US composites epoxy reviews?

[ctswf]

Hi, please post any results you have had with this product.

I used two coats of their 4:1 epoxy on 3/4" tongue and grove plywood for an aluminum boat deck. I did not use fiberglass cloth. I coated the top, bottom, and sides.
Deck was finished with interlux interdeck non skid paint.

A few weeks later once the boat was exposed to rain/heat/sun, the plywood is checking or cracking badly in some areas.

I don't feel like it was the epoxy at fault, but before I order the same product again, wondering if I should pickup a more expensive product like west systems.

Still not 100% sure what went wrong... poor wood quality, moisture in wood, poor ventilation in the floor, something I did wrong somewhere...
I'm going to sand the paint off in place, and re-epoxy it with fiberglass cloth this time.

The 4:1 system was used because of the temperature march, it was applied in a heated garage and seemed like a great product but I have nothing to compare it with.

thanks

 

[Woodonglass]

Re: US composites epoxy reviews?

As with any Paint project it's all about the prep. What did you do to the Epoxy prior to applying the Interlux paint? Did you follow Interlux's recommendations as far as using the PreKote or Epoxy PrimeKote 404/414 primer? Did you scuff with 100 grit, and wipe down with Acetone? Were you careful about not introducing any contaminates to the deck during the painting process. Handprints, Footprints, Sweat etc... How is the deck secured to the boat? How much Flex is there in the deck? Lot's of variables to consider.

 

[GWPSR]

Re: US composites epoxy reviews?

I'm also using 4:1 from USC. I found it to absorb really well into the plywood when sealing. The layers I applied were not really thick enough to crack. Have you explored those cracks to see if they are just in the paint or through the epoxy as well?

 

[GT1000000]

Re: US composites epoxy reviews?

Is the plywood made with exterior grade glue?

 

[ctswf]

Re: US composites epoxy reviews?

Yes it did crack through the epoxy as well.
It appears to be shrinkage or slight cupping every 3 to 4 inches causing cracks at the wood grain, mainly only on 1 of the 4 pieces of plywood.

I really think it's the wood, moisture stuck in the wood or the stress I put on the wood. I talked about this some in my restore thread (in my sig) but I did have to stress the wood a little before the epoxy was put on the top coat.
The locaton of the stringers on this metal boat were in such a place that the floor is slightly bowed up in the middle causing some stress on the wood when i riveted the edges down
I took it as normal, but looks like it was not.

I was just wondering if the high priced epoxy is so bullet proof that its worth getting for my second attempt.

The epoxy was prepped and painted according to interlux instructions, which is no primer at all when applied to epoxy directly. The paint adhered very well and doesn't look to be part of the underlying issue.

yes ply is made with exterior glue

 

[GT1000000]

Re: US composites epoxy reviews?

You may have just gotten one bad sheet of plywood and the slight stress on it from bowing may have caused the delamination...
I might suggest, if you decide to replace this sheet, instead of repairing it, turn the top grain 90?...or if you decide to repair it, remove any bad sections or cut a slight V along the delaminated areas, and make a peanut butter consistency epoxy to fill the low spots before reapplying the topcoats...

 

[Bwana Don]

Re: US composites epoxy reviews?

I've used West System on mahogany seats, and then Spar over top. It's awesome stuff, brilliant shine, paid an arm and a leg for it. I've used US Composites and then painted over it. it's priced right and does the job.

I agree with GT's analysis. I'll use West System on my dash and US Composite on the floor.

Don

 

[jigngrub]

Re: US composites epoxy reviews?

What grade is your plywood? ABX, BCX, CDX? If it's a lower grade like CDX there may be some large voids between the face plies and this could've caused the checking because you stressed the plywood when fastening it.

I don't care for tongue and groove anything in a moist environment, there's no room for the swelling and shrinking if the wood gets wet and this will cause warping, checking, and cupping. I know some people like the T&G because they don't want to install a framing member on the joint, but that's not good carpentry.

I haven't used the 4:1 mix from USC, but I used the 635 3:1 and was well pleased, it penetrates superbly (even in 90*+ heat) and is tough as train wheels.

Instead of using glass cloth, I'd use more coats of epoxy instead. 4 coats will give you a mirror finish that will be nearly as durable as a Sheet of Lexan bonded to the top of your decking.

Since the temps have risen in your location since March, you may want to consider switching to the 3:1 mix.

 

[SlimJPope]

Re: US composites epoxy reviews?

I have been working with the 3-1 and really like it, built and installed a new transom, reinforced the hull, and now working on putting in my seats all with the 3-1 from u.s. composites.

You can see what I've done here,

http://forums.iboats.com/boat-resto...rebuild-transom-seats-hull-repair-581009.html

 

[magnumdeke]

Re: US composites epoxy reviews?

I have not documented it yet in my resto but I did mention that there was a reason for my push to put the Nautolex in, ihave had my boat in and outside. Once I had the deck down I new I was on a time table, deck had two coats of epoxy on both sides before rivets went in, it sat out side for a month off and on then we had a week of hard summer sun and I had put the bow seat piece in, basically in one week of uv exposure the bow piece started powdering off and the floor developed a "bubble". differing amounts of total exposure but definite UV breakdown. Sanded out and reapplied heavily and then covered with vinyl.
I had pics of what happened but I can not find em at the moment, for me it was definite Uv break down, sanded out and reapplied heavily and it looked like jigs glass photos. I believe it will hold up nicely, does not like hot UV exposure!!!!!!!

 

[low277]

Re: US composites epoxy reviews?

I have read that most common types of ac, bc plywood has a pine or fir face ply that is very prone to " checking" and that this will happen even if it is coated with epoxy resin alone. If you check some of the wooden boat / canoe forums they always use some type of cloth with the epoxy resin to prevent this "checking" from happening.

 

[Yacht Dr.]

Re: US composites epoxy reviews?

I dont care what you use to Bridge the gaps .. its gonna fail.

Use the fiberglass when doing larger supports. If you want to put "glued" things in there .. its gonna fail unless you Dowel or biscut. And even then its a hit and miss if you dont glass over the joints ..


We are not making cutting boards here ..

YD.

 

[Auger01]

Re: US composites epoxy reviews?

That checking will happen in most wood if you don't put a layer of glass over it. I would reccomend a layer of 10oz. woven glass over the wood to prevent that.