Fiberglass problems

ty.man

ty.man

Active Member
So I've been working on my cafe seat and carved the floral foam and taped it off like the dime city video shows and then I got cloth, mat and resin from auto zone and had my first try at laying cloth over my mold. It's been about 20 hours and Its obviously dry but still has some tacky parts and the cloth is pliable and easy to move. Not hard enough to take it off the mold. What's the problem here? Not enough hardener in the resin?
 
the problem is probably the resin, auto zone stocks that stuff and it lives there until it's sold, I'd bet some stores have cans that have been on the shelf for a year or three, it has a stable shelf life of about 6 months max, plus, the stuff they sell is called "non spec" resin, meaning it's garbage that has no control of the styrene/polyester/filler ratio and will cure at a rate of wheneverthefuckitfeelslikeit/hour. get some real resin from uscomposites, fiberglasssite, fiberglast, fiberglasssupply, etc., follow the catalyst ratio and it will cure to 90% full hard in about 8 hours at 65 degrees
 
What was the temperature of your materials when you started? You cannot work with epoxy resins below about 55 degrees. If the resin and hardener are not at least at a working temperature when you mix it, it will never catalyze, not even if you move it to a warm area afterward.
 
Roc City Cafe said:
the problem is probably the resin, auto zone stocks that stuff and it lives there until it's sold, I'd bet some stores have cans that have been on the shelf for a year or three, it has a stable shelf life of about 6 months max, plus, the stuff they sell is called "non spec" resin, meaning it's garbage that has no control of the styrene/polyester/filler ratio and will cure at a rate of wheneverthefuckitfeelslikeit/hour. get some real resin from uscomposites, fiberglasssite, fiberglast, fiberglasssupply, etc., follow the catalyst ratio and it will cure to 90% full hard in about 8 hours at 65 degrees
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This. Look into West Systems and MAS Epoxies. I've had really good experiences with both. The only downside is they're a bit pricey.
 
So my problem stems from both the autozone resin and the working temperature being about 40 degrees. If I tried to lay more cloth over with the cheap resin but in a warmer temperature (70 degrees in my apartment) would that help any?
 
ty.man said:
So my problem stems from both the autozone resin and the working temperature being about 40 degrees. If I tried to lay more cloth over with the cheap resin but in a warmer temperature (70 degrees in my apartment) would that help any?
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It would help. It can't hurt to try a small patch to see how it works before you go all out.
 
The temperature was DEFINITELY a deal breaker. Read the label, it should tell you what the working temperature range is. I wouldn't assume the resin was bad. It didn't have a chance with the low temperature.

Don't attempt to try to fix what you've started. You have to start over with new cloth. The cloth you have used is saturated with resin that will never harden, and coating it with a shell of cured resin will give you bad results and a weak final product that will not hold up. Cut your losses, and throw away what you have done so far. Don't throw more good materials after bad.

Also, don't stink up your apartment unless you don't mind being evicted, AFTER you poison yourself from sleeping there with those fumes.

Store your materials in your apartment, and have them nice and warm. Even put the cans of resin in warm, (not hot,) water to make sure they are at a good temperature. THEN go outside with your stuff to mix and apply. Pick a relatively warm day.

If your bathroom has power ventilation, you could consider doing it in your bathroom. Make sure you keep the exhaust fan on until there are no more fumes. The neighbors will complain, (rightly so,) if you stink the place up, and you really, really don't want those fumes in your living space.
 
Hi yeah its gone what we call over here as "staying green " :'( it aint gonna cure proper but mix another batch of resin n cat dont try compensate with extra cat ya only gonna overcook the whole thing :eek: mix it well let the air bubbles settle out of it make sure ya got a warm area lay up one or two layers more matting that will cure real good and help therma cure the under layer enough to use as mold / plug :D only down side ya gonna stink out ya apartment so shut the door behind ya and go down the nearest bar ;D cheers man gud luck ;)
 
No, you can't "therma cure" the layers that are already there. That resin will never catalyze if it isn't up to temperature when it is mixed. Those materials are trash, and should be thrown away and start over.
 
Are you being serious about the bathroom vent? Because I do have one and its the smallest room in the apartment so it Tends to be the warmest. When redoing this should I start with a layer of cloth or a layer of mat? And should i do multipe small pieces or multiple medium pieces until the seat is covered or does that not matter? I was going to start with a layer of cloth and then reinforce with Mat underneath with multiple layers.
 
As stated before, remove the not hardened resin and fiber before redoing it.
And in my opinion it was most likely the lack of hardener in the combination with the low temperature,
Polyester mixed with hardener will create heat by itself (If you ever mixed a bigger batch then needed and forgot to take care of the can you've mixed it in You'll know what I mean! :p )


A well ventilated area is required, although minor exposures to polyester fumes is not lethal it can give you a headache.

There's some variation on how you could apply the FG to your shape. But first off I would recommend cutting out the shape of the seat from the FG. Personally I would try to keep it in one large piece overall with some smaller patches for the corners/edges.
Then mix your resin with hardener, apply some resin to the seat then lay on your precut FG and add more resin. Spread the resin all over the shape and roll it in to the FG with an aluminium roller to get all the air out and as much resin in (leave no white areas). Repeat until you feel you have reached your wanted thickness.

How many layers of FG you'll need all depends on what type of FG you got (like 300g/m2 or 600g/m2).
If you later want to add layers on the inside make sure you scuff it up with like a 40 grit paper before so the resin get something to adhere to.
 
Yeah, if the bathroom is ventilated, it might be the best place to do it. Keep the door open just a crack to maximize airflow while still containing the fumes in the room.

I like to start with a layer of cloth. Use one big piece or a few good sized pieces, not multiple small pieces. Press into place, fold over where needed to make it go to shape. Use a disposable natural bristle brush to apply the resin and saturate the cloth. Don't use synthetic brushes.
http://www.harborfreight.com/pack-of-36-2-inch-industrial-grade-chip-brushes-4182.html

Here's are a couple of pretty good videos.
http://youtu.be/yJ4RMWz0ISc

http://youtu.be/M82uS_OUNB0

BTW: These guys are idiots for using an angle grinder with a cutting disk and not wearing HEAVY leather gloves. One time of cutting a big ol' notch in your knuckle teaches you that. The second guy is not wearing a respirator when he is sanding and grinding. I can't emphasize enough the dangers of silicosis. DO NOT BREATHE THAT SHIT!
 
Mr.B said:
Polyester mixed with hardener will create heat by itself (If you ever mixed a bigger batch then needed and forgot to take care of the can you've mixed it in You'll know what I mean! :p )
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It won't create heat if the materials are cold when they are mixed together. They will just sit there, and not react at all.

Mr.B said:
A well ventilated area is required, although minor exposures to polyester fumes is not lethal it can give you a headache.
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Headache is the result of over-exposure and means "Remove to fresh air."
Truly, anyone who works with this stuff should read the MSDS sheet first. Headache is one of the signs of toxic overexposure. Just because it's not a "lethal" dose, doesn't make it OK.

Mr.B said:
If you later want to add layers on the inside make sure you scuff it up with like a 40 grit paper before so the resin get something to adhere to.
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Good suggestion. Follow up layers require sanding first for them to be able to stick.
 
AlphaDogChoppers said:
It won't create heat if the materials are cold when they are mixed together. They will just sit there, and not react at all.
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I've had some different experience there, While working on my boat I did some fiber work in 12-15C and it worked quite well.
Although I was a bit worried that it wouldn't fully harden.

AlphaDogChoppers said:
Headache is the result of over-exposure and means "Remove to fresh air."
Truly, anyone who works with this stuff should read the MSDS sheet first. Headache is one of the signs of toxic overexposure. Just because it's not a "lethal" dose, doesn't make it OK.
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You are absolutely right! Of course it's not OK! I was a bit diffuse there what I meant was that working with polyester in a restricted time-table and not on a daily basis is not the same as working with it 8 hours a day every day. So the less time your exposed the less dangerous it is.

And I think some people are more sensitive to the polyester then other, My buddy gets it quite shortly after working with it meanwhile I haven't gotten at all.
 
Dude! 12C is 54F. That is at the bottom end of the acceptable temperature, but will usually work OK if you pre-warm the materials a little.

You may have noticed that I often emphasize safety. As an old man, I regret the many times I was not serious about safety when I was young. Those injuries add up over the course of a lifetime.
 
AlphaDogChoppers said:
Dude! 12C is 54F. That is at the bottom end of the acceptable temperature, but will usually work OK if you pre-warm the materials a little.

You may have noticed that I often emphasize safety. As an old man, I regret the many times I was not serious about safety when I was young. Those injuries add up over the course of a lifetime.
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Yeah, I figured it would just work, what worried me the most was that over night the temperature dropped to around 8C in the "tent" I was working in.

I understand why you do it, and I'm glad that you are doing it!
There is always risks when fabricating/building stuff, Especially when chemicals and power tools are involved.
 
I think the most important thing is that the materials are in the working temperature range when they are mixed. Then the chemical reactions will begin. If they are too cold when they are mixed, they will never catalyze. I learned that lesson the hard way. You have to have everything warmed up before you start. I suppose you may have been taking some risk if the epoxy was not fully cured before the temperature dropped. It might have cause the chemical reaction to stop. I'm thinking, though, that once you have the reaction going, it'll probably be OK unless it gets quite cold very quickly after you get started.

I was doing epoxy floor paint in my original shop during the winter. I had to heat the living shit out of the place to get the concrete up to 50F before I started. To make sure the concrete was up to temp, I put a thermometer on the floor, and laid a batt of fiberglass on top of it.
 
I had a similar issue with a repair I made on a conveyor chain gaurd, and to avoid having an OSHA violation I had to figure out something to do. On a whim I took the rest of the hardener I had (just a few drops) and spread it on the area. I did not think it would work, so I was planning on another fix and gathered some materials to do so. When I got back (10 minutes), its was starting to get tacky and did harden. I mixed by weight, so I am sure it was not a mixture issue. I do remember it being cold. I did not even consider material temps.

I am not suggesting that this be a permanent fix, however I know when I built my seat if I had to trash it because it did not set up I would have been ticked off. I would consider it because it could save your mold. see if it sets up and then spead a release on it and lay on top of it.
 
I found some great advice here and was hoping I could get some help with my fiberglass problem.

I have an old fiberglass gas tank that needs repair.

The seems at the bottom have come apart. I'm curious if sanding and laying new mat and resin would be the best fix or if there is a caulk type sealer that can be used for this repair.

I can provide photos if it would help.

Thanks
Bill
 
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