Glue and epoxy question - do they play nice?

[Aint2Proud]

Will Titebond III bond to cured epoxy? My walls have a dado that will slip over the floor. Earlier on I expoxied one side of the dado and I just want to make sure I don't need to do something further. Thanks.

Ryan

[afreegreek]

you can get a bond but only a weak one.. you need the surface of the epoxy as rough as possible. something like 60 grit.. a construction adhesive such as PL Premium Sikaflex 291 would be better..

[wannabefree]

Simple answer -- no. Titebond, like all aliphatic resins, works by partially penetrating the surfaces of the material it is bonding. It can't penetrate epoxy. It will get some adhesion to a rough surface as afreegeek says, but it won't last after bouncing down the highway a while.

[Steve_Cox]

Why not use epoxy with an adhesive filler for this joint since you already have epoxy on one side?

[Aint2Proud]

Unfortunately that's what I was thinking. I sealed the one side because of plywood that came down to the dado on the interior skin of the wall and started looking at it last night.

I have PL Premium and used it to attach the outside skin. That was the first time I used it and even with weight on the wall the skin came out wavy because of the expansion. I DON'T want that to happen with the wall connection to the floor/trailer. Does Sikaflex expand? The epoxy with filler is interesting, but my experience with the hardener I have (Medium) is that I won't have enough time to get the wall on and positioned before it takes hold. I want at least 10 minutes to be able to apply the adhesive another 5 to get the wall into place and clamped. My hardener is good for about 15 minutes, which does not give me any wiggle room. If that is the best way to go I will order a new batch of hardener, but would like to look at other alternatives if comparable. Thanks.

Ryan

[aggie79]

I have PL Premium and used it to attach the outside skin. That was the first time I used it and even with weight on the wall the skin came out wavy because of the expansion.
Ryan

Ryan,

Please excuse this question. Did you use polyurethane (PL) glue - "Gorilla glue" - or did you use PL Premium?



The reason I ask is that PL glues do foam when they cure.

I used PL Premium to attach my sidewalls to the floor and bulkheads and to attach the plywood skins.



The bulkeads fit into dados and the floor fits into a rabbet. After I applied the PL Premium, I did use screws to fasten through the sidewalls into the bulkheads and the floor.

On the plywood skins, a j-roller was used to "spread " the beads of adhesive and screws were used as temporary fasteners.



I may have been lucky, but I didn't see any expansion of the PL Premium or waviness in the plywood skins.

[Aint2Proud]

I am new to all of this so ask away!

In response - I did use the PL Premium, not Gorilla Glue. You got me thinking that maybe I just used a bit too much on my framing or the weight was not centered directly over the framing (or both). My wall skins are 1/8 inch thick so they are probably more susceptible (sp?) to deforming. If PL doesn't expand like I originally thought then I will use that. Thanks!

Ryan

[aggie79]

I am new to all of this so ask away!

In response - I did use the PL Premium, not Gorilla Glue. You got me thinking that maybe I just used a bit too much on my framing or the weight was not centered directly over the framing (or both). My wall skins are 1/8 inch thick so they are probably more susceptible (sp?) to deforming. If PL doesn't expand like I originally thought then I will use that. Thanks!

Ryan

Ryan,

The PL Premium is pretty thick (is the better term "viscous"?) stuff. It won't lay down flat without persuasion.

From this board, I've learned that there are several approaches to getting it to work. On flat areas, a notched trowel like what is used for vinyl flooring can be used to spread it out. (This stuff is hard to clean too, so you the disposable plastic notched trowels are probably better than the metal ones.)

For my exterior 1/8" sidewall plywood I just squeezed out the beads of PL Premium on the framing, applied the plywood, and then rolled it out using a j-roller to squish it down.



As far as the sidewalls to bulkhead and floor, I put these together before I applied the outside plywood. The screws I used to fasten everything together before the PL Premium set were enough clamping pressure.

If you haven't applied your aluminum, you could also use screws, either permanent or temporay, to hold everything together while the PL Premium set.

[Larry C]

Unfortunately that's what I was thinking. I sealed the one side because of plywood that came down to the dado on the interior skin of the wall and started looking at it last night.

I have PL Premium and used it to attach the outside skin. That was the first time I used it and even with weight on the wall the skin came out wavy because of the expansion. I DON'T want that to happen with the wall connection to the floor/trailer. Does Sikaflex expand? The epoxy with filler is interesting, but my experience with the hardener I have (Medium) is that I won't have enough time to get the wall on and positioned before it takes hold. I want at least 10 minutes to be able to apply the adhesive another 5 to get the wall into place and clamped. My hardener is good for about 15 minutes, which does not give me any wiggle room. If that is the best way to go I will order a new batch of hardener, but would like to look at other alternatives if comparable. Thanks.

Ryan

Ryan.
I'll address the epoxy question:

1) when you mix thickeners into the epoxy it slows the cure, especially when you spread the mixed, thickened epoxy, onto the glue surfaces quickly. you are decreasing the mass which will slow the exothermic reaction happening in the mixing cup.

2) Also, cooling the mixture in the refrigerator/freezer will dramatically slow the cure. You can also start with unmixed, chilled, resin/hardener, but it can be a little more difficult to mix the resin/hardener throughly.

$.02
Larry C

[Steve_Cox]

Ryan,

In regard to the epoxy question... what Larry said

[afreegreek]

I have used epoxy a lot and I've tried all the tricks.. chilling resin is one that works ok on paper but in reality doesn't gain you anything.. the minutes you theoretically save in working time is eaten up by trying to mix chilled resin.. in fact the opposite has given me better results.. warm the resin to about 90 degrees and mix then pour the resin into a chilled pan..

you have to be aware of the results you want too.. if it's for bonding, thick (chilled resin) is ok but for wetting out glass it is not. for that, warm runny resin is much better. just use small batches and get it spread out asap..

epoxy manufacturers spend plenty of time and effort ($$$) to give you the best possible results at 70 degrees.. mucking about with temperature is not usually going to improve the result by much if at all.. if your room, work piece, and resin are at 70 degrees, that's about perfect..

[S. Heisley]

It depends on the kind of PL Premium glue:

PL Premium Polyurethane Construction Adhesive or the kind like Aggie79 shows does not expand as much as some.
PL Premium Polyurethane Wood Glue expands a lot and then oozes out. That one has a short shelf life after opening, too.

[schaney]

I use West Systems epoxy, at 70 degrees the pot life of their hardeners is; 205 9-12 mins, 206 20-25 mins, 209 40-50 mins. Getting some slower hardener for your resin should do the trick. In my experience being colder has little effect on pot life, although it does extend the full cure time.

[afreegreek]

I use West Systems epoxy, at 70 degrees the pot life of their hardeners is; 205 9-12 mins, 206 20-25 mins, 209 40-50 mins. Getting some slower hardener for your resin should do the trick. In my experience being colder has little effect on pot life, although it does extend the full cure time.

YUP... THE DIRECTIONS ARE ON THE CAN!

[Larry C]

I have used epoxy a lot and I've tried all the tricks.. chilling resin is one that works ok on paper but in reality doesn't gain you anything.. the minutes you theoretically save in working time is eaten up by trying to mix chilled resin.. in fact the opposite has given me better results.. warm the resin to about 90 degrees and mix then pour the resin into a chilled pan..

you have to be aware of the results you want too.. if it's for bonding, thick (chilled resin) is ok but for wetting out glass it is not. for that, warm runny resin is much better. just use small batches and get it spread out asap..

epoxy manufacturers spend plenty of time and effort ($$$) to give you the best possible results at 70 degrees.. mucking about with temperature is not usually going to improve the result by much if at all.. if your room, work piece, and resin are at 70 degrees, that's about perfect..

Afreegreek,
Before bashing my suggestion, did you actually read what Ryan was asking??

Here it is:


"The epoxy with filler is interesting, but my experience with the hardener I have (Medium) is that I won't have enough time to get the wall on and positioned before it takes hold. I want at least 10 minutes to be able to apply the adhesive another 5 to get the wall into place and clamped. My hardener is good for about 15 minutes, which does not give me any wiggle room. If that is the best way to go I will order a new batch of hardener, but would like to look at other alternatives if comparable".

Your response to my suggestion to slow his medium hardener for longer work time:

"I have used epoxy a lot and I've tried all the tricks.. chilling resin is one that works ok on paper but in reality doesn't gain you anything"..

I too have worked with epoxy a lot! I believe your above statement is just plain WRONG.......

I regularly chill my epoxy mixed with thixotropic agents to slow the cure. I do this for bonding large surfaces, not glass wet out. I always warm my resin/hardener in a sink of hot water even when I will be chilling it after mixing thickeners. 70 degrees is not warm enough from my experience even with thin epoxies.

I recently laminated my 5x8 sandwich floor with epoxy. I was working with 6 oz. batches. My thickened epoxy starts to set up in about 25 minutes. To slow the process, I put my cup of mixed, thickened epoxy in a bowl of crushed ice. This dramatically increased my pot life allowing me time to spread the multiple batches of the mixture without rushing. It worked perfectly.

I have been using this method for years. For me it works on paper and in practice...

To prove my point (see pictures):
Yesterday, I mixed a small batch of thickened epoxy and covered the cup with plastic wrap, I then placed it in the freezer of my refrigerator. This morning, I removed the mixture from the freezer. The epoxy was the same consistency I had mixed yesterday. I slapped some on 2 sticks and let it set. It's now been 2-1/2 hours, the mixture is stiffened quite a bit, but probably needs another half hour for initial cure.

I am not trying to get into a PiXXing match, but when it comes to epoxy there are so many tricks and methods that work for one person, but don't work for another. Chilled epoxy for gluing works for me.....

Right from the freezer after 17 hours:



3 hours of cure time, still a little soft.....