Hi anyone know what you use to repair a 4" split in the plastic bottom of a soft top surfboard, will epoxy stick?

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Hydrosurf said..
Hi anyone know what you use to repair a 4" split in the plastic bottom of a soft top surfboard, will epoxy stick?

hot glue gun maybe? as for epoxy, mix up a little and see if it will stick when soft, some epoxies work on some plastics, but you want an epoxy that will flex with the plastic. Call West Systems tech support and ask them, for an epoxy make sure it cures for 5 days or more so that it is waterproof, otherwise water will turn it white and soft.

Its almost certain to be thermoplastic, which epoxy will not stick to.
They're almost unrepairable. But if its in a relatively non stressed area and you don't mind it being visible, use white Sikaflex221 or similar as it will remain flexible but set a lot harder than silicones etc.
Light weighting as it cures, smooth out the join with a wet finger may help with finish

Thanks Mark I will try sikaflex, cheers

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Sandman1221 said..

Hydrosurf said..
Hi anyone know what you use to repair a 4" split in the plastic bottom of a soft top surfboard, will epoxy stick?

hot glue gun maybe? as for epoxy, mix up a little and see if it will stick when soft, some epoxies work on some plastics, but you want an epoxy that will flex with the plastic. Call West Systems tech support and ask them, for an epoxy make sure it cures for 5 days or more so that it is waterproof, otherwise water will turn it white and soft.

What sort of epoxy are you using that goes white and soft if you don't let it cure for 5 days ??

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Mr Hooper said..>>>> What sort of epoxy are you using that goes white and soft if you don't let it cure for 5 days ??

Possibly one with the wrong mix ratio, or in sub zero temps.

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decrepit said..

Mr Hooper said..>>>> What sort of epoxy are you using that goes white and soft if you don't let it cure for 5 days ??

Possibly one with the wrong mix ratio, or in sub zero temps.

If you expose it to salt water before it is fully cured Six10 epoxy will turn white and soft in my experience and according to West Systems technical support. The problem is the directions on the tube of Six10 epoxy do not say that!, they only say wait 24 hr before applying a load. Tech support did say said wait 48 hr before exposing to salt water, but I had waited over 48 hr and with temperatures well above the minimum, so 5 days is probably a better time.

If that's the case it sounds like you shouldn't use it in water at all. Better off using proper resin with the correct additives.

^^^ +1

And also if its been 48hrs and above the min temp required then it didn't mix right.
Forget the little auto mixing thingies on a caulking gun tube that help boaties use tons of the stuff on their fillets. Forget adhesives.
Get quality normal resin and measure accurately.

Given your low temps at times (?) a fast surf resin would help. Many can laminate a board and then do the other side in around 3hrs. In summer I'm getting 2hrs set time with an ultra clear laminating epoxy that you can also add things to, to make it a filler or adhesive etc.

Then again what would I know, I only repair half the board and ignore the rest.

West Systems has G/Flex that bonds to some plastics. I used it for a starboard formula with tufskin, which I believe is ASA (similar to ABS). When you use it in that type of plastic, you need to prep the surface really well: either 60 grit sandpaper or oxidize the surface with a torch (remember not to burn down your house). I used both methods and it worked.

the first thing you should do is try to find out what material your board is made of.
www.westsystem.com/specialty-epoxies/gflex-650-toughened-epoxy/

There is only one epoxy you can use for this repair. West systems G flex resin But the smallest kit is 1 litre and it costs min $100. This resin was developed for repairing thermo formed plastic kayaks and it works well. I have used it myself on ASA skinned (plastic wrapped) boards and there is a demo video out there somewhere in which they cut a plastic kayak in half with a chainsaw and then stick it back together with a strip of 10oz and one coat of G flex then proceed to ride it down a bumpy wet grass hill like a toboggan with 3 large blokes in it to showcase how strong the bond to plastic is.

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mob dog said..
There is only one epoxy you can use for this repair. West systems G flex resin But the smallest kit is 1 litre and it costs min $100. This resin was developed for repairing thermo formed plastic kayaks and it works well. I have used it myself on ASA skinned (plastic wrapped) boards and there is a demo video out there somewhere in which they cut a plastic kayak in half with a chainsaw and then stick it back together with a strip of 10oz and one coat of G flex then proceed to ride it down a bumpy wet grass hill like a toboggan with 3 large blokes in it to showcase how strong the bond to plastic is.

Was this it? Hahahah

You see what happens when you use the correct product as opposed to some handyman goop !
That's right, it actually works

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mob dog said..
There is only one epoxy you can use for this repair. West systems G flex resin But the smallest kit is 1 litre and it costs min $100. This resin was developed for repairing thermo formed plastic kayaks and it works well. I have used it myself on ASA skinned (plastic wrapped) boards and there is a demo video out there somewhere in which they cut a plastic kayak in half with a chainsaw and then stick it back together with a strip of 10oz and one coat of G flex then proceed to ride it down a bumpy wet grass hill like a toboggan with 3 large blokes in it to showcase how strong the bond to plastic is.

The smallest kit available is 118ml per bottle and costs 31 usd.

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WillyWind said..

mob dog said..
There is only one epoxy you can use for this repair. West systems G flex resin But the smallest kit is 1 litre and it costs min $100. This resin was developed for repairing thermo formed plastic kayaks and it works well. I have used it myself on ASA skinned (plastic wrapped) boards and there is a demo video out there somewhere in which they cut a plastic kayak in half with a chainsaw and then stick it back together with a strip of 10oz and one coat of G flex then proceed to ride it down a bumpy wet grass hill like a toboggan with 3 large blokes in it to showcase how strong the bond to plastic is.

The smallest kit available is 118ml per bottle and costs 31 usd.

Glad to hear West Systems has an epoxy for that type of repair!, like I said, give them a call, their tech support is easy to get a hold of. But check with support on how long the epoxy needs to cure before exposing to water or salt water, and at least double whatever time they say just to be safe, though would give it at least 5-7 days in temps above 72 degrees F and humidity below 65%.

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Mark _australia said..
^^^ +1

And also if its been 48hrs and above the min temp required then it didn't mix right.
Forget the little auto mixing thingies on a caulking gun tube that help boaties use tons of the stuff on their fillets. Forget adhesives.
Get quality normal resin and measure accurately.

Given your low temps at times (?) a fast surf resin would help. Many can laminate a board and then do the other side in around 3hrs. In summer I'm getting 2hrs set time with an ultra clear laminating epoxy that you can also add things to, to make it a filler or adhesive etc.

Then again what would I know, I only repair half the board and ignore the rest.

Well you were wrong about epoxies not sticking to thermoformed plastic!, so will have to take whatever you say with a grain of salt from now on. You also said water based acrylic craft paints should not be used to touch up color on board ding repairs, and you were wrong about that too!

So now you have convinced Hydrosurf to do a hack repair of the board, when they could do a proper permanent repair.

Mark, I think when you see something about repairing boards that you are not familiar with, you jump to the conclusion it is the wrong way to do it and give reasons why, even though you have not tried it yourself.

As for Six10, it is an adhesive thicken epoxy and takes longer than regular epoxies to fully cure, 10 days according to West Systems. In my case, just a little of the epoxy turned white and semi-soft on the surface (needed a knife blade to scrape it off), below was fine and the wing inserts on my foil which were glued in with Six10 have held up to multiple impacts with no damage.

Thanks for all the great info guys. I think you all should try making your own board in order to understand more about epoxies

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Hydrosurf said..
Thanks for all the great info guys. I think you all should try making your own board in order to understand more about epoxies

Well that has not helped Mark!, so why should I?

And my advice to you Hydrosurf is beware of free advice, cause that is just what it is. Now if you had called West Systems technical support you would of gotten free advice true, but it would be for that companies products, and that it not the same as getting free advice from someone on this forum.

Here we go, can see on the main page Grantmac commented, but I can not see their post, and glad!

GFlex is good stuff, just expensive and brown. Used it a bunch on ABS skinned boards with good success.
If it was cheaper I'd probably use it still.

The thing to remember from all this is there are people on this forum who use epoxies, and then there are people who design, make, and sell epoxies. If you want clear advice from a knowledgeable source whose livelihood depends on giving correct information like West Systems, then ask them! They even have a printed Journal called EPOXYWORKS dedicated to things made and repaired with their epoxies.

I'm gonna have a go at making a board, using only Six 10 and water based craft paints. I'll let you know how it goes

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Mr Hooper said..
I'm gonna have a go at making a board, using only Six 10 and water based craft paints. I'll let you know how it goes

Don't forget to use plastic foil.

I'm out. I bow to the superior knowledge the one who can't make epoxy set in 3x the allotted timeframe and it fails when wet.

I knew about Gflex. l am a convert and now agree that buying a $100 product to fix a split in a $100 softie is the go.

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Mark _australia said..
I'm out. I bow to the superior knowledge the one who can't make epoxy set in 3x the allotted timeframe and it fails when wet.

I knew about Gflex. l am a convert and now agree that buying a $100 product to fix a split in a $100 softie is the go.

, bye, and I mean that in a nice way, just will not be seeing your posts anymore.

Thank god for small miracles.

Anyway ....... I reckon, leave the vent screw alone .

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aeroegnr said..

mob dog said..
There is only one epoxy you can use for this repair. West systems G flex resin But the smallest kit is 1 litre and it costs min $100. This resin was developed for repairing thermo formed plastic kayaks and it works well. I have used it myself on ASA skinned (plastic wrapped) boards and there is a demo video out there somewhere in which they cut a plastic kayak in half with a chainsaw and then stick it back together with a strip of 10oz and one coat of G flex then proceed to ride it down a bumpy wet grass hill like a toboggan with 3 large blokes in it to showcase how strong the bond to plastic is.

Was this it? Hahahah

Yeah that's the one I forgot about the bit where they drop it off the bridge

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Sandman1221 said..

Mark _australia said..
^^^ +1

And also if its been 48hrs and above the min temp required then it didn't mix right.
Forget the little auto mixing thingies on a caulking gun tube that help boaties use tons of the stuff on their fillets. Forget adhesives.
Get quality normal resin and measure accurately.

Given your low temps at times (?) a fast surf resin would help. Many can laminate a board and then do the other side in around 3hrs. In summer I'm getting 2hrs set time with an ultra clear laminating epoxy that you can also add things to, to make it a filler or adhesive etc.

Then again what would I know, I only repair half the board and ignore the rest.

Well you were wrong about epoxies not sticking to thermoformed plastic!, so will have to take whatever you say with a grain of salt from now on. You also said water based acrylic craft paints should not be used to touch up color on board ding repairs, and you were wrong about that too!

So now you have convinced Hydrosurf to do a hack repair of the board, when they could do a proper permanent repair.

Mark, I think when you see something about repairing boards that you are not familiar with, you jump to the conclusion it is the wrong way to do it and give reasons why, even though you have not tried it yourself.

As for Six10, it is an adhesive thicken epoxy and takes longer than regular epoxies to fully cure, 10 days according to West Systems. In my case, just a little of the epoxy turned white and semi-soft on the surface (needed a knife blade to scrape it off), below was fine and the wing inserts on my foil which were glued in with Six10 have held up to multiple impacts with no damage.

Ouch! Bit harsh. Actually he is dead right about epoxies not sticking to plastic. I have found this out the hard way myself many times. G flex is a specialist product and vastly different from all other epoxies it is super thick and more like glue than resin.