Gelcoat impact spider crack repair?

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rich201283

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I have an impact spider crack on the top side of my ufo 34, Whats the best way to repair?

Do i grind the stress lines back to the laminate then fill with epoxy? How easy is it to get a colour match?

I just dont want rain getting in
 
When I had one repaired on my boat the guy who did it ground the laminate back a good few mm. Then built the GRP back up before re-gelcoating. He said if you don't the star crack will just re-appear.

Matching the colour will depend on what you're trying to match to but there's an art to it and you might find you need alot of different colours to get just the 'white' you need.

I had a few smaller jobs done on the boat at the same time too and the cost was only around £150, he threw in a litre of matched gelcoat too for me to keep.

I don't know where you are but I think this was him:

Finish 1st
Phone: Fax:
Mobile: 07713 158751 Skype:
Web: Email: andrew_wickenden@yahoo.co.uk
Address: 69 Palfrey Heights, Brantham, Manningtree. CO11 1SG
Fibreglass repair colour match specialist. For all types of Fibreglass.

C.
 
Epoxy is generally not very UV resistant, so deck repairs are usually done with ordinary resins and gelcoat used in GRP construction. Matching the colour is not easy, as said above, and I have paid a professional to do small gelcoat repairs on my boat.
 
Gel coat repair

I would seriously consider painting over the cracks with a polyurethane 2 pack paint. This is a resin in itself and can be quite viscous so it will enter the cracks and has very good adhesive qualities. The main problem will be getting the colour right. But then you have that problem with any gel coat and by not grinding out the cracks you have a much smaller area to paint. You may be able to tint the paint with a universal type pigment or the paint shop may supply a little pigment as required to get the right colour.
On the other hand if the hull is old and well damaged it might be time to repaint the whole hull. good luck olewill
 
You could try one of these kits:

http://www.repairproducts.co.uk/page79.htm

In a previous life I was a silk screen printer, we didn't have the pantone system that litho printers have for colour matching and so we had to do it all by eye. Whites can come in a multitude of shades.
Take a good hard look at your gelcoat and try to decide what kind of 'white' it is (assuming your boat is white). Does it have a tinge of pink to it, or yellow (creamy) or is it blacky?
Sounds weird, it's hard to explain but mine definately has a brighter, harder tinge, which would mean there's some (tiny amount) of black in it and no red, yellow or blue.

This website is pretty helpful:

http://www.boatus.com/boattech/casey/02.htm

Andrew told me to never use any abrasive less than 180, build the coat high and leave it proud, and always clean thoroughly around the area before you start otherwise you'll end up with a permanent witness mark.

The colour match is the hardest part, filling, shaping and polishing is easy enough. I did a couple of repairs this winter using the gelcoat mix I'd been given. Not as good as Andrews work but it passed.

C.
 
rich201283 said:
I have an impact spider crack on the top side of my ufo 34, Whats the best way to repair?

Do i grind the stress lines back to the laminate then fill with epoxy? How easy is it to get a colour match?

I just dont want rain getting in
Click to expand...

I did such a repair to a well worn Colvic Victor about a month ago.

With a fairly large spider crack on the topside about six feet aft from the bow.

First washed the area on the hull.

Treated the area with oxalic acid solution to remove the staining.

Lifhtly sanded (400g) the area to remove the remaining marks.

Tack ragged the area.

I drilled a tiny shallow countersunk hole at the outer end of each crack to stop any spreading further.

Then using an 18volt grinder with an extra thin disk I V'd out every crack. (took some time)

Tack ragged away the dust.

I filled all the cracks with white gell coat thickened with silica. I needed two white gellcoat repair kit's containing - gellcoat, catylist and silica from the local chandlery to do the job. Epoxy cannot be used on the topside as it get's attacked with UV over time.

The owner was not too concerned with an exact match as the hull was so bad elsewhere and the basic match was quite good. He really wanted to make sure that all the cracks were sealed at as low a cost as possible and there was a time restraint for the boat being relaunched.

When dry sanded the area back and repeated the tack rags, filling and sanding a couple of times more until the surface was flat.

Used progressively finer wet and dry then polish.

I was then asked to repair all the other cracks, bumps and marks on the hull.

The original gell coat on that particular hull was reasonably thick in places so I got off with quite a lot of sanding. I would think that a UFO would also have a fairly thick layer of gellcoat.

The colour match is such that the crack cannot be seem without close inspection.
 
Do i drill down on the end of each crack to stop it spreading?
What woul you use to v shape the cracks and how wide would be sufficient?
I was thinking of using a dremel.

Also is it gelcoaut i need to use and not epoxy?
 
flipper said:
I have a Wests fibreglass repair manual and a book on repairing GRP boats, both in PDF, that I can send if you PM your email address.

Patrick
Click to expand...
can you send them also to me?

[edited by admin - please use private message function instead of posting email addresses on the forum. Thanks!]
 
rich201283 said:
Do i drill down on the end of each crack to stop it spreading?
What woul you use to v shape the cracks and how wide would be sufficient?
I was thinking of using a dremel.

Also is it gelcoaut i need to use and not epoxy?
Click to expand...

1 - Yes
Drill at the end of each crack with no more than a 2mm drill but only as deep as the taper on the end of the drill bit.

2 - You only need a very narrow v cut. One of the important things is to make sure that both sides of the original crack are cleaned off otherwise you will get a dark line along the track of the original crack caused by dirt in the walls of those cracks. Even 2mm would be suficient in some cases.

3 - A dremmel would be fine. I did not use one because my cheep copy one has burnt out.

4 - Definately Gellcoat not epoxy. If epoxy is used it will discolour very quickly with time even when coloured by using white epoxy colouring paste. I found that out the hard way.
 
LadyInBed said:
I've not come across the term 'Tack ragged' before, please enlighten me.
Click to expand...

http://lmgtfy.com/?q=Tack+rag

TACK CLOTH (ták klôth; a.k.a tack rag; tac cloth) is a specialized type of wiping cloth that is treated with a 'tacky' material. It is designed to remove loose particles of dust, dirt and lint that would contaminate a surface that is to be painted, coated, laminated, photo-etched, or otherwise finished.
 
repair

Have used dremel with v shaped bit on star crack on hull with good result years ago. Gave a good v shape to fill in.

john
 
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