Glassing sequence questions

Topics pertaining to fibre glassing, finishing issues, concerns and tips, epoxies and epoxy problems/resolves
kjay
Posts: 149
Joined: Thu Oct 26, 2006 2:03 am
Location: brisbane

Re: Glassing sequence questions

Post by kjay » Fri Aug 10, 2012 12:18 pm

Sea-Bee, Having just glassed and bogged my second hull this week I would suggest in theory Terry's process is the "best practice" option. however you will be in for a huge day as you say, I did the same way as martica, glassed, sanded, then bogged. If you went with doing everything in the one day you would have to work out how you are going to bogg the inboard side of the mini keel with out touching any of the just glassed hull. not sure how you would get away from leaning on the hull, if you were to have problems with the wet glass pulling at all the problems would just start to compound and you could end up in real trouble with thing starting to cure, The geougen bros book and ATL are happy with the 80grit sand between glass and bogg, Just remember to add the hardener to the bogg mix as it is a bitch to scrape off two days later when you realise what you have done.
good luck and have fun sanding.

John

Darren
Posts: 58
Joined: Thu May 29, 2008 8:37 am
Location: Launceston, TAS

Re: Glassing sequence questions

Post by Darren » Fri Aug 10, 2012 5:22 pm

I think the Gougeon brothers book recommends initially coating the ply. The logic being that dry ply absorbs the epoxy, and you can be left a bit resin poor in the glass (perhaps without realising, resulting in a poor wood/epoxy bond, and not enough resin in the glass near that bond. You need resin in the fibre matrix to ensure the fibres are all bonded together, otherwise, the glass does not have its expected strength.

Quick edit: If your building a ply/epoxy boat, get the Gougeon Brothers on Boat Building, and read. Keep it under your pillow at night.

sea_bee
Posts: 107
Joined: Sat Jul 09, 2011 6:09 pm
Location: Pillar Valley NSW

Re: Glassing sequence questions

Post by sea_bee » Fri Aug 10, 2012 8:29 pm

Darren wrote:If your building a ply/epoxy boat, get the Gougeon Brothers on Boat Building, and read. Keep it under your pillow at night.
And best of all, it is available as a free download at
http://www.westsystem.com/ss/assets/How ... 061205.pdf

sea_bee
Posts: 107
Joined: Sat Jul 09, 2011 6:09 pm
Location: Pillar Valley NSW

Re: Glassing sequence questions

Post by sea_bee » Fri Aug 10, 2012 8:37 pm

kjay wrote:... I would suggest in theory Terry's process is the "best practice" option...
... problems with the wet glass pulling ...
John
Thanks John

I can see that you are right about trying to apply fairing compound over wet glass, but what about on the dry side of "tacky", when the glass has set, but is still green enough for a chemical bond? Like getting into applying the fairing first thing the next morning?

Would that see the job done without sanding of the glass before the fairing?

Chris

kjay
Posts: 149
Joined: Thu Oct 26, 2006 2:03 am
Location: brisbane

Re: Glassing sequence questions

Post by kjay » Sat Aug 11, 2012 6:58 am

Sea Bee, Yes you are probably able to do that, not sure when amine blush starts to appear during the cure if at all, you may need to do a test piece to check the curing to green stage

Darren
Posts: 58
Joined: Thu May 29, 2008 8:37 am
Location: Launceston, TAS

Re: Glassing sequence questions

Post by Darren » Mon Aug 13, 2012 12:00 pm

sea_bee wrote: And best of all, it is available as a free download at
http://www.westsystem.com/ss/assets/How ... 061205.pdf
That's a handy tip - My printed one is somewhat of a family heirloom. It's not resulted in any boats yet though (but it is about to produce a caravan). A family of dreamers I'm afraid.

mahnamahna
Posts: 580
Joined: Wed Aug 02, 2006 4:48 pm
Location: Gosford NSW

Re: Glassing sequence questions

Post by mahnamahna » Tue Aug 14, 2012 9:23 pm

I applied my fairing compound (bog) onto the "green" resin next day. I finished glassing at around 8pm and was in the shed next morning at 6am applying the bog. It has bonded beautifully. No peel ply, no sanding of just the epoxied glass. I had a mixing error and had to remove 2/3 of the first hulls bog with a one inch chisel. Not fun. Took me 2 weeks!!! But that aside, I would still apply the bog wet on tacky or wet on green. Much easier. Why sand more than you have to, and why use peel ply when a chem bond is so much stronger. Having said that, the level after the glass is only bog and paint, super bonding is never going to be tested. But chem is better than mechanical.

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