Tribalvision
Well-known member
looking good.. any chance of making your update pictures larger? It's hard to see any details
Anyone good with fiberglass?
- Thread starter tegguy
- Start date
roblouvasz
Well-known member
Hey tegguy, are you going to use fiberglass resin or epoxy resin? I've never had much luck with fiberglass resin and switched to epoxy resin from West Systems. How about you tribalvision? Fiber or epoxy?
Tribalvision
Well-known member
I used polyester resin from US Composites. For what I was doing, I dont need the costly Epoxy Resin
roblouvasz
Well-known member
It's been years since I've used it. All I remember is that the mix ratio is important and it stinks. I'd mix a small batch around 2-3 oz. just to find out how long you have to work with it. Try it on a test piece of fleece.
roblouvasz
Well-known member
How do you measure for the mix ratio? The West system has pre-measuring dispensing pumps.
I have a mixing cup
Tribalvision
Well-known member
humidity is a minor factor I wouldnt even worry about it.. But Temperature 100% effects the cure time because heat is what cures the mix. I used 16 oz mixing containers and a MEKP bottle with a dispensing gauge on it. It's called the measure-matic and was worth its weight in gold.
http://www.shopmaninc.com/containers.html
I used 2 and 3" chip brushes I bought from Harbor Freight by the box.
http://www.shopmaninc.com/containers.html
I used 2 and 3" chip brushes I bought from Harbor Freight by the box.
Luckily it's Florida do I should have good drying time. That measurement device would have been a great thing to have. I wonder if my local fiberglass place has something like that. I bought a couple brushes how many do you think I need? I have like 4 or 6 right now.
Tribalvision
Well-known member
Remember, when applying the mat, dont cut the pieces. Doing this will leave an edge you will have to sand/fill. Instead, just tear off pieces of mat and apply. I usually pre-tear a pile of mat before I mix the resin so I dont waste time.
I am unable to tear I went with fiberglass the weave stuff what would you recommend then? This is what I have http://www.aircraftspruce.com/catalog/graphics/rutanFiberglassCloths.jpg
Tribalvision
Well-known member
unless you keep the brush soaking in a can of Acetone, you'll need a brush every time you do a fiberglass session. It will harden like a brick each time. thats why i just bought the box and tossed them when finished.
I'll probably just swing by harbor freight and get some. I need acetone I completely forgot I don't have any.
Tribalvision
Well-known member
That is not Mat, that is cloth. that is for shaping, not for strength. You want to use 1.5oz chopped strand mat and about 5 layers of it for strength. You cant do all 5 layers at once. You'll probably do about half the box per session.
http://www.uscomposites.com/mat.html
Urgh. The place I bought it from said it was for strength I was planning on cutting it into strips and thought that would work. How much a difference will it make if I were to use 5-10 layers? I have a feeling I don't have enough anyways so would it be a bad idea to use what I have and then do a top layer(s) with mat?
Tribalvision
Well-known member
the problem is the cloth is too thin. you need a dense enclosure so you do not have a box that flexes or resonates. I feel if you use the cloth first you will really just be wasting the resin. I would use cloth for an amp rack or a dashboard. stuff like that. If you use it on the box, it will flex and crack.
Even if the build has to wait, get the right stuff. No sense doing the work and having to grind it off. They sell Mat and Resin at boat stores. It's a little more money, but if youre in a pinch they have it
Even if the build has to wait, get the right stuff. No sense doing the work and having to grind it off. They sell Mat and Resin at boat stores. It's a little more money, but if youre in a pinch they have it
It just ***** cause I feel like I just wasted so much money on something I was told would work. Also how do you estimate how much mat to get? I just kinda winged it when I bought this stuff but if I have to go I'd like to have a more precise amount.
Just to be sure I'm following this is what your talking about http://3.bp.blogspot.com/_UOe5QneVnus/TRz60ASwi8I/AAAAAAAAAAw/dpQTO8RU-v4/s1600/kitty_hair.jpg
Just to be sure I'm following this is what your talking about http://3.bp.blogspot.com/_UOe5QneVnus/TRz60ASwi8I/AAAAAAAAAAw/dpQTO8RU-v4/s1600/kitty_hair.jpg
Tribalvision
Well-known member
you can set the default size in photobucket. this will let you just copy/paste but will make them larger
Tribalvision
Well-known member
yes, thats what im talking about. just make sure it's 1.5oz chop strand mat. measure the box and times it by 6. this will give you 5 layers and some extra. when I built mine, I just ordered 15 yards of it on a roll so I had plenty
For the life of me I can't find it right now I tried to adjust just the single photo size but it didn't change anything.
Tribalvision
Well-known member
I couldnt find the default setting anymore either. but you can mouse over the fullsize image and a small menu will appear at the top. there you can resize.
Tribalvision
Well-known member
return it, or save it for another project
Tribalvision
Well-known member
I usually tear a couple big pieces for the big spots, and small pieces for the curves etc. anywhere from 10" to 2" just tear up alot of them and set them next to the project.. Even if you run out of resin to use them all, you will always need them for the next batch. Not much you can do about the mess. It comes with being custom.
Alright well I'm going to try to make it to the fiberglass place tomorrow after school (I hope they are open late enough). I also need to try to get the fleece on the box tomorrow to save time on Sat. I have everything for that I just need to put it on and take my time to get it looking right.
Tribalvision
Well-known member
I used a large screwdriver to mix the MEKP with the resin. When the mix changes color and has an even color, you're ready to apply. I usually paint a small area, apply the mat, then blot on the resin and force it into the mat by blotting. add the next piece but overlap slightly so there's no holes in your work. when it's all soaked, smooth out the fibers standing up and use a roller or paintbrush to press out the excess resin. You dont want puddles anywhere. You'll have about 15 minutes to work before it starts to gum up on you. Thats why I have the Mat all torn and ready. dont want to spend time getting more.
let the resin residue harden in the cup and harden on the screwdriver. When its curing, you will feel the cup get hot. when it cools, its cured. when its cured, just flex the cup and pop it out and toss it. Take another screwdriver and just hit them together to chip the resin off the screwdriver
let the resin residue harden in the cup and harden on the screwdriver. When its curing, you will feel the cup get hot. when it cools, its cured. when its cured, just flex the cup and pop it out and toss it. Take another screwdriver and just hit them together to chip the resin off the screwdriver
Tribalvision
Well-known member
You're correct in taking the time to get the fleece right. This will be the base for your design.
Thanks for the info I'm nervous and anxious on this. I need to do one last check to see if my angle is too tight for my sub woofer (make sure the magnet doesn't hit the floor) I don't think it will but I'd rather know now than later.
Tribalvision
Well-known member
The one thing good about fiberglass is if you screw up, just grind,cut it off and add another layer. My truck was also my first attempt at fiberglassing. You'll be fine.
Tribalvision
Well-known member
you dont want to go too tight because it will tear at the staples. but if you leave it too loose, it will sag when wet. You dont have a large open area on the front, but the top will want to sag so i would make it a bit tight up there
Tribalvision
Well-known member
You'll feel it get hot, then it will cool. When its cool to the touch and not sticky, you can move to the next layer
Sent from my <~ Galaxy SII ~€
Sent from my <~ Galaxy SII ~€
Cloth has strength - problem is that layer to layer you don't get good bonding. You need a layer of mat between layers of cloth. Most of your strength will come with overall thickness in this application not as much from which type of glass you are using.
+1000000 on HF chip brushes
You can do multiple layers at once especially once you have a semi-rigid form to build upon. It is actually better to do as much as you can at once to get the resin to link across layers. Trick here is not to mix it too hot so you have more open time.
Get a fiberglass roller - they will work wonders at getting bubbles out of the glass.
Finish the top layer with cloth and use a bondo spreader to smooth it out, you will thank yourself when it comes time to then follow on with bondo as you fair the whole thing out to get it smooth and shiny.
+1000000 on HF chip brushes
You can do multiple layers at once especially once you have a semi-rigid form to build upon. It is actually better to do as much as you can at once to get the resin to link across layers. Trick here is not to mix it too hot so you have more open time.
Get a fiberglass roller - they will work wonders at getting bubbles out of the glass.
Finish the top layer with cloth and use a bondo spreader to smooth it out, you will thank yourself when it comes time to then follow on with bondo as you fair the whole thing out to get it smooth and shiny.
Voi
Well-known member
Are you saying that alternating layers of cloth and mat increases bond strength between layers? If so is that because the more random nature of the strands in mat gives some mechanical bond between layers?
I agree about multipe layers at once. I've done that but I would definitely use polyester and not epoxy for that. Somebody on the one of the previous pages mention epoxy and I'm not sure it was the OP or not.
[EDIT] OP was not the one who mentioned epoxy. Disregard. I've used both epoxy and polyester on fiberglass and one thing polyester does betting is soak into thick layers of fiberglass, especially mat.
Last edited:
Zeke
Well-known member
I ran a laminating shop a 100 years ago and I don't see significant extra strength using cloth in between. Depends on how thick you want your layup. You might have to go at it twice. Making molds, we built them up slowly over days.
Mat holds a lot of resin. A chopper gun makes it even worse. A heavy, resin rich part. You can lay down the mat and wet it out and roll it. Then lay in the cloth. The cloth allows you to use the rubber squeegee to ensure even distribution and work any air bubbles out. If you over-wet the part, you can squeegee some excess out over the edge.
And, cloth makes for a nice look on the backside of the part. I can't remember the exact weights of the materials, but the best I can remember is part has a minimum of 2) 1 oz. mat layers and a 2 oz cloth over the top. That should give you a finished thickness of an 1/8th " or better.
Mat holds a lot of resin. A chopper gun makes it even worse. A heavy, resin rich part. You can lay down the mat and wet it out and roll it. Then lay in the cloth. The cloth allows you to use the rubber squeegee to ensure even distribution and work any air bubbles out. If you over-wet the part, you can squeegee some excess out over the edge.
And, cloth makes for a nice look on the backside of the part. I can't remember the exact weights of the materials, but the best I can remember is part has a minimum of 2) 1 oz. mat layers and a 2 oz cloth over the top. That should give you a finished thickness of an 1/8th " or better.
