Super Jet New to glass building need help choosing the right stuff

[CRJ]

OK, i want to do this right, i dont want to run to the local hardware store and use their junk resin and glass. Im taking a SN and building a AM hull this winter. rocker the nose, shorten the back, bob holds, ect. ive seen tons of different mats and weights, but havent a clue what to get.

ive been told epoxy is the way to go, so thats fine. but what glass should i be using? ill be moulding the bottom, and top decks and im assuming the tray.

any tips? what to put where? I know theres a ton of info on here but to sift through it would be years lol.


thanks!

 

[yz250f]

I'm in the exact same boat. I want to modify a square and make a mold. From what I've found so far you'll want to be in the 50-60oz range for your hull thickness. As for the mold I haven't found anything. But I would imagine you want it fairly rigid, but not so rigid that you can't torque it to get it to pop off of your molded part. I have done fiberglass work before. For tighter areas use about a 8-12oz mat. For bigger areas with less shape, use a 17-24oz mat. Be sure to wax up the mold really well or the new part won't pop loose. I also understand that gel coating your mold helps a lot with making a quality part. This is mostly what I have found through research, not personal experience. So if I am incorrect on a few things don't blame me. Just stating the basics of what I have found. Good luck.

 

[88kawi5fiddy]

for sticking together a snsj bottom and 300sx hull, we used 1708 biax for structural (read: strength) integrity and stiffness. 4oz to follow foam shaping and 8 oz on top after we shaped the 4oz to the foam shapes. for molding you will need to clean your mold, probably acetone, and layer on mold wax and some (i believe) pva release agent.

rdrttoy 's 2008 sj build he makes some pieces, other thing to do is go in the builds section. look for a really modded build like the iron man one. read through it and if the builder doesnt state the weights of cloth just PM them. builders are usually happy to help and have a true interest in the sport.

 

[tom21]

what you are asking for is a huge amount of info. Im not even sure I understand what you are going to do? you are planning to make a complete hull and are starting out with no experience at all? not saying that you cant pull it off but holy cow dude. thats taking a big bite to start with.

on the other hand if you meant you were going to mod your hull then that is a little more realistic and easier to accomplish right off.

youtube is your friend. search is your friend. nobody is going to be able or likely willing to publish a friggen book to just answer your "simple" question.

here are the basics

to make a plug (the actual part or shape)
get the shape you want however you like. lots of mediums will work and it doesnt really make much difference what you work the shape in. I like bondo. I have used wood, plaster, foam, epoxy, clay etc. once your shape is complete its best if you can prime it or at the minimum have a surface that can be sanded until smooth. if you dont know how to sand something to get a smooth and straight surface then you have a whole other world of info you need to get familiar with.

when you shape is smooth( sanded and polished)
you will wax the surface multiple times, at least 2 times and then use pva to aid in release. otherwise you need to wax until a fesh piece of masking tape does not stick to the surface.

apply gelcoat to the surface. tooling gelcoat to be specific. this will allow you to have a surface that can be sanded an polished to high gloss which makes your part come out easier and look its best. also allows for multiple parts to be made.

next you will cover the gelcoat with resin and thin chop glass. making sure you not have any air bubbles. the cheaper the resin the more it will shrink usually. epoxy shrinks the least or not at all. some poly resins can shrink up to 6%. now that your first layer is set up you can sand down any high spots and scuff the surface and begin to add more layers. I would not go more than 1/4 inch at one time. usually 2 or 3 layers of heavy chop or biax works good. depending on how thick the part is your mold will be usually be double thick of that. you will want to add some wood supports to keep the part from warping over time and from heat. those get glassed in after the layup to back up the mold.

pull your part from the mold and sand and polish.

making a part is pretty much the same process as making the mold. you will need to figure out a layup schedule or make some test pieces to determine what your schedule will be.

please understand that this is in no way a complete guide or description of all the things you will have or want to know. its is just a basic outline and one based solely on my experiences, which may or may not be good practice. there are always shortcuts and there are always better ways to go about anything. that is up to you. but this should get you on the path or at least help you ask better questions to help find the answers you seek.

youtube is awesome in that sometimes its just easier to see it done or see some details that maybe werent in print or were taken for granted. its taken me years to get to the understanding I have now and everyday or at least every week I learn more.

 

[Quinc]

OK, i want to do this right, i dont want to run to the local hardware store and use their junk resin and glass. Im taking a SN and building a AM hull this winter. rocker the nose, shorten the back, bob holds, ect. ive seen tons of different mats and weights, but havent a clue what to get.

ive been told epoxy is the way to go, so thats fine. but what glass should i be using? ill be moulding the bottom, and top decks and im assuming the tray.

any tips? what to put where? I know theres a ton of info on here but to sift through it would be years lol.


thanks!

If you read through a few build threads most people use the 12oz and 17oz Biaxial glass: http://www.uscomposites.com/specialty.html If you want to save on weight and don't mind spending more you can use S-glass. For epoxy use the FAST hardener. Yes medium sounds like a good compromise but it is slow. It was taking up to 24 hours to fully harden in 40-55F degrees.
http://www.uscomposites.com/epoxy.html

Also buy a roller!

And check out Lamar's thread: http://www.pwctoday.com/showthread.php?t=417485