wide tray glassing tonight.. tips appreciated

[yamahaulass]

First fiberglass job. I cut the sides of the tray off and and defoamed then used 2pt foam to get a rough shape of how i wanted it. I then cut and sanded the foam to my final desired shape. I plan to lay glass directly on the foam now.
Questions are:
Using 1708 how many layers is ideal?
is there anything specific about bonding the new glass the old?

any other tips are appreciated

 

[NooberJet]

Im no glass expert but I know prep is really important. I believe you use acetone to clean the area then give it a good scuff for the epoxy to bond to. Then final wipe down with acetone again and lay it up. Im unsure of how many layers needed but id imagine staggering the layers would be best. Pics go a long way here so others can help you more directly

 

[yamahaulass]

Just finished the left side, I'll do the right another day.

I ended up at 3 layers under my foot and basically a single layer with a lot of overlaps on the side rail. The 1708 did not take the shape well as one piece so I cut 6 inch strips and ran them vertically the entire length.

 

[McDog]

One layer was really stingy for that job. I would have done at least two, and three just to have peace of mind.

Main thing to note is that it is ideal to have the gel coat removed from where it is attaching too. Glass bonds best to glass. If it's a square then it's metton and just get it really rough.

The other issue that you will have is that biax doesn't set up waterproof no matter how many layers you use. Water will seep through the tiny imperfections like swiss cheese and soak your foam. You will need to seal it by either slathering on microballoons mixed with epoxy or gelcoat, marine tex, etc. Good luck.

 

[Vumad]

1 layer of anything is insufficient for a new part. It also creates a lot of weakness to cut the glass. In the future you need to use more layers of a lighter glass. For instance. 3 layers of 1208 is better than 2 layers of 1708. Heavy glasses should be reserved for fast bulking. The gaps in the weave of a single layer wont fill with resin and it will leak. Several layers will ensure you dont have gaps that dont have resin. You also benefit from strength in mutiple layers. Lighter fabrics will confrom betterand ylu can avoid cutting.

Next time some better planning will help you emmensely. You posted at 5pm you were doing the job and 10pm it was done. That was not a request for help but rather an announcement you were beginning. Let us know a few days in advance next time and we can provided better advice before you do the job.

 

[Vumad]

One layer was really stingy for that job. I would have done at least two, and three just to have peace of mind.

Main thing to note is that it is ideal to have the gel coat removed from where it is attaching too. Glass bonds best to glass. If it's a square then it's metton and just get it really rough.

The other issue that you will have is that biax doesn't set up waterproof no matter how many layers you use. Water will seep through the tiny imperfections like swiss cheese and soak your foam. You will need to seal it by either slathering on microballoons mixed with epoxy or gelcoat, marine tex, etc. Good luck.

What makes you say that the number of layers of biax does not matter? What is your experience with this? What fabrics do you prefer? I once made something out of a single layer of 1208 and it leaked but 2 or 3 and it did not.

 

[McDog]

I have built and repaired many hulls over the years. I have made build threads for several. I tend to prefer 12oz biax for the main tray and maybe some lighter weave for weird angled places around footholds.

Can you build a waterproof container out of net and glue with enough layers? Maybe, but the odds are not in your favor. I have pressure tested several foamless aftermarket hull tray compartments and every one of them had pinhole leaks somewhere. Do you really think an amateur can do better with enough layers of glass and resin?

It's better to build it for the strength you need and then to seal it.

 

[yamahaulass]

Below the line is 2-3 layers, above 1-2. I think 1208 definitely would have been better to use but all my searches led me to go with the 17Oz. So what can I do at this point to make it better?

 

[McDog]

I would rough it all up with a dremel, put another layer on the side, and slather thickened epoxy on the whole area. I prefer microballoons because it's cheap, lightweight, and easy to sand smooth the high spots when it dries. You want it to be a cake icing/peanut butter consistency when you apply it using spatula and fingers to get it as smooth as possible over the whole area that was open.

When I do a tray I try to save as much of the original as possible to lay the glass back over. Which minimizes the area that I have to cover with thick epoxy.

 

[yamanube]

I would get a nice tight weave, thin weight glass to cover it all up as well. I use 1208 for large expanses like that but try and drape a layer of 9oz S glass or a light satin weave E glass over it and onto the existing hull to tie it all together and get a cleaner final surface.

 

[McDog]

If it was a visible surface I would totally agree, but he has biax already and it's all getting covered with pad and turf anyway. It can be on the rough looking side and not matter. No doubt lighter tight weave glass would be better, but he could do it "good enough" with what he has on hand.

If you aren't in a hurry or a teenager on a serious budget then yamanube's way really would be the ideal best way in your situation.

 

[Roseand]

All that work and no footholds?

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[CD155MX]

All that work and no footholds?

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All that talk and still no backflip?

 

[Roseand]

All that talk and still no backflip?

People make flips look way too easy.. Lol. Someday I'll get one around. Someday..

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[Vumad]

I have built and repaired many hulls over the years. I have made build threads for several. I tend to prefer 12oz biax for the main tray and maybe some lighter weave for weird angled places around footholds.

Can you build a waterproof container out of net and glue with enough layers? Maybe, but the odds are not in your favor. I have pressure tested several foamless aftermarket hull tray compartments and every one of them had pinhole leaks somewhere. Do you really think an amateur can do better with enough layers of glass and resin?

It's better to build it for the strength you need and then to seal it.

Do you always seal with a mix of microspheres even when just reinforcing? Or only when building a fresh part / surface? Im getting away from modding hullsto building parts but i will still be making repairs which includes filling large gaps.

 

[Vumad]

Honestly, and im not trying to sound like a dick, so please dont take it that way, but i would cut and grind that hack job out and start over. I dont get the curve in, very rough finish, bad layup, doesnt look rolled...

Cut it out. Grind back down to barehull. Prep better this time. Spend more time shaping before glassing this time. Work with a lighter more confromable weave like 1208, finishing with a layer of 10oz and then conform cloth, and feather it into the hull. Plan out foot holds or an actual wide tray. Ask first, measure twice, cut and glass last.

Otherwise, if it is acceptable to you, similiar to what mcdog said.

 

[McDog]

No. Just over the areas that are open to the tray or foam. If it's an open tray or polystyrene filled then you can fill it with water to check for leaks, if it's pour in foam then overkill is the best method because there is no way to test it. I'll try to find some photos.

If you are making parts then I expect you would be vacuum bagging and I doubt you would need it. I'm sure there are better methods than mine when building parts. Nate D would be a good resource on that.

 

[McDog]

http://www.x-h2o.com/index.php?threads/mark-gomez-superjet-gets-some-love.147133/page-4

Page 4 and 5 and 6 show how I do it. All the areas that are bare foam or open between pieces get slathered in microballoon epoxy before I lay glass in order to seal it all in one layup. None is needed where glass is laying on glass. I also use the thick epoxy to help any stubborn areas lay down better.

 

[yamahaulass]

It's 4.5 inches deeper at my toe. The curve was just to taper off to standard width at the front instead of just boxing the whole thing out. Crappy job? Probably, but I don't have the talent or budget to get upside down I just need it to hold up chasing boats.

 

[McDog]

There you go then. Follow my first advice and you are good to go. Good luck!