Wrapping plywood with fiberglass

[flamron]

How do you guys get the edges to lay down?

I'm having some trouble with it and would love some tips.

Pics:

That is the bottom of the piece. I'm having issues with the edges mostly.

I'm a total glass newbie, so anything would help.

Thanks guys,

 

[ondarvr]

Re: Wrapping plywood with fiberglass

What is it you plan to do with these pieces of plywood?

Glass does not wrap around square edges, so you need to use a router and put a nice radius on anything you want to wrap, but even then it may not be easy to do.

Do one side at a time and then come back and wrap the edges later with strips of mat.

 

[flamron]

Re: Wrapping plywood with fiberglass

These are flanges that are going under the deck to patch. I wasn't too worried about their looks, but I do want to get a good seal on the larger board.

Here is my last attempt:

It is better, but I'm still bubbling the edges a bit. Not sure if that is critical or not (I assume it is important to not bubble up).

 

[ondarvr]

Re: Wrapping plywood with fiberglass

The mat looks too wet, with too much resin it will start to fall apart and be difficult to control, use only enough resin to wet out the glass.

Pre-wet the wood with resin, let it get hard, or least starting to gel, then do the glass work.

 

[flamron]

Re: Wrapping plywood with fiberglass

That would sound about right I'd guess. It feels like it is taking a lot of resin to make the fiberglass "disappear". I read that in the DIY as long as the glass disappears, you are good.

I've got a couple more boards to do today - the heat will be my limiting factor today for the afternoon with 90+ temps.

I'll try using less resin on these and see how that works, along with the prewetting/setting up and see how it goes.

Thanks ondarvr!

 

[maagee79]

Re: Wrapping plywood with fiberglass

u need to make sure u get all of the air pockets out of it before it drys. i see u have a lot of trapped air. what r u using the glassed boards for?

 

[Woodonglass]

Re: Wrapping plywood with fiberglass

Flamron,
Couple of tips. Pre cut your glass as close as you can to fit the piece you are covering. Allow for the Overlap of the edges. Mark the edges with a magic marker and then, PRE-CREASE these edges by folding them and using a piece of wood to crease them or borrow your wifes Iron and a towel and iron them. 2nd tip is to Stick Pins to Hold the glass in place. Grease em down with vaseline so they won't stick. Some guys even use staples to hold it down. It does appear you are using to much resin. Coat the wood first then apply the mat and then recoat the mat. Try using a plastic putty knife to spread the resin around instead of a brush. Also cut back on the catalyst a little bit to give you more working time but not too much or you'll weaken the resin. Don't be afraid to use your hands to help mold the glass. It just looks to me like you need to be more precise in your cutting and measuring of the glass and use less resin.

 

[flamron]

Re: Wrapping plywood with fiberglass

Thanks woodonglass.

I'll give all of that a shot as well.

The plus side is, I can't be any worse than I already am!

 

[Yacht Dr.]

Re: Wrapping plywood with fiberglass

How do you guys get the edges to lay down?

I'm having some trouble with it and would love some tips.

Pics:

That is the bottom of the piece. I'm having issues with the edges mostly.

I'm a total glass newbie, so anything would help.

Thanks guys,

Its real simple flamron .. why you are having the mat "lifting" and air pockets ..

Its not a case of too much resin in your layup..

Its a cause of Improper PREP in your ply edges .. I can Guarantee you did NOT seal those ply edges prior to your lams.

That is why Proper prep on your wood is Paramount before your layups !! ..

It Does not matter if its the Edge or the face of ply that you want to apply Glass and resin.. IF its NOT Prepped correctly your in for trouble ( I keep saying this over and over again ! ) .

Think of a "Suction Cup" .. it works because there is No release of air into the cup from the substrate .. peeps dont use suction cups on CDX or OSB or ACX or Bare Marine ply .. it will not hold there cups. .. you have to make your wood like Glass Before you even think about Layups .. so the glass/resin works the way its intended ..

Mebbe I will do a Iboats ONLY vid for this Cause and affect of Improper prep from different kinds of wood/lam .. Now things are winding down for me .. Ill talk to VT and see what he thinks about that ..

Its your wood prep plain and simple ..mat will conform to almost any radi ..given the proper prep ..

YD.

 

[DeepBlue2010]

Re: Wrapping plywood with fiberglass

YD, Would you please elaborate on the proper preparation? I was under the impression that laminating the edges with fiberglass is what seals them! What did you mean by .. "I can Guarantee you did NOT seal those ply edges prior to your lams"? What type of sealing would you do before fiberglassing?

Ondarvr, I heard that the first coat of resin on the wood should be "thinned" to better penetrate the wood; is this true? If yes, what thinner and what ratio? I am talking about the wetting coat that involve no glass at all

Sorry Flamron, did not meant o hijack your thread. I think the questions are as relevant to your project as they are to mine.

 

[ondarvr]

Re: Wrapping plywood with fiberglass

NO THINNERS... use it as is.

I say it that way not targeting you, but because this old wives tail refuses to die.

Sealing the wood is pre coating it with resin.

And although someone thinks it has nothing to do with the amount of resin used, I can assure you that when the glass is over saturated it becomes a difficult to use mess rather quickly.

 

[Woodonglass]

Re: Wrapping plywood with fiberglass

I agree with ondarvr about using to much resin. Question. Did you precoat the wood prior to laying the CSM? Did you pay close attention to saturating the edges with resin? Were there a LOT of voids in the edges of the wood? Did you attempt to FILL any of the voids prior to precoating the wood?

 

[flamron]

Re: Wrapping plywood with fiberglass

I did precoat all the sides - but I did this the day before glassing the pieces. Perhaps another precoat right before application is in order? I sanded the wood with 80 grit before precoating as well, and then blew/wiped them clean (air and acetone) and let the acetone "burn" off before continuing.

No voids were in the wood. Possibly because this is MG plywood? (but I'm betting some voids are possible, and I'll fill those if needed if I come across any).

YD - that video would be a great asset for sure! Anything I could see would be fabulous! I seem to do well with emulating stuff when I see it, so that would be an invaluable piece for any newbie I'm sure.

Thanks again to all: YD, ondarvr, woodonglass, and everyone else. Like I said - I'm a total rookie on this stuff. I spent days of searching on here and the internet, and didn't really come across anything that fit my questions. It seems like glassing is almost an artform - probably why I stink at it!

 

[Woodonglass]

Re: Wrapping plywood with fiberglass

Sounds good. Yes, always apply resin first and then lay the mat and then apply more resin. Like I said I like to use a plastic putty knife to spread it around and then a chip brush that I cut about an inch off the end of the bristles to make it a little stiffer. DON'T brush it. DAB it. Brushing will pull the Fibers and make a mess. If you Did not put resin down first then that can make it a bit harder but again looks to me like too much resin. Try this for Grins Take a small piece precoat it like before and let it dry. cut a piece of mat like I suggested and Precrease the edges. then coat the piece including the edges with a light coat of resin and place the mat. Then use the chip brush to Dab NOT brush some more reson on or use a small plastic putty knife to spread the resin around again just a light coat just enuf to wet out the glass. the resin coming up from the bottom and what you put on from the top should NOT take all that much. Practice with a small piece using this method and see how you come out. Try it and see how you come out.

 

[flamron]

Re: Wrapping plywood with fiberglass

Excellent! I have one more smallish piece that I can try this on before I go to the big section.

If my son ever falls asleep for his nap, I'll run out and give it a try. Otherwise, it'll be later tonight.

Thanks Woodonglass! If you ever make it over to NW AR, look me up. I'd be happy to take you out for a ride once I get her done!

 

[ondarvr]

Re: Wrapping plywood with fiberglass

What can happen on wood or any other porous surface, is when the resin starts to cure it will generate some heat. If the conditions are right then the heat will expand the air and it has nowhere to go and bubbles up the laminate. Sealing the surface eliminates this type of air, plus it won?t be able to draw any air out of the wood even if the heat doesn?t create a problem, but it?s not the only type of air and I don?t really see it in your pic.

 

[flamron]

Re: Wrapping plywood with fiberglass

The bubbles you see just kept coming back - FWIW. I kept trying to get it to lay flat, but they just kept coming up.

Is that an indication of too much resin? Or is that the heat issue you mentioned ondarvr?

 

[Woodonglass]

Re: Wrapping plywood with fiberglass

To me what I see is just the glass lifting off the wood. If you crease it that will help. Use your fingers to smooth it down and keep working it especially right when it start to tack up. Careful though, it's stringy and will start to lift on you and get crazy, fresh resin will help lay it back down if it's not to hard. Again a putty knife works good.

 

[flamron]

Re: Wrapping plywood with fiberglass

I have some of those plastic squeegees from US Plastics - should I give those a try? That and the trimmed paint brush for dobbing.

 

[Woodonglass]

Re: Wrapping plywood with fiberglass

Perfect!!!

Did you ever PM me your SHIPPING Address??