Bubbles, Blemishes, and Holes in first layer of fiberglass?!

[JimC3]

Hello,
With absolutely no maritime experience, I decided the sea was calling and build a 12 foot sailboat in my basement. After applying the first layer of fiberglass, I noticed there were many bubbles and some places where the weave is still showing. After another coat helped nothing, I tried sanding with 80 grit paper as someone instructed me that was the best coarseness for dry sanding fiberglass. The sanding just created holes where the cloth is showing through and after another layer of resin instead of bubbles, there are just opaque rings everywhere :facepalm: . Like this:

After fiber-glassing over all that hand stained wood and seeing a bunch of opaque shapes as the result is extremely distressing. Since I live in the middle of the country there is really no one local I can ask either.
So can someone give me (a total novice) some advice? Should I try using a really fine sandpaper?
Thanks in advance!
Jim

 

[JimC3]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

Here's a better picture:

 

[Three08]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

Did you clean the surface before glassing? I'm no expert but it looks to me like a big air bubble in the second photo, the white spots in the first photo kind of look like it didn't get wet out properly but I may be wrong, it's a little hard to tell. In other parts it looks like to much resin, but I don't think that would be the cause of this issue. Are you using epoxy? What sort of cloth are you using? Oh, I just noticed you mentioned the wood is stained, did you check to make sure the stain is compatible with the glass your using. From what I've read regardless of what stain you use it should be allowed to dry completely before fiberglassing over it and even then it's best to still check with the glass manufacturer. No doubt some with a lot more knowledge then me will come along soon to help you out.

 

[tpenfield]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

fiberglassing over stained wood . . . that's a new one . . . at least for me. Perhaps that may be related to the problems?

 

[jigngrub]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

I've always found it helpful to practice and experiment on smaller items and scrap before taking on a job I have little or no experience with.

Are you using the proper tools? Have you watched any instructional videos for laying glass? Youtube has quite a few vids for glassing boats, kayaks, and canoes... it may be helpful to watch some of them.

 

[JimC3]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

Hello all!
Thanks for a fast response! For the majority of the stained surface the fiberglass layed absolutely beautifully, it's just a few spots where there are bubbles that I've tried to sand down. In general what would be the best grit of sandpaper to use to remove the bubbles without scuffing up the rest of the fiberglass or creating gouging holes like I did? I've been using Raka fiberglass and resin. Like I said, for the most part the weave filled perfectly, but there are just a few spots where it's a little opaque or there's bubbles.
Thanks again!

 

[jbcurt00]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

Epoxy or polyester resin?

The cloth you used may have been subjected to moisture, which causes it to be less likely to accept resin very well, which results in areas of the weave looking white. Even 'just' sweat drops from your hands or dripping from your brow....

"....Fiberglass cloth is coated with a special sizing to make it compatible with epoxy resin. This sizing is sensitive to water and can be damaged or removed if water comes in contact with it. The result will be a glass weave that looks white. Be careful not to have water on a surface or on your hands, that could come in contact with fiberglass cloth. Be wary of a "sale" on cloth that might be water damaged."

From here..

More pix of your project? Welcome to iboats.

 

[Woodonglass]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

How long did you let the Stain dry before applying the Epoxy? To do the repair and make it look acceptable you will need to sand off the resin and glass down to the wood and then cut a Patch piece of glass to fit the area as precisely as possible and then apply the resin to the cloth. What weight of cloth did you use? How long has the epoxy cured on the boat? What were the Temps when you were glassing?

 

[JimC3]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

Thanks everyone for being so welcoming! I used epoxy resin and 7 ounce plain weave.The stain was definitely dry before I applied the resin. Here is another picture of an opaque spot:


So if I do sand down all the bubbles and the opaque spots, what exactly should I sand them with (fine or coarse paper?) and how do I prevent the fringing like this?:


I was instructed to use 80 grit paper on the fiberglass but that just lead to gouging...

Thanks again!

 

[Woodonglass]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

180 grit and from the pics you have a LOT of resin pooled up. Lot's of think coats is much better than one heavy coat. Usually takes 4-6 coats to get a boat done. To much resin will cause the cloth to lift and you'll get bubbles etc. An Xacto knife is helpful to cut the cloth away and then place your patch.

 

[JimC3]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

Thanks for the tip on 180 grit sandpaper! I figured I was over killing the resin. 4-6 coats is a great tip too. The cloth in the picture can't be cut away with a knife, it unfortunately solidified, just opaque. So sanding the ring away with the fine sandpaper is my best bet? I can also sand away the pooled fiberglass with the 180 grit paper without any negative effects that make the cloth visible, correct?
Thanks again for all the help! It's great to talk to real mariners, there are none to be found in my land-locked state!

 

[Woodonglass]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

Well, I'm not sure you could call me a "Mariner" but I have worked with epoxy to some extent and love working on boats. I will be starting my own Partial Wooden Boat build next spring. After sanding away the glass and feathering it all out towards the center, make sure and wipe it all down with Acetone before applying the patch.

 

[JimC3]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

I was successful at sanding down the ugly parts!:joyous: I gave it another glaze of epoxy but it ended up running again...
It never really looks like it has another layer until it's too thick... I'll just have to go really thin next time.
Back to sanding...:cold:

 

[jigngrub]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

What brand/supplier epoxy are you using?

 

[Woodonglass]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

Epoxy requires Patience. That's why I said multiple thin coats. You cannot get in a hurry. For patches I prefer to use the Fast Set epoxy. I can get 3 - 4 coats in a day using it. I would try to get the area as horizontal as possible. Will help with the runs.

 

[jigngrub]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

I would try to get the area as horizontal as possible. Will help with the runs.

You got that right! That's why I asked what kind he was using.

I sealed some door frames and the main entry to my house (all vertical applications) with some leftover 635 thin medium this past summer, and even though it was hot outside I had a heck of a time with that stuff running. Finally figured out to do a section or a frame and stop, then "babysit" the area with a brush... brushing out drips as they formed until the resin became stiff enough to not drip.

If I had it to do over again I'd order the 150 thick epoxy with the medium or fast hardener instead of trying to use the 635. The 635 is definitely not for vertical applications.

 

[JimC3]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

Hello again!
This question is beyond the scope of the thread. I'm nearing the 6 coat mark and everything's looking pretty smooth but there are still some dents for various reasons. I've worked so much with Bondo and the thought of returning to it for the top layer is nauseating. Is there a different type of putty substance that will fill in dents and help smooth out the top layer? The plumbers putty I've found impossible to smooth. Is there a different way than Bondo? Or is miracle fiberglass clay the work of fiction?
Thanks again!
Matt

 

[jigngrub]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

I like the SM Fairing Compound, just mix it with your epoxy resin to make your filler:

Fillers

You make it with epoxy, so it will stick to epoxy. It's also a nice brown color so it won't stick out too bad.

 

[Woodonglass]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

Dents??? Pics would help.

 

[73Chrysler105]

Re: Bubbles, Blemishes, and Holes in first layer of fiberglass?!

I say you paint a very light coat od spray paint over it and with a long board sand until that coat of paint is completely gone then the entire thing will be even as can be.