Help!! Epoxy as Glue No Good??

T

toolarts

Member
Joined
12 Nov 2005
Messages
35
Visit site
I just read a note in a review of a Larry Pardey book in which it was implied that he doesn't like epoxy.

I made up my boomkin using mortice and tenon joinery and glued the joints with epoxy...Is this weak???

It will be exposed to saltwater but mainly spray, but the boat is in the water (salt) year round. Should I have used something else to glue it, like plastic resin glue or resorcinol glue??

I am now repairing my bowsprit and was planning on laminating a new 2X8 piece to the bottom of it to replace damaged wood. Is epoxy the wrong adhesive to use?

Help!!!
 
Larry Pardey is a Master Craftsman and a die hard traditionalist - he has no need for epoxy, because he can acheive perfect joints anyway. The boats he builds are works of art - look at Seraffyn and Taleisin for example. Simply exquisite.

Epoxy was designed for ordinary folk like us to use in the applications that you describe, and it works brilliantly!
One advantage (or disadvantage sometimes) is that an epoxy joint is usually stronger than the wood itself - if it fails, it will be the wood that tears, rather than the epoxy joint 'giving way'.

By all means use epoxy for the repairs to your bow sprit.
Just make sure that the wood you are using, and bonding to is clean and dry.
 
Im not sure if this will help but it does show that the M&T is the king of joints .
If the Epoxy has filled all the voids in the joint then i dont think there is any need to worry .
Joint test
The host sounds like the bug in the film Men in Black /forums/images/graemlins/grin.gif
 
I'vce read most of Larry's books [and bought not a few], also met and talked with Larry and Lin when they were in Sydney. What Bajansailor says is absolutely true; Larry doesn't need glue at all; I'm sure that he only uses it to keep the water out of the joints! It's one of the things that he bangs on about with which I take issue with him. I've used epoxy without failure, and resorcinol which failed very soon after installation. Epoxy is very tolerant of poor fits and low clamping pressures. Resorcinol requires perfect fits and extreme clamping pressures, so that as much of the glue as possible is driven out of the joint. I have also needed to undo a joint glued by epoxy. I used a heat gun to soften the epoxy. The timber was well charred by the time I separated the two pieces. I was satisfied that no joints were going to come undone because of the Australian summer sun [up to 44 deg. in the shade, more in the open.] Q.E.D.

Peter.
 
Umm, pretty much what everyone else has already said, but IIRC epoxy can soften at higher temperatures; this could theoretically be an issue in hot climates.

It's a good book, by the way, except that I'm sure his proportions for the tenon in the heel of the mast and the mortice in the mast step are wrong, or a misprint.
 
Epoxy doesnt soften until about 150 -200c IIRC Mirelle - even the most dire global warming is unlikely to reach that!

I think Larrys problem with Epoxy as a glue is that you have to have a reasonable amount in the joint - and his are too good a fit for it to work properly!

FWIW I long scarphed a length 3"x2" of Iroko using standard epoxy with some thickening to hold it in the joint. It was then fastened with quite a strong curve in it as a rubbing strake and I was concerned the timber would split with the curve, but the scarph is still good as new 4 years on.
 
Aren't there UV issues with using epoxies on glued spars ?So paint it ! But...A painted wooden spare invites decay that wont be spotted under the paint so easily as under the more maintenace demanding varnished finishes. This would especially be where fittings are clamped on to the spar.
Hence a continuing acceptance of resourcinol type glues?
 
I scarphed an extension into my fir mast and boom 12 years ago, with epoxy, no signs of anything wrong, yet! My brother had his mast joins fail, after going from british columbia to california, resorcinol! it doesnt like being frozen, then warmed up again!
There is not a lot wrong with epoxy for general work, although it is still not approved for use in the manufacture of marine ply, but is used to scarph sheets together. I wouldnt worry about epoxy, great gap filling properties.
 
Re: Help!! Epoxy as Glue No Good??

Yes I believe there are UV issues with Epoxy, but surely unless you are using teak, which is unlikely with spars, it will be overcoated with either a paint or a varnish system which will give UV protection anyway?
 
You probably are one already, Pete! However, I've seen people who have been banging wooden framed houses together as quickly as they can all their life, and I wouldn't call them craftsmen by any means. I've also seen varnished clinker dinghies built by amateurs which are floating pianos.
Peter.
 
Re: Help!! Epoxy as Glue No Good??

Epoxy is degraded by UV but if you are using it in a joint the only part of it exposed is the minute end on glue line so it is hardly relevant.
 
Re: Help!! Epoxy as Glue No Good??

UV rays turn epoxy yellow, so a two pack varnish is used as protection, so colour stays clear, (a one part varnish on epoxy will go bright yellow! I learnt the hard way)
 
[ QUOTE ]
serious question.
how does one become a master craftsman ?
i,ve been a carpenter for 42 years , including a 5 year apprenticeship how do i become one ?

[/ QUOTE ]

Two years City and Guilds , one year advanced craft and a skills test = Master carpenter and joiner on paper /forums/images/graemlins/blush.gif Joke isn't it . I think after 42 years you have been a master carpenter for a good 30 years .
 
You must log in or register to reply here.

Share this page

Top