Fibreglass Surface Cracks

[Barking Mat]

Whoops, just read all the above and Chris Stevens no' 42. I can only (and for the first time) completely disagree with you. Irrispective of the age of GRP sand off all the gelcoat, clean up with acetone, ensure youve used a good grip abrasive for the polyester resin to attach, clean with acetone, mix up polyester resin, spread all over glass mat and ensure no air bubbles by repeated tamping, place gooey mess over old bit, if it risks to slip, slide or fall off, attach with plastic sheet and gaffer tape, we do this in upside down positions on up to 40 year old boats, and NEVER had a problem.

It's not rocket science, 4 percent catalyseur double or triple that in winter.

 

[ajlelectronics]

But is is still not osmosis, it is absorption.

 

[Chris Stevens]

But is is still not osmosis, it is absorption.

Its osmosis if you are a yachtie paying for repairs.................

 

[Vmax1974]

Sorry just seen this

I have been working with fibreglass as a laminator since 1996 so have learned a thing or 2

The crazing you see looks like its caused by the surface shrinkage on the gelcoat it is purely cosmetic and doesn't cause structural damage and due to the resin content of the fibres will still be watertight

Flat the area back so you can't feel the crazing polyester prime as its cheaper than epoxy anyway or even just 2k plastic primer and paint the surface i have done repairs for people that wanted me to re-gelcoat the surface but if you ask me its an unnecessary expense

 

[addjunkie]

Not all boat people are loaded, some are, but most are not, they spend every spare penny to go boating, often for far less than the cost of your wifes car.

You can be a yacht for a grand, barley the price of a tig.

 

[Chris Stevens]

Not all boat people are loaded, some are, but most are not, they spend every spare penny to go boating, often for far less than the cost of your wifes car.

You can be a yacht for a grand, barley the price of a tig.

Those who can afford £10k for osmosis repairs seem quite well off.

 

[MG David]

Vmax, would it be worth him putting some surface tissue on after he has sanded the gel coat off?

 

[Chris Stevens]

Sorry just seen this

I have been working with fibreglass as a laminator since 1996 so have learned a thing or 2

The crazing you see looks like its caused by the surface shrinkage on the gelcoat it is purely cosmetic and doesn't cause structural damage and due to the resin content of the fibres will still be watertight

Flat the area back so you can't feel the crazing polyester prime as its cheaper than epoxy anyway or even just 2k plastic primer and paint the surface i have done repairs for people that wanted me to re-gelcoat the surface but if you ask me its an unnecessary expense

Do you know Gary Bates who runs East Coast Fibreglass Supplies?

 

[cumbriasteve]

I may as well throw my two pence worth into the debate:

I think the marks are gel coat reaction to contaminants in the mould or mix and not cracks, saw it a few times when we used to lay up boat hulls.

We once had a batch of mould release wax that ruined three hulls before we figured out what was causing it.

 

[Vmax1974]

Do you know Gary Bates who runs East Coast Fibreglass Supplies?

Am there just about every 2 weeks as they are only 40 mins drive so i save on postage and collect

I have met gary a few times very knowledgeable fella

 

[Chris Stevens]

Am there just about every 2 weeks as they are only 40 mins drive so i save on postage and collect

I have met gary a few times very knowledgeable fella

Thought you might know them. Think they are probably the biggest online supplier of GRP related things in the UK now.

 

[Vmax1974]

Some really talented lads (and lasses) there too

 

[Chris Stevens]

Some really talented lads (and lasses) there too

Martin I think is East Coast tech guy? Talked to him quite a few times about suitable resin systems for bike fuel tanks, which they used to get asked about a lot.

 

[addjunkie]

Can you use fiberglass bike fuel tanks on the road?

 

[Chris Stevens]

Can you use fiberglass bike fuel tanks on the road?

I guess you can, as the ban on anything other than metallic bike tanks was lifted years ago. Most GRP bike tanks will fail in time though, as they are quite fiddly to make, and most producers use either the wrong materials or wrong production techniques............

 

[brightspark]

I had one on my Norton. came of on a bend and cracked it all picked the bike up and the petrol p....ed over the silencer and was steaming luckily it never went up .there not good if u ever have a head on with a car. tank rips off and can go through the car windscreen and incinerate anyone in it if it sets on fire

 

[addjunkie]

Guess ill have to watch the how to make an ali petrol tank, with two bits of string, 2 stones and a couple of twigs twigs videos on you tube then....

 

[Chris Stevens]

Making a good quality GRP tank isnt that difficult, but not the type of project for anyone who needs to rely on the net to help with info on how to do it.................

 

[addjunkie]

Making it isnt the problem, its making the plug, then the mould that would be the issue for me.....time versus cost, probably easier to buy one.

 

[Chris Stevens]

Why not use an existing tank for plug? If not making one from PU foam doesnt take that long, and if its for a popular bike and looks nice, you may well be able to sell a few if they are well made and resist E fuels..................