Speargun carbon problem

[slpoh]

Got a new carbon roller speargun.Use it twice and after first time using it I noticed a small chip underneath the gun.patch it with epoxy,and second time use it,there is another chip on the carbon.Is there any other carbon gun has the same problem ?I don’t think it is normal like this.

[doyenofcastle]

may be epoxy coat on CF have an adhesion problem

[popgun pete]

Not hitting against something in transport? The weight of a carbon gun sitting on a small projection like a protruding nail head creates a high contact pressure.

[slpoh]

Notice this first time of use.Thought hitting something.Watch out the second time when using..Then found out second chip. I’*m very sure that it didn’t hit anything.Wrote to the manufacturer,no reply.

[Sebastian2]

Is that an Orca? If so I've had the same thing with mine. The coating seems to chip quite easily, haven't had that happen on other carbon guns. Just a few boat rides and it has some pretty good chips. Maybe there is an adhesion problem. The coat also appears quite thick on mine, wonder it that makes it more prone to coming off in chunks. It should however not affect that gun as it doesn't damage the carbon fibers. But yeah its a bit disappointing.

[slpoh]

Originally Posted by Sebastian2

Is that an Orca? If so I've had the same thing with mine. The coating seems to chip quite easily, haven't had that happen on other carbon guns. Just a few boat rides and it has some pretty good chips. Maybe there is an adhesion problem. The coat also appears quite thick on mine, wonder it that makes it more prone to coming off in chunks. It should however not affect that gun as it doesn't damage the carbon fibers. But yeah its a bit disappointing.

Yes,it’s an orca.Thought I’m the only one have the problem, I think orca gun is like this. I just got an answer from the manufacturer and he told me the chip is due to scratches,but the gun has a 4mm carbon.So I should not worry and it is just aesthetic and the gun will last forever. I haven't see any chip on my other carbon speargun and it’s true,a bit disappointed.Anyway apart from the chip problem,it is a very good gun.

[spearq8]

Most likely they used a spray gun thinned with acetone to put on layers. It is very tricky to add layers of epoxy and has to be timed perfectly between coats. It has to be just tacky before applying the next coat ... if you wait a little too long then surface will not adhere properly unless you sand it.

It is an easy fix though. Just use tape around the damaged area with the area open, then scratch and sand the exposed area making sure it is free of debris or oils. Then add a layer of UV stabilized epoxy that is just a little above the surface. Once cured you can sand down the epoxy flat and you won't even notice it was fixed. I would certainly not consider what is in the picture as purely "aesthetic" as it is quite deep and can eventually allow infiltration of water into the CF ... which will make the job dramatically more difficult to fix.

[slpoh]

Originally Posted by spearq8

Most likely they used a spray gun thinned with acetone to put on layers. It is very tricky to add layers of epoxy and has to be timed perfectly between coats. It has to be just tacky before applying the next coat ... if you wait a little too long then surface will not adhere properly unless you sand it.

It is an easy fix though. Just use tape around the damaged area with the area open, then scratch and sand the exposed area making sure it is free of debris or oils. Then add a layer of UV stabilized epoxy that is just a little above the surface. Once cured you can sand down the epoxy flat and you won't even notice it was fixed. I would certainly not consider what is in the picture as purely "aesthetic" as it is quite deep and can eventually allow infiltration of water into the CF ... which will make the job dramatically more difficult to fix.

Thanks for the information.I just fill up the chip area with epoxy.But it just dissapointed and troublesome to patch up a hole every time went fishing.
Went fishing twice and each time a hole.Don’t know if have any method to avoid this?like spray a coat of protection use on surf boards or …..?

[spearq8]

Originally Posted by slpoh

Thanks for the information.I just fill up the chip area with epoxy.But it just dissapointed and troublesome to patch up a hole every time went fishing.
Went fishing twice and each time a hole.Don’t know if have any method to avoid this?like spray a coat of protection use on surf boards or …..?

If this is a common occurrence, then for sure they used the wrong epoxy ... or used the correct epoxy but thinned it with acetone or some other chemical, to increase the spray ability of the epoxy. It is also possible that they were not careful in having exact mix ratios (eg. too much hardener or too much resin for the optimal mix). This makes the epoxy lose some of its designed characteristics (eg. flexibility or strength) and it becomes brittle and can chip instead of having a dent or ding. You can definitely add a few extra layers of good quality epoxy to reduce chances of chipping out pieces. I would use something like West Systems 207 hardener with WS 105 resin. You would have to totally sand the entire gun for proper adhesion and maybe put 3 coats at correct time intervals where you only add an extra layer when the epoxy is still tacky. You might need to factor in a few hours and use timer to make sure you add the next layer at correct time (this is ambient temperature dependent). Once done you will have an extra "shell" around your original epoxy. 207 is very good in that it is clear and doesn't yellow. WS epoxy is also a very good epoxy. I do see tons of cheap epoxy being sold online, mostly for use in clear poured table top finishes or for clear resin casting items ... but to be honest a lot of those epoxies are just bad, or at least bad for spearguns ... and while some work perfect, others are horrible.

Using a solvent to thin your epoxy is a much easier and quicker method, but it will drastically affect the compressive strength of the epoxy, so we do not recommend this method. However, if you still go ahead with this, here are some of the solvents we suggest you use.

[slpoh]

Thanks a lot for the information.

[armandozx]

gun prob hit against something and it shipped there, To get the best top coats things (panels, composites) have to be sanded where its for lamination or finish work. Sanding is what gets you one material to adhere to the other and fully penetrate in the microporosity of the sanded surface. It's possible that after their vacuum process they failed to properly prep the gun for the new coats and OR TOO MUCH MATERIAL WAS USED, AND NORMALLY THIS WILL BREAK BECAUSE IT BECOMES BRITTLE, expect this to happen more often if that's the case. Materials have specs for a reason, sometimes if you go over the mil's (thickness of recommended product spec, this could happen, if the carbon was contaminated with some type of grease from fingers or any other place you can also get adhesion/bonding problems.

Either way, doesn't look that its structurally compromised and that's good. Get 280-320g piece of sand paper and make contact with everything you wish to cover then acetone wipe after sanding and a fine brush. Do a small touch-up, once it hardens you can sand it down to level with 800-1200g (water preferably.) You don't need to thin anything because you're not going to spray that void. But do sand it to promote adhesion for long-lasting results.

[popgun pete]

If you click on the images then they go up in size and in the first one you can see the carbon weave exposed. That the material has come away in a near perfect circle makes you think of a blister effect. In the second photo you can see a dull spot in the finish and a second smaller one below it, I wonder if there are more of these on the gun and they mark the weak spots.