Resin selection, old topic, but so many variables

General Composites Discussions Composites Talk
#1

Guys, I know this particular topic has been beaten to death, and I apologize for bringing it up AGAIN, but I have not been able to select a resin suitable for my application, mostly due to inexperience.
I know the question is subjective and the options are vast, which makes it even harder but I am hoping that a few of the guys from here can recommend or at least somewhat agree on a resin that will work for me.

I am making jet ski hoods and handlepoles, and various other structural parts. I will also be making Wakeboards soon, and other pieces mostly no bigger than an wakeboard.

I have been under the impression that epoxy is what I need, but I hear a lot of talk of vinylester resin also.
I would need the resin to have good UV resistance, a suitable viscosity for infusion, and ideally not break the bank. I do live in Florida, so a longer working time would be better for me, due to the ambient heat, and having to wait 24 hours or so to demold is not an issue. Cost is an issue, but I understand the need to buy a quality product, so I dont mind paying a reasonable price for what im getting but certainly cant afford to spend unnecessarily.
Previously I have used US Composites 635 with marginally acceptable results, (mostly pinholes, uneven resin flow, and some areas totally unsaturated. Its seems a bit thick? Granted I am new to this so some of the error could certainly have been on my part.

So, what will it be?
I am looking for specific product names and numbers that can be purchased in the US market…

I have heard also of a product sprayed into the mold before infusion, its a clear polyester resin, that is epoxy compatible, and supposedly works miracles for surface finish…http://www.easycomposites.co.uk/products/polyester-gelcoat/epoxy-bonding-polyester-gelcoat-clear.aspx?LineItemId=0b376162-616c-4bd7-9540-01c9a543365d

I looked into ordering some, over $100 usd just to ship! No thanks

#2

As cost seems to be a real issue, I would recommend looking into polyester and vinylester. You can use a poly gelcoat and a vinylester resin for a good combination of structural quality and cost reduction. Epoxy, while a great product, isn’t always necessary to create a sound product. Vinylester has good adhesive quality and is much “tougher” than polyester for a slight premium over poly.

Clear gelcoat comes in two varieties - marble clear and metalflake clear. Some would add neutral gelcoat as a third clear but I don’t really think of it as clear. You’ll want to order “metalflake clear” gelcoat. It results in a waterclear coating that will allow the flber to show beautifully. The metalflake clear sprays on a little cloudy but as the entrained air releases, it turns clear before it gels.

As for the problems you are seeing, more info would be needed but I’ll give you a few ideas to look at. First, what is the centipoise of your resin? For infusion, 100-150 cps is the norm. Some claim a higher cps of up to 350-400 is workable but I’ve found too many issues at that viscosity. Pinholes can come from a variety of issues from viscosity to volitalization of the resin. You might look at your vacuum level. I generally infuse at about 15" Hg. Closeouts and dry areas are almost always operator error. Make sure you aren’t bridging, both laminate and bag. Are you using a flow media? Sometimes tailoring the flow media can solve flow problems. Be careful if using a tackifier (use as little as possible). While on the subject of tackifiers, I’ve noticed several recommendations for using Super 77. Although Super 77 works, I prefer resin compatible adhesives like Infuzene or NauticGrip when infusing polyester and vinylester.

#3

Great info Roger thanks! What vinylester is good for infusion?

#4

If you are infusing, you want to use epoxy. Polyester and vinyl ester will boil under vacuum, especially in the heat. You could use poly infusing resin, but I’ve never tried it. You could also not pull a full vacuum.
However, no epoxy is UV proof, even the ones that claim to be. So you’ll have to clear coat the part. Either in mould like the GC50 you mentioned (which I suspect is a rebranded MGS T30), or after the part comes out.
Don’t know where to buy in the US, but you’re looking for a resin with a viscosity value around 300 mPas.

#5

Not to be argumentative (well, maybe just a little) but polyester and vinylester resins are used extensively with infusion processing. As I alluded to in my previous post on this thread, infusing at about 15" Hg pretty well handles resin volatilization problems. There are a variety of methodologies that can be incorporated in infusion with PE and VE resins.

As examples of products made with PE and/or VE think of boat hulls. Most boat builders would go broke trying to infuse with epoxy. Large hulls can use hundreds, even thousands of pounds of resin. There are many boat builders that build quite successfully with infused PE and VE. Along the same lines, I’ve built 8.3 meter (approximate) wind blades with a special high elongation polyester resin. They infused perfectly and performed better than computer modeling predicted.

PSComposites,

I don’t have the stock numbers in front of me but I’ll see if I can rustle some up for you tomorrow. In the meantime, any of the major resin manufacturers should have info on their websites.

#6

To Rogers point, most marine applications are VE and not Epoxy. It’s only the ultra high end performance boats that you will find epoxy. Since PS Composites mentions wakeboards I’m sure you know Mastercraft, Malibu/Axis, Tige, Supra, etc… They all are VE deck/hull. My boat which you can see in my avatar is infused with VE. I’ll look for the part# cause all the materials were from CCP.

#7

Never had a problem with using polyester and a vacuum… Scott Bader do an infusion PE resin Crystic 701 PAX so there should be no problem using that… I would suggest the OP try that or get a VE infusion resin. But I would think there is too much post processing with an Epoxy for some to make parts that are profitable.

http://www.ecfibreglasssupplies.co.uk/images/TechnicalDataSheet/1893.pdf

#8

Here are some part numbers:

Reichhold Polylite 33282 is a polyester infusion grade resin. It works very nicely and is attractively priced. I am using it right now for some industrial parts in an VARTM process.

Reichhold Hydrex 33385 is a vinylester. I’ve used it in the past on some boat projects as well as some wind blade stuff.

AOC Hydropel RO15-AFP is a vinylester. I have not used this but was told by a trusted source that it is the cat’s meow. If I ever build boats again, I’ll be looking into this one more.

Ashland G-300 is a polyester. I used this when building wind blades. Although I can recommend it because it processes well and has a low exotherm in mass, it is a custom blended resin and available only in small bulk quantities (2000 lbs).

#9

I forgot to give relevant info. These are all visual carbon parts…

#10

Most of my parts are cosmetic too… I only ever use polyester resins…

No need to lacquer them and they come out of the mould and only need trimming…

I just buy a good quality clear gel coat and a normal laminating resin… Nothing fancy just bog standard stuff… This photo was from just after I first started making parts… My technique has improved since then and so has the quality of my parts.

#11

Roger, very helpful, thanks! Are these resins all clear and UV resistant?

#12

They are not clear as in water clear. They all have a bit of color but in thin section, I don’t think you’d notice, especially with carbon as a backdrop. They are not really rated for UV as far as I know. That is the job of gelcoat. For the best UV protection, it would be best to go with a urethane clear coat applied after demolding.

For what it’s worth, 8-10 years ago I built some carbon wheel tubs for the hot rod shop that was next to me using a polyester infusion resin that looked good right out of the mold. I can’t remember the resin brand or number (it was a sample), but it had a slight blueish tint that you couldn’t see in the molded part. These were made with metalflake clear. After the parts were trimmed to fit, they shot them with several coats of clear. Shiney like a new dime.

#13

Great thanks Roger!

#14

Roger, can you tell where we can buy a good poly resin for infusion in the US?

Also are you using gelcoat in your infusion projects?

#15

I get a lot of stuff from Composites One, including infusion resin. They are a distributor that deals in bulk.

If you are not prepared to buy drums of resin, you could try Fiberlay. They sell gallons and fives as well as drums. They have several warehouses in the US. Their main office is in Seattle, WA. You can get contact info at fiberlay.com. US Composites is near me in West Palm Beach, FL and they sell a lot on the web. I don’t know if the have infusion grade resin but it’s worth a shot.

All the infusion parts I’ve done to date have been gel coated.