Epoxy Resin?

[jemyers10lber]

Hey guys I have a question. We have been putting epoxy resin on all of the wood that is going into the Bumble Bee resto. We put the first coat on and it cured just fine. Well we put the second coat on and it will not cure. Dont know why. We measured and mixed everything the same. It has been setting on there for almost a week now and its still tacky. We mixed some more up the other day and done the back sides but we added the gray coloring to it and it set up in 24 hours just like glass. So I guess the question is do we just give it a little more time to cure or can we mix up another batch and coat over top of it in hopes that the hardener reacts with what is already there?

[ShawnD]

Scrape and reapply?

[Jwengerd]

sounds like you messed up your ratio when mixing it. Your better off just sanding it off or scraping and re applying. Are you sanding /using acetone in between coats? not sure how long your letting it go between coats, if your under 4hrs you can reapply another coat without sanding.

[javelin90]

I have some questions,
Did you use the epoxy/resin hardender from the same batch or another bottle?

It is either a bad batch of hardener or the ratio is off. What cure hardener did you get?

slow/hot weather
medium/average climates
fastcold weather

if your going to fix it, you will need to scrape the non-dried epoxy off as much as possible, then you will need to use little acetone on the non-dried epoxy, then once the epoxy layer that is dried then might require some minor sanding.

When your applying the epoxy what process are you doing?
If your going to place 3 layers of epoxy typicall you need to apply each layer as the first layer is getting tacky. If you wait till each layer is cured/dried than minor sanding is required to make sure that the second layer bonds the prior layer.

Typically you need to lay the first layer and when that one is tacky then lay down another layer of epoxy and again tacky lay the 3rd final layer down.

The reason for this is to ensure that each layer chemically bonds to the prior layer to prevent possibility of future delamination and also 100% waterproofing. Visit the boatbuildercentral.com website
and you can see the process.

im me if i can help you!

[rockitsauce]

That has happened to me with a bad bottle of hardener. I had to grind down and redo. Sad thing is, it took me 2 batches to figure out what the problem was as I thought I did a math blunder on the first one.

[jemyers10lber]

Thanks for the replies. We have made sure that we used the exact amount recomended for the mixture of the resin and the hardener. I'm pretty sure that we may have not got it sanded good enough. We will sand the other down good and reapply. Thanks again. This is our first go at this so I'm sure we didn't do it exactly correct. I will keep you updated. Thanks again.

[thomasfouraker]

Shake both the epoxy and the hardener before pouring to mix.
Ensure correct ratios.
Mix thoroughly resin and hardner.
Don't allow the resin to get wet while it's catalyzing.
Ensure proper ambient temperature that the ratio is indicated for.

Other than that, I imagine it would just be a bad batch. Also, epoxy will stick to epoxy and poly resin and vinyl resin. Poly and vinyl will not work with epoxy so stick with epoxy throughout the duration.

[BASSCAT7]

As said, Polyester resin is difficult to adhere to Epoxy resin, so if you make a repair or build from Epoxy, you'll have to always use Epoxy if any further repairs are made.

Epoxy resins also have no UV protection at all and if they are in an area that will be exposed to sun need to be painted/coated or they will yellow and start to crack.

Measuring is critical in Epoxy use, unlike polyester where you can be off a little, Epoxy resin/catalyst needs to be measured exact as there is little room for error in the mix.

[jemyers10lber]

It called for a 3:1 ratio. So we were mixing it at 12 oz :4 oz. We never had a problem with any of the other coats hardening up. And all of the resin and hardener is the same batch as all the other. It all came from the same jug of each. We have been measuring them both out into seperate containers that have the measurements on the side so that we know how much we are mixing. Must not have got enough hardener in that mix.

So we need to sand it down, then reapply? Is that correct?

[dr]

Not an answer, but I suppose sanding something which is tacky would be messy. On a side note, west systems dot com, has a lot of epoxy FAQ's. search for booklet 002-550. I use it a lot for technics and such.

[jemyers10lber]

Thanks! I'll give it a look.