Fiberglassing... A Pain

[StrapsTivis]

So, wow.. I've done fiberglassing in small areas somewhat successfully.. but WOW.. doing large areas is a different ballgame all together. Looking for some help. I'm using a Chopped Strand Fiberglass Mat with Bondo Fiberglass Resin. The Resin tells me, that once I mix it I have 12 min to work with it, so I try to work fast.

- I used a paint roller to roll some Resin on the surface
- I laid the Fiberglass mat on top,
- I tried to pour out resin on top of the mat, then roll it out with a roller.

That last step did not work. The resin absorbed fast, which didn't allow it to spread very well, then the strands would come off the Mat, and get caught up on the roller and make the roller unusable.

So, for the next area I tried to put MORE on during the start, on the bare surface.. hoping when I put the mat on top it would soak thru. This didn't work either, so I put more resin on top and tried that again, same results as before.

I'm thinking there has to be a better way to do this, and I'm just not seeing it. I know the less resin you use the better, I did a single layer of mat over a 55" x 100" area yesterday and used a gallon of resin. Maybe that's about right, but to me it sounded like too much.

Thanks for any and all advice.

 

[sphelps]

What type of roller are you using ? A bondo spreader works pretty well also sometimes ..

 

[StrapsTivis]

It was just a run of the mill paint roller with an extending handle.

 

[rcmpvet]

Try to obtain one of these:

http://www.rona.ca/en/laminate-roller

 

[Mr.Stickney]

No expert here but it sounds like there wasn't enough resin. Using 1.5oz CSM I was using 110-120 ml per square foot. Based on your surface are im thinking you should be 4500-4600 ml's

About a quart short by my math.

A tip given to me by WOG is have another batch standing by with hardener to match and that way if you come up short you can mix it up real quick, and if you don't need it, you haven't wasted anything!

Did you seal the wood with resin prior to laying down your CSM? You'll be surprised how much resin a piece of plywood can soak up and if its not sealed it will pull it right out of the fiberglass.

 

[StrapsTivis]

Try to obtain one of these:

http://www.rona.ca/en/laminate-roller

I just ordered one from Amazon, I'll give it a shot!

 

[StrapsTivis]

No expert here but it sounds like there wasn't enough resin. Using 1.5oz CSM I was using 110-120 ml per square foot. Based on your surface are im thinking you should be 4500-4600 ml's

About a quart short by my math.

A tip given to me by WOG is have another batch standing by with hardener to match and that way if you come up short you can mix it up real quick, and if you don't need it, you haven't wasted anything!

Did you seal the wood with resin prior to laying down your CSM? You'll be surprised how much resin a piece of plywood can soak up and if its not sealed it will pull it right out of the fiberglass.

No I didn't seal it before, but it was also going over an old layer of Fiberglass that I sanded up a bit... I don't know if that makes a difference or not.

I did have another 1/2 quart that I used to fill in some dry areas.. I didn't get them all completely clear because like you thought.. I ran out of Resin and Hardener. I have more of that coming as well.

 

[52FordF2]

Does Bondo Fiberglass Resin have WAX in it?
If it does you need to sand every layer after it dries, if you need to lay down some more CSM, resin, and/or gelcoat.

WOG may know, I'm not an Okie just an old fart some times

 

[tpenfield]

I would think that the Bondo resin has wax since it is a consumer oriented brand. As far as using CSM, rolling it is futile. That is why a cloth is better. But if you do use CSM you have a couple of options . .

First, lots of resin on the surface before you lay on the CSM. Then I either use a piece of fiberglass cloth over it to roll the resin out or I use a sheet of plastic drop cloth to cover the CSM and roll it out.

Putting resin on top of CSM is pretty futile as well, it is best to get the resin to come up from the surface through the CSM as that cases the air pockets out.

 

[Mr.Stickney]

Bondo fiberglass resin most certainly has surfacing wax in it.

 

[gm280]

Straps, certainly not an expert here either by any standard or stretch, but I have used 20 gallons of resin now and went through the learning curve as well. I use 4" roller that I got from Lowe's. I roll on 435 laminate resin and soak everything first. Then lay out the CSM and start rolling it into the resin. If it looks like there isn't enough resin from some dry areas, I roll on some more. The roller will pick up the CSM strands if you have too little resin, OR if you keep rolling over the area more then needed. I found out that rolling on the resin and moving along works better for me. It is a learning experience and I would stop using Bondo resin and buy laminate resin for what you are doing. As previous stated, Bondo resin has does have wax in it. While you can use that, the wax will have to be removed if you decide to lay any type fiberglass over top of previous laminate. You can do that with both sanding AND then washing the area using Acetone. I use some Lacquer Thinner as well and that works. But most use Acetone. Even laying fiberglass over the fiberglass you just laid will have to be clean first. Usually folks lap previous areas a couple inches as they lay more. So search the net for 435 laminate resin and buy it from a vender. It will be cheaper and work better. But this is just my $0.02 cents worth. Here are the 4" type roller a lot seems to use.

 

[jbcurt00]

I just ordered one from Amazon, I'll give it a shot!

I'd cancel that order, no reason to use that roller, unless your putting vinyl flooring down on the deck once you get the glass work done.

If you used a regular paint roller, unless it was a short nap, I'd suspect it would pickup the fibers from the CSM.

• Apply resin to the plywood surface
• Once that begins to tack up, roll out additional resin
• Apply CSM into resin
• Roll out CSM as necessary to 'push' resin up thru CSM

What ratio MEKP are you using? Metric works great:

• 100Mil of resin needs between 1Mil & 2Mil of MEKP (1%-2%)
• If you are working in the sun, use less then 1.5% MEKP (in above 100Mil sample, you use 1.5Mil of MEKP as a base line)
• If it's HOT, use 1% MEKP
• If it's cold, use up to, but no more then 2% MEKP
• If you get @ 12min per Bondo working time (at 1.5% MEKP) and 'need' a little more working time, use 1.25% MEKP

Bondo is typically a lower quality resin that has an unknown shelf life before you bought it, and it has wax in it. None of that is good....

Did you read WOG's post in your other topic about these soft spots http://forums.iboats.com/forum/boat-...floor-question ?

If you decide to just patch the soft spots. you'll mix the resin with the hardener and then apply a liberal coat to the plywood. Let it set for an hour and then apply another coat of resin and lay some 1.5oz CSM down on top and use a short nap roller to smooth it down and apply a bit more resin when and where needed. Less is more Use just enough resin to make the glass go clear. Make SURE and coat the edges well and get glass on them as well. Take a look at this and I think you'll find it helpful...
Fabricating Decks, Stringers, and Transoms

Or have any comment on this reply:

As others have suggested, this is the sign of someone who patched over significant problems.


I'm not sure what you mean by this. If by "hardener", you mean the MEKP catalyst that causes the resin to harden, then you put it in each batch of resin you use to wet out the fiberglass. On the other hand, if "hardener" refers to the wax that allows the final layer to fully cure (and not remain tacky), that is generally added only to the final coat.


Not sure I understand the question.

It sounds like you would really benefit from checking out the boat more thoroughly. It seems unlikely, but you might find there isn't that much damage beneath the decks. But you rally need to check before you take people out on the boat.

Good luck, and if you do decide the boat needs restoration, there is lots of help here for you!

If you'd have read the link WOG posted about the Fabrication, you'd have gotten good info about what rollers to use, and how best to apply the resin, the ratios of MEKP to use and how to work the fiberglass to avoid the problems you've encountered.

A 55X100 are doesn't sound like a small soft spot as described in the other topic I linked. Above somewhere you mentioned going over the fiberglass that was already there, so you didn't pull any of the old rotten deck that was beneath the 3/4in plywood someone covered up an ugly mess w?

Again, take note of comments suggesting this is likely not a wise plan of action, and could leave you w an unsafe boat w/ unknown hidden problems you've covered up. Just like whoever laid that 3/4in plywood.....

And CSM isn't sufficient if you're using it to tab the hull to deck joint, that needs to be 1708 or similar, details also provided in the fabrication link WOG posted