Araldite

[RussianRouter]

two tube mix,how good is this bonding metal to MDF?

Changed me mind on using kitchen worktop for my router table top and opted fof 25mm MDF.

Got two 6" rulers to embed either side of the plate in the MDF for setting up the guide fence accuratley and need to bond them so they don't rise out of the recess.

 

[jimi43]

If you are going to use Araldite I would make sure it is the original and not the fast set as that is rubbish IMHO.

Why not use contact adhesive or double sided tape?

Jim

 

[woodbloke]

If you are going to use Araldite I would make sure it is the original and not the fast set as that is rubbish IMHO.

Why not use contact adhesive or double sided tape?

Jim

Agreed, the original is phenomenal...stay well away from the quick setting stuff - rob

 

[ondablade]

One risk with bonding a long piece of metal on something like MDF or wood regardless of the glue is differential expansion. It's hard to guess whether or not you might have an issue at 6 in, but it may well be pushing it a bit.

The way this problem is normally addressed is with a flexible adhesive and/or a thicker bondline (layer of adhesive) - the first especially is not really an option with an epoxy.

For sure it'll bond and stay put if you use epoxy, the question is for how many months/years - the epoxy being very strong but not very flexible would very possibly eventually cause the MDF to fail behind the bond. A lot would depend on how humid/changeable the environment is.

Other critical issues with epoxies are make sure you have the mix volume exactly right (the chemistry is such that a certain amount of A links with a certain amount of B - too much of one or the other weakens it), make sure they are very thoroughly mixed.

Something flexy that will cure through a thicker bond line like a high grade silicone is worth looking at - it won't stress the MDF. Here's a 'rolls royce' source with lots of choices and able to advise: http://www.intertronics.co.uk/products/ ... m#silicone Failing that a high end bathroom type silicone would almost certainly do OK, but don't use a cheap one. Get a neutral (non acid) curing one if you can, and don't press the rule down so hard as to squeeze out too much of the silicone.

As Jimi says a double sided tape could be a good option too, but the MDF surface would need to be very smooth (otherwise it'll just contact in spots), not 'hairy' and dust free. You probably should go for one with an elastomeric/rubbery backing with a bit of thickness to accommodate a bit of out of flatness and give flexibility. Here's a source that can advise too: http://www.tapes-direct.co.uk/index.php ... &cPath=139

Unibond have a double sided No More Nails branded permanent double sided tape much like this out now in hardware shops too, they claim it to be 'permanent' (ha!) for household bonds. It might be a good and very convenient choice.

Whatever you choose make a few trials and see how it goes. Don't forget too to sand and solvent wash the metal to help the bond - a stainless rule might be no harm either.

Pardon if this makes a meal of it, but maybe others have an interest in the topic too....

 

[paulm]

No need to set the fence up accurately in that manner, as it's only a single point of contact for the timber at the router bit, which is circular, you could have the fence totally skewed relative to the table top, as long as the router bit is exposed the correct amount for what you are doing.

You need to test the latter with scrap anyway regardless of how the fence has been set which won't of itself achieve what you need.

Hope that makes sense !

Cheers, Paul

 

[RussianRouter]

No need to set the fence up accurately in that manner, as it's only a single point of contact for the timber at the router bit, which is circular, you could have the fence totally skewed relative to the table top, as long as the router bit is exposed the correct amount for what you are doing.
Cheers, Paul

True,but as I'm putting a clamping piece on the same rail as the guide fence then I need to make sure its level pegging.

I'm about to cut the rebates for the rails today so when I have done it I'll post a pic to show what I'm on about.

I'm not prepared to pay a ludicrous price for a piece of plastic ie featherboards

 

[Dibs-h]

Why don't you get one of those plastic\flexible tape measures that tailors\ seamstresses have and glue that down. Failing that I have seen some "tape" with graduated markings for things like this.

 

[RussianRouter]

Plastic will scratch,Dibs

These rulers are anodised,I think it will stick fine? because I've glued brass to wood in the past with the original Araldite.

 

[9fingers]

Rulers offset to the side of the plate will be no help in setting the fence.

The only distance that is relevant on a router table is the distance measured at right angles from the fence to the cutter on a line that passes though the cutter centre and that is the one place where you cannot put a rule.

Bob

 

[OldWood]

Rulers offset to the side of the plate will be no help in setting the fence.

The only distance that is relevant on a router table is the distance measured at right angles from the fence to the cutter on a line that passes though the cutter centre and that is the one place where you cannot put a rule.

Bob

Actually I'm not terribly sure that agree totally with that. I'm not that up on all fence clamping techniques but mine is a home made affair that has two clamping screws such that I can 'creap' one side to give fine adjustment by pivoting the fence. I've seen me put pencil lines on the table top to show how much this creap is which would be so much easier and more accurate if I had a rule in place.

I would agree from experience that rules on both sides of the plate would not serve any purpose, but one would, and in reality any distance from the plate as it is not doing a 'real' measurement.

Rob

 

[9fingers]

That is the point Rob. The ruler is not doing any useful measurement!

Bob

 

[OldWood]

That is the point Rob. The ruler is not doing any useful measurement!

Bob

Bob - to be pedantic, it wouldn't be doing any 'real' measurement, but in the scenario I'm talking of, it would be doing 'useful' measurement, albeit it could just be a series of numbered marks and not a true ruler.

Rob

 

[srp]

A ruler is a waste of time on a router table. In fact, though there are scales on my bandsaw, circular saw and radial arm saw I never use them as they aren't anywhere near accurate enough - I always measure off the blade or cutter with an engineers rule, depth gauge or digital calipers. I should really have a 'horseshoe' gauge - the Trend one looks a bit mickey mouse but that's the sort of thing.

If you really must stick rulers on then double sided tape is the best option. If a wood to metal epoxy bond fails, it is almost certainly lack of adhesion to the metal, not differential movement, that is the problem. Epoxy doesn't stick well to metal unless it is completely clean and unoxidised (which means abrading the metal with wet and dry soaked in the resin to exclude oxygen, not practical with Araldite as it is too thick). Epoxy adhesives are very flexible (we used to make tensile testing samples with it and they stretched an incredible amount before failure, something like 130-160%). But as I said, it's all a waste of time.

 

[RussianRouter]

A ruler is a waste of time on a router table.

But you use a ruler to mark the depth of cut on the wood and then position the fence so that the cutters blade aligns with that mark right?

 

[srp]

You might do. I don't. I set the fence to give the correct depth (or width) of cut. That way I'm only measuring once. No eyeballing involved.

 

[OldWood]

......And I use a test piece to get the tool height I require and then creep in the fence to get the depth of cut.

There's no way I would ever work off a measurement as it would really be meaningless in terms of the fence position wrt the cutter and how much cut you are going to make per pass.

I would suggest, like the others, George, that you are going down the wrong path. If the commercial boys are incorporating such a feature by all means do so, but I think you will find that no one actually does.

Rob