Reply
 
Thread Tools Search this Thread Display Modes
 
Old 10-12-2020, 10:00 PM   #1
Veteran Member
 
City: Semiahmoo
Vessel Name: Ardeidae
Vessel Model: Defever 44
Join Date: Dec 2019
Posts: 47
Epoxy or Polyester, how do you know which?

I saw a suggestion on another thread that said, if you have screw holes or you a going to make any, in your deck, you should drill an oversized hole and fill it with the proper resin, epoxy or polyester. There was no information on how to know which to use. It just said that it had to match what was used on the deck GRP. My question is, how do you know what that is, or how can you find out? Does it really matter? I'm looking at cracks that need repair also. I've never worked with fiberglass before but, I'm up (down?) for learning. I'll try to include a picture.
Click image for larger version

Name:	Cracks in hardtop.jpg
Views:	94
Size:	49.3 KB
ID:	108877
__________________
Advertisement

jbloyd is offline   Reply With Quote
Old 10-12-2020, 10:16 PM   #2
Guru
 
boatpoker's Avatar
 
City: Port Credit
Vessel Name: DIRT FREE
Vessel Model: Benford Fantail 38
Join Date: Sep 2012
Posts: 2,814
Epoxy boats are extremely rare due to the high cost of epoxy.
New epoxy will bond to old polyester
New polyester will not bond to old epoxy.

Epoxy has a much better adhesive quality than polyester regardless of the original resin

If in doubt use epoxy.
__________________

__________________
It's taken me 69yrs to get it right. I ain't changin' now !
If you can live with the consequences, go for it - wg
Y'am what y'am an' thats' all that y'am - Popeye
I had an allergic reality - Jillie the Bean
boatpoker is offline   Reply With Quote
Old 10-12-2020, 10:24 PM   #3
Guru
 
Comodave's Avatar
 
City: Au Gres, MI
Vessel Name: Never Say Never
Vessel Model: President 41 DC
Join Date: Jul 2015
Posts: 9,975
For repairs I prefer epoxy. It is stronger and will grab onto the old fiberglass better. It is a bit more expensive but it is probably insignificant in the overall scheme of things boating.
__________________
Boat Nut:
If you are one there is no explanation necessary.
If you arenít one, there is no explanation possible.
Comodave is offline   Reply With Quote
Old 10-12-2020, 10:29 PM   #4
Veteran Member
 
City: Semiahmoo
Vessel Name: Ardeidae
Vessel Model: Defever 44
Join Date: Dec 2019
Posts: 47
Comodave & boatpoker, thanks. Epoxy it is. Takes the guesswork out and, in either case, as long as I use epoxy the end result will be superior to poly.
jbloyd is offline   Reply With Quote
Old 10-12-2020, 10:48 PM   #5
Guru
 
Comodave's Avatar
 
City: Au Gres, MI
Vessel Name: Never Say Never
Vessel Model: President 41 DC
Join Date: Jul 2015
Posts: 9,975
You canít go wrong with epoxy if you can afford it.
__________________
Boat Nut:
If you are one there is no explanation necessary.
If you arenít one, there is no explanation possible.
Comodave is offline   Reply With Quote
Old 10-13-2020, 05:01 AM   #6
Guru
 
psneeld's Avatar
 
City: Ft Pierce
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 22,383
The problem with epoxy for repairs is if you you want to gel coat over it.

Normally it is not recommended or claimed possible....but West Systems claim it is if you prep it right. Google and look for their online repair manual.
psneeld is offline   Reply With Quote
Old 10-13-2020, 05:37 AM   #7
Guru
 
O C Diver's Avatar
 
City: Fort Myers, FL... Summers in Crisfield, MD
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 9,562
Quote:
Originally Posted by psneeld View Post
The problem with epoxy for repairs is if you you want to gel coat over it.

Normally it is not recommended or claimed possible....but West Systems claim it is if you prep it right. Google and look for their online repair manual.
Just did it Saturday. Bonded in a piece of Coosa board that had 1/4" of fiberglass (polyester) already on it, with West System and bonding filler. After it cured and off gasses (about 5 days), I sanded it and wiped it down with acetone. 2 layers of gelcoat, and the project in the anchor locker is done. No issues with adhesion.

Click image for larger version

Name:	20201011_091158.jpg
Views:	89
Size:	75.1 KB
ID:	108878

This picture is from 5 years ago when Sean increased the divider height. No adhesion problems.
Click image for larger version

Name:	20201011_091258.jpg
Views:	78
Size:	78.5 KB
ID:	108879

Ted
__________________
Blog: mvslowhand.com
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
O C Diver is offline   Reply With Quote
Old 10-13-2020, 05:44 AM   #8
Guru
 
psneeld's Avatar
 
City: Ft Pierce
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 22,383
I have always avoided it due to the " advice"...wonder if it is just another boating urban myth from people not doing certain or adequate prep? Or it works better with epoxies that cure faster but less or no amine blush?

Curious minds want to know....
psneeld is offline   Reply With Quote
Old 10-13-2020, 06:20 AM   #9
Guru
 
O C Diver's Avatar
 
City: Fort Myers, FL... Summers in Crisfield, MD
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 9,562
I think it comes down to surface prep. Throughly sand off the surface and wipe it down twice with acetone. It works for West System anyway. Can't say whether it works for other epoxies.

Ted
__________________
Blog: mvslowhand.com
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
O C Diver is offline   Reply With Quote
Old 10-13-2020, 07:34 AM   #10
Guru
 
boatpoker's Avatar
 
City: Port Credit
Vessel Name: DIRT FREE
Vessel Model: Benford Fantail 38
Join Date: Sep 2012
Posts: 2,814
Amine is water soluble, so fresh water will remove.
If the epoxy is clean, sanded and primed with two part primer, gelcoat adhesion is not an issue. One part primer sorta maybe works a bit sometimes.
__________________
It's taken me 69yrs to get it right. I ain't changin' now !
If you can live with the consequences, go for it - wg
Y'am what y'am an' thats' all that y'am - Popeye
I had an allergic reality - Jillie the Bean
boatpoker is offline   Reply With Quote
Old 10-13-2020, 07:48 AM   #11
Guru
 
psneeld's Avatar
 
City: Ft Pierce
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 22,383
Thats the rub, West recommends a primer transition, others not.
psneeld is offline   Reply With Quote
Old 10-13-2020, 09:07 AM   #12
Veteran Member
 
lwarden's Avatar
 
City: San Diego
Vessel Name: North Star
Vessel Model: Lindell 36
Join Date: Jun 2020
Posts: 94
On the question of filling holes; I use West System epoxy mixed with colloidal thickener (Cabosil) and a small amount of short milled fibers 1/8" mixed to a consistency which won't sag. For a cored area like foam or balsa core I prefer not to over-drill the hole but instead use a bent nail in a drill to ream out the core inside the skin, over-drilling just enough to get out the waste core. A vacuum on the opposite side of the hole from where you insert the nail helps to remove debris. Then load epoxy mix into a syringe and inject into the hole.

Regarding amine blush, soap and water cleanup after BEFORE any sanding or better yet, use a layer of peel ply which will allow you to strip the amine blush off without cleaning. Never had an issue with gelcoat over epoxy.
__________________
North Star
Lindell 36, Twin 370hp Cummins
lwarden is offline   Reply With Quote
Old 10-13-2020, 11:38 AM   #13
DDW
Guru
 
City: San Francisco
Join Date: Apr 2018
Posts: 1,351
For filling holes, the West Six10 works really well. Caulking tube dispensed, long cure time, will not run out of a hole even overhead. It is pre-thickened. The only downsides of it are it is relatively expensive, and the shelf life it about a year (then is starts to go lumpy).
DDW is offline   Reply With Quote
Old 10-13-2020, 12:30 PM   #14
Guru
 
Lepke's Avatar
 
City: Between Oregon and Alaska
Vessel Name: Charlie Harper
Vessel Model: Wheeler Shipyard 83'
Join Date: Jun 2016
Posts: 2,073
I use to build epoxy boats and had no problem with gelcoats. Also no blisters or delamination problems, even in major collisions. Epoxy bonds to anything better than poly.
For screws in wood, fiberglass, or fiberglass cored boats I use West 404 high density filler. Besides strength it also helps adhesion. Screws hold better to epoxy than to any other material.
For setting screws, I drill an oversized hole and fill with West epoxy and 404 mix. The hole is deeper than the screw length. Later I drill a pilot hole slightly larger than I would for wood or fiberglass because the threads don't penetrate the much harder epoxy as well. When I drive the screw, I put a small amount of epoxy down the hole as a lube. The screw is bonded to and encased in epoxy. Water will never weep down the threads. Items like stanchions, properly done, will never become loose again. To remove the screw later may require a small impact tool. The tool I use to drive screws has an impact function.
When setting in epoxy, you don't need a screw as long or as big as would be used without epoxy.
Lepke is offline   Reply With Quote
Old 10-13-2020, 02:22 PM   #15
Guru
 
Seevee's Avatar
 
City: st pete
Vessel Model: 400 Mainship
Join Date: Sep 2016
Posts: 2,587
Quote:
Originally Posted by Lepke View Post
I use to build epoxy boats and had no problem with gelcoats. Also no blisters or delamination problems, even in major collisions. Epoxy bonds to anything better than poly.
For screws in wood, fiberglass, or fiberglass cored boats I use West 404 high density filler. Besides strength it also helps adhesion. Screws hold better to epoxy than to any other material.
For setting screws, I drill an oversized hole and fill with West epoxy and 404 mix. The hole is deeper than the screw length. Later I drill a pilot hole slightly larger than I would for wood or fiberglass because the threads don't penetrate the much harder epoxy as well. When I drive the screw, I put a small amount of epoxy down the hole as a lube. The screw is bonded to and encased in epoxy. Water will never weep down the threads. Items like stanchions, properly done, will never become loose again. To remove the screw later may require a small impact tool. The tool I use to drive screws has an impact function.
When setting in epoxy, you don't need a screw as long or as big as would be used without epoxy.

Lepke,


Do you mix the 404 in the epoxy? I use West GFlex for about 95% of my epoxy projects, fill, screwholes, deep dings in the gel coat. However, by it self, it's hard to sand and smooth for a coat of gel coat. It has a brownish tint to it and takes several layers of gel coat to cover. To make it easier I use a product called Evercoat Formula 27, a toothpaste consistency light filler that is solid white and really easy to sand, and then gel coat over that.


Was thinking, perhaps the 404 (which is white) mixed in the epoxy might work better? Comments?


BTW, I've also tried adding a white pigment to the epoxy but doesn't work real well. Still hard to sand, but requires fewer gel coats.
__________________
Seevee
Seevee is offline   Reply With Quote
Old 10-13-2020, 02:48 PM   #16
Guru
 
obthomas's Avatar
 
City: Seabrook Texas
Vessel Name: TheVenture
Vessel Model: 1985 Bestway Labelle Sundeck 40ft
Join Date: May 2013
Posts: 533
Polyester has some cohesiveness and very poor adhesion but is cheaper than epoxy.
Epoxy has great cohesiveness and very good adhesion but costs more.
I use Epoxy in almost every instance.
To me polyester is a good filler.
obthomas is offline   Reply With Quote
Old 10-13-2020, 03:52 PM   #17
Guru
 
City: Anacortes
Join Date: Nov 2012
Posts: 972
Timely. Thanks for the input from those with the nuance.

Iím about scope a winter project of building a new transom door. Will probably do epoxy with gel as soon as I figure out how to replicate all the compound curves. But that will come later.
ghost is offline   Reply With Quote
Old 10-13-2020, 03:54 PM   #18
Senior Member
 
Brisyboy's Avatar
 
City: Brisbane
Vessel Name: Malagari
Vessel Model: Island Gypsy 36 Europa
Join Date: Mar 2015
Posts: 341
Quote:
Originally Posted by Lepke View Post
I use to build epoxy boats and had no problem with gelcoats. Also no blisters or delamination problems, even in major collisions. Epoxy bonds to anything better than poly.
For screws in wood, fiberglass, or fiberglass cored boats I use West 404 high density filler. Besides strength it also helps adhesion. Screws hold better to epoxy than to any other material.
For setting screws, I drill an oversized hole and fill with West epoxy and 404 mix. The hole is deeper than the screw length. Later I drill a pilot hole slightly larger than I would for wood or fiberglass because the threads don't penetrate the much harder epoxy as well. When I drive the screw, I put a small amount of epoxy down the hole as a lube. The screw is bonded to and encased in epoxy. Water will never weep down the threads. Items like stanchions, properly done, will never become loose again. To remove the screw later may require a small impact tool. The tool I use to drive screws has an impact function.
When setting in epoxy, you don't need a screw as long or as big as would be used without epoxy.
Thanks Lepke great explanation - just to take this a bit further -is it possible/practical to drill and tap a plug such as you describe and use a course thread machine screw?
__________________
George
Brisbane
IG 36 Europa
Brisyboy is offline   Reply With Quote
Old 10-13-2020, 03:57 PM   #19
Guru
 
Lepke's Avatar
 
City: Between Oregon and Alaska
Vessel Name: Charlie Harper
Vessel Model: Wheeler Shipyard 83'
Join Date: Jun 2016
Posts: 2,073
Quote:
Originally Posted by Seevee View Post
Lepke,


Do you mix the 404 in the epoxy? I use West GFlex for about 95% of my epoxy projects, fill, screwholes, deep dings in the gel coat. However, by it self, it's hard to sand and smooth for a coat of gel coat. It has a brownish tint to it and takes several layers of gel coat to cover. To make it easier I use a product called Evercoat Formula 27, a toothpaste consistency light filler that is solid white and really easy to sand, and then gel coat over that.


Was thinking, perhaps the 404 (which is white) mixed in the epoxy might work better? Comments?


BTW, I've also tried adding a white pigment to the epoxy but doesn't work real well. Still hard to sand, but requires fewer gel coats.

404 in epoxy is a very light tan. You can mix 404 anywhere from a little to putty-like. For small batches I use a drill and a small paint mixer. I found for mixing color in epoxy, you need more color than in poly. West epoxy with 404 seems to be immune to UV in cases where I left the epoxy exposed to sunlight for a couple years. I have vacuum sanding tools and don't find sanding epoxy noticeably different. And I probably use much coarser grit than most people. I usually start with 40.

A somewhat recent experience, I'm in my 70s now, I hired a house deck fiberglasser (son of a friend). I have an old, large wood boat with plywood over the original planked deck. (Not a good idea to hire a house anything to work on a boat) But I let him do part of reglassing the deck. When I do fiberglass over decks, mostly on commercial boats, I do an overlap so no hull flexing causes cracks where they joined. I didn't supervise and came back to find butt joints.

I use to be a fisherman and I go out in big waves in the PNW and my hull flexes. In big waves, if you have your eye near the deck on the stern and look towards the bow, you can see the main deck flex about a foot. All the butt joints near midships cracked. As a temporary fix I ground out the cracks, mixed West epoxy and 404, and filled. Meaning to come back and install an overlap patch. But I didn't get to it for a couple years and in the meantime managed to be in some waves larger than the ones the made the original cracks. But all my fixed joints held and didn't crack. If I hadn't been sold on 404, I would be now.

The boat came with poly fiberglass and cloth decks and cabin tops. To remove the old glass, I picked up a corner near the stem and ripped the whole deck off, the foc'sle, the sides and stern in one continuous piece. Just cutting the waste to a manageable size as I went down the deck. About a 30 minute job, plus clean up, no power tools, on an 83' boat, by an old man. So much for poly holding quality. And I did the same many times, the same way, when I had a yard, redoing decks done by some poly yard. Poly doesn't stick good to anything, including itself.
Lepke is offline   Reply With Quote
Old 10-13-2020, 05:07 PM   #20
Veteran Member
 
City: Semiahmoo
Vessel Name: Ardeidae
Vessel Model: Defever 44
Join Date: Dec 2019
Posts: 47
So much to learn...

A lot of great information here. I'll start with the West videos/tutorials and find something disposable to practice on before tackling the cracks. I'm going to put a couple of "C" clamps (with 2x4 buffers) on the areas to see if they will need to be repaired under pressure or just filled.
__________________

jbloyd is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 05:08 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012
×