Are PVA (TiteBond II or III) glue joints which are left to cure in cool-ish temps (50 degrees F or so) less strong than joints dried at higher temps - or does it just take longer for the glue to set strongly? Getting chilly at night now and not really practical to bring glue-ups inside the house from my unheated shed.
FoggyTown
Glue is temperature sensitive, will take longer to cure than during warm weather.
Might consider using heat lamps over night on joints to speed up curing.
Lew
As long as you're above the chalk temperature, they will eventually cure to at least near full strength. I'm sure there's research on whether there's an effect or not, but I don't have a reference to it.
The critical item is to check the manufacturer's "chalk temperature" for the particular formulation you're using -- that's the point at which the glue will not set at all, but simply crystallize.
One of the advantages of TiteBond III is the lower chalkpoint--47F iirc. Type II is a fair amount higher although I don't recall the actual number offhand. If you're getting to the point of the material itself approaching 50F, I'd definitely be going to the Type III on general principles.
If you can warm the work area somewhat while working and doing the glueup, then let it cool gradually overnight after done, you can probably get a reliable bond if it doesn't cool too quickly -- the drying time will still be within an hour or so.
But, the suggestion of some heat lamps or other localized heat source is a good one for safety. Hardly anything would be more frustrating than doing a complex glueup only to find out if didn't hold completely owing to a few degrees too cool in the shop...
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Oh, the thing I was going to add -- for sure take the glue into the house and keep it in a warm location; don't leave it out to reach the near-critical temperature to start from.
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Ooooooooooo! Good point! Hadn't even thought of doing that.
FoggyTown
'Foggy',
Lew's comment about adding heat with 'lamps' is the simplest way to go. However I definitely DISAGREE with the idea of 'HEAT lamps'. Beside being relative expensive, they are TOO 'efficient'. They are designed to heat things and they do that job EXTREMELY well . . . sometimes to the point of COMBUSTION.
I DO use 'lamps' . . . actually just 100w lightbulbs. I have a 'Dollar Store' Styrofoam cooler for my 'working' epoxy - room for the cans of Resin & Hardener and a METAL frame 'droplight'. Keeps things 'just toasty' so they mix & spread well. I made a 'Lamp Rack' from a length of '2x ' stock, some 'lamp wire', and a half-dozen 'porcelain' lamp sockets. I wired them up in parallel so I can unscrew as many of the bulbs as a 'control'.
Working on a hull, and applying the epoxy, for example. I'll place this 'rack' with maybe all lights on, under the overturned boat. When I'm finished for the evening - I'll maybe 'unscrew' {a turn or so} maybe every other one. If I can throw an old tarp or blanket over everything, I may just leave the first & last lit.
I got this idea about . . cough, cough . . years ago, when I was in SEA. We used to keep a 60w {or so} lit in our lockers - to keep the mold from taking over ! More recently, the concept {low heat source & convection} was also used in a film {photography}drier I built.
Regards & Good Luck, R> "FoggyTown" wrote:
Absolutely.
You must keep the lamp far enough from the object being heated to prevent burning of the surface.
Lew
When I was a floor mechanic, we had a milk crate of cold sensitive stuff, in the van next to the glue buckets. Every night, from October to April, we were supposed to bring that the crate and glue tubs inside.
We NEVER remembered.
We could have bought a garage for the van with the amount of glue we bought to replace cold damaged material!
I'd suggest storing the cold-sensitive stuff in the house, and going to get it when you need it, as opposed to remembering to bring the stuff in when necessary.
Lew, I wasn't casting aspersions {or any other kind of bait}. Sometimes that 'heat' is a cumulative effect . . . starts at 'just warm' and goes up while your attention is elsewhere, or you leave for the night, etc. Not to mention the accidental & unrealized movement to a closer positioning, etc.
Or . . . maybe I'm just more paranoid then most.
Regards, R>
They are designed to heat things and they do that job EXTREMELY well . . . sometimes to the point of COMBUSTION.
NBD, but when you are dealing with a thermal energy source, a modicum of caution is to be expected.
But then again, maybe I expect too much.
Lew
Type III is 47° F and the Type is 55° F
That's about what I thought, thanks, but didn't remember the Type I/II number well enough to try to quote it/them...
That's a good point, but I find that everything should be at the same temperature. So, the glue should be >55, as well as the room, the pieces to be glued, etc.
I too work in an uninsulated shop, although it's not unheated. As winter approaches, and -25 temps are not unheard of, I have to come up with strategies that will ensure the glue won't fall apart after I'm finished. I've experienced that because I didn't know about the chalk-up temperature.
Last winter, I was making small boxes, so bringing stuff in wasn't impossible. Glue-up was the last step before I came in, and by the time I was ready to do the gluing, all surfaces were warm enough to glue.
This winter will be bigger pieces, and I'm not sure what I'm going to do. Maybe schedule gluing for the middle of my shop time, and keep heat on for a couple of hours before I shut it down. Either that or face SWMBO in the AM with scowls and mutterings about how I buggered up her kitchen (which I built)(which doesn't matter cause it's hers now)with clamped up pieces of wood.
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