Alternatives to West System Resins?

[Beausoleil]

What cheaper alternatives are there to Gougeon Bros. West System resins?

For internal work - like tabbing of bulkheads and stringers, is something like Bondo 404z OK? According to the 3M spec sheet, "Bondo® Fiberglass Resin is the same high-strength polyester resin that is used to build most boats. Can be used alone or with fiberglass tape, cloth or mat to repair damaged fiberglass boats, snowmobiles, jet skis, bathtubs and showers." Heck, it even looks ok for hull repairs if that's true.

At $US37.99 at Autozone, it's a hell of a lot cheaper than the $US94.99 that West Marine charges for West System 105 resin.

[Christian Van H]

Polyester resin is not a replacement for epoxy. It's adhesive properties are lacking, and it's best suited for original fiberglass lay-up. I use MAS epoxies exclusively ( Epoxy - MAS Epoxies: Home - Build & Repair Boats & Marine, Non-Skid Repair, Cars & Automotive, Woodworking, many other projects - Composites, Fiberglass Resins, Hardeners, Glues, Adhesives ). I find their flexibility superior to West, but I'm not sure you are going to save much...

[colemj]

fgci.com

Mark

[Cadence]

You might look to see if System Three is avaliable. It's an epoxy like West Systen. It is a two to one ratio as opposed to one to one.

I would stay away from polyester unless you are laying up a hull or trying to bond directly to glass. Insure plenty of tooth on the glass being bonded to.

[David M]

Alternative: http://www.smithandcompany.org/

[Cheechako]

If you are tabbing in Bulkheads and interior furniture, polyester resin is fine. Until recently nearly every boat built (without a molded interior pan) was done this way. SYstem 3 Epoxy is good, not sure if they are still around.

[Beausoleil]

Originally Posted by Cheechako

If you are tabbing in Bulkheads and interior furniture, polyester resin is fine. Until recently nearly every boat built (without a molded interior pan) was done this way. SYstem 3 Epoxy is good, not sure if they are still around.

In this case, it's for tabbing in mounting rails for under-sole "shelving" and "flooring" to increase usable storage space, and for mounting of water pumps. Polyester resin ok for this, or epoxy?

[Cheechako]

If I understand you right, this is under the cabin sole (oh the joys of 51 ft...room everywhere you look!) It should be fine, the key is to grind the old glass until it is a clean dry surface. Then "paint" with the same type of resin you are going to use for tabbing.. on the old glass and the wood... The resin you ar using should be finishing resin that will not dry tacky. If you do the above "painting" just prior to tabbing you can use the same resin. If not, then you want laminating resin for the painting... it stays tacky... doesnt have the wax in it. I believe you can just buy resin and add the finishing wax... The people at FIberlay or somehwere llike that can help sort this out, but easiest to just "paint" and install each small area at the same time.

[s/v Jedi]

I would use epoxy even if that means I need to skip some nights drinking Cuba Libre's ;-)

Only epoxy gives you the molecular bond which is what you really can use with shelves etc.

cheers,
Nick.

[Cadence]

System Three is around, Google them.

I would use 20 grit discs for the sanding 12 to insure tooth. The painting with the polyester is the right way to go. If you are trying to bond to plywood you can thin somewhat with acetone. It will help with penitration of the wood. A word to the wise, the catalyst is MEK peroxide. Will cause blindness deluted to a few ppm. Wear glasses.

[GDFL]

I've had very good luck with US Composites epoxy. They are out of west palm, FL I believe. Much less expensive than West and no perceptible difference in quality.

[roverhi]

When building our Westsail 32, decided to move a bulkhead I'd laminated in with polyester resin. I'd ground the FRP hull layup with a grinder and wiped it down with Acetone before doing the lay up. I managed to break the resin bond between the hull and the tabs by flexing the bulkhead back and forth. The resin stayed attached to the wood but broke away from the hull. Since I'm a bit anal, will only use epoxy now to bond to FRP layups.

In defense of the polyester bond. Never had a problem with any furniture or bulkheads breaking loose in service with the polyester FRP boat to hull bonds on the W32. The boat has been sailed over 50,000 miles, one hurricane, and 5 days hard on the wind so had some pretty serious use. The bond on the bulkhead I tore out failed after severe racking. I expected the FRP layup to fail, not the bond with the hull, however. I have had some bulkheads and furniture come loose on the two of the three production boats that I've owned. My good old 40 year old Pearson seems to be holding up, however.

I use System Three epoxy. It doesn't have the blush problems that some people report with West System epoxy.

Aloha
Peter O.
Pearson 35

[Maren]

Originally Posted by Beausoleil

What cheaper alternatives are there to Gougeon Bros. West System resins?

System Three (as noted before)
MAS
EAST This is a link to a dealer, I can't find the company.

Basically, no matter which one you get, a quality epoxy will cost you.

[Cadence]

Something you may want to concider for bulkheads. Make a foam (polyester, styrofoam melts with resin) section, and glass over it to the hull. A tappered top hat is the best I can do as an explanation. Glass the bulkhead on the inside of it. this displaces the stress point at the hull over the width of the top hat and the feathered area on the hull._/ \_. imagine a line acrosss the top and the bulkhead sitting on it.

[forsailbyowner]

I would go with polyester. I tore my dinghy in half last year by leaving it attached to davit lines when a storm moved in. It filled up with water when a wave hit then was ripped in half the long way when the stern rose. I feathered the edge back the required 12x hull thickness, washed with mineral spirits then acetone 2x, then laid the void full of alternating roving and mat. The hull is about one eighth inch or less thickness. I weigh in at 260 and have no problem standing on the repair. Boatyard resin that would be appropriate for tabbing was $15 a gallon at FGCI. They have scrap roving,mat and stitchmat for $2 a lb. Their epoxies and polyesters are as good as any on the market. FGCI.com or stores in ft lauderdale and st petersburg Fl. Over the years I've gone through hundreds of gallons of their polyester resins and have never had an issue. They also provide excellent technical advice