%, mixed well and applied by brush (it was a bit too tight in the pit to use a roller)
I mixed a total of 5l of topcoat and I would say I had about an inch left in the bottom of the last bucket when I'd finished (about 5.5 sq/m of surfaces to coat)
The finish was really good and I left it at that for a couple of hours before checking for anything that needed a touch with sandpaper.
As I said, the surface is still tacky now nearly a week later and in this heat. Its not wet and is rock hard but colour will lift onto an acetone rag so obviously not right. I'm just glad I didn't do the whole lot!!!
The only thing I can think is that the Topcoat may have been too warm when I applied it as we'd had a couple of good days before, or the heat had affected the catalyst which was already in the dispenser.
The only other option is that I've been supplied Gelcoat instead of Topcoat but this is probably unlikely.
Has anyone got any other theories before I start the pond (and re-do the filter pit)?
At the moment I am toying with the idea of ordering new topcoat and catalyst as I couldn't bare the thought of rubbing the whole lot down if it goes wrong again!!!
Thanks in advance.
-
25-06-2020, 04:34 PM #2
Hi, sorry to hear about your issues. It does sound like you may have added it to a hot surface??
There are some details here.
https://www.grproofing.com/troublesh...t-still-sticky
You mentioned that it is no longer tacky but will leave a residue if wiped with acetone, is this not normal? I thought the acetone causes topcoat to become softer.
I am by no means an expert here and you have far more experience. Just trying to save you having to redo it?
Sent from my iPhone using Tapatalk
-
Hawk101 Thanked / Liked this Post
-
25-06-2020, 04:49 PM #3
Thanks for the reply mate.
The surface wasn't warm but the Topcoat itself might have been too warm, which makes the wax content too thin to rise to the surface and cut off the air to the topcoat (or so I've read)
Never had a problem with it before now but I cant recall ever having glassed while we've had such good weather.
Its literally the only thing I can think of apart from bad catalyst or it hasn't got any wax added (gelcoat)
Edit:
The surface is hard but very slightly tacky to the point you would only just notice by hand, and as you say colour will lift with an acetone rag, which it shouldn't.
-
25-06-2020, 04:53 PM #4
-
25-06-2020, 07:07 PM #5
-
25-06-2020, 08:14 PM #6
-
27-06-2020, 11:45 AM #7
My initial thought was "that's gelcoat". I would try a small test patch and see if you get the same results. If so, it will eventually go off. Allow two weeks or so.
If it is gelcoat, you can still use it on the pond, add 2% wax solution to the gelcoat as that is exactly how topcoat is made. I have done this before, it works perfectly. Try a patch with wax added. See if that goes off like you'd expect topcoat too.
If the test works well and it is indeed topcoat, then in the filter bay, if its really gloopy, you can wipe acetone on and scrape it off. If that doesn't work, you can sand it off. If it is hard enough to sand I would try and go over the tacky bits again with a hot mix of top coat. Again try test patch first as its a bit 50/50.
If it works Make small batches or go quickly. Have spare pots and rollers incase it goes off too quick. There's every chance that will be a permanent fix.
If you have to sand it. I use an angle grinder with a 125mm foam sanding pad and 60 or 80 or 120 grit velcro sanding disks. That will make short work of it.
Good luck.Last edited by Alburglar; 27-06-2020 at 06:30 PM.
2660 Gallons. 4" Bottom Drain and Skimmer. Draco Solum 16 Drum. Anoxic Filtration. Air lift returns.
-
29-06-2020, 11:30 AM #8
Thanks mate,
Its a weird one! I was the same as you and initially thought it was Gel Coat but I've done a test patch since and its set fine BUT it was a lot cooler and I used fresh catalyst so god knows what the problem was with the first go. That being said, the topcoat in the filter pit has hardened up but I now don't have any confidence in it, time to ring Mr Alexander!!
I'll keep you posted.
-
30-06-2020, 11:54 AM #9
Just a quick update,
I've been in touch with Ken and all I can say is what a top bloke!!
Loads of advice over the phone, a quick juggle of his diary and he's coming in the morning with fresh Topcoat to finish the pond off.
If I'd wanted to do it myself he'd have given me as much free advice as I'd needed which is pretty rare these days!! Good old fashioned service!!
Kens going to have a look at the Topcoat I was supplied to see if there is anything obviously wrong with it.
He did say that there has been a bit of a spike in Topcoat problems which MAY be down to a bad batch from a particular supplier, but at the moment its only guesswork.
-
01-07-2020, 12:16 PM #10
So, Ken's been and sorted the pond for me!
Turned up early morning, checked all the glassing, few bits of prep and nice shiny new topcoat.
Can't thank him enough for slotting me into his busy diary!!
If you're looking for a no nonsense Fibreglass Contractor at a reasonable price, give him a call or PM him through the forum.
-
01-07-2020, 06:22 PM #11
Not like this miserable git then?
2660 Gallons. 4" Bottom Drain and Skimmer. Draco Solum 16 Drum. Anoxic Filtration. Air lift returns.
-
01-07-2020, 06:26 PM #12
-
01-07-2020, 06:30 PM #13
... It was on the video 'FAQs about my job'
... I think it's a thing called glass bubbles, but I'm not sure.
... Maybe Ken knows?2660 Gallons. 4" Bottom Drain and Skimmer. Draco Solum 16 Drum. Anoxic Filtration. Air lift returns.
-
01-07-2020, 06:35 PM #14
Maybe this
https://www.easycomposites.co.uk/#!/...rospheres.html
Sent from my iPhone using Tapatalk
-
01-07-2020, 06:42 PM #15
I thought it was that, but I've watched a few youtubes of people mixing it up and it didn't quite look right, so I'm not 100%.
You used to be able to get 'chopsies' which is glass strand chopped up finely. I used to make it but it's a bit of a task doing it on a large scale.2660 Gallons. 4" Bottom Drain and Skimmer. Draco Solum 16 Drum. Anoxic Filtration. Air lift returns.
-
freddyboy Thanked / Liked this Post
-
01-07-2020, 06:50 PM #16
Al, have a look on '' the general section '' page 16, first thread down Gpr lining by stuffyrat , might explain the abrupt reply
-
01-07-2020, 07:12 PM #17
I bet he's fun at a party.
Manners cost nothing.2660 Gallons. 4" Bottom Drain and Skimmer. Draco Solum 16 Drum. Anoxic Filtration. Air lift returns.
-
01-07-2020, 07:31 PM #18
in another video (i've watched loads of his... me thinks too long not wearing a vapour mask!) he says it's just talc mixed with resin - i.e, the stuff you sprinkle on your bits... I've looked this up elsewhere and it seems to ring true. Also, you can use the microglass beads from easy composities - i've used those with epoxy resin at school when building our race cars. Makes a paste for patching mould work. But the bubbles are bad news to breathe in!
Also, I should add - The guys at Easy Composites are top blokes - They've given me soo much advice with the school projects and really know their stuff - I bet they'd help or tell you for sure if you gave them a call (they're trading at the moment as well) I wish I'd brought my kit from them rather than the other supplier, but they don't do gel coat with wax already in it to make flowcoat.. you have to roll your own, so I thought I'd save the hassle... turns out that may not have been the best choice if you've been following all the recent 'flow coat' issues in various threads!)Last edited by RobWinter; 01-07-2020 at 07:57 PM.
-
01-07-2020, 07:39 PM #19
Also.. I did actually buy some non perfumed talc off amazon for a quid (who actually uses it in 2020 lol!) for this purpose, but didn't go that route in the end. I just used Ideal Seal automarine to seal around my return and skimmer. If you're trying to seal in between the PU sheets, then I guess that's different. In my case I went with foil insulation boards and used foil tape on the seams.
I can try a tester if you want? still got a smidgen of resin left! (before you blow your budget on talc lol!)Last edited by RobWinter; 01-07-2020 at 07:54 PM.
-
freddyboy Thanked / Liked this Post
-
01-07-2020, 08:14 PM #20
I've heard of talc being used before, but i just assumed that was a bit old school and perhaps there was something more appropriate. However ken reckons snowcal, which is line marking chalk powder (calcium carbonate).
And yes a tester would be good. I've been using pu18 to seal the pu boards to my tub, but then I have to wait 24hrs before I can crack on glassing over the top.Last edited by Alburglar; 01-07-2020 at 08:21 PM.
2660 Gallons. 4" Bottom Drain and Skimmer. Draco Solum 16 Drum. Anoxic Filtration. Air lift returns.
-
freddyboy Thanked / Liked this Post
Running heater at low temp?
Covering the pond with polycarb should be enough to stop water temps dipping below 6C for the most...