Fiberglass question.

[Jay Sco]

I'm working with fiberglass for the first time and have ran into a question. I am glassing over two 14" balls using mat and Bondo brand resin with the supplied liquid hardener. I pre mixed about 1/4 gallon of resin and about 1/2 of one tube of hardener, used the same mixed batch for both balls. These were both done about 6hrs ago, the one on the left is almost completely hard all the way around, the one on the right is still soft and sticky.
What gives? I did the top half of both, then the bottom half, so I don't think segregation could be an issue.
These will be for holloween (DeadMau5 heads), will 2 coats of mat be sufficent?

 

[Tribalvision]

you may not have mixed it well enough.. try using a heat gun on the sticky one to assist in curing. 2 layers is fine for decoration unless you intend to stand on it.

 

[CAOS]

Is the sticky one the second one you did? I agree that you likely didn't fully mix. Stay away from Bondo brand anything if you can, its pretty much that hardest stuff to work with.

 

[Jay Sco]

I think you guys are right that I didn't fully mix.
I did the top of the left one, then top of right, then bottom of left, then bottom of right. That's the order of hardness too...hardest part is top of left, etc...

****. I'll check in the AM before I go to work. If by chance it's still soft to I put more mat over it or do I have to take it all off and start over? Do you think it will cure eventually even if not mixed thoroughly? The resin in the tray was gumming up by the time I was done.

 

[thadru2001]

Is the sticky one the second one you did? I agree that you likely didn't fully mix. Stay away from Bondo brand anything if you can, its pretty much that hardest stuff to work with.

Interesting... I figured Bondo was one of the better brands. What do you recommend?

 

[ez-duzit]

If it's still sticky brush or wipe on a thin coat of hardener. And, as has been suggested, you could try accelerating the cure by using heat. If you were very careless with mixing, it might never cure completely.

 

[kams1973]

Try heat first, and be patient.

 

[Jay Sco]

Thanks all. They were still tacky this morning so I set them outside to get some sun throughout the day. I'll check again when I get home and I'll go from there. If needed I'll try hardener and a heat gun, hope they can be salvaged.

 

[383 240z]

Worst case, mix up some more resin, and make one more layer of mat. Keith

 

[Jay Sco]

Worst case, mix up some more resin, and make one more layer of mat. Keith

I wanted to use two layers anyway, but the first needs to be set. These will be masks for my kids so it's very important for the inside to be hard and fume free.

 

[trainer]

I wanted to use two layers anyway, but the first needs to be set. These will be masks for my kids so it's very important for the inside to be hard and fume free.

Put them in the sun and let them harden. Polyester resin is very forgiving as far as resin/hardener ratio is concerned. If you want another layer of mat, then put it on before the first coat fully sets up.
AS far as brand is concerned, theres more difference in how fresh the resin is than what brand name is on the can.

 

[Jay Sco]

Update.....got home and they were both almost all the way cured! I'll put them out again tomorrow just to make sure. You guys are great!
One more question. I'm going to do one more coat of mat since I'll be drilling/cutting this I want it to be plenty strong. Should I just lay over what I have or sand then lay another coat? Trainer said lay coat #2 while the first is still tacky, but I wanted to make sure coat #1 hardened first.

 

[ez-duzit]

You must sand before adding anything more. And prevent all contamination. Clean with denatured alcohol.

 

[road]

I build large scale rc boats .
When glassing I like the resin to set over a week , a slow cure is said to be stronger. But then I am not wearing my hulls on my head . the resin smell would be a concern .

keep the pics coming
I would like to see the final masks.

 

[CAOS]

Interesting... I figured Bondo was one of the better brands. What do you recommend?

Rage Gold!

 

[HMCFab9]

Rage is a GREAT filler.
I use part # 100-105 (Quart size)
I personally don't care for rage gold.
Seems like it doesn't spread as smooth & sands a little harder, but use whatever works for you.

 

[Hot Chop shop]

I know nothing of working with fiberglass but please post a finished pic of the deadmau5 mouse head when your done
Also you better add some cool lights to it

 

[raceman17]

Your kids are going to have a headache!

 

[Jay Sco]

I know nothing of working with fiberglass but please post a finished pic of the deadmau5 mouse head when your done
Also you better add some cool lights to it

Nor do I but now is a good time to learn. I'll post progress/finish pics as I take them. No lights or music, this is time and money consuming enough already.

Your kids are going to have a headache!

Good, then they want to eat all their candy! I should have just bought some plastic globes like I found online today....oh well. Maybe I'll stick a Fabreez in there when I'm done.

 

[trainer]

If the smell inside is too strong, wash it thoroughly with soap and water.
Papier mache may have been a better choice for this project....but carry on!

 

[ez-duzit]

The smell does not wash off. It is the resin and hardener out-gassing, which diminishes over time.

 

[Jay Sco]

Just an update. I sanded and started to put on a second coat but this time mixed too much hardener *facepalm*, luckily I started at the bottom where the hole for the head-hole will be, that's the part that really needed a second coat. Anywho, now I know about the heat from the chemical reaction....that stuff gets hot!!! I set it on the ground an poured some water on it.
Next day I sanded again and cut out the bottom using my jigsaw. I figured its so thin so I can use whatever blade, right? I opted for a new wood scrolling blade that the fiberglass anhialated without hesitation. Same with the second blade for the second ball.
I'm learning all about fiberglass, the hard and expensive way.
So any suggestions on what else to use? I've heard of a jigsaw blade used for ceramic, will this or metal blades work? I still have a few long cuts to make.

Luckily the odor isn't too bad anymore so the kids will be fine. Unfortunately I glassed with my car wide open and the convertable top down, so my interior still smells like resin *another facepalm*.

 

[ez-duzit]

Use either a bi-metal or grit blade.

 

[Jay Sco]

Bi-metal works a lot better than wood blades! I got the mouth cut out on them with no problem. I still have a ways to go and only 9 days to get them finished. Should be pretty easy from here, biggest part now is fiber glassing the ears. More pics coming soon.