cyrus77

iTrader: (4)

Using West Systems. how much to grind old fiberglass? If I am grinding roving do you make it perfectly flat with 80 grit? Anyone use the Norton wire wheel?
Thanks

phragle

iTrader: (3)

Is it an epoxy boat to begin with??

cyrus77

iTrader: (4)

No not expoxy.

phragle

iTrader: (3)

Any special reason your using west instead if say VE?

cyrus77

iTrader: (4)

No. I just know of WS. I am grinding now and want to get the maximum adhesion, but no one has any pictures on the internet of grinding Glass.

Unlimited jd

iTrader: (5)

What are you doing exactly?

glassdave

iTrader: (1)

maximum adhesion is with 36 grit for a purely physical bond, or any other bond really. Epoxy rely's almost completely on a mechanical bond so the area must be 100% prepped, that means a thorough sanding and grinding. if it is partially sanded and there are even small areas between the sand scratches even that will decrease bond by whatever percentage is not sanded. I do prefer vinylester (still an epoxy in a styrene matrix) over a straight up epoxy though. A good VE gets ya great physicals at a fraction of the cost and will be more then most will ever need.

ramos45

iTrader: (1)

Dave, I followed all the rules when I redid my bilge but I do have a question on methodology. Why is it still necessary to sand/grind the existing fiberglass only to adhere new fiberglass to it? I understand if it's covered with gel or paint, the glass needs to be exposed but I mean when it's already bare glass all inductions given still say to grind it. Couldn't you just wipe clean and laminate the new glass?

phragle

iTrader: (3)

grinding gives it a good clean tooth

ramos45

iTrader: (1)

Understood, thank you.