Gelcoat repair advice

nik · 28 November 2006, 13:24

Hello, I need some advice about gelcoat repairs.

I have a horizontal gash, about 18 inches long on the lower part of the hull. This has gone down to the GRP.

I don’t think I can do this repair in one hit because the gelcoat would probably sag and drip before I could get any tape on it.

So, I was thinking I could put on a thinner layer of gelcoat, wait till this has set but is still tacky, then apply another layer of gelcoat on top.
Is there any problem with this idea?

I have read about something called a “styrene attack”, but I don’t really understand it or if it is applicable in this case.

I will be doing this outside, so the air temperature is not likely to be above 12 deg C.
Thanks, Nick.

Rob Sayer · 28 November 2006, 15:42

I have used Plastimo gelcoat filler successfully, ene colour as long as its white.
If cold warm with a heat gun,will go in one coat

nik · 28 November 2006, 17:26

Unfortanately I am using black. I also have no power available.
I have thought about strapping a hot water bottle to the side though.

Richard B · 28 November 2006, 21:41

You really do need power! I used a hot air gun to get the gash really warm and dry first.

Best method is to overfill the damaged area and sand it back once it's cured. Use a cork block, or improvise if it's a concave area (I used a coke bottle!) You will need a selection of grades of paper, the finest will polish the area up a treat. Make the effort to get some matching gel coat as even first time repairs can be almost invisible.

Aidan · 30 November 2006, 15:58

Hello Nik,

You will need to dry out fully any moisture so that it does not trap within repair.
I suggest that you use Hair drier and small genny. Hot air gun very good too such as Black and decker as long as you do not over heat.
I am not a Gel coat specialist but I would dry out entire area as moisture can travel by what I believe is called capillary action.
If it was me, I would dry out and apply a light coat of resin or paint to cover the gash and a bit around. This will keep it safe for the moment and further ingress.
You gotta get the moistue out before you seal..
Aidan

nik · 30 November 2006, 19:04

Hmmm, how do you know when it is all out. It has only been in the water for about an hour after the damage, and has been out of the water for a couple of weeks now.
Nick.

Biggles · 30 November 2006, 19:46

Its probably dry.
With regards your heat problem what about a gas heater of some sort. Obviously you've got to be careful but I should careful use of a gas blowlamp will dry out any moisture. Use a battery drill to grind out any dirty fibreglass, clean it with acetone then effect your repair.
If you do the job mid day you should get the best of the weather as well.

Richard B · 30 November 2006, 20:00

Quote:

Originally Posted by Biggles

careful use of a gas blowlamp

Quote:

Originally Posted by Biggles

Use a battery drill to grind out any dity fibreglass

Be careful, don't drill too far into the charred remains of the hulk you just set fire to with the gas blow lamp!

I used a Dremmel with a tiny milling bit for this, and that was plenty big enough.

Biggles, you sound like the Frank Spencer of gelcoat repairs!

Biggles · 30 November 2006, 20:11

Oh well,

Everything in moderation. I'm sure he didn't think to stick the blowlamp up against the gelcoat. Nice of you to point out the obvious Richard.

And I'm sure I mentioned to be careful. More obviousness as well.

Biggles · 30 November 2006, 20:13

I normally use a Dremmel and actually never thought of that until you mentioned it, because I don't have a battery powered one but I'm sure you can get them. Nice of you to remind us of that one as well Richard.

Richard B · 30 November 2006, 21:46

Quote:

Originally Posted by Biggles

Oh well,

Everything in moderation.

Especially moderation! Some things are a no go though, and just accept that putting a gas blow torch anywhere near a GRP hull is not sensible.

nik · 01 December 2006, 19:25

Spoke to humber today, they are pretty certain there will be no water ingress to the fibres. Just make sure that the GRP is dry on the surface.

Also have solved the power problem. I am going to park the boat on the hard, lean it over to one side and use the power supply on the hard, (£12 a day mind).
Nick.

Biggles · 01 December 2006, 19:38

Saves on gas then. LOL.

Biggles · 01 December 2006, 19:46

Quote:

Originally Posted by Richard B

Especially moderation! Some things are a no go though, and just accept that putting a gas blow torch anywhere near a GRP hull is not sensible.

I think it was a train of thought well worth exploring. In the absence of any other ways of drying out the Fibre Glass some portable source of heat was going to be required. And heating by some sort of gas implement seemed like a route persuing. Therefore I think your jovial attitude to my offers of advice to nik when you had no viable answer yourself were totally destracting from the thread, and if instead you had devoted some of your thoughts to helping someone in need you might have been able to have come up with a more suitable answer.
As luck has it Humber believe he won't have any trouble with water ingress and any way nik has managed to source some electric now, so he won't need to resort to gas. it was a last resort anyway but one that with some care and thought would have worked.

codprawn · 01 December 2006, 20:26

From the photos in Paul Tilley's workshop it looks like he uses a very large gas blowlamp - as my tubes don't look very melted I assume it is fine as long as you don't get too close!!!

Biggles · 01 December 2006, 20:34

Cheers Codders for the moral support.

Richard B · 01 December 2006, 21:40

Quote:

Originally Posted by Richard B

You really do need power! I used a hot air gun to get the gash really warm and dry first.

Quote:

Originally Posted by Biggles

you had no viable answer yourself

Quote:

Originally Posted by Biggles

nik has managed to source some electric now

Biggles, you really do need to engage brain before hitting keyboard!

Nik - I have a set of boat stands you could use instead of propping the boat on one side.... sounds like the damage is right the way underneath?

nik · 01 December 2006, 23:06

Thanks Richard,
I dont think I need them though. The idea of putting the boat on the hard and tipping it was to get easier access and get the damaged area closer to vertical rather than upside down.

Otherwise I can shove the boat partially off the trailer, the front will come up clear of the rollers allowing easier access, I will make sure it remains attached so that it does not come off the trailer too much.
Nick.

Nos4r2 · 03 December 2006, 16:45

Quote:

Originally Posted by nik

Also have solved the power problem. I am going to park the boat on the hard, lean it over to one side and use the power supply on the hard, (£12 a day mind).
Nick.

Bloody hell. 4 days of that and you could buy your own cheap genny.