Hey everyone, hows it goin. ok, so today i started my first ever fiberglass project in my little brothers SUV, it's a mitsubishi montero. im putting a single 10" mtx 5500 single 4 ohm woofer in it. he listens to rock so i figured a 10 would be perfect in a sealed enclosure. today i went to the store got all the resin, hardener, mat, brushes, aluminum foil, making tape, ect ect. ive never done this before but i have read alot of forums on it and thought i would try it out. ( not in my vehicle of course ) so far tonight i got the foil layed in the area i want the enclosure. after i got that how i wanted it i put a quick thin layer of resin down then put the mat down. i learned fiberglass dries VERY fast and you need to prep a small area that you plan on doing RIGHT AWAY! and be prepared to go through a few brushes . and i also had to dispose of two mixes i made that i put to much hardener in, i can eyeball it out now to where it suites me! anyways; after i figured out how fast it dried i started prepping the area right before i layed the mat down and pressed it down with the brush and then brushed it out. seemed to work very well. i got two layers of the bottom down. i do have pics< i will put them up tomarrow!!!!

if you guys have any input or suggestions that would be GREAT!!!!! thanks in advance.

Eddie G

I would use small batches and try to cut the pieces of mat before mixing the resin and hardener. Also, it will help the curing process if you lay 2-3-4 layers at one time. Be careful not to add too much hardener with multiple layers as there's a risk of too much heat.

My brushes lasted generally for quite a few batches of resin....

BRUSHES, BRUSHES, BRUSHES... Did you use anything for a release agent? Where did you buy your resin and what brand are you using? Brands like Elmers and Bondo are weak and shrink like crazy. Is the resin gelling up on you? If the resin is curing too fast you may be using too much catalyst. Try adjusting your mixture so it is not so hot. Another thing you can do to increase pot life is to mix the resin in a wider cup and keep the mixture shallow. This will help keep things cool. Since you are building an enclosure I recommend using some sort of woven mat. It is much stronger than chop mat and it lays flatter. Are you using any form of roller? You want to keep things as clean and flat as possible. This will save you a ton of time on sanding.

thanks for the tips. ya the stuff sometimes jells up if i use to much hardener. im using the bondo brand. what is a good brand to use? and the heat. on one batch that i had to dump i dumped it in aluminum foil and covered it. about 20 minutes later not thinking i picked the foil up to throw it away. WOW was i in for a surprise. that was HOTTT!!!!! i will get the pics posted today after work. thanks!

Eddie G

Any polyester resin regardless of brand will succumb to shrinking, and cracking if mixed to hot ( add to much mekp ). Best suggestion I can offer is to have everything laid out before you start mixing the resin. Have pieces of mat ready , your brush(es) ready, a couple pairs of rubber gloves, and a wet out area. Then shake the can of resin before you pour it out to mix it. Make sure the last thing you do before laying mat is adding in the mekp and stirring. When laying the mat alternate the bias ( direction) of each successive layer, and lay as many layers at a time as you are comfortable with. If your molding a shape and want it to keep the shape. Leave the glass on the mold to fully cure for several hours if not a day or two.

thanks for the tips. ya the stuff sometimes jells up if i use to much hardener. im using the bondo brand. what is a good brand to use? and the heat. on one batch that i had to dump i dumped it in aluminum foil and covered it. about 20 minutes later not thinking i picked the foil up to throw it away. WOW was i in for a surprise. that was HOTTT!!!!! i will get the pics posted today after work. thanks!

Eddie G

The heat is a good thing. The heat comes from the chemical reaction between the resin and the Methyl Ethyl Ketone Peroxide ( MEKP aka catalyst ). Without that heat would would be in for a messy sticky glob

you can also add a thining agent to the mix to slow the curing process and it helps if you have a cup to put the brush in so it lasts a couple batches. i think its acetone not sure its been a while

you can also add a thining agent to the mix to slow the curing process and it helps if you have a cup to put the brush in so it lasts a couple batches. i think its acetone not sure its been a while

Just don't add so damn much catalyst in the first place Pot life for polyester resin mixed properly is anywhere from 15-30 minutes depending upon atmospheric conditions. Yep acetone will remove un cured resin

You can pick up much better resin at a local marine supply store if you have one available. US Composits and LBI both make some fairly good products for those that need to order online. Select Products is another option but it is overpriced. Though they do have a bubble gum option if smell is a problem for you.

US Composits

LBI Glass