gap-filling adhesive (wood to wood)

sarabande

sarabande

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I am refitting some mahogany lips to the plywood cockpit seats. There are some small gaps (about 1 mm) which cannot be accounted for by the sash clamps applying pressure.

I think the old glue (about 40 yrs old) was Cascamite, which seems to be unavailable in my part of the world, so I am experimenting with Evostik External Wood Glue ( a PU one, I think) mixed with West Systems Microfibres 403 for some bulk.

The attached pic shows the adhesive and fibre mixture in place on some rough wood (to give an artificial gap). The problem is that after nearly six hours in the warmth of the kitchen, my test piece shows little sign of the adhesive going off to the clear glue line I'd expect.

View attachment 32202


Does anyone have any experience of Evostik and its gap-filling properties please ? And particularly whether it might work with MicroFibres in the situation I have described ?

Or should I mount an expedition to by some Cascamite from the V&A ? I really don't fancy using proper West resins in the small quantities I need for this job, mainly bcs I don't have experience with it :wimpicon:
 
West systems is simple. If you have it, and your using small quantities then mix it by weight on a set of kitchen scales. The ratio is the same as mixing by volume.

With microfibres it will be structurally sound with as much as a three mill gap.
 
Try a polyurethane glue like Pur Glue. single pot moisture curing although not a structural gap filler. Perfectly adequate in your application. Totally reliable curing, needs no filler and leaves a clean glue line.

Epoxy thickened with microfibres and microballoons, structurally strong also good but messy, expensive in comparison and probably OTT for the job.
 
I don't know where you're located but Cascamite is still available. Regarding the Evo Stik Exterior glue, I'm pretty sure its a PVA base of sorts and really needs to be under pressure in a thin film to maintain its bonding qualities. When you have an excess of it, it very often doesn't dry clear, just rather milky. If you've mixed it with microfibres it definitely won't. It'll look like congealed porridge, just as it does when mixed with clear epoxy.

If you are just trying to fill a gap of about a 1 mm (which isn't a lot), why not just apply a little of the evo stick at a time, and if you want to match it in with your mahogany... mix a little mahogany dust in with it.
 
Be grateful that you cannot find any Cascamite. It is horrible stuff, extremely hard and brittle when cured and prone to failure. There is only one adhesive suitable for gap filling worth considering and that is epoxy with a suitable filler. I always use SP 106 as that is what my supplier stocks, though I am sure the West equivalent is just as good.
Measure the quantities needed with kitchen scales, wear nitrile gloves, mix thoroughly and clean uncured glue with meths. Very simple, and at least as simple as messing around trying to make your own gap filling creation with PU and 403.
 
Woodlouse said:
West systems is simple. If you have it, and your using small quantities then mix it by weight on a set of kitchen scales. The ratio is the same as mixing by volume.

With microfibres it will be structurally sound with as much as a three mill gap.
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srp said:
Be grateful that you cannot find any Cascamite. It is horrible stuff, extremely hard and brittle when cured and prone to failure. There is only one adhesive suitable for gap filling worth considering and that is epoxy with a suitable filler. I always use SP 106 as that is what my supplier stocks, though I am sure the West equivalent is just as good.
Measure the quantities needed with kitchen scales, wear nitrile gloves, mix thoroughly and clean uncured glue with meths. Very simple, and at least as simple as messing around trying to make your own gap filling creation with PU and 403.

Not many kitchen scales weigh to the precision need for mixing small quantites...... Ours is 2 grams at the bottom end of its range ( 5g higher up)

A couple of small syringes would do the trick although Maplin offer several pocket scales with resolutions of 0.1g or 0.01 g
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OP. I've been doing loads of gluing recently on my boat and dinghy. I've got in my garage cascamite, epoxy glues and some Gorilla Glue. This stuff is the most remarkable glue I've ever seen. It dries harder than wood and is very very easy to use. Check it out online and you can get it in home base. It will do your job perfectly
 
You can also mix in the sawdust of the wood your using into adhesives such as Evostick wood glue. This is a cheap and traditional method of filling gaps when gluing it also dries to the same colour as the rest of the wood as it is the same stuff. I too have heard good things about Gorilla Glue although I've never used it myself.
 
srp said:
Be grateful that you cannot find any Cascamite. It is horrible stuff, extremely hard and brittle when cured and prone to failure. There is only one adhesive suitable for gap filling worth considering and that is epoxy with a suitable filler. I always use SP 106 as that is what my supplier stocks, though I am sure the West equivalent is just as good.
Measure the quantities needed with kitchen scales, wear nitrile gloves, mix thoroughly and clean uncured glue with meths. Very simple, and at least as simple as messing around trying to make your own gap filling creation with PU and 403.
Click to expand...

+1
 
follow up to the glue test...

I think I have been hasty and over-enthusiastic (not an unknown Sarabande characteristic :) )

This morning, after the piece had sat above the Rayburn overnight, the (patented) mixture appeared to have set hard and with an almost translucent glue line. I tried twisting the pieces apart, and ooops !

View attachment 32213

The adhesive in the middle has not set properly and is still malleable. The hardened mixture at the edge is still plastic when prodded with a small screwdriver blade. On the whole not a successful experiment :)

Back to using properly compatible materials I guess.

Thanks everyone for your skilled and experienced comments. Seems like any word ending in -mite generates equal numbers of lovers and loathers.
 
In my view, post 5 sums it up.

You can get PU stuff at Trago Mills. Best to have other things to do with it, as it does not have a great shelf life in the shed. On the other hand, if you purchase a small West kit, it seems to remain usable forever.
 
oldbilbo said:
Don't mock! There's lots and lots on the web about 'em.... < http://tinyurl.com/ptt9xzz >

And I know that IPC pensioner James J. knows about this issue. If you have an FRP-built boat more than a dozen years old.... Be afraid. Be very afraid! :eek:
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Glad mine was exactly 12 years old in February. Know the exact date the hull was moulded. Being built in Bavaria they mix beer in with the resin - kills the blighters off before they get a chance!
 
I recall one yacht surveyor - Bob Evans, a one-time senior RN engineering officer - explaining to me in the mid-80s why he was looking behind several panels of interior trim. "I'm looking for any evidence of Northern Polyestermites. These come to the surface on the inside face of hull mouldings and strong daylight on the outside can show up their tracks - while the other type, the General or Southern Polyestermite, seems to prefer the external surface....."

It's not every hull form and resin type that is vulnerable to them, of course, and it may be they haven't spread as far east as Bavaria. Ask your surveyor what his professional association now advises. :cool:
 
Buy a small bottle of Gorilla glue from B&Q, an excellent foaming glue, sets fairly quickly too. No point in buying more than you need as it has a habit of setting in the nozzle and top of bottle. I have been a carpenter for a lot of years and it is the best type of glue to go for ( other brands available. )
 
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