Fiberglass resin question

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Displaced Canadian

Displaced Canadian

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If I put in less hardener will the resin cure slower or just not as hard? I'm trying to get a little more working time. I do the 10 drops per ounce as per the directions and have about 10 min working time. I would like to get about 15 min. any ideas?
 
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I have limited experience - but I think you have to use a system that is slower hardening rather than trying to vary the hardener
 
The "hardener" causes a chemical reaction. If you are too light on the hardener the result may be a geltanous mass which may never harden and at best be tacky. Follow the manufacturers directions. There are several excellent tutorials on this sight for reference. Plan your mix, pour, embedding, etc. to shorten your time required.
 
The Penguin said:
To further clarify - I've used West Systems for building & customizing jetski parts. For that system It's not the resin that changes but you use a different hardener to give you more pot life:

WEST SYSTEM | Products | Product Selection Chart
Click to expand...

Shawn
I believe the west coast system is an epoxy part A & B measured by weight. Shawn have you used the W.C. epoxy for casting. I thought about it epoxy tends to yellow a bit but they have a crystal clear but it's a little pricey.

Displaced Canadian said:
If I put in less hardener will the resin cure slower or just not as hard? I'm trying to get a little more working time. I do the 10 drops per ounce as per the directions and have about 10 min working time. I would like to get about 15 min. any ideas?
Click to expand...

Christopher
I think you mite be using a polyester resin if you are adding drops. The most recommended resin for fiber glass is the west coast system Shawn mentioned but it is an epoxy.

I use Silmar 41 P.R. and add 3-4 drops of MEKP. It will give you a little more open time take longer to cure over night and will be less brittle. There are so many variables it gets complicated.

I also have found that epoxy and P.R. don't like each other.

Good Luck
Bruce
 
bruce119 said:
The Penguin said:
To further clarify - I've used West Systems for building & customizing jetski parts. For that system It's not the resin that changes but you use a different hardener to give you more pot life:

WEST SYSTEM | Products | Product Selection Chart
Click to expand...

Shawn
I believe the west coast system is an epoxy part A & B measured by weight. Shawn have you used the W.C. epoxy for casting. I thought about it epoxy tends to yellow a bit but they have a crystal clear but it's a little pricey.
Click to expand...

I wouldn't say measured by weight necessarily - though you could certainly do that if you knew the weights needed. West Systems has a set of metered pumps. Insert pump "A" into the resin, and pump "B" or "C" in the hardener. which pump (B or C) depends on the type of hardener.

anyway - you use 1 pump of resin to 1 pump of hardener. I use it for reinforcing inside jetskis using carbon fiber, fiberglass or texalium. I'm not going for a "visual" carbon look - but I'm sure you could use it for that. I do recall some of my friends that do high-end custom work talk about some resins "blushing" or yellowing. I don't think West does that.

I've also seen it used for laminating tropical hardwoods for use in building spearguns.
 
It is safe to add fewer drops to your mix. Any instructions that I have ever read gives variable ratios depending on temperature and humidity. I generally use a 6 drops/ounce for the winter and 5 drops for the summer. If I want more working time I use the 5 drop method and then place the mold in the oven at 150 degrees. It will start the catalyst process within 5 minutes. I made a batch last night, worked with it for 25 minutes and popped it in the oven. This method works well for me.
But as I always say, ask 10 different people, you get 10 different answers.
 
Bowl Slinger said:
It is safe to add fewer drops to your mix. Any instructions that I have ever read gives variable ratios depending on temperature and humidity. I generally use a 6 drops/ounce for the winter and 5 drops for the summer. If I want more working time I use the 5 drop method and then place the mold in the oven at 150 degrees. It will start the catalyst process within 5 minutes. I made a batch last night, worked with it for 25 minutes and popped it in the oven. This method works well for me.
But as I always say, ask 10 different people, you get 10 different answers.
Click to expand...

please be very careful putting liquid resin in an oven. fires have happened.

http://www.penturners.org/forum/f18/fire-extinguisher-good-55425/
 
Bowl Slinger said:
It is safe to add fewer drops to your mix. Any instructions that I have ever read gives variable ratios depending on temperature and humidity. I generally use a 6 drops/ounce for the winter and 5 drops for the summer. If I want more working time I use the 5 drop method and then place the mold in the oven at 150 degrees. It will start the catalyst process within 5 minutes. I made a batch last night, worked with it for 25 minutes and popped it in the oven. This method works well for me.
But as I always say, ask 10 different people, you get 10 different answers.
Click to expand...

Exactly there are so many variables. Don't forget about mass the thicker the pore the more heat you generate less drops. The thiner just the opposite. Ambient temp. effects it a lot also ideal is between 75-80 below 65 you got problems. Also if you try and push it by curring in an oven or more MEKP that can have it's own problems more brittle or cracking. I found it best to be patient. A slow cure 12 hours latter the surface is still tacky. You should be able to remove from mold and leave set (I put mine outside) for a few hours and they should cure. Remember we're talking PR here.

Displaced Canadian said:
If I put in less hardener will the resin cure slower or just not as hard? I'm trying to get a little more working time. I do the 10 drops per ounce as per the directions and have about 10 min working time. I would like to get about 15 min. any ideas?
Click to expand...

Christopher
We are assuming your using PR because you mention drops. Just want to get back to the O.P. "Fiberglass Resin" traditionally PR would be the last choice for Fiberglass resin.

Russianwolf said:
Bowl Slinger said:
It is safe to add fewer drops to your mix. Any instructions that I have ever read gives variable ratios depending on temperature and humidity. I generally use a 6 drops/ounce for the winter and 5 drops for the summer. If I want more working time I use the 5 drop method and then place the mold in the oven at 150 degrees. It will start the catalyst process within 5 minutes. I made a batch last night, worked with it for 25 minutes and popped it in the oven. This method works well for me.
But as I always say, ask 10 different people, you get 10 different answers.
Click to expand...

please be very careful putting liquid resin in an oven. fires have happened.

http://www.penturners.org/forum/f18/fire-extinguisher-good-55425/

Absolutely never place the liquid resin in an oven rite after adding catalyst. Remember the catalyst generates heat by a chemical reaction and a lot of it. If you put it in a heated environment your just asking for trouble. Now I do preheat my molds to about 125 no more than 150. I also preheat my resin by putting my container in hot water before adding the catalyst about 110 then mix and pore the resin and leave set at room temp. 75-80. Perhaps that is what Bowl Slinger meant.

Keep it safe have fun
.
Click to expand...
 
I bought the can from Lowes, it says fiberglass resin on it. It says 10 drops per ounce of resin. It is light brown in color. However it smells exactly like the can of PR that I bought yesterday. I'm using it to make Micarta like blanks. Casting epoxy doesn't work as well as I would like, the blank is too soft and frays when turned. I tried an epoxy bar top finish, much harder, turns better but still a little soft. It is a much harder blank, just need about 5 min more working time. Now, off to the shop to experiment.
 
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