The Poet Creek Express - Foamie Hybrid

[OP827]

From the datasheet, it looks like the PL300 glue needs to evaporate in order to cure. Sanded surface foam has no pores to outside, so no, it is not porous. Let me know how it goes. The glue should cure on the perimeter to some extent, up to 2 inches I guestimate before it becomes self-sealed, similar when it is in a tube.

[KCStudly]

Yup. The starter piece became the destructive test piece. Not so much because the product would not stick foam to foam, but because of a combination of factors. That pesky issue of the strap/stretcher clamp method not being good at pulling sideways on a nearly flat surface was the big one, and that other thing. You know, lack of air flow thru foam complicated by my application method.

I don't think it is an air cure issue per se, otherwise how does it stick to wood and brick? I suspect that it is a water evaporation/absorption issue, or lack thereof. The stuff is water cleanup while soft, so that tracks. So it has the same issues as the other glue options: don't use too much product, and make sure you clamp it well.

Here’s what I found when I pulled the stretcher off. The sides and bottom of the starter panel where attached well, but the top had pulled away and there was up to about 1/4 inch gap.


It seems like the stretcher had slacked up in the middle and allowed the panel to spring away from the hatch along most of the top edge. I could see where the adhesive was strung and had dried bridging the gap in several places.

Karl and I kind of poked around and pulled on it a little to see how hard it was stuck and whether I should cut it back to where it was soundly attached, peel it all the way off or just try to re-stick the top edge. The little bridges of PL wouldn’t let it go back everywhere, even after slicing them, and the more we pried and probed the more it seemed like the panel might come back off.

It seemed to tear at the PL if we just kept steady pressure on it and did not rush the process, but I wouldn’t call it easy. It didn’t just zip off, in fact it broke into a few pieces due to the amount of force we had to apply; but at least it tore at the PL and not the foam.


Now I had used a generous amount of the PL300 and some of the beads were pretty fat, so I wasn’t totally surprised that there was still wet goop in the heart of them. As advertised, the edges of the beads had cured and sealed the rest inside. Where I had spread the perimeter edges of the panel to about 1 to 1-1/2 inches wide (using a flat spreader this time) it had dried fully. Referring back to the label instructions, it says 1/4 inch vertical beads 10 inches apart, and to fasten and prop for 24 hrs.

I think my using a zig-zag triangle pattern in some spots didn’t help any (maybe sealed more air out), that the larger beads (a result of squeezing the trigger harder with slower travel speeds on the nozzle) are wasteful, and that my earlier success gluing some of the smaller panels to foam was probably attributed to the notched trowel technique (wherein the notched application controlled the bead size to one that would dry completely and provided air channels to help cure).

Anyway, if I am going to try the PL300 some more, I would use fewer vertical beads, flatten them with the notched trowel, and be sure to spread the edge beads so the troughs cut across the beads letting air in to the field. But I think I might go back and try either the 3M green contact adhesive, or reconsider thickened epoxy, for the larger panels on the hatch at least.

As far as the cleanup and getting back to where I was before this little setback, I started by scraping the top of the bumper and along the wooden cleat. Here’s what it looked like after busting the starter panel off.


And here’s what it looked like after scraping.



The rest was a combination of damp paper towels to get the uncured stuff, and peeling what would roll up easily. It took some experimentation but what seemed to work the best for the rest of it was a combination of scrubbing fairly rigorously with the damp paper towel (just the right amount of friction and lubrication) combined with peeling with the pads of my thumbs in a dragging motion. That did a reasonably good job of rolling the PL off of the foam without gouging like sandpaper would, or pulling up big chunks of foam. Here is where I left off, ready to try again (or something else).

[OP827]

KC, I personally used thickened epoxy with good results.
I also noticed that thickened for just right consistensy the epoxy has a better ability to screep and comply and distribute evenly and thinly between surfaces than for example TB2 due to epoxy's much longer working and curing time. That is why I changed to epoxy for plywood lamination to foam and am happy with how it worked. The cost increase seems insignificant because I ended up using significantly less epoxy volume that I had to use for fast drying TB2. Sometimes if you add the final thickness of glue in the cost calculation, the epoxy cost increase may be not as high as I anticipated. For 5'x3' ply lamination to foam I used approximately 200ml total of epoxy mix, or two mix batches of less than half of 250ml cup. I used perhaps 500ml of TB2 for 1'x5' ply I glued first. Just a note you would already know about not to mix bigger batches as they would very quickly go off hot in minutes and solidify in seconds. In case I started to feel that the cup is getting warmer, I could mitigate the epoxy going wasted by quickly spilling and spreading the epoxy in a bigger cup or a surface and that would stop the epoxy warmup and I still could continue normally for half hour of so with my work. Sorry for a long post on this, just sharing my experience here with you and hope it helps you with your choices.

PL300 appears to be ehtylene glycol water solution based. Therefore if you decide to glue with it on large non-porous panels I would consider doing some holes or kerfs in them for the glue to be able to dry and cure.
PL300 will stick to brick and concrete well because those materials have micropores that are connected to outside which allow the glue moisture to evaporate and escape first inside the pores and then eventualy outside, similar to TB2 glue action. XPS foam does not contain open pores, the cells are are practially 100% sealed.

Oleg

[KCStudly]

Thank you very much for weighing in and helping. There is no post that is too large, at least not by my standards, so don't give that a second thought.

Tonight, before reading your post, I had already decided to add a few shallow kerfs to the new starter piece (only a couple of pics, so I'll load those another time). I still haven't decided which product I will use to stick it down or how I will attempt to secure it for curing, but I figured that the kerfs won't hurt with regard to forming on the curve, and with the drying thing, too, if I go that way. I also made another notched trowel with slightly wider and deeper notches. Deeper to compensate for the angle that card wants to "squeegee" at.

On the first layer of foam I used 1/2 inch deep kerfs, but for these I just went 1/4 deep to try and stay out of the future round over on the sides.

[OP827]

Glad I could help KC. 1/4 inch deep kerfs at the same distance apart as you previously had good experience should work. PL300 should dry in a similar time as your first layer with kerfs. I like your positive attitude for the circumstances. I had one pretty bad glueup failure with a destructive piece too in my build. Cheers.

[GPW]

So let me get this straight ... The Kerf cuts are not for the bending , but to allow air to get to the glued bits to aid drying ? .... That’s Brilliant really !!!

[KCStudly]

Both, really, but yes, more for the ventilation on this gently arched profile at the bottom of the hatch. In fact, I had only put 3 kerfs about 2-5/8 inches apart (equal spacing), but I am thinking that I might add another set, doubling the pitch, despite the fact that I will have a lot more kerf filling and fairing to do on the roof edges later.

Also, the notched trowel I think is a big factor. Along the edges where I used that technique on the top part of the roof I can see plenty of areas where the valleys in the adhesive didn't get fully squeezed down, so those must have added a ventilation affect, too.

[KCStudly]

Just a quick post to show the pics from yesterday.

Stop me if you’ve heard this one before (bah-dump-bump). Dry fit the replacement starter piece. (The strip of scrap pink foam on the floor is acting as a drip catcher.)


Shorty vent kerfs. Tonight I messed with sealing up the table saw cabinet and configuring for dust collection before adding another set of kerfs here. (I’ll save the dust collection mods for its own post when I get done fiddling with that; the shop vac filters are too expensive to clog them up with foam dust, so I’m bodging Karl’s old dead shop vac into a Thein cyclone separator… mostly just ruminating over the starter strip.)


I plan on experimenting with a different notched ‘trowel’ to see if I can find a happy medium between PL300 application time and still be able to spread the beads out some without making large areas of wet spots (… or I might give up on laminating with the 300). The notches were made with the homemade hole punch; just a piece of 1/8 nom Sch 40 pipe with the end ground to a taper (my hole punch set was at home).


Yvette has convinced me to go look at a couple of kittens tomorrow and Rocky has been acting a little lonely, too. Somehow she thinks that we are going to take a couple of gray shorthair tabbies (8 wk old male and female litter mates) home with us. My argument is that if there were 6 of them we wouldn’t take all 6, but somehow I see myself losing this one. After all, I got to pick last time.

[Wolffarmer]

Do you think a small fan blowing air through those kerfs would help to cure the glue?

[KCStudly]

Maybe. Not a bad idea, worth trying, and I have a small fan in the loft that I use to try and keep cool when it is really hot (I like to use the big floor standing fan to pull fresh air in from the window, feeding across the front of the cabin down the length of the loft toward the ridge vent at the other end of the building, but that leaves dead air in the area between the cabin and bench; so the small fan is handy for "task" work). It was 90 deg F in the loft when I got there today.

[Wobbly Wheels]

It was 90 deg F in the loft when I got there today.

It seems like it wasn't that long ago you were packing the glues around in the Jeep to keep them warm enough to use

[KCStudly]

Seems just like yesterday.

Been doing this over 3 years now.

[GPW]

Three years of FUN !!!

[tony.latham]

Seems just like yesterday.

Been doing this over 3 years now.

Tony

[Wolffarmer]

Seems just like yesterday.

Been doing this over 3 years now.

Sing it with me now. "What a long strange trip its been "