Thread: bote cote epoxy troubles - filling biggish holes and remain clear.

Yep same experience with Botecote, don't think it is really for filling a viod as it is for gluing and coating.
I've not used West epoxy only the fillers.

Hi Daniel,

I use Bote Cote all the time, seems to always set clear when applied in paint like thickness. Unfortunately for you though it always seems to set opaque when left in a lump ie anything left in the container or filling large holes. Not sure if the air temperature will change this result, but the colder the weather the more opaque it seems to be!

I'd give Boat Craft Pacific a call and explain what your trying to do and find out whether their resin will do what you want.

Cheers
Mike

hi mike
i take it that once it is set, then thats how its going to be regardless of time.

its a bit of a spew, im making a table and just sent it off to the sander. So it looks like when i get it back ill have to get to it with the chisel.

Originally Posted by mrtayls

hi mike
i take it that once it is set, then thats how its going to be regardless of time.

its a bit of a spew, im making a table and just sent it off to the sander. So it looks like when i get it back ill have to get to it with the chisel.

Fraid so, I did a table last year and there is no change at all.
There was a thread recently in I think the woodworking general about this with some good suggestions on the best way to handle the issue. One I have also tried that works is tinting with Westons Prooftint, still no good if you want a clear look.

Interesting you have had good results with West in the past as Rand suggests perhaps talk to Boat Craft about it.

Howdy,

Wrong material for the job.

The general epoxy resins are not really meant to be clear. Most of them have some sort of colour in the two components that you cannot see when epoxy is applied thinly - but in thick pour you will be able to see the colour.

The other thing is if you look at the clarity of the original resin and the original hardener before they are mixed you can have some idea of the finished transparency. The resin component of boatcote is not clear as it has some agents added to prevent it from slumping, some UV filters and other things.

WEST system epoxies have a hardener that is a brown colour.

Bote Cote do have a material that is clear - I had to look at the name - "Pour on Gloss"
Pour On Gloss : Boatcraft Pacific. , Share our passion!

I have seen the results several times - that it produces a smooth, thick finish with high transparency. But you would still be up against the heat problem - so you would have to check.

WEST System might have something sort of suitable as well - but I don't know their range.

There is nothing perfect for the job you are doing - so it is important to do a trial.

A big problem with deeper holes is the thermal problem too. Epoxy gives out heat as it cures, which is not a problem for applying to a surface, but when you have a deep hole there can be quite a volume of epoxy in there and the heat cannot get away. The heat can discolour, cause outgassing, expand existing air bubbles and all sorts of things. It can happen with any product that produces heat.

With filling deep holes with anything I would strongly recommend you do a test first. Create a hole in some similar wood and fill it with the proposed product. It is not a simple thing to achieve even with the right product.

The other risk is that the resin can go yellow over time if not protected from UV by a coating with UV filters. For boats normally a "spar varnish" or paint.

The advantage of a product with an epoxy base for you job is that it usually doesn't have any thinners added to the mix. So what you mix stays put.

With polyester resins they usually contain styrene which evaporates so the resin shrinks as it cures - it also doesn't stick to wood particularly well. However there are some specialist polyester resins that might be worth a look too. Contact FGI and explain what you need.

But always a trial run with this type of work - it is not easy.

Best wishes
Michael Storer

Most epoxy resins will cure with a cloudy look, if contained or of sufficient film thickness. The faster the hardener the more likely this will occur. The actually color depends on several factors, modifiers in the hardener, chemical reaction in the epoxy container (especially metal cans), but most importantly of all are the bubbles, the damn bubbles.

Bubbles are introduced as soon as you start to mix. The only way I know to avoid bubbles is to use pressurized mixing, where the two liquids are literally mashed together in a vacuum. Since we all don't have access to NASA's equipment or an autoclave, we mix by hand or by machine. I intentionally mix very slowly when doing bight finish coatings for this reason. I also use extra slow hardener too, so the bubbles have a chance to rise to the surface and pop, before the goo kicks off.

Bubbles are such an issue with epoxy, that special hardeners are used (like West System 207) which decrease the amount of bubbles and also have less "stuff" that can add color to the cured resin. In fact, bubbles are counted and calculated into equations of cured resin strength, during testing and reinforcement evaluations.

In this case, the epoxy did what it's supposed to do, it cured. I'm not sure what the UV inhibtor used in Bote Coat, but I can take a guess and it isn't clear.

In short, if you want clear epoxy in holes this deep, you'll have to use special clear coat epoxy and pour in 3 mm deep sections at a time, 6 mm if you feel bold. As Mik has mentioned, the exothermic nature of epoxy can also cause bubbles as well as other issues.

If it was me and I wanted clear plastic filled holes, I'd use polyurethane. I'd use a two part, dead clear LPU and this will likely get you what you need (a clear filled hole).

That is a good idea PAR,

LPU - two pot polyurethane. It will stick to wood and will be clear-ish.

Big thicknesses of polyurethane sometimes tend to come out rubbery rather than hard. Any comments?

MIK

Well, honestly I've never applied LPU thick enough for it to get rubbery, so I'm at a lose. Top coat with epoxy?

It sometimes happens with stuff you leave in the tin or tray. It must go hard eventually.

Supaglue! or Cyanoacrylate - neat, not the rubber modified stuff.

I use it for wood turning when I'm working on heavily "figured" burls, turns well and polishes up a treat for a near perfectly clear filler.

Bunnings do sell a two pack epoxy for flow coating woodwork but I've had mixed results, you absolutely MUST have a perfectly clean and dust proof work area or it won't work. Use an acetate film to squeegee excess if you don't like the finish too thick.

Good luck with CA in big lumps....the sort of holes these guys want to fill would take half a bottle..and in those quantities I think you will have all sorts of problems with CA.


I just wonder why you would want a big hole filled clear???

The boat coat certainly does cure milky in large sections, west system less so.

But remember over time, regardless of the funkyness of the resin ..it will change colour with exposure to UV light.
Even crystal clear polyester resin will go very yellow in time.

cheers

Glass rod, cut to length.

Hi all,

In relation to getting a clear finish with bote cote epoxy, what Michael Storer says about using the pour on gloss is technically correct although it is only used for interior finishes as it has no UV inhibitors at all and will deteriorate in about 6 months maximum in outside conditions. What bote cote do offer these days is a resin without the thixotropic agent in it which is what causes the the opacity problems, the use of this new resin has solved a hell of alot of these dilemmas. Plus if you are putting any epoxied product outside you must still put some kind of clear topcoat with great UV inhibitors over the top such as Aquacote clear which is also a bote cote product, for more info go to boatcraftnsw.com.au

Envirotex is one pour-on epoxy that doesn't bubble, even when it's thick. It's the only one I've used that I think would work 100%, and it is absolutely clear with no milkiness at all. I used to use it for restoring the wooden cabin trims of old Mercs, and I always had 100% success with it. However, have not used it on boats.