Polyurethane Resin vs Epoxy

[afreegreek]

OH, and polyester stinks more for a longer time and will give you a headache if you use it indoors. keeping your significant other happy may be worth the extra money for the epoxy..

[parnold]

OH, and polyester stinks more for a longer time and will give you a headache if you use it indoors. keeping your significant other happy may be worth the extra money for the epoxy..

That's a good tip, but I don't have a significant other anymore, plus I got two gallons of polyester resin given to me as samples since I sell the company's full product line. It's hard to beat free.

[synaps3]

I'll be building in a parking garage -- no big deal on the odor thing.

[starleen2]

I'll be building in a parking garage -- no big deal on the odor thing.

Just don't be mistaken for a Meth lab

[afreegreek]

OH, and polyester stinks more for a longer time and will give you a headache if you use it indoors. keeping your significant other happy may be worth the extra money for the epoxy..

That's a good tip, but I don't have a significant other anymore, plus I got two gallons of polyester resin given to me as samples since I sell the company's full product line. It's hard to beat free.

and free can convince the significant other that poly smells great!

[DasBaldGuy]

I am fibreglassing my tear using good old polyester resin and glasscloth.

I will repeat what others have said, but over all, I give Polyester resin a big thumbs up. I have used it a lot over the past 15 years and have never had a problem with it. It is easy and fun to work with.

I have made several speaker boxes and furnature and all sorts of odd wooden and/or plastic structures using poly resin and have never had a delamination issue.

I believe in it so much that I have coated the entire underside of my tear floor with poly resin and black roof tar-goo. I also plan to coat the exterior walls and roof with poly resin, glass cloth and then automotive paint and clear coat for final water proof and UV protection. I am sure that in 5 years the tear will still look day-1 fresh.

Polyester Resin is cheap, easy to find (lowes, home depot, the andersons, meijer etc) and fun to work with.

Remember, your tear is not a boat and shouldn't be submerged underwater.

[afreegreek]

I'll be building in a parking garage -- no big deal on the odor thing.

well, I've used both a lot over the years an'd I've seen what happens over time. sure epoxy is better but poly is more than good enough so it doesn't really matter if epoxy is better or not. poly will work great for what you want to do. just make sure the wood is dry, you sand shortly before you apply the resin, get all the dust off and follow the instruction for adding the catalyst. it's different that epoxy.. epoxy is a set ratio 1 to 1 or 2 to 1 etc. with polyester, the catalyst has a variable ratio. the more you use the faster it will set but too many people go whole hog thinking if 2 is better than 1, the 3 must be even better and end up cooking the resin. you want to use the least catalyst, not the most for you given situation. the other thing is the unwaxed resin will not air harden and will remain sticky. you'll need to get the wax and add it into the resin on your last coat. the alternative is to get waxed resin but you will have to add the subsequent coats before the last has cured or you'll have to sand first.

go here.. http://www.fibertek.ca/resin.htm

[glassice]

With west you pay lot of $ all for not a thing. ON epoxy,For best results weigh out the required amount of resin, divide this by 100, then multiply by the Hardener ratio found on Hardener container (weight) to give you Hardener quantity. Then mix well. Always use the correct Hardener for Epoxy Resin as most of the Hardeners are not interchangeable unlike Polyester Resin. GET resin with NO WAX in it. You don't have to sand between coats if done in a few days. And wax gets in the pores .The the best is Vinyl Ester Resin it only $75.00 to 125 a gal but I think free is the best! UNWAXED resin will not air harden and will remain sticky. you'll need to get the wax and add it into the resin on your last coat. NO after a day are 2 put car wax on it THAT will take the sticky out of it and wax's won"t be in the pores !

[synaps3]

Wow, thanks for the tips everyone! I wasn't expecting such support, with how many people on this forum preach CPES and epoxy nonstop.

Thanks for the link, afreegreek, but I'm probably just going to buy the Bondo-brand stuff at Home Depot.

What is the exact procedure for applying the poly resin, and fiberglass?

I'll take a stab at it, but can someone clarify a few points, just to make sure I have the procedure right?

Procedure:
1. Mix poly resin (be minimalistic on hardener)
2. Apply poly resin layer
3. "Wet out" fiberglass and apply on joints <- Can someone explain this step?
4. Apply more poly resin layers, each time mixing a new batch
5. Apply wax? What type?
6. Automotive enamel
7. Automotive clearcoat (optional)

Thanks again for all the help!

[glassice]

Bondo-brand stuff at Home Depot. has the wax in it so if you stop for more than 5 hr you will need to sand with 220 grit DRY and wipe with ACETONE . Go to harbor freight get a box on sale 2' chip brushes around$10 .oo for 36 DO NOT WAST YOUR MONEY buying roller out rollers use 3' foam roller are make your own with stars washers small round,stars,round ....you can pull apart stoke in acetone to clean up buy cheep laytex gloves X LARGE easier on and off . DO SMALL AMOUNTS TELL YOU GET USE TO IT prow harden ,resin in to paint tray with $0.59 liner. Just toss liner to clean up. Save the bag all this came in when doing a corner that wont lay flat put the bag over it bush out all the air it will hold tell cure WHEN YOU WET OUT LET SET FOR A FEW MI. LET THE GLASS RELAX THEN ROLL OUT . Have 2 gal of acetone there before you start!

[starleen2]

Procedure:
1. Mix poly resin (be minimalistic on hardener)
I use disposable clear plastic cups and mark about 8 oz fill line with a sharpie on each - to get the 8 z fill line use a measuring cup and fill with water to 8 oz and pour into the cup - mark line on cup. Make several of these. Your resin will come with instructions of how many drops of hardener per ounce of resin - just do the math
2. Apply poly resin layer
Can be done with brush or roller - just know that this is a one time use for the roller or brush - I usually use an aluminum pan and small roller to get the job done - later you can break out the cured resin from the pan and reuse the pan again.
3. "Wet out" fiberglass and apply on joints <- Can someone explain this step?
By wetting out - you are saturating the fiberlass and it will turn almost transparent depending on the thickness of the glass matt. If you use FG tape, then just soak what you need for the whole seam in the resin and apply to the seam - thus both sides are saturated - sdmooth out any runs or bubble. Advice: get a box of disposable latex gloves - your hand will thank you
4. Apply more poly resin layers, each time mixing a new batch
5. Apply wax? What type?
The stuff you buy at HD ot lowes does contain wax and you will have to a light sanding between coats
6. Automotive enamel
7. Automotive clearcoat (optional)

Thanks again for all the help!

[glassice]

Use foam rollers are you will get the fuzzy and a strait path for water when they fall apart just toss .If you want a high shine you will have to block sand BUY 2 pack of 220 wet and dry DO NOT USE YOUR HAND TO SAND it not flat the LAST layer should be top Vail no print through easier to block sand look here first be for home dipo _Fabric http://www.fibreglast.com/category/Fiberglass_Fabric. when you get good 5 gal bucket painter screen 9"' roller 4 foot pole 1 gal at at time .I person to lay mat 1 to roll you can do a Corba body ( IF it don't bite you) with 4 layers of mat and woven in less than 2 hr It just like painting your house. Even better cut preprage tape down bag put in your autoclave come back unbag bolt down go camping

[afreegreek]

Wow, thanks for the tips everyone! I wasn't expecting such support, with how many people on this forum preach CPES and epoxy nonstop.

Thanks for the link, afreegreek, but I'm probably just going to buy the Bondo-brand stuff at Home Depot.

What is the exact procedure for applying the poly resin, and fiberglass?

I'll take a stab at it, but can someone clarify a few points, just to make sure I have the procedure right?

Procedure:
1. Mix poly resin (be minimalistic on hardener)
2. Apply poly resin layer
3. "Wet out" fiberglass and apply on joints <- Can someone explain this step?
4. Apply more poly resin layers, each time mixing a new batch
5. Apply wax? What type?
6. Automotive enamel
7. Automotive clearcoat (optional)

Thanks again for all the help!

for the amount you'll need it may be cheaper to go to an industrial supply like the one I posted. by the time you add up the resin, the hardener, the cloth/matt/tape, the mixing pots, brushes/rollers etc you may come out cheaper AND you'll get better quality, fresher resin. at least call around with a list and get quotes. they will also give you expert advice. it's one stop shopping and you get exactly what the pros are using..

wetting out.. this just means applying the resin to the cloth. glass is clear when soaked in resin.. the styrene in it dissolves the starchy white binder and the glass goes clear.. when you wet out the cloth/matt/tape, all you want to do is put enough resin on so the cloth goes clear.. LESS is better than more as long as you've saturated the cloth. you can tell because it is not whitish anymore.

resin when mixed with the catalyst starts to react and it will first "gel" up, then it will go solid but soft, then it will harden.. once the resin starts to gel, it gets thick and won't saturate the cloth very well, will not dissolve all the binder and the cloth will stay whitish. you want to do all your wetting out before the resin starts to gel. that's why you only mix enough to do one step and mix fresh resin for the next step. don't mix a bunch up the keep going back to it. it's better to make small batches and use them up as fast as you can, then mix more.

wax is probably not really wax as is table wax or candle wax. it's an additive, and what it does is make the resin harden without being sticky. the resin without wax will harden but remain sticky. this is for multiple layups. the waxed resin is for the last coat. you can buy it both ways or you can buy unwaxed and a little bottle of the wax to add in with your last batches (last layer of resin)

spend some time poking around that link.. you'll pick up a lot just from there.

anyway, you can go to a place like that and tell them what you're doing and they will set you up with the right products, supplies, and how to info or you can save a few bucks (maybe) and talk to the kid with the nose ring at Walmart and get some stale budget brand resin..

[glassice]

What nice about fibreglast is they have a material calculator http://www.fibreglast.com/fibreglast_materials_calculator and it plain old wax It's lack of air that make it cure you can put tinfoil trash bags the lowest cost is car wax from the 99 cent store. Are just leave in the sun for a few days That helps if you did not add the harder right put a clear painter tarp $0.50 over it and leave in the sun. When we bid a job I use the calculator it will get you close that way you can shop around. I am not with fibercast ,we get are res in toes 275 gal. When you get wax in the pores it make more work for you to paint with car paint. The res 8.8 pounds per gal

[Jst83]

Ok been watching this topic, I just have to ask. I see where you talk about painting the poly resin but how does poly work when used over just stained wood with no paint top coat? I'm going with the wood look on my present build.