1) how do you clean your brushes? in between coats? i used acetone and it just clumped and made it impossible. so i trashed it.

2) when im mixing resin i added some amount of hardener, the resin started clumping after about 5-6 minutes, but then when i was done the thing hasnt dried and its been sitting overnight so i figure i didnt add too much...

 

What type of resins are you using? Epoxy? Polyester?

Your resins should have a specific ratios.
Are you complying to them?
ie: Three parts resins to one part hardener (3:1). Not enough and it will not cure completely, too much and it will turn yellow and even start to smoke.

How hot and humid is the area you are working in? Are you in direct sunlight?
If you are in a hot humid climate laying glass will be more difficult.

You have to let your brushes soak in the acetone and it will brake up the resins. Rinsing them wont do much. Have more than one brush so you can continue working.

 

epoxy, not humid, not in sun, mixing as per hardener instructions.

 

Strange

Are you thoroughly mixing the two parts? Usually with the stuff I use. When I stir it the epoxy will turn from clear to almost a white fog. Then it will go back to clear again once it has been laid.

Are you using fast curing mixtures. The stuff I use(west systems) takes about 24 hours to cure completely but is tacky/firm after about one hour.


Also the epoxy will cure faster if it is left in the cup. It turns into a oven retaining its own heat causing the curing reaction to accelerate.

Experiment with this if you have some materials to spare.
Mix a small batch and impregnate a small piece of fiberglass with half of the resin and let the other half set in the cup.
The epoxy on the glass should still be supple while the stuff in the cup will start to harden much faster.

 

yeah im actually using some crappy bondo brand resin that i founf in our baja bay.
this is why im learning some composite stuff. and i have a lot of material to work with.

EPON is the other brand of resin i have to use, but i havent opened it yet.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dfoxengr &raquo;</TD></TR><TR><TD CLASS="quote">1) how do you clean your brushes? in between coats? i used acetone and it just clumped and made it impossible. so i trashed it.

2) when im mixing resin i added some amount of hardener, the resin started clumping after about 5-6 minutes, but then when i was done the thing hasnt dried and its been sitting overnight so i figure i didnt add too much...</TD></TR></TABLE>


1) I always buy bulk cheapos and throw them away after one use

2) If your epoxy/resin containers don't have pumps, I'd recommend figuring out the proper mixture by weight and using a scale.

 

ok im using polyester resin now, but when that runs out i have a gallon of epoxy resin to use.
are there differences between the two mixing wise? theres no instructions on the gallon.

whats the difference between MEK and MEKP. because you can buy a quart of MEK for like 8$ at lowes.
why cant you use MEK for hardener. the can said it can be used for epoxy thinning.
and wikipedia says "It is used for synthesis of methyl ethyl ketone peroxide, a catalyst for some polymerization reactions."
if i remember right, synthesize means that the MEK is used for making the MEKP?

thanks


Modified by dfoxengr at 7:51 PM 6/14/2006

 

also when curing why does my fabric turn green?
bondo brand polyester resin and hardner, fiberglass cloth?

edit:
green because the can i was using was who knows how old.
brand new can and its the goldish color.


Modified by dfoxengr at 3:32 PM 6/19/2006

 

i'm with enzo on the brushes deal. just buy the cheap ones and toss 'em when you're done. a lot of times, you'll spend just as much on thinner (acetone) as you would on a new brush.

as for mixing ratios, do your best to find out what brand resin/hardner you have, and look it up either online, or by calling the company. epoxy resins vary a bit, but almost all polyester resins i have used are between 2 and 3% hardner by weight.

the color is just the color of the resin when it goes off. you can get crystal clear resins, just gotta look around for them. you usally won't find it at home depot next to the fiberglass boat repair kit .

 

right this was just some random stuff i found in our bay to learn and practice with.

anyone able to answer the other ?s i posted 3 posts up?

 

?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dfoxengr &raquo;</TD></TR><TR><TD CLASS="quote">ok im using polyester resin now, but when that runs out i have a gallon of epoxy resin to use.
are there differences between the two mixing wise? theres no instructions on the gallon.

whats the difference between MEK and MEKP. because you can buy a quart of MEK for like 8$ at lowes.
why cant you use MEK for hardener. the can said it can be used for epoxy thinning.
and wikipedia says "It is used for synthesis of methyl ethyl ketone peroxide, a catalyst for some polymerization reactions."
if i remember right, synthesize means that the MEK is used for making the MEKP?
Modified by dfoxengr at 7:51 PM 6/14/2006</TD></TR></TABLE>

Every epoxy is different, a common mix ratio is 2:1 by volume but it's not always the case. Physically mixing the two is the same pretty much from resin to resin. MEKP is to MEK as rubbing alchohol is to beer. Well not exactly but you need MEKP not MEK to catalyze poly resin. I've never been a fan of thining any epoxies or even polyester for that matter since it changes the finished properties of the resin. If you thin anything don't add much. The best way I've seen to change viscosity is with temperature. Another thing you should know is how old your resin is, that can change a lot of things.

 

and epoxy hardener is not MEKP right?

do they sell epoxy hardener at boat stores, or only polyester stuff at marine places?

 

Correct, you cannot cure epoxy with MEKP. MEKP is sort of a generic catalyst for ester resins. There really is no generic hardener for epoxies thta i know of. Specific hardeners are meant to be used with the same brand of resin. I have never mixed resins and hardeners from different manufacturers but I wouldn't trust the results.

They should sell epoxies at most boat stores. Epoxy will be more expensive but it really depends on what you are using the resin for.

 

cool thanks for the info.

-derek

 

I always use this stuff: http://cgi.ebay.com/ebaymotors...QrdZ1

 

I just bought some of that epoxy last week, seems to be some good stuff at a good price.

 

does it dry clear or the yellowish? doesnt really matter im just curious.

also what makes epoxy better?

 

It dries totally clear. I like it because it's low viscosity which makes it easy to wet the fleece when glassing over wood frames.

It's also easy to manipulate drying times. If you apply it to something and let it sit in a room temperature garage, it will take about 12 hours to tack and 24 hours to cure. But if you apply it to something then put it out in the sun, it will tack in an hour and cure in about 4.

The only downside is that it doesn't cure super hard compared to other epoxies. When it fully cures it still has some flex to it.

Oh, and it also comes with pumps which is a plus.