Gelcoat Repair filler or Flowcoat for minor repairs?

 

I have a few stone chips/ minor scratches as well as some wear marks/ indents where from the keel rollers (they have developed over time through travel/ pressure on the same spot when its on the trailer) on the hull of my boat that Id like to fix

 

Ive been doing some reading on whats the best stuff to use- flowcoat or a gelcoat repair filler and Im getting mixed info that I was hoping someone could help clear up through actual experience with them:

 

- Gelcoat repair filler: I got recommended a product called Septone Gelcoat repair filler, so ordered some of that. It appears easier to use that flowcoat as it sticky/ more workable- less liquidy than flowcoat When it arrived, the label says “not for use below the waterline unless the top is coated with a waterproof finish” although other people have said they use it on the hull with no problems. After some googling, it seems like older tins of this stuff didn’t have this warning on them- so either it’s a result of ass covering by the company or they have recently changed the recipe? Im thinking this might be meant for boats that stay in the water, but it might be OK for trailer boats when they are only in the water for 48 hours or so max etc. it’s a polyester resin Kit as opposed to a epoxy. Google again says that this may end in a tacky surface…

 

- Flowcoat: Again, google says that flowcoat is basically gelcoat with a wax mix to make it cure better/ non tacky etc. Bit more painful to use on the hull (vertical/ angled surface) from past experience as its runny.

 

That’s the background of where Im at basically. I guess the questions are:

1) Is the Septone Gelcoat repair filler OK to use on a trailer boat for below the water line?

 

2) Will the Septone or the flowcoat produce a harder/ better wearing finish (especially on the roller weat patches on the keel?

 

3) Overall, should I be using flowcoat or the gelcoat filler? (the bits Im repairing aren’t bad damage- stone chips, small scratches and then the roller wear which is a bit bigger)

Im obviously leaning towards the flowcoat option, just wanted some additional info, especially if one will give a harder/ better wearing result that the other, on the above if anyones had any direct experience- the internets throwing up a fair bit of conflicting information

 

Cheers in advance  

 


Posts: 196

Date Joined: 15/01/10

I got a mobile guy to come

Sat, 2018-10-13 17:57

I got a mobile guy to come around and repair my boat, and he would mix his own gelcoats. I do remember the differnce between the first and final mix was the wax. The first mix had no wax and was used to fill the scatches/chips and was allowed to cure 24hrs. He applied a second coat to the deeper scratches as the first application was not quite enough agained allowed to cure. The final coat was with the wax added to his mixture and the reason was purely to allow the repair to be sanded. ie if you were to sand the repair without the final coat with the wax you would have alot of trouble trying to break the surface to sand the repair. Sorry dont recall the product he used.

 

 

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null

Posts: 549

Date Joined: 30/12/09

I would just use gelcoat

Sun, 2018-10-14 10:28

I would just use gelcoat itself with catalyst. Etetch out the chip and fill it with a mixed brew of gelcoat and catalyst. Just do small batches so it doesn’t go off. Once filled get some masking tape and cover the gelcoat over to try and mould it into the shape it needs to be if on a radius or on the flat surface. That way you aren’t rubbing down a big lump and also helps doing upside down work. When rubbing back use a block otherwise you tender to rub back around the edge of the repair more and then expose the fibreglass  

The wax is generally used for when you are spraying the gelcoat on and it’s going to be finished surface only to be polished.  The wax just takes away stickiness. If you’re not going to bother about rubbing back the repair then use some wax. If you do rub it back once you do give it a polish and wax once completed. 

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ranmar850's picture

Posts: 2014

Date Joined: 12/08/12

if you need to fill a little more

Sun, 2018-10-14 10:55

 Upside down can be difficult. Try and fill with resin and some chopped strand rovings, it will always sag and run. The way around it is to get some Cabosil powder ( actually called fumed silica??? ) a really fine, white powder that you mx with the resin prior to adding hardener. Get it to the  consistency required, add catalyst, apply to the repair area. Get the consistency right, it won't sag. Then flowcoat over that.

gruntre69's picture

Posts: 509

Date Joined: 15/10/16

 I've use the Cabisil and it

Sun, 2018-10-14 11:22

 I've use the Cabisil and it works great, you just keep adding till you get it as thick as you want. Great bog that's fully compatible with the resin system you are using and aslo makes a great glue. You can also get a product called PVA which can be sprayed over the gelcoat to seal and set. This is what I have used to make repairs before and avoid adding wax. It just skins off a micro layer which seals the surface. after the Gel hardens you just wash it off with water. You need a spray gun to use this.

Gelcoat and flowcoat are the same thing when finished. Gelcoat is designed to stay tacky because it is for spraying onto a mold and either more layers of gel or laminate layers are sprayed on top of it, hence the name "GEL". The tacky finish allows perfect adhesion of subsequent layers. Removing air from it allows it to harden fully either by an new layer of gel, the wax addition which rises to the surface and effectively seal out the air (Flowcoat) or by spraying the PVA on top to seal it.

The wax layer of the Flowcoat is VERY thin. Manufacturers use it to finish the insides of molds like gunnels and bilges where a polished finish isn't necessary and the gun Flowcoat finish is acceptable. They often fleck some colour over it as well.

I don't know about the septone product you refer to but remember that trailer boats spend 99.9% of their lives out of the water so I wouldn't worry too much about water line issues on a trailer boat...

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 Marine trimmer NOR (available for clears, tops, carpet, upholstery, custom equipment covers)

Posts: 315

Date Joined: 19/06/14

Rockhopper

Mon, 2018-10-15 13:21

Flip me your mobile if you’re still in Cvon. If you are we can catch up and I’ll help you out. .  

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 My wife understands why I clean my rods n reels in the shower....

 

Quobbarockhopper's picture

Posts: 357

Date Joined: 28/05/10

 legend mate, will PM you

Mon, 2018-10-15 20:18

 legend mate, will PM you

walloped's picture

Posts: 160

Date Joined: 08/04/12

Or get an ali boat big fella!

Mon, 2018-10-15 21:04

Or get an ali boat big fella!

Quobbarockhopper's picture

Posts: 357

Date Joined: 28/05/10

...and a back brace and then

Wed, 2018-10-17 15:19

...and a back brace and then learn how to spray paint in Wheatley colours instead... 

 

 

brown364's picture

Posts: 154

Date Joined: 25/08/15

Nor

Tue, 2018-10-16 20:34

 Any recommended suppliers for fumed silica and flowcoat products as i am in the midst of repairs myself? Tia

Marineboy's picture

Posts: 627

Date Joined: 14/03/14

Nor

Wed, 2018-10-17 17:20

hawke bros in Osborne park are fibreglass gurus, they have all the gear and will chew your ear off with help and advice.

Cheers

mark 

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 My spots are so secret even the fish don't know about them !

Posts: 549

Date Joined: 30/12/09

I just to go to the aqua

Wed, 2018-10-17 00:23

I just to go to the aqua technics yard and offer them a carton of beer or two and use to get a heap of resin and glass and gel coat.  

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 Get busy living, or get busy dying!

gruntre69's picture

Posts: 509

Date Joined: 15/10/16

 I used Kirkside in Osborne

Wed, 2018-10-17 10:37

 I used Kirkside in Osborne park and bought some colouring powder to colour match from Whitworths. Be careful if colouring white, you only need a mminiscule bit to get an off white colour..

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 Marine trimmer NOR (available for clears, tops, carpet, upholstery, custom equipment covers)

brown364's picture

Posts: 154

Date Joined: 25/08/15

cheers

Thu, 2018-10-18 20:11

 Marineboy & Gruntre69! stopped in at Hawkes on way past and i am sorted. Dont know anyone that covers seats out there do ya. have some old flip tops that may need a spruse up!

brown364's picture

Posts: 154

Date Joined: 25/08/15

ended

Tue, 2018-10-23 21:42

 up going to both and Kirkside gets the thumbsup on price and info. worked out nearly 40% cheaper on product purchases. Now to complete the work and get wet!