Epoxy: Techniglue Versus West Systems

[thumbsucker]

Can anyone enlighten me to the relative differences and merits of Techniglue Two-Pack Epoxy Gels versus West System Epoxy. Two-Pack is more costly however, for woodwork in particular for joinery purposes which will give a stronger and more durable joint?

[Scissors]

Caveat: I'm not a glue chemistry savant.

Techniglue is premixed with a thickener while WS is a 'pure' resin. WS is more versatile and will (I'm guessing) provide a slightly superior bond as it can be tailored for the application, but Techniglue is more convenient. I have used both, but for woodworking applications I prefer Techniglue as it's less fuss.

Both are made by the same company so I'd guess that the actual resin and hardener components are similar.

[thumbsucker]

I did some further digging and found two data sheets for West Systems (http://www.westsystem.com/webpages/userinfo/moreinfo/properties.htm) and Techniglue (http://www.atlcomposites.com/pdf/tech_glue_R60.pdf).

I had to do conversions from PSI to MPa to have a standard for comparison. I used this conversion tool (http://www.chapelsteel.com/psi-mpa.html).

Cured Properties

Techniglue

Tensile Strength: 25 - 30 MPa
Compression Yield/Strength: 12 MPa
Flexural Strength: 20 - 25 MPa

West Systems

Tensile Strength: 7846 psi >> 54 MPa
Compression Yield/Strength: 11418 psi >> 78 MPa
Flexural Strength: 14112 psi >> 97 MPa


I am unsure what I am comparing as both use different names to describe things I am not familiar with. If the conversion is true it seems that West Systems is far stronger then Techniglue.

Can someone shed further light on these numbers?

[Scissors]

I don't think you can directly compare the figures, you are comparing a "neat" resin to a glue.

[thumbsucker]

I don't think you can directly compare the figures, you are comparing a "neat" resin to a glue.

What do you mean "neat" resin?

As I understand it the data for both is for their mixed and Cured Physical Properties?

[Scissors]

Neat is their word for "no thickener/filler, etc" it mentions it on the top and bottom of the WS page you linked. Basically, to get a workable wood glue you need to thicken/fill the WS, which will alter its properties. I don't think it matters much really, either is strong enough that it isn't really an issue with wood.

EDIT:

http://www.westsystem.com/webpages/userinfo/manual/

It mentions the difference between different 'thicknesses' there in the "adding fillers and additives" section.

[thumbsucker]

Neat is their word for "no thickener/filler, etc" it mentions it on the top and bottom of the WS page you linked. Basically, to get a workable wood glue you need to thicken/fill the WS, which will alter its properties. I don't think it matters much really, either is strong enough that it isn't really an issue with wood.

That makes sense, thank you.

I think I will stick with WEST SYSTEST'S.

[mat]

You can certainly use the west system neat but it is on the runny side.

The other advantage of west is that you buy fast or slow hardeners.

[Timbre Surfer]

just veering to the left slightly, what is the difference between epoxy and polyester resin for joining wood? is it to do with the finishes that one can apply to epoxy that you can't polyester?

[thumbsucker]

You can certainly use the west system neat but it is on the runny side.

The other advantage of west is that you buy fast or slow hardeners.

Interesting I have been using west system neat all the time. Do most people mix it with a filler to thicken it? However does this weakens it at the same time?

And give you more a Techniglue style product?

[meerkat]

I have never used poxy for general woodworking, only on boats.

There are two that I have used, microspheres that thickens the poxy to make it easy to fill and sand etc.

For real additional strength microfibres are used.

These fillers are used a lot with boats for many purposes and tends to stick to most things. Me in particular :- :D

For added waterproofing you can also add a "thinner" (TPRDA) that permeates the wood even more.

Boatmik has a great site. http://www.storerboatplans.com/Faq/faqindex.html
(http://www.storerboatplans.com/Faq/faqindex.html)
Worth a look :2tsup:

[Dan]

There was a bit of discussion (http://www.woodworkforums.ubeaut.com.au/showthread.php?t=48748)a few weeks back about the differences between to two. I came to the conclusion that if you want to stick bits of furniture together, use Techniglue. If you mess around with boats and want to seal ply, glass hulls and run fillets then use the resin and add fillers when you need to. I may have over simplified things.

[Scissors]

Interesting I have been using west system neat all the time. Do most people mix it with a filler to thicken it? However does this weakens it at the same time?

And give you more a Techniglue style product?

Although it weakens the resin in terms of strength per whatever, the bond between two pieces of timber joined with filled WS should be stronger than neat WS. I have noticed whenever I have been lazy and not used filler in WS the resin has wicked into the timber possibly leaving a somewhat starved joint. In the WS users guide I linked to earlier it discusses the different thicknesses of epoxy and which applications they should be used for.

And yes, WS + filler = Techniglue-ish result.

I think Dans summary is very apt, for general furniture applications Techniglue is better, for more specific applications WS is better. WS is (funnily enough) a system, very flexible but somewhat involved, Techniglue is just a damned good glue. Oh, and Mat, you can get fast and slow hardeners for Techniglue too.

[journeyman Mick]

just veering to the left slightly, what is the difference between epoxy and polyester resin for joining wood? is it to do with the finishes that one can apply to epoxy that you can't polyester?

Polyester resin shouldn't be used as a glue, it lacks the strength of epoxy.

Mick

[Timbre Surfer]

Polyester resin shouldn't be used as a glue, it lacks the strength of epoxy.

Mick

can it be used as a filler if already glued with durabond? is there any finish that won't stick to a resin (epoxy or polyester) as i heard oil based products don't do well...:?

thanks guys, sorry to slightly hijack this thread Thumbsucker

[journeyman Mick]

can it be used as a filler if already glued with durabond?...............

Not sure, but I wouldn't do it, the only way to find out if they're compatible is to run tests yourself, and check them over 1 month, 3 months, 6 months etc.



................is there any finish that won't stick to a resin (epoxy or polyester) as i heard oil based products don't do well...:?...............

Generally AFAIK epoxy needs to be coated with epoxy paint or etch primer, but there's probably other finishes that would be compatitble, you may need to consult manufacturer's literature or do your own tests.

Mick

[rrich]

Neat is their word for "no thickener/filler, etc"


As in "Scotch, neat".