Author Topic: Bubbling Epoxy during a repair, Help Please  (Read 6897 times)

PJBrendel

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Bubbling Epoxy during a repair, Help Please
« on: August 18, 2015, 01:36:37 PM »
So my son put his knee through the deck of my Starboard Blend. It's a carbon board so I got some West System Epoxy, Carbon Fiber and watched a few videos.  I used to repair my boards in the Seventies so I didn't think this was going to be a big deal.

I prepped the area really well. Unfortunately the ding went all the way through to the foam so after removing loose material and doing a little under cutting I had about 1/4 of an inch to fill in some areas.

I mixed two small batches of epoxy, one with Q-CEL as a filler and one without. I first coated the the entire area to be filled with the epoxy.  Almost immediately I saw bubbles forming in the epoxy. The bubbles continued forming at a rate that was beyond the size of any void the epoxy could be filling. 

I did go on to add some of the resin with Q-CEL. This was probably a mistake as some small bubbles came up out of the filler.  I knew better but wanted to get the repair done.

I still need to sand and add a few layers of cloth but I'm hoping someone can clue me into my bubble problem.  As a chemist I figure there must be a reaction going on between the epoxy and something in the surfboard.  I thought that epoxy was used because it didn't react with EPS foam.

Thanks in advance for any help.

Paul

PonoBill

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Re: Bubbling Epoxy during a repair, Help Please
« Reply #1 on: August 18, 2015, 01:50:23 PM »
Probably just the epoxy running into voids. the air has to go somewhere. If it was bubbling briskly instead of just a few slow bubbles than you might have generated too much heat with too much epoxy in one place. If you have to fill a void bigger than perhaps 1/4" deep and an inch square you should patch it with foam. Relying on goop to do the job is never a good idea. Even two-part foam isn't a great repair.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

PJBrendel

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Re: Bubbling Epoxy during a repair, Help Please
« Reply #2 on: August 18, 2015, 02:04:39 PM »
Thanks for your advice Bill. Once cleaned up the ding was more of a Z shaped crack with the top and bottom of the Z being about an inch and a quarter in length and the diagonal being about two inches. The crack was only about one quarter of an inch wide so I thought I could get a way with filling the crack and then using a few layers of carbon fiber to get the repair flush with the deck.
I think you make a good point about the heat. The epoxy was given to me and it came with Fast Hardener.  I guess the EPS foam is more porous than I realized, but I was thinking something was reacting or maybe I neglected a prep step.

supuk

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Re: Bubbling Epoxy during a repair, Help Please
« Reply #3 on: August 18, 2015, 02:12:52 PM »
the problem is the board is gassing out while you are doing the repair most probably due to the temperature rising. Take the vent plug out and have a thermometer to had were the board it. Wait for the temperature to start dropping in the eve and then give it a hour or so for the board to stabilise and do the repair as normal.

PonoBill

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Re: Bubbling Epoxy during a repair, Help Please
« Reply #4 on: August 18, 2015, 02:34:31 PM »
UK is right, something that deep will outgas a lot. EPS is super porous. At this point the worst is probably over.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

supuk

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Re: Bubbling Epoxy during a repair, Help Please
« Reply #5 on: August 18, 2015, 02:50:14 PM »
in less a eps board is 100% sealed any work weather it is a ding repair or actual glassing or hot coat should be done when the board is in a climate controlled room or when the temp is stable or slightly dropping. When I'm building a board i don't consider it fully sealed until the second hot coat is cured.

PJBrendel

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Re: Bubbling Epoxy during a repair, Help Please
« Reply #6 on: August 18, 2015, 03:57:10 PM »
Thanks all!
Unfortunately the board has no vent plug so there was no where else for the gas to escape. I did make the mistake of doing the repair in the early afternoon and it was hot.  I had intended to do it in the morning but other things came up. So although initially in the shade by the time I go to it a large portion was in the sun, causing it to heat up even more. Probably a rookie mistake but I learned something.  I'll finish it tomorrow evening when the temp is cooling down.

Weasels wake

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Re: Bubbling Epoxy during a repair, Help Please
« Reply #7 on: August 19, 2015, 09:13:28 AM »
Next time, if it happens again, add a retrofit vent plug first (super easy), and leave it open during the repair process.
http://www.fiberglasssupply.com/Product_Catalog/SurfSailcom/surfsailcom.html
Scroll down the page and you'll see the vent plugs.
It takes a quiver to do that.

PJBrendel

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Re: Bubbling Epoxy during a repair, Help Please
« Reply #8 on: August 19, 2015, 09:27:55 AM »
I think that's a great Idea.  I may even try to add one during the winter.

mrbig

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Re: Bubbling Epoxy during a repair, Help Please
« Reply #9 on: August 19, 2015, 10:10:07 AM »
I have experienced the same bubbling and used SLIGHTLY less catalyst. Problem solved..
Let it come to you..
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SMIK 8'8" Short Mac Freo Rainbow Bridge
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supuk

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Re: Bubbling Epoxy during a repair, Help Please
« Reply #10 on: August 19, 2015, 11:08:29 AM »
a vent plug will not be enough to solve the problem if the  temperature is rising by more than 1-2 deg tops the only way you can sometimes cheat it is by using a vacuum on the vent plug to reduce the pressure inside the board very carefully but then sometimes you can do the same thing but in reverse trust me i do ding repair every day.

Do not adjust the amount of hardener used in epoxy it is not like polyester resin. If you do not use the correct ratio of part a to part b the resin will not cure properly.

mrbig

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Re: Bubbling Epoxy during a repair, Help Please
« Reply #11 on: August 19, 2015, 11:47:22 AM »
Charlie, you are correct!! I am usually making tiny batches to repair small dings and am measuring  by eye. Also not recommended. But I did notice that if I used slightly less 4% guesstimate, catalyst the bubbling went away.

Completely different than the poly of old. I suspect that there was something else going on as well that I missed. Like loosening a vent plug!  ::)  ::)
Let it come to you..
SMIK 9'2" Hipster Mini Mal
SMIK 8'8" Short Mac Freo Rainbow Bridge
SMIK 8'4" Hipster Twin
King's 8'2" Accelerator SharkBoy

Bean

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Re: Bubbling Epoxy during a repair, Help Please
« Reply #12 on: August 19, 2015, 12:23:59 PM »
If you positively have to get an EPS repair done in rising temps, you could ice-bag the board.  Ice sometimes also does the trick for fin removal and installations in hot temps.  But, I personally like what it does for my beer...mmm ice cold Heineken.   

PonoBill

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Re: Bubbling Epoxy during a repair, Help Please
« Reply #13 on: August 19, 2015, 02:50:08 PM »
Using less catalyst is effective in slowing the reaction for Poly, but means your resin won't fully harden for epoxies. the reaction isn't catalytic, its actually molecule to molecule polymerizing and becoming longer.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

PJBrendel

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Re: Bubbling Epoxy during a repair, Help Please
« Reply #14 on: August 20, 2015, 08:28:53 AM »
Well the good news is that last night in the cool of the evening I was able to apply a few layers of cloth.  There were no bubbles and the cloth laid flat and smooth.  After sanding and finish coating later I think I'll be ready for the weekend.

 


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