epoxy

Discuss shaping and repairing techniques here.

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tiger
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Re: epoxy

Post by tiger » Wed Aug 17, 2011 11:00 am

I reckon go a hair finer Natho. In my experiences with EPS/Epoxy they have a much corkier feel, especially when riding a wave. I actually didn't like combo in a decent wave board, but like it in a groveller. The light corkiness seemed to be a problem for stability with speed and bumpy surface conditions, as well as in and around the whitewater.

With compsand I reckon dimensions can remain the same, cos the skins seem to dampen the corkiness back to that similar of PU.
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Re: epoxy

Post by Natho » Wed Aug 17, 2011 11:05 am

Thanks Tiger. Yeh based on my limited experience with these boards I would agree with your comments. This will be for a small wave quiver. Im thinking about 1/16 - 1/8 thinner, and just a little finer in the rail.

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Re: epoxy

Post by ric_vidal » Wed Aug 17, 2011 11:16 am

Natho wrote:Thanks Ric, I meant to say XPS/ Epoxy not EPS.
Natho, watch heat with the XPS, I have seen some 'orrible things happen... exposure inside a car (nose/tail), and especially in direct sunlight.

You can actually melt it, and as always, don't go near it with acetone or polyester, unless you want a chasm.

I shudder at the mention of the stuff - XTR :x

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Re: epoxy

Post by Natho » Wed Aug 17, 2011 11:30 am

Thanks for the tips Ric. This is not XTR as such but it is XPS foam with epoxy resin. Yeh I will certainly be extra careful. Was going to take a couple of em on my next trip to Hawaii, but given the heat issue I may leave these ones at home. Thanks again.

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Re: epoxy

Post by Natho » Wed Aug 17, 2011 1:10 pm

I also hear that XPS can have delamination issues? Anyone care to comment? Other than venting is there a more simple wat around this?

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Re: epoxy

Post by ric_vidal » Wed Aug 17, 2011 5:19 pm

Natho wrote:I also hear that XPS can have delamination issues? Anyone care to comment? Other than venting is there a more simple wat around this?
Natho, quite a number of the XTR boards, which is XPS foam, de-laminated. May have to do with the cell size as it tends to be fairly fine, then again so is some of the PU foam and they seem to have very few problems these days.

Also seen a few de-laminated sections on Firewires, both in the glass and those with balsa springers.

Think it pertains more to the resilience of epoxy though which is much more flexible and probably has a better memory than polyester which tends to crush and shatter so when you get compressions the resin follows the foam, in epoxy it wants to stay the shape it was so as the foam compresses the epoxy wants to spring back. This will then result in a delam.

I’m no chemical engineer but am also of the opinion that XPS has a very plastic almost oiliness to it. Could just be a false impression on my behalf.

Can you avoid it? Depends on how hard you are on decks and the density of the core itself or you would need to migrate to a compsand which relies on the integrity of the skin.

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Re: epoxy

Post by Natho » Thu Aug 18, 2011 12:00 pm

Thanks Ric, Ive heard the delamination issue can also be caused by slight gas build up under the glass? High heat can set this off?

Anyway Ive got three boards coming, 2 XPS/ Epoxy and 1 PU/ Epoxy. I will be interested how they compare to normal PU boards. Luckily they are only costing $200 - $250 per board at 'mates rates' so if the XPS is an issue then its a risk I will take just to try it out. They are not HS.

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Re: epoxy

Post by ric_vidal » Thu Aug 18, 2011 4:31 pm

Natho wrote:Thanks Ric, Ive heard the delamination issue can also be caused by slight gas build up under the glass? High heat can set this off?
Natho, I can only recount what used to happen on the XTRs which of course are XPS foam.

They were laminated and looked as good as gold, then put in an air-conditioned room so the exotherm wasn't too bad, come back later and all manner of things could have happened... rivers of lifting glass, bubble areas, sink holes. No consistency to how they came out at all.

Same sort of thing happened on the filler coats, wells and sink holes and no rhyme or reason. Some were nigh on impossible to fill, they would just bubble away even when the resin was close to set so thicker. Same thing can happen with EPS and PU usually next to the stringer. We call 'em a 'breather'.

I believe HS has their fair share of these little issues as well.

Not much point venting as XPS is closed-cell, so how is the expansion going to make its way to the vent. The XTRs had a series of punch holes running parallel to the rails. Still saw one older one from the US that was VERY out of shape.

Avoid decals with large areas of black or dark colours... yes I am serious.

Now you may understand why a lot of manufacturers aren't too keen on the tech.

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Re: epoxy

Post by Natho » Thu Aug 18, 2011 4:49 pm

Hmm thanks Ric, as for the black decals...Ive also heard to avoid dark board bags and try and only use white for the same reason. Im still keen to try one or two but would be nervous paying full dollar for one.
All this said I have a mate who only rides XPS and he has ridden a heap of em with very few issues at all. I guess it also depends on how much experience the manufacturer has with XPS too.

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Re: epoxy

Post by Natho » Thu Aug 18, 2011 5:13 pm

BTW just spoke with a shaper who has a heap of experience with XPS blanks. He reckons the delamination issue is greatly decreased if you 'roughen up' the blank before glassing, rather than sanding the blank smooth. This allows the resin to absorb into the tiny grooves created which assists with the resin bonding to the blank. He says that the delamination issue is due to the fact that XPS does not absorb the resin as well as PU, and leaving the blank slightly scratched up greatly assists. He also uses slightly more resin than normal, and reckons venting is a waste of time. Anyway theres another opinion.

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Re: epoxy

Post by alakaboo » Thu Aug 18, 2011 7:31 pm

ric_vidal wrote:The XTRs had a series of punch holes running parallel to the rails.
I saw a lot of them on the secondhand racks a few years back. You probably know which stable they came from...
I thought the punch holes were from the shapers pencil marks affecting the bonds :oops:

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Re: epoxy

Post by ric_vidal » Fri Aug 19, 2011 3:14 pm

Natho wrote:BTW just spoke with a shaper who has a heap of experience with XPS blanks. He reckons the delamination issue is greatly decreased if you 'roughen up' the blank before glassing, rather than sanding the blank smooth. This allows the resin to absorb into the tiny grooves created which assists with the resin bonding to the blank. He says that the delamination issue is due to the fact that XPS does not absorb the resin as well as PU, and leaving the blank slightly scratched up greatly assists. He also uses slightly more resin than normal, and reckons venting is a waste of time. Anyway theres another opinion.
Certainly makes sense Natho, physical bond, not chemical. As I said earlier... cell size.

Could also relate to the thickness of epoxy and drain out. Think of it this way, epoxy takes longer to cure so the resin could potentially pool between the glass and foam... just a theory. The one thing you can do with epoxy is be quite heavy handed with a squeegee.

To me vac bagging would be most beneficial at so many different levels.

Funnily enough, and I have noticed this with PU boards glassed with epoxy as well, scuff marks disappear more readily. Lot of the XTR boards were fairly rough but more around the rails but that also related to the nap of the foam. It is quite a different beast to shape.

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Re: epoxy

Post by diggerdickson » Tue Sep 06, 2011 2:01 pm

Ive decided to steer away from epoxy and just use uv for a while, at least a few years :lol: :lol: :lol: untill I feel Im getting okay at glassing, which will probably take a few years, then will definately give it a go.
no, Im not a surfer, Im just a garbage man".

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Re: epoxy

Post by Natho » Tue Sep 06, 2011 2:30 pm

Salty, so far no issues with the XPS, though its still early days. My shaper said he also now sprays the blanks with a sealer which has greatly reduced any gassing issues for him (Im not talking fart talk here). I think Marty is onto the same thing I still won't be leaving my boards in a hot car though, just in case.

He did say if they do show any delam issues under the front foot than its easy to fix and then should not happen again. We will see.

im loving the extra spring and livlieness im getting out of the epoxy/XPS and epoxy/EPS boards (with normal stringer). Great in smaller clean waves and Im finding no issues with the boards being 1/8 thinner than my norm.

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Re: epoxy

Post by ric_vidal » Wed Sep 07, 2011 10:45 am

diggerdickson wrote:Ive decided to steer away from epoxy and just use uv for a while, at least a few years :lol: :lol: :lol: untill I feel Im getting okay at glassing, which will probably take a few years, then will definately give it a go.
Epoxy gives you more time, DD... can be good, can have its drawbacks as bubbles can appear after you have done what you believe is a good lamination. And I am not talking outgassing.

Epoxy, quadraxial glass and carbon (uni-directional) reinforcing at the tail did not help my most recent light-weight (PU) blank. Probably could have left it longer to cure, but then I would have missed the boat, literally. :D

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Re: epoxy

Post by Jorgo » Wed Sep 07, 2011 2:23 pm

Speaking of the boat Ric - did you get waves again on your second jaunt to the equator?

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Re: epoxy

Post by ric_vidal » Thu Sep 08, 2011 9:18 am

Jorgo wrote:Speaking of the boat Ric - did you get waves again on your second jaunt to the equator?
Maybe, J-Lo :D None of these are me, obviously! Banged off a zillion photos and spent plenty of time testing my 2 epoxies. Surfed myself silly this day, straight through lunch on my own, and came in when the body gave up - typically now feel like I should have gone back out just before dark. Could hardly see the next day the eyes were so shot.

Fun wave this one, nice wall out the back, fuller mid section then scoot again on the inside. Smacked the reef a few times…
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Re: epoxy

Post by Jorgo » Thu Sep 08, 2011 1:46 pm

Oh - yes I see :D it looks very sad there and dirty and all sorts of unpleasant. Damn it was this time last year I was packing my bags for Sumatra :cry: Oh well as you say - you surf yourself silly and then regret at leisure not going out again.

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