Newbie stuck with a red gum slab

[MacS]

Dave,

Yes, epoxy will adhere to polyurethane, it will also adhere to metal and glass. First wipe it with white spirits to clean it.

If you going to strip it, then get a pair of nitril gloves they are much cheaper then the neoprene heavy duty gloves.

[astrid]

we are still not getting any advise re the dam?
astrid

[astrid]

dave,
re dam
I know a guy that makes tables etc with bark edge
I'll ring him when I have a mo and ask how he does it.
I dont think you need worry about the poly, you,ve only put it in the surface cracks, right?
just sand it to surface, the araldite/clear epoxy will cover fill and stick and the final finish will go on top,
i'll get back asap
astrid

[MacS]

Modeling Clays, are commomly used to build dams.

Epoxy Putty, is also used when certain chemicals may effect the modeling clay.

[davep]

Hi gang, thanks greatly for all this info.

We'll get into the project shortly. I'm sure we'll have more questions as we go.

Thanks again Dave & Di.

[davep]

Hi folks,

Hope your x-mas break is going well.

We have steered away from doing anything to our bar top, but now finally at the stage that we now do need to finish it.

It's best we reckon to stay away from epoxy resin as we do want a matte finish once done. The idea of tinting Araldite appeals to us, but our big concern still is the Northane Clear Gloss polyurethane which is in all the cracks and also forms a border around the cracks, very noticable on the top. My pics on the first page show this.

Will Araldite stick to the polyurethane? Should we get rid of the polyurethane, if so with what? We'd hate to finish the whole thing to see bordered cracks all over this.
Would it take much sanding to get down through the surface polyurethane?

Can Araldite be sanded easily? I've always used Plastibond, but the idea of Araldite setting clear we like. If we did not tint it at all how would it look? We do not want a shiny surface.

We have small craters in the top with polyurethene in them. Do we put the Araldite in these to cover the poly? Once finished, how will these craters look?

I've bought a Metabo SXE-450 random sander for the job. Thinking to level the whole slab out with this and a steel ruler for reference.

Thanks as always for all your help, we really need it now.

Dave & Di.

[Skew ChiDAMN!!]

The Metabo SXE-450 is a nice unit. Take it from a bloke who bought one only a few months ago and still has tool-lust for it.

A wide-enough drum-sander would be perfect but, sadly, I can't point you to anyone in SA with one. The ROS & a steel ruler will do the job provided you have the time to do it. Either way should solve any & all questions about the little "dimples" of poly.

That'll still leave the poly in the deeper knots of course, but I'd take up RufflyRustic's suggestion of experimenting on an off-cut - or anything with a knot or two to fill will do, to see how epoxy/araldite/whatever goes over the poly. Use 'em to test a few different fillers, they'd also answer later questions about "will it sand?" and choice of finish over whatever's chosen.

(An offcut would be better, as that'd give you a more accurate idea of colour changes too. But if you haven't one too hand...)

Personally I avoid Araldite, as I find that for any decent thickness of fill it always traps air-bubbles. And if I'm still trying to extract those bubbles when it starts to gel, well... I end up with a right cloudy mess.

Also, I'm not sure what to use as a wetting agent with Araldite. (Although I've been told small amounts of turps will thin it & extend the working time) With epoxy, I can simply dampen the knot with some of the drying agent before doing the pour, to reduce the chance of bubbles being trapped in the grain.

Even if you don't want the filer to be Xtal clear, you don't really want airbubbles trapped in it. Tinting it can be effective, especially if it's only a smokey effect. Something else done more easily with epoxy than araldite.

Epoxy can be sanded/burnished to a matt finish provided you give it enough time to cure. Like, weeks. Rustin's Burnishing Cream (sold to burnish back Rustin's Plastic Finish) works well for me.

As for where the poly has soaked into the end-grain around the knots, the news isn't good: get used to it. They're a part of the knot now. Nothing I can think of will remove all the Poly, not without leaving something behind. It you're lucky, the mark just becomes less obvious.

Under the finish no-one will give a second thought towards 'em... except you & your SWMBO. (Been there, done that. )

[Petethebutcher]

Hi Dave,
You have brought out some interesting solutions for your job. I'm sorry I can't add anything as I'm still in the planning stage of a similar project. However I once read an article where the epoxy that filled the cracks etc was coloured black to add to the rustic look.
Cheers
Peter

[Tonyz]

not trying to be rude but what happened to/with Bodgy from ?

[Harry72]

Mate when you coat the whole slab in polyU you will not see those edges of the filled area as the whole slab will be the same colours!

You can use polyU as filler(its not ideal but it works), but it must be layered on thinly otherwise as it dries it will crack. If you keep tipping polyU into the cracks and letting it drain out and set it will eventually fill after many applications.

Epoxy/casting resin would have been the best but it will drain through just like the ployU.
Oh and araldite is epoxy resin, hint dont use the 5min stuff for this application!

[Skew ChiDAMN!!]

You can use polyU as filler(its not ideal but it works), but it must be layered on thinly otherwise as it dries it will crack. If you keep tipping polyU into the cracks and letting it drain out and set it will eventually fill after many applications.

I'd taken him to mean he wanted the knots and borer holes in the side filled flush with the surface. They look to be fairly large 'oles and would take a trillion coats to fill. Otherwise, as you said, they'd crack.

Epoxy/casting resin would have been the best but it will drain through just like the ployU.

Yup. But you can plug the bottoms of cracks/gaps with duct tape/plasticine/whatever and totally fill the holes/cracks completely in one poor if you use a fluid enough epoxy.

Oh and araldite is epoxy resin, hint dont use the 5min stuff for this application!

It's fairer to say that Araldite is "an" epoxy resin. They're not all created equal, after all. (I won't have the 5 or 15min stuff in my shed. )

In my experience Araldite tends to be too thick to flow through deep cracks, and on warm days can still start to gel very quickly, even with reduced amounts of dryer. Great for gluing things together, but not so good as a filler. Gimme good, runny stuff every time.

[Harry72]

"Yup. But you can plug the bottoms of cracks/gaps with duct tape/plasticine/whatever and totally fill the holes/cracks completely in one poor if you use a fluid enough epoxy."

I realise that Skewy, but any thicker than 5~6mm and you can risk cracking and face some shrinkage.
Your spot on with the Araldite, its not designed to be a good filler its designed as a glue.

[davep]

Hi gang,

Thanks for all the info. I guess we'll have to leave the poly borders and hope once it's finished that thay'll not be so noticable.

We are worried about using epoxy as it always seems to finish shiny, not to mention sounds difficult to sand back down. Is there a putty product that would work in all our cracks and holes? Near black or dark brown is the colour we'd want.

Do we use builder's bog as suggested? Is this like Plastibond? I ask as I certainly have used Plastibond over the years, although never coloured it.

Feast Watson Flat Proof is probably the final coat we'll apply, have used this on another bit of furniture being a bench chair. Not sure if it is heavy duty enough for a bar top though,

Thanks again, Dave & Di.

[davep]

Thinking "Plastibond Builder" with black oxide might be our answer. As suggested though I need to try an offcut, sadly will only have a tiny bit.

Each end of the slab needs to be cut square, do I just mark it up and cut away? I have a 8 1/4" 1450 watt circular saw The slab is 2" thick. Will this be okay?

Thanks, Dave.