Thanks: 0
Likes: 0
Needs Pictures: 0
Picture(s) thanks: 0
Results 1 to 6 of 6
Thread: A quick question re wetting out.
-
7th July 2014, 12:57 PM #1SENIOR MEMBER
- Join Date
- Aug 2008
- Location
- Birkdale
- Age
- 51
- Posts
- 279
A quick question re wetting out.
I am repairing a damaged fibreglass kayak. It has a few cracks which I have glassed over, but one of them has not completely filled the weave(It was getting dark and I didn't see it). Now that he epoxy has gone off, how do I get the weave to fill properly. Will I need to sand it back completely to achieve a good bond or is there another way? I don't want to sand it right back as this will compromise the strength of the glass, and require another layer over the top.
-
7th July 2014 12:57 PM # ADSGoogle Adsense Advertisement
- Join Date
- Always
- Location
- Advertising world
- Age
- 2010
- Posts
- Many
-
7th July 2014, 02:25 PM #2
My understanding is that the epoxy does not fully cure for some days so you still get a chemical bond for 2 or 3 days after the last coat.
I find I need numerous coats to fill the weave completely and I don't sand between them unless there are already enough coats to provide a buffer against sanding through to the glass.
My opinion is that assuming you only did the repair yesterday your best course is to get a thin fill coat on ASAP and then follow up daily until happy with the result.Cheers, Bob the labrat
Measure once and.... the phone rings!
-
7th July 2014, 04:09 PM #3
Epoxy (depends on the hardener and environmental conditions) will be past is chemically active range from 12 to 24 hours. Fast hardeners sooner, slow or extra slow hardeners later. I consider all epoxy formulations cured after 18 hours and assume I need to wash any potential blush off, then "tooth" the surface for the next coat.
You don't have to grind down into it, just a good 80 - 100 grit scratch is all it takes. You just want to knock the shine of it and add a scratch, for the next coat to "key" into mechanically.
Add some balloons or other light weight filler to this coating, so you do fill the weave, in one shot.
-
7th July 2014, 04:47 PM #4SENIOR MEMBER
- Join Date
- Aug 2008
- Location
- Birkdale
- Age
- 51
- Posts
- 279
Thanks for the replies, guys. I ran the cabinet scraper lightly over the patch, then put another coat over the top to fill the weave. The original epoxy was about 19-20 hours old, but with some cool overnight temps (9-10 degrees c), it wasn't fully hardened, so hopefully everything will be ok, and there will be a sufficient bond.
-
8th July 2014, 02:54 AM #5
Epoxy cure rates can be all over the place, but the rule I use is the thumbnail test. If you can easily dent the fresh, but dry coat with a thumbnail, it's still chemically active and you can over coat without sanding and rely on a good chemical bond. If you have to push fairly hard to make this dent, technically it still may be chemically active, but I don't trust it and will wait until it's like rock and sand, knowing I'll have a mechanical bond instead.
Boats are full of mechanical bonds, so nothing to work about, just a little extra work. Since it was relatively cool, you'll probably be safe. The reason I'm so cautious about this is simply, most folks don't have good environmental controls, so their coatings are prone to blush, dust, dirt and suicidal bugs. Given this, most DIY coatings need some "dressing" before the next coat goes down.
-
8th July 2014, 07:54 AM #6SENIOR MEMBER
- Join Date
- Aug 2008
- Location
- Birkdale
- Age
- 51
- Posts
- 279
Thanks PAR. The epoxy was a little harder than you describe, but still way too soft to sand. I'm quietly confident that it will be ok. Hopefully by giving it a light scrape over the top of the weave, there will be a mechanical bond if there is no chemical bond.
Similar Threads
-
shellac+wetting+agent
By justwantin in forum FINISHINGReplies: 11Last Post: 26th February 2014, 12:03 PM -
quick Question
By leroy in forum METALWORK FORUMReplies: 6Last Post: 6th September 2012, 03:46 PM -
Very Quick Question
By Powerb in forum WOODWORK - GENERALReplies: 11Last Post: 31st January 2010, 10:31 AM -
wetting a slab to raise grain
By jabell in forum WOODWORK - GENERALReplies: 8Last Post: 29th March 2009, 01:41 PM -
Quick question. . .
By Jedo_03 in forum WOODWORK - GENERALReplies: 10Last Post: 22nd July 2006, 10:30 AM