Fiberglassing Question. Hopefully not a stupid one.

[kcs1211]

Im glassing my dog house. Got the first coat on, now getting ready to wrap in cloth.

Can I use the fiberglass tape? Seems it would be a lot easier to wrap it in tape then try to get the cloth to stay put.

What are the disadvantages to this?

Thanks for any help.

 

[kcs1211]

Re: Fiberglassing Question. Hopefully not a stupid one.

Anybody? Im waiting to wrap it right now. Waiting for your approval/disaproval. Help.

 

[Numlaar]

Re: Fiberglassing Question. Hopefully not a stupid one.

I don't think tape would be a good idea...

For starters, its really meant just for joints... also, because it has a "finished" edge on it to keep it from fraying, when you resin it in, it leaves a higher "lip" along the two edges because of this finished seam. (Trust me I know hehe just taped a bunch of things into my boat).

If you are doing a larger surface area, I would stick with woven cloth or CSM. CSM if you need the strength (it will use a LOT of resin), Woven if you just want to seal it up for waterproofing.

Hope that helps!

Num

 

[kcs1211]

Re: Fiberglassing Question. Hopefully not a stupid one.

I really appreciate the help. Tape is out, guess I'll go fight with the cloth a little bit.

Thanks again.

 

[Mark42]

Re: Fiberglassing Question. Hopefully not a stupid one.

Try rolling the resin on then lay the glass. Mat alone is a pain. See if you can find a mat/cloth combo, it will be easier to deal with. If you are using cloth alone, describe the problems with the layup. Maybe we can help.

 

[kcs1211]

Re: Fiberglassing Question. Hopefully not a stupid one.

Im using cloth. I don't think its a problem laying it down, but I just thought wrapping in tape would be easier.

I am worried though, I laid down the first coat of resin. This morning, it looked ok, now, there are quite a few small air bubbles in it. They weren't there this a.m. Im going to sand it and lay down the cloth.

Should I be worried about the bubbles. Should I sand them down and put another layer of resin down before the cloth?

This is my first attempt at fiberglass. Im not expecting perfection, but hoping for function. Thanks for any help.

 

[rngale]

Re: Fiberglassing Question. Hopefully not a stupid one.

Im using cloth. I don't think its a problem laying it down, but I just thought wrapping in tape would be easier.

I am worried though, I laid down the first coat of resin. This morning, it looked ok, now, there are quite a few small air bubbles in it. They weren't there this a.m. Im going to sand it and lay down the cloth.

Should I be worried about the bubbles. Should I sand them down and put another layer of resin down before the cloth?

This is my first attempt at fiberglass. Im not expecting perfection, but hoping for function. Thanks for any help.

did you hot coat the wood u mad e the box out of first? Because if you didnt you can get air in the laminate form the underside as the plywood, wood, "breathes" when the resin cures. The other question would be if you did the laminating in the sun? And if useing multiple batches of resin u need to make sure that the outer or last batches of resin dont cure well ahead of the resin below.

And if i confused you im sorry

 

[109jb]

Re: Fiberglassing Question. Hopefully not a stupid one.

Air appearing in the layup could be from the underlying wood continuing to soak up resin. I started sealing the wood with a coat of laminating resin and letting it cure. After cure I then do the layups and haven't had any more problems. I have also heard that the wood gives off gas/air as it heats up. If you are doing the layups outside in the sun this could be it too.

 

[lowkee]

Re: Fiberglassing Question. Hopefully not a stupid one.

I am worried though, I laid down the first coat of resin. This morning, it looked okay, now, there are quite a few small air bubbles in it. They weren't there this a.m. I'm going to sand it and lay down the cloth.

Should I be worried about the bubbles. Should I sand them down and put another layer of resin down before the cloth?

Pictures would help a lot here, as there is a cut-off point when it comes to air bubbles. It is possible to have hundreds of tiny bubbles over a large area and be fine, it depends on what it'll be used for and how it happened.

Was the 'bubble layer' just resin or a layer of wetted glass? Is the wood pressure treated? How long has the wood been drying before you used it? How much hardener did you add?

If it won't be difficult, just sand it down and not risk it. You don't have to do a full resin coat before glassing. Most restoration junkies here simply roll on resin then immediately lay on the glass. This not only helps wetting it out, but also holds the glass in place while you wet it out and gives you a free hand for conforming the corners. I, personally, don't ever resin anything I plan to later glass, as it'll get plenty of resin when I glass it.

 

[kcs1211]

Re: Fiberglassing Question. Hopefully not a stupid one.

I didn't build the box, its been on my boat since 1976. I stripped the vinyl and glue off it and sanded it down. It sat in the heat for 4 days so Im pretty sure the wood was dry.

So, should I sand out the bubbles, or just lay down the cloth?

Thanks again.

 

[kcs1211]

Re: Fiberglassing Question. Hopefully not a stupid one.

I will try to take some pics later today.

It is my engine cover that Im glassing. It doesn't have to be real strong, but will need to be able to hold someone sitting on it. It already did before I started, and I figured glass would just strengthen it even more, plus make it water proof, and look better then the 30 year old vinyl.

Thanks again for all the suggestions.

 

[Numlaar]

Re: Fiberglassing Question. Hopefully not a stupid one.

If it is just a few small bubbles, and its not structurally important, then I think you will be ok, and dont need to sand it down and start over... could be from the old glue that was used even though you sanded it, maybe something chemically was causing it....

You said its just to add strength to an old doghouse that was already strong, and to seal it up.

I use the method lowkee described when glassing with cloth (it soaks a lot easier than CSM). I dont even roll it, I just use the throw away chip brushes.. brush it on, lay down the cloth which starts to soak in right away, then brush on more resin until its completely covered and the cloth is soaked through.

 

[Mark42]

Re: Fiberglassing Question. Hopefully not a stupid one.

It never hurts to sand between coats. The smoother the surface, the better the lamination. Noting worse than laying up over bumpy glass. Don't have to go nuts, just knock off the the high spots and sharp loose strands. Then there is less chance of pulling/runs in the cloth.

 

[lowkee]

Re: Fiberglassing Question. Hopefully not a stupid one.

Nothing worse than laying up over bumpy glass.

Ha! I couldn't agree more! Be sure to sand down anything nearing the size of a grain of rice or larger. You will nearly always get an air bubble and if you don't it means you applied way too much resin

 

[kcs1211]

Re: Fiberglassing Question. Hopefully not a stupid one.

Well, I took your guys advise and I think (hope) its going to turn out ok.

I lightly sanded it down, then laid the resin right on top of the glass. There was two small bubbles (in the glass) after I smoothed everything out that I could not get smooth. Im not sure how that will effect the final finish.

There is 2 or 3 loose strands that I learned quickly you don't want to pull. Do I sand those out after it dries?

The stuff I used is Evercoat Premium Resin, it says that I have to sand in between coats if it cures, I assume that is for better grip for the new coat, how do I sand this coat without damaging the cloth? Im worried I used the wrong stuff because now that I clearly read it, it says finishing resin.

Even though I used a mask, im still spinning a bit, nothing a couple beers can't enhance.

 

[lowkee]

Re: Fiberglassing Question. Hopefully not a stupid one.

The two small bubbles are likely wax left over from the initial coat. Likely low spots your sander missed. Speaking of wax.. Finishing resin means it has wax in it, which is why they tell you to sand, because you need to remove the wax from the surface. I also recommend following the sanding up with a wipe down of styrene.

When you do sand, you don't need to sand much, just enough to break the surface. You won't be ruining the cloth by doing so, as it takes more than a scuff to rip through a new layer of glass. For the mask, make sure you use a real mask, one with dual cartridges meant for enamel painting. You might as well sniff glue (you pretty much are) if you cheap on the mask.

 

[kcs1211]

Re: Fiberglassing Question. Hopefully not a stupid one.

The two left over bubbles are folds I couldn't get out of the cloth, I smoothed them flat as I could get them, but it had already gotten tacky and I couldn't move it anymore. Are small folds bad, other then visually?

I truly appreciate all the help.

 

[ondarvr]

Re: Fiberglassing Question. Hopefully not a stupid one.

Pre-coating the wood with resin is very important and this coat of resin needs to be at least getting hard before starting any glass layups. If you don't do this the wood can suck resin out of the glass leaving dry spots, plus you can end up with large air bubbles as the air in the wood expands as its heated.

If you let finishing resin cure, as in tack free, the surface needs to be thoroughly sanded before another layer can be applied.