Looking for an adhesive. Needs to bond wood (lauan) to steel. Primary attachment will be self-tapping screws, but for the spaces in between I need something to hold it in place when I put paint on it, humidity changes, etc to prevent it from getting wavy.
Also needs to be not hateful to remove if I need to replace the lauan later.
I'm tired of making theater flats out of wood and having them break, so I'm going to weld up some 1.5" thin wall square tube steel and slap lauan on them instead.
Hot glue gun?
I've had good luck with construction adhesives. Loctite PL3X is the specific one that I've used in the past with really good results for metal to metal, foam to metal, foam to concrete, and wood to concrete. I can't imagine it wouldn't work for metal to wood.
I've also found this site to be really useful: http://www.thistothat.com/cgi-bin/glue.cgi?lang=en&this=Wood&that=Metal
To remove it, heat up the metal with a heat gun or a propane torch to soften it up some.
wae said:I've had good luck with construction adhesives. Loctite PL3X is the specific one that I've used in the past with really good results for metal to metal, foam to metal, foam to concrete, and wood to concrete. I can't imagine it wouldn't work for metal to wood.
I've also found this site to be really useful: http://www.thistothat.com/cgi-bin/glue.cgi?lang=en&this=Wood&that=Metal
That website is going to waste so much of my time. Thank you.
Shadeux said:Hot glue gun?
I use hot glue a lot in theater. The problem is that it needs to be assembled hot for it to work, and unless I spend a lot of time with a torch heating the whole frame I think the glue will hit the steel and harden pretty quickly. Still, worth experimenting.
I've used Gorilla Glue construction adhesive to attach wood to concrete with great success. Have not tried steel but I'd be wiling to give it a shot based on the concrete experiment.
Double sided 3m foam tape works well. We use it to hold on cabinet door panels on dish washer fronts. It has never fallen off in 20 years of installs.
In my line of work, one of the products we sell are engineered surge bins that have a high-build epoxy liner known as epigen painted on. Can't help thinking that once it has been slapped on, you could readily stick timber to it; once the epoxy migrates into the timber you'll never get that sucker off again.
I was thinking the answer was epoxy, until I read that you want to be able to pull it apart. Just today, I was removing brickmold in preparation for replacing a rotted door frame, and I was surprised to see how well plain old "Alex" latex caulk bonded the brickmold to the J-channel of the vinyl siding. So, caulk? But it's still going to suck when you try to pull it apart.
If you're using screws, you want something very much non-sticky to just take up the space, like a nice thick layer of peanut butter. 
Keith Tanner said:I've used Gorilla Glue construction adhesive to attach wood to concrete with great success. Have not tried steel but I'd be wiling to give it a shot based on the concrete experiment.
Gorrila glue will definitely do the job, except for the " not hateful to remove if I need to replace the lauan later" requirement. Once its there, its there
Dumb question, why are you wanting to glue it and not just use tapered self-drilling flat head screws only? What thickness plywood?
I know this isn't the meme or photo thread, but this is just too perfect.
Some ideas, with embarrassingly bad sketches (my excuse: I have a cat sleeping on top of one arm...)
1988RedT2 said:I was thinking the answer was epoxy, until I read that you want to be able to pull it apart. Just today, I was removing brickmold in preparation for replacing a rotted door frame, and I was surprised to see how well plain old "Alex" latex caulk bonded the brickmold to the J-channel of the vinyl siding. So, caulk? But it's still going to suck when you try to pull it apart.
If you're using screws, you want something very much non-sticky to just take up the space, like a nice thick layer of peanut butter.
The caulk idea is good. I once held a cb antenna on a jeep with red RTV. Was fine.
VolvoHeretic said:Dumb question, why are you wanting to glue it and not just use tapered self-drilling flat head screws only? What thickness plywood?
5mm Lauan underlayment. If you use enough screws to keep it planted, you're using a crapload of screws. The goal here is to use about 6-8 small flathead screws that I can bury flush as a positive, mechanical securement and adhesive in between so it stays flush in between. Lauan likes to swell when you paint it, but it's pretty compliant. I have to use screws to be legal for overhead lifting when used as a flown scenic element. Otherwise I would be looking for a more permanent glue and deal with the frustration of grinding it off when I have to replace the lauan.
Example: When I build regular wood flats, I glue and staple, and I use a ton of staples, like every 4 inches or so, otherwise the paint will cause enough swelling to rip the glue... or just rip the wood fibers under the glue and cause a belly in the skin.
flat4_5spd said:I know this isn't the meme or photo thread, but this is just too perfect.
That's fkn classic
Oapfu said:Some ideas, with embarrassingly bad sketches (my excuse: I have a cat sleeping on top of one arm...)
- there is a "removable weatherstripping" type of caulk, intended as a sealant rather than adhesive so it may not stick well enough, and/or very thin bondlines could become a PITA to remove (esp. if stuck together a long time)
- Intentionally use bad adhesive joint design: apply a fillet bead of standard permanent-strength construction adhesive ONLY AFTER the luan has already been screwed to the metal frame (like if you were trying to seal the corner with caulking). Cut thru the bead to remove the luan (probably easier said than done). At least you won't need to completely remove all of the remaining adhesive before putting on new luan.
- Something completely different: permanently glue pieces of 1x2 to the back of the luan, then screw thru the sq tube perimeter frame into the 1x2. Leave a gap when gluing down the 1x2 and you could semi-tension the luan?
I like the outside-the-box thinking. I also like the RTV and construction adhesive ideas. At least those will come off with a wire wheel on a grinder.
I was also thinking this morning (best thoughts happen in the shower) that I can usually get two years out of a lauan flat, so maybe if the adhesive were more sticky, it would be worth the extra effort of stripping it later. If I had to do this every 6 months, I would want something a little easier to remove, but I think I can deal with more effort as long as I'm doing it less frequently.
Time to try. I'm ordering the steel today and I'll start making up the frames. I think I might get a construction adhesive and an RTV and build some of each. Whichever one proves best a year from now can be the method moving forward.
The frames will be something like this:
I think you want 3M VHB tape. They do one that is basically the snot used to stick credit cards to letters, just on a peel and stick roll. You can get it in various widths and thicknesses to suit your surfaces. I will check my sample bin when I get home to see if I have a direct part number.
They're going for a slightly more permanent solution than you are, I think, but what do RV manufacturers use to attach the luan to the frames?
Don't forget the back side. If you can get 2 years out of the luan, you can put a 2nd layer on the back for 2 more years before you have to strip it.
Wood flats aren't easy to use the back. Keystones get in the way. Steel flats should be welded and be perfectly capable of being double sided easily.
Also...
Would you have to strip it? Couldn't you add a 2nd layer of luan over the first?
Curtis73 (Forum Supporter) said:VolvoHeretic said:Dumb question, why are you wanting to glue it and not just use tapered self-drilling flat head screws only? What thickness plywood?
5mm Lauan underlayment. If you use enough screws to keep it planted, you're using a crapload of screws. The goal here is to use about 6-8 small flathead screws that I can bury flush as a positive, mechanical securement and adhesive in between so it stays flush in between. Lauan likes to swell when you paint it, but it's pretty compliant. I have to use screws to be legal for overhead lifting when used as a flown scenic element. Otherwise I would be looking for a more permanent glue and deal with the frustration of grinding it off when I have to replace the lauan.
Example: When I build regular wood flats, I glue and staple, and I use a ton of staples, like every 4 inches or so, otherwise the paint will cause enough swelling to rip the glue... or just rip the wood fibers under the glue and cause a belly in the skin.
How about sealing all sides of the plywood with an oil based primer which shouldn't warp the wood before you attach it to the framing with whatever method you prefer?
wae said:They're going for a slightly more permanent solution than you are, I think, but what do RV manufacturers use to attach the luan to the frames?
The ones I've repaired look like a pretty standard gray construction adhesive, but I don't know what formulation.
SV reX said:Also...
Would you have to strip it? Couldn't you add a 2nd layer of luan over the first?
I could do that and have done that before. The only real downside (other than weight) is that you can no longer bolt two flats together and have a flush surface. I do like the 2-sided approach. I could skin the opposite side and rip off the old luan. Leave it ugly until I need to re-re-skin
You'll need to log in to post.
