My glass did not harden, why?

[lmannyr]

I mixed 1 pint of polyester resin with 1/8th once of hardner. Put enough cob-o-sil for a thicker than syrup but not as thick as vasiline consistancy. Mixed it all up for about 10 minuntes and made sure I couldn't see the cob-o-sil. I put it down around 730 Last night in West Palm Beach, Florida. Checked the status after work today and only a paper thin top layer was semi hard.

The boat is covered when I'm not working on it with tarp (my shade placed over the bimini top pulled from bow to stern) and then a plastic water proof tarp on top of that.

I would have thought it would have gotten hard within a couple of hours. What did i do wrong?


THanks!!!

 

[gcboat]

Re: My glass did not harden, why?

Did the directions recommend covering with saran wrap? Was the mix on the money? How old was the product? Sometimes you will need a plastic barrier like applying gel coat ( the saran wrap thing ) for it to cook off. Quite possibly just let it sit for another day or so and see what happen.

 

[lmannyr]

Re: My glass did not harden, why?

The Mix chart had gel coat in the mix. The same amount of gel coat as resin was mixed..


1/8 ounce of hardener 1 pint of resin and 1 pint of gel coat.

Wouldn't taking the gel coat out of the mix make it harden quicker? The sales guy did not say a thing about adding gel coat. He walked me through the store telling me what I needed. He knew I was a novince.

What is the purpose of the saran wrap? How am I gonna saran wrap the large areas? How does the saran wrap get removed after (and if) the resin cures?

I bought the supplies less than a week ago.

 

[ondarvr]

Re: My glass did not harden, why?

1/8th of an oz is about 4 grams, 1 pint is about 454 grams, so you had less than 1% catalyst, you need about 2% for it to cure well. You should use about 10 grams in the next batch.

It still may get hard, but may not be as strong as it could be.

 

[ondarvr]

Re: My glass did not harden, why?

The saran wrap only helps the surface cure and not be tacky, it won't have an affect on the the cure of the resin below the surface.

 

[lmannyr]

Re: My glass did not harden, why?

Well today I preped another surface for resin.

I mixed 1 pint of resin with 1/2 oz of hardener. It is 75 degress in overcast weather. I mixed for about 5 minutes and rolled the mix onto the surface. I'm gonna go for dinner so hopefully, it will harden this time.

Only thing I noticed when I roled it on was it left very wavy marks. it wasn't smooth. It a 1/4 " nap I think. It's raining right now so I'll verify that later.

Hopfully it will smooth out.

Thanks

P.S. The previous mix did not harden more than a paper thin paper soft top layer. I wiped it up dumped it in the trash. That sucked!

 

[lmannyr]

Re: My glass did not harden, why?

Sure enough, it was dry to the touch within a few hours.

Question:

How deep of an area can I pour and still harden? I have these 1 inch deep channels that I want to fill. Do I do a little at a time or can i just level it in one shot?

Thanks!!!

 

[ondarvr]

Re: My glass did not harden, why?

If you are trying to get the resin to level and flow, what's the reason for adding the cabosil? Cabosil will do exctly the opposite of what you want, it thickens the resin and lets it move less.

If you want it smooth, use a plastic spreader to move the thickened resin where you want it, a roller will add resin to both the high and low areas, you want nothing added to the high spots and the low spots filled. The plastic spreader will only fill the low areas, you may need to do it couple of time to get it level.

As I said in your other post, resin has little or no strength, so using it to fill anything more than just some minor surface imperfections normally results in cracking and chipping in the near future. This will be even more of a problem if the area flexes or is stressed at all.


It makes little difference what you use to fill the 1" areas as long as you glass over the the top of them, resin wouldn't be my first choice, but would work. A light weight filler of some type would work better and still needs to be covered for it to hold up.

 

[lmannyr]

Re: My glass did not harden, why?

What kind of sandable filler would you recommend for my purpose?

Thanks for the relies.

 

[wire2]

Re: My glass did not harden, why?

I've used common auto body filler on fibreglass (the proverbial Bondo) with good results. Rough up the resin first for it to stick well, prime & paint after.

 

[lmannyr]

Re: My glass did not harden, why?

Have you had any problem with it cracking?

 

[ondarvr]

Re: My glass did not harden, why?

Bondo can work and not crack, it just depends on where and how you use it. As I mentioned in your other thread, If this area doesn't see much water then even bondo will work, but there are better more water resistant products for sale at the same places, many say marine or waterproof on the can, they will all work better than resin.

The type with fiber in them are stronger and will resist cracking better, but that doesn't mean you can fill a 1" deep valley and not need to to use glass over it to prevent it from cracking.

 

[jtexas]

Re: My glass did not harden, why?

Sure enough, it was dry to the touch within a few hours.

Question:

How deep of an area can I pour and still harden? I have these 1 inch deep channels that I want to fill. Do I do a little at a time or can i just level it in one shot?

Thanks!!!

Thickness really has nothing to do with it - it cures *much* more slowly while exposed to air - which is why the saran wrap cover. Fill 'em up all at once, no problem.

Marine-tex is kind of pricey for large projects but it is an excellent fiberglass putty.

 

[ondarvr]

Re: My glass did not harden, why?

Thickness has a great deal to do with it, laminating resin is not designed to be use as a filler, it's formulated for laminate thicknesses of about a 1/4 inch or less, not a 1" inch deep and 1 or more inch wide valleys. Resin gets very hot when it cures in a mass like that, it typically shrinks a great deal and cracks. covering the surface with saran wrap or something similar, has no affect on how fast it cures, it does have an affect on the surface though, letting it cure without being tacky.

Marine tex would be very expensive to use as a fairing compound and would be much harder to sand than even the resin would be.

 

[jtexas]

Re: My glass did not harden, why?

Thickness has a great deal to do with it, laminating resin is not designed to be use as a filler, it's formulated for laminate thicknesses of about a 1/4 inch or less, not a 1" inch deep and 1 or more inch wide valleys. Resin gets very hot when it cures in a mass like that, it typically shrinks a great deal and cracks. covering the surface with saran wrap or something similar, has no affect on how fast it cures, it does have an affect on the surface though, letting it cure without being tacky.

Marine tex would be very expensive to use as a fairing compound and would be much harder to sand than even the resin would be.

I stand corrected.

 

[ondarvr]

Re: My glass did not harden, why?

Sorry for it sounding so blunt, I just didn't want him fill the channels and then have a smoking, stinking, cracked mess. It rarly happens, but I have seen fires start from hot curing resin in a bucket or dumpster.

 

[BillP]

Re: My glass did not harden, why?

Thicken polyester with chopped strands of fiberglass if you want a structural filler for dings. You can make your own strands by cutting up glass cloth. Cabosil has zero structural value...it thickens but also weakens.

b.

 

[lmannyr]

Re: My glass did not harden, why?

how much phenolic microballoons do I mix in with the resin.

I guessed on the mixures and noticed when I layed out the resin on a horizontal surface, the microballoons would separate. This would leave small clear areas without the microballoons.

The phenolic microballoons I purchased from boaters world did not come with a recomendation.

Thanks.

P.S. Fiberglassing really sucks!!! (just think prep, prep, prep, prep. It's all about prep. lots of prep and more prep. then after more prep then prime and paint.

This is takes some patience. Oh boy.

 

[BillP]

Re: My glass did not harden, why?

how much phenolic microballoons do I mix in with the resin.

I guessed on the mixures and noticed when I layed out the resin on a horizontal surface, the microballoons would separate. This would leave small clear areas without the microballoons.

The phenolic microballoons I purchased from boaters world did not come with a recomendation.

Thanks.

P.S. Fiberglassing really sucks!!! (just think prep, prep, prep, prep. It's all about prep. lots of prep and more prep. then after more prep then prime and paint.

This is takes some patience. Oh boy.

It varies but a good rule of thumb to start with is 1:1 ratio (in volume).

 

[ondarvr]

Re: My glass did not harden, why?

Add some cabosil too, this will help keep the ballons in suspension and will make it easier spread.