Lots of Fisheyes \ Epoxy Seperation

General Discussion
1

Hi,

Im attempting to repair an old kiteboard i had hanging round - i know its not a surfboard, but id rather make and rectify the mistakes i`ve made on this than the next surfboard i shape!

Ive had to take the board back to the carbon fibre in places where there was delamination and major cracks from impacts. Its been going well until i finshed the repairs and thought id sand the whole base back and put a light coat of epoxy as a gloss coat on to finish it off properly.

I have done this twice now(!) and both times got a really bad reaction where the epoxy is laid on, looks ok for 10 mins, then starts to seperate all over the board. 

THe second time, i did this, i was ultra careful, using gloves, got rid of all the dust afterwards, then applied it with a nice new brush. Still got the reaction though!

I`m using resin research epoxy (no thinners( eg additive f or anything). Its probably about 18 degrees ish in space.

The only thing i can think of is that im really short on resin at the mo, so was a bit mean with it going on thin. Could this cause the reaction? When i did the repairs, it went on thicker and didnt seperate.

 

Here`s some pics - 

Thanks, Mike

2

http://www2.swaylocks.com/node/1007898

3

Is that epoxy gloss coat laid directly over the carbon fiber, or over fiberglass over the CF?

4

Its surface contamination from wax or silicone that was applied to the board at some point in its life. 

5

It’s a surface tension issue, with a few possible causes. Use more resin and if you see any separations like in the pics use your finger and lightly rub the epoxy to connect it back together.

~Brian

 

6

 

the board was carbon fibre with some form of resin from the factory over it. I sanded the whol board (inc my repairs which were fibreglass over the exposed carbin fibre) with 80 grit sandpaper so it was even all over and not shiny anyway and then laid my glos coat over this. Just to fill in old scratches and give it a nice finish really.

Not sure of the boards history, it was a friends which he gave me when it broke a couple of years ago. 

Like you said, could be contamination from some point. I thought i would`ve got rid of anything in the boards original resin as i really sanded it back.

The question is, should i spend time sanding it back for the third time(!) and possibly wasting more resin! 

If there was no contamination, is it possible i could get that reaction from not using enough resin? It went on really nice and i thought it looked really good until i checked back 20 mins later!

7

Did you mean that you did not use "Additive F"???

I agree with mako's surface contamination theory. 

To correct I would sand it off and before trying again give your space time for all the dust and debris to settle...like 24 hrs. Then wipe down the surface with a lint free cloth or paper towel with a bit of denatured alcohol (some will disagree with this part), let it dry for several hours. Also I would definitely use "Additive F". I imagine it's still pretty cold there right now... I like to warm the "Additive F" in a hot water bath to make sure it's dissolved well. Look at it to make sure it's perfectly clear and not cloudy.  I've used RR in very cold weather here in North Carolina (snow on the ground) and I either heat my space or I warm the Resin (never the hardner) and I don't store the resin, hardner or F in the cold.

I had this issue on several builds with RR and later found that my air compressor was most likely the culprit, spewing vaporized oil into my shop. I don't use it now for several days before using RR and have never experienced this issue again.

Good Luck!

 

8

Randy at Channin used to make their own mixture of waxes and silicone ? for the final rubdown before bagging, they shipped boards to Orlando for the Surfexpo and one looked like the head of a cut nail punctured the deck.

Tony brought the board to my factory after the shop for repair, It was sanded thoroughly, filled, glassed, hot coated, sanded, but when glossed over, it was fish eye city like your board.

The waxes and silicones are able to penetrate below the top coat some how ? took several glossed before it was suitable to rub out.

Greg Loehr said many years ago that some really cheap epoxies won’t even let another epoxy bond to them, the anhydrides ?. I bought some cheapo epoxy for 25 bucks a gallon, repaired an EPS board and glossed it with Poly, the Poly wouldn’t even begin to gel, used it to glued up multi stringer poly blanks, the Polyester wouldn’t gel over the glue lines ?

So, there can be many reasons as to what and why this is happening

9

some good advice here so far,

if you combine them all, you may see the big picture.

resins used for laminating are seldom very good as a 'paint'

the resin only needs to 'wet' out the cloth.

generally, any product used as a paint has additives that act as a 'surfactant' to reduce surface tension between the coating and the substrate your trying to coat. (better self leveling and less fisheyes)

I believe Additive F is the equivalent of a surfactant for RR epoxy.

That will certainly improve matters.

However, if the surface is contaminated in any way (i.e finger prints, oils, wax, silicone, release agents)  any coating will fish-eye

or worse.... and bead up like rain drops on a waxed car.

odds are good that they used something to help pop it out of the mold.

there is also the unlikely possibility that your non-blushing RR really did leave a non binding residue ( amine blush) that contaminates the surface for any additional layers.

just kidding....but it happens with a lot of epoxies.

 either way, its still not great as a paint/varnish if your looking for showcase results.

for the next try:

give some thought to possible contamination sources.

surface prep, wash, sand, clean, dry

(i'm one that does not like denatured alcohol, but only because of the stuff that makes it 'denatured :)

use additive F.

warm the resin, warm the room with the board, as well.

brush out a thin layer on a "SMALL" area of your board to test the process and save materials until things are sorted.

no worries (there's always real paint)

-bill

 

 

 

 

 

 

 

 

10

Thats exactly whats happened with this- no reaction until that final coat.

Not sure what to do with it now, but i`ll probably end up following what woody above does.

Resanding it again, then gloss it again using some additive f this time (what exactly does that do - make it flow better?) and warm the resin up beforehand - it is pretty cold here still.

Will let all the dust settle before cleaning the baord this time too.

Just have to summon the will to go and sand it again for the third time now!!

11

[quote="$1"]

Randy at Channin used to make their own mixture of waxes and silicone ? for the final rubdown before bagging, they shipped boards to Orlando for the Surfexpo and one looked like the head of a cut nail punctured the deck.

Tony brought the board to my factory after the shop for repair, It was sanded thoroughly, filled, glassed, hot coated, sanded, but when glossed over, it was fish eye city like your board.

The waxes and silicones are able to penetrate below the top coat some how ? took several glossed before it was suitable to rub out.

Greg Loehr said many years ago that some really cheap epoxies won't even let another epoxy bond to them, the anhydrides ?. I bought some cheapo epoxy for 25 bucks a gallon, repaired an EPS board and glossed it with Poly, the Poly wouldn't even begin to gel, used it to glued up multi stringer poly blanks, the Polyester wouldn't gel over the glue lines ?

So, there can be many reasons as to what and why this is happening

[/quote]

Yes to everything JimP says....There's lot's of wierd stuff that can happen....And it has happened to me!

But I also see a person not following the rules. The simple RR rules layed out time and time again....I'm sure someone can post the link to the Epoxy primer thread. Or to the thread I did for first time glassers.

Clean hands. Clean shop. Proper mix. Proper mix time. Add F. Proper shop temp. NO SOLVENTS.

18c= 64.4F....too cold...Proper shop temp means that you and all your chemicals are at proper temp.

24c would be great.

If my project went wierd on me like yours did....I would continue to stir my epoxy mix and continue to apply resin to that spot and lightly brush it off. I've had some saves and some blobs........Sand it , fix it........

12

Cool - thanks guys for advice.

 

I`ll follow the guides above - it think getting  everything clean of dust after sanding and using some additive f might be the key for me. Temperature might be a prob though! Just starting to warm up here - is about 10c here now outside - might have to stick the resin bottles on the radiator to warm them up!