Forums > Windsurfing General

Repairs gone wrong

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Created by flatchat > 9 months ago, 5 Jun 2020
Subsonic
WA, 2963 posts
8 Jun 2020 7:23PM
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Subsonic said..

Mark _australia said..
Small nose repair like that just sand out to a nice bevelled oval about 50% larger than the cracks and about 2mm deep (max) hopefully seeing hi density foam there not styro!
4 or 5 layers of 4oz glass getting progressively bigger and cap with a 2oz bigger than all (helps with less fill)
blend edges out with a bit of filler once cured.

If no hi density foam I'd be going much wider and over the top with more glass as it would be like bloody eggshell nose.

Make that charcoal colour with black, white, little bit of green and purple, matting additive.





You might be right. being the nose, they might've had a brain fart and put some high density in there...

I'll post a picture when i've opened it up on monday or tues night.

Im pretty sure they've put some through the back half. Thats where all the load is. but theres none through the front half on the bottom. I doubt theres any through the front half on top.


So it turns out JP have done something better than i thought. Underneath the "eggshell" was a far more durable layer of something far harder wearing. Don't think it was kevlar, but similar material which got the furry look when sanded. It hasn't been damaged by the impact at all, just the outer "show" layers were. So the repair just got easier again...

kato
VIC, 3340 posts
9 Jun 2020 12:43PM
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Subsonic said..

Subsonic said..


Mark _australia said..
Small nose repair like that just sand out to a nice bevelled oval about 50% larger than the cracks and about 2mm deep (max) hopefully seeing hi density foam there not styro!
4 or 5 layers of 4oz glass getting progressively bigger and cap with a 2oz bigger than all (helps with less fill)
blend edges out with a bit of filler once cured.

If no hi density foam I'd be going much wider and over the top with more glass as it would be like bloody eggshell nose.

Make that charcoal colour with black, white, little bit of green and purple, matting additive.






You might be right. being the nose, they might've had a brain fart and put some high density in there...

I'll post a picture when i've opened it up on monday or tues night.

Im pretty sure they've put some through the back half. Thats where all the load is. but theres none through the front half on the bottom. I doubt theres any through the front half on top.



So it turns out JP have done something better than i thought. Underneath the "eggshell" was a far more durable layer of something far harder wearing. Don't think it was kevlar, but similar material which got the furry look when sanded. It hasn't been damaged by the impact at all, just the outer "show" layers were. So the repair just got easier again...


Gota take the wins when ya get them. A good news story

Sandman1221
2776 posts
14 Jul 2020 2:38AM
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Subsonic said..
Slightly off course, not a repair gone wrong, but i figured i'd put it on here to open the thread up a bit more. Managed to ding the nose on my JP 175 today (i did it just for this thread) typical mast impact.

Relevant info: board is made of carbon. Previous openings have revealed that what will probably be underneath is straight to styro. I've had to do enough repairs now that i have my own ideas how im going to fix it (it's actually an easy fix) but thought i'd put on here anyway, see if i can learn anything new....

How would you fix it?

edit: it bled some water out whilst sitting in the sun, so needs opening up.


stand board on nose for several days with paper towel under it, replace towel when wet, when paper towel stays dry wipe epoxy over crack, worked for several cracked noses with no delamination after several years in hot weather.

yarraw
VIC, 23 posts
12 Aug 2020 5:24PM
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Just completed repair to carbon 170-220 Enigma boom. The adjusting clip/collar broke on one side, due to the carbon tube being paper thin underneath where the holes are located. Used 4 layers of carbon/epoxy to thicken area where holes are, then re-drilled holes.

The boom arm outside diameter is 27.0 mm and the new collars are 26.0 mm inside diameter, so a VERY tight fit. Sanded the boom arm down to 27.0 mm (about 1.5 mm wall thickness), and also sanded inside of collar by about 0.5 mm. Slightly softened and expanded the new collar by heating in boiling water, and then was able to fit onto boom arm with vaseline lubrication and twisting, then tapping with hammer.




















SaltySkiffies
NSW, 28 posts
27 Aug 2020 10:42AM
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I'm currently trying to avoid a repair gone wrong, so a quick question for everyone. I've been patching up some cracks on the nose of my board and the repairs have now been filled (with epoxy and microbeads) and ready for fairing. There's no way I'd be able to paint the board in time for the weekend, so if I leave the patches unsanded (to avoid any water ingress in case it's still a little porous) am I fine to sail it or should I just hold off and paint it first?

mark62
490 posts
27 Aug 2020 5:36PM
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SaltySkiffies said..
I'm currently trying to avoid a repair gone wrong, so a quick question for everyone. I've been patching up some cracks on the nose of my board and the repairs have now been filled (with epoxy and microbeads) and ready for fairing. There's no way I'd be able to paint the board in time for the weekend, so if I leave the patches unsanded (to avoid any water ingress in case it's still a little porous) am I fine to sail it or should I just hold off and paint it first?

I don't think epoxy and micro beads are porous so I reckon you'll be fine for a weekend session. If your really worried about water ingress, maybe hand paint just the repaired epoxy areas for a bit of extra sealing, it going to be sanded back at some stage anyway.

Stretchy
WA, 914 posts
27 Aug 2020 6:21PM
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SaltySkiffies said..
I'm currently trying to avoid a repair gone wrong, so a quick question for everyone. I've been patching up some cracks on the nose of my board and the repairs have now been filled (with epoxy and microbeads) and ready for fairing. There's no way I'd be able to paint the board in time for the weekend, so if I leave the patches unsanded (to avoid any water ingress in case it's still a little porous) am I fine to sail it or should I just hold off and paint it first?


A quick and dirty spray of the nose with acrylic will only take a few minutes and will be dry an hour later.
you can sand it back later to do a tidy job

Mark _australia
WA, 22089 posts
27 Aug 2020 9:40PM
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If your filler coat isn't water proof now, it won't be when painted.
Should be fine to use as long as you over filled it

SaltySkiffies
NSW, 28 posts
28 Aug 2020 7:30AM
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Thanks everyone!

djl070
WA, 290 posts
28 Aug 2020 4:00PM
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Mark _australia said..
I also would not say just a wrap is sufficient. On a SUP shaft I sleeve it with commercially manufactured carbon tube and have still had a re-break when the mould release still existed and it let go.
Clean clean clean, rough it up, clean again, sleeve and maybe then a bit of a wrap externally.

Done right its fine, I have a Maui carbon slalom boom that had 5 breaks and put back together by a pro repairer. Its got many years of big guys sailing it overpowered, no issues.


Hi Mark, I know that boom well as it was mine,was too inexperienced to fix it.
Paul did a real good job of fixing it and probably stronger than when it was new now.

MarkSSC
QLD, 631 posts
29 Aug 2020 1:00PM
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Gestalt said..
i repaired my carbon boom by adding a carbon tube sized to fit the internal diameter of the boom arm. it extends well into both sides of the break. one advantage of this method is you can push the break back together so it's not really that visible and the grip remains in pretty good nick. it's an easy process with almost no sanding, cutting and mucking about.

it's a solid repair. actually stiffer than the original boom now.

i would not trust a repair without a dowel.


It makes sense. I have seen mainspars and structural longerons repaired on aircraft wing, and the engineering concept is similar. Retaining strength and spreading the load should make it as strong as a new one, maybe a little (grams) heavier.

MarkSSC
QLD, 631 posts
29 Aug 2020 1:03PM
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SaltySkiffies said..
I'm currently trying to avoid a repair gone wrong, so a quick question for everyone. I've been patching up some cracks on the nose of my board and the repairs have now been filled (with epoxy and microbeads) and ready for fairing. There's no way I'd be able to paint the board in time for the weekend, so if I leave the patches unsanded (to avoid any water ingress in case it's still a little porous) am I fine to sail it or should I just hold off and paint it first?


I just get some 50mm silver tape and cover the area. It protects it from water until you are happy with the repair work. The tape is waterproof for a long time because the are on the nose is not under water for long periods. You can make it quite neat and it keeps you on the water.



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"Repairs gone wrong" started by flatchat