PsiPhi
08-07-2007, 01:08 AM
Before I start to glue my boat together . . .
I was reading (spec sheet for a glue I think) that if you clamp it too tightly while the glue is curing it will weaken the join - by squeezing most of the adhesive out of the joint before it sets.
Now, most of the build diaries I see on the internet show photo's, with 4,783 clamps per linear inch of a joint being glued.
Are spring clamps a no-no?
Are ratchet clamps any better?
Are a few weights off the (unused) multi-gym a better solution?
If you're speaking of epoxy then yes, too much clamping pressure will starve the joint. Most all other adhesives, typically used in boat building require considerable clamping pressure, some need very high amounts. Epoxy can also run out of a joint, if the adhesive filler mixture wasn't thick enough to prevent this. There's not much more depressing then a joint, that looked good last night when you applied the epoxy, but was found the next morning with a pile of hardened goo, pooled at the bottom of the work. For the most part, epoxy joints need enough clamping to insure alinement and contact, that's it. Anything more is pushing goo out of the joint.
The amount of pressure is application and adhesive specific, some tasks require little, while others may need more convincing. I've used concrete blocks, bricks, sand bags, fat friends (okay skinny ones too), spring/bar/C/parallel screw/lap/etc. clamps, you can't have enough (I have over 200). Clamps are a handy thing, but most often you'll find you can use wedges, weight or other devices (usually shop made) to keep things from moving around.
There's a huge difference between cheap clamps and good ones. Harbor Freight (or similar quality) clamps can explode under pressure (I've been there), so if you need to hold something that can hurt you if it lets go, then use good clamps, unless you're into cool looking scars.
PsiPhi
08-07-2007, 07:54 PM
I intend to use epoxy.
Actaully, I went down to Boat Craft yesterday lunch time and got some Bote Cote epoxy, hardener and glue filler, so now I have to use epoxy.
I also picked up thier "Boat Building with Bote Cote" book. Speaking as a totally uninitiated newbie, I think it might be the best five bucks I've spent so far.
