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All About Guns What's your weapon of choice, and why? Discuss the beloved speargun here!

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Old 10-26-2018, 04:58 AM   #16
Diving Gecko
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Re: Carbon Wrap

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Originally Posted by Mikel_24 View Post


I use stuff bought my resins, vacum bags, tacky tape, breather/peelply/release material, etc here: https://www.castrocompositesshop.com...ging-materials

The three ply material I am talking about is this one: https://www.castrocompositesshop.com...#/153-size-1_m

Totally recommended.

Regarding shutting off the vacum pump... Well. I tried. Tube vacum bag, tacky tape o both ends, etc. I set up a valve right next to the bag on the vacum line. Barb fittings and hose clamps. Tight.

When you have a good vacum the breather material gets translucent, showing that it is beeing squeezed against the object and absorbing excess resin. Well, as soon as I closed the valve (and shut off the pump), the breather material lost it's translucent-ness... to me it was an indicator that some air was getting in and I was loosing vacum. Could be through the seams in the tacky tape joints (most likely), or through the valve (unlikely) or barb fittings (unlikely as well).

I didn't feel comfortable with it and decided to leave it on.

Probably once it has gelled enough, you can shut it off no problem. As easy as leaving a leftover in a cup as a sample to check periodically how much it has cured. Keep in mind that resin in a pot gells faster than when spread out (increase in temperature due to the exothermic nature of the curing process)

Peel ply gives a nice texture. Some people like it as is to get a mate finish. I think it helps to mechanically bond the top coat if you aim for mechanical adhesion. I try my best to apply the topcoat when the previous layer is not fully cured (tacky) so you can still take advantage of the chemical bond (stronger)

Mikel
All good points. And yup, it's probably just a tiny leak somewhere along the tacky tape.

Yes, peel ply was specifically made so that you could do secondary bonding without having to prep the surface, e.g. no sanding needed - just pull off the peel ply last minute and do your next operation onto that surface.

What do you use for top coat? The laminating resins I have actually don't really work well for top coat. They haze or yellow pretty easily.
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Old 10-26-2018, 05:01 AM   #17
Mikel_24
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Re: Carbon Wrap

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Originally Posted by Diving Gecko View Post
I think Majd mentioned, that Soller sells a bagging sleeve? That means less seams to seal and reduced risk of leaks.
The vacum bag film can be bought in two main form factors: Plain sheet material or tube (roll).

For our uses the tube is much easier, because you only have to worry about making the ends airtight. The so called tacky tape is used for this purpose.

This is what I use: https://www.castrocompositesshop.com...#/154-size-5_m

Several widths available.

Unless you get a fancy valve/outlet of some kind, you will have to make a passage for the hose to exit through one of the ends.

Here is where most of the problems (leaks) show up. It is not easy to create 100% wrinkle free seams and air will leak in through these wrinkles.

The Ziplock bags are great and airtight (pretty much). So are the water bladders used for backpacking and such. Great engineering there. The problem is, again, the outlet for the hose AND finding those comercial ready made bags in the propper size.

Mikel
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Old 10-26-2018, 05:06 AM   #18
Mikel_24
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Re: Carbon Wrap

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Originally Posted by Diving Gecko View Post
What do you use for top coat? The laminating resins I have actually don't really work well for top coat. They haze or yellow pretty easily.
This is what I use for top coat: https://www.castrocompositesshop.com...ight-1_0_38_kg

UV filter and designed specifically as Top Coat. Works great and doesn't run/drip easy (although I use a rottisiere setup anyways)

Mikel
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Old 10-26-2018, 05:17 AM   #19
Diving Gecko
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Re: Carbon Wrap

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Originally Posted by Mikel_24 View Post
This is what I use for top coat: https://www.castrocompositesshop.com...ight-1_0_38_kg

UV filter and designed specifically as Top Coat. Works great and doesn't run/drip easy (although I use a rottisiere setup anyways)

Mikel
Yep, the vast majorities of laminating epoxies have zero UV protection in them. So far, I have decided not to care - but the hazing on my last resin was a bummer.
I got you on the rotissirie, I have the parts somewhere. All this stuff is so cheap here in China, so I just need to whip up some brackets on my 3D printer and I am good to go.

Now, since you seem to enjoy this as much as I do here's a trinket for you: Some cool tinkerer recently designed an Arduino powered vac pump controller with amazing features. Once, I find the time, I'll prolly make one, too. But I have a pro SMC pressure switch on my pump already (again, dirt cheap second hand in China) so I am not in a hurry:
https://www.rcgroups.com/forums/show...m-Gauge-Switch

Another one here:
https://www.rcgroups.com/forums/show...ump-controller

I love this internet age where people just design pro level featured stuff and give away the designs for free! It's just amazing.
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Old 10-26-2018, 06:55 PM   #20
eddie1987
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Re: Carbon Wrap

Thanks for all the great information guys( would still be totally lost without it haha)... I have ordered all my supplies , they will take a while to reAch but once they do I’ll do an update on how the guns come out.. thanks!!!


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Old 10-27-2018, 04:27 AM   #21
spearq8
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Re: Carbon Wrap

I put the sleeve on the gun when the gun is totally dry. I think using adhesive spray complicates things as you can't really move the sleeve around after it is on and might not allow a smooth final pull back when you want the cloth to drape nicely over the gun. On a long gun I actually have two suction areas (one muzzle area and one on handle area) to ensure a good pull down. Another thing is that the cloth changes once you wet it and you want to be able to move things around … which might be difficult to do if you use adhesive spray. I do use adhesive spray when making handles with CF tape.

As for vacuum leaks … I think you should keep vacuum on till the gel time of the epoxy, especially if you will not be checking in on the progress every few minutes. A leak can basically make it impossible to fix the gun if it hardens and is just not worth the risk. For a vacuum bag I now use large sleeves that you can easily slip a fully clothed up gun into. This means you only have two small sides to make leak proof rather than have to make up a full bag. This has made making a bag dramatically easier and quicker and more leak proof … plus you only need a few strips of the sticky tape to seal the bag. I actually can even get a way with vacuuming only a part of the gun (usually muzzle or handle area) without losing vacuum. If you have not used these vacuum bag sleeves I really recommend you give them a try!
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Old 10-27-2018, 05:01 AM   #22
Diving Gecko
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Re: Carbon Wrap

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Originally Posted by spearq8 View Post
I put the sleeve on the gun when the gun is totally dry. I think using adhesive spray complicates things as you can't really move the sleeve around after it is on and might not allow a smooth final pull back when you want the cloth to drape nicely over the gun. On a long gun I actually have two suction areas (one muzzle area and one on handle area) to ensure a good pull down. Another thing is that the cloth changes once you wet it and you want to be able to move things around … which might be difficult to do if you use adhesive spray. I do use adhesive spray when making handles with CF tape.

As for vacuum leaks … I think you should keep vacuum on till the gel time of the epoxy, especially if you will not be checking in on the progress every few minutes. A leak can basically make it impossible to fix the gun if it hardens and is just not worth the risk. For a vacuum bag I now use large sleeves that you can easily slip a fully clothed up gun into. This means you only have two small sides to make leak proof rather than have to make up a full bag. This has made making a bag dramatically easier and quicker and more leak proof … plus you only need a few strips of the sticky tape to seal the bag. I actually can even get a way with vacuuming only a part of the gun (usually muzzle or handle area) without losing vacuum. If you have not used these vacuum bag sleeves I really recommend you give them a try!
I realized I have been using bag "sleeves" most of the time - it's just that they are 1m wide, haha. Anyways, I haven't really had big leaks on those either. But for smaller parts, I have since changed to using either a DIY silicone bag made from thin silicone sheet or just the before-mentioned vacuum storage bags. Surprisingly, the latter has been the most leak proof. Last winter I was laminating a small camera holder in one of those storage bags. It was cold, so after pulling a vacuum, I clamped the hose, removed the pump and then hung the small bag above a radiator over night - it lost no pressure at all.
As for the small DIY silicone bag, the advantage is that I can get lazy on the pleating and it being silicone, it releases easily, too.

If you are using breather ply, besides absorbing excess resin, it works to distribute the vacuum evenly all through the bag. Or rather, to all of the area that the bleeder ply covers.

Last edited by Diving Gecko; 10-27-2018 at 05:14 AM.
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Old 10-27-2018, 02:48 PM   #23
eddie1987
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Re: Carbon Wrap

I found some vacuum sleeves from

https://www.fibreglast.com/product/P...Peel_Ply_Tapes

Vaccuum bags in tubes comes in different widths 24” 48” and 60”

Ordered some of the 24”
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