Teardrops n Tiny Travel Trailers

Hi all, I will be using 3M fastbond to glue my 1/8 ply to a 1 inch inner foam core. My question is who here has used it? How far does it stretch? Do I need 1 gallon orb1 quart? And what are the application recommendations? Roller, spray?

I am gluing both inner and outer ply to the foam, for all walls, floor and ceiling. I do plan to use TBII to glue ply to the minimal framing. I also plan to clamp and weight.

Thanks for the advice!

I used Fastbond to attach the solid insulation to the interior walls of my trailer. A pint covered the entire interior (think typical teardrop size) on both surfaces. I brushed with disposable foam brushes because I wasn't going to spray in an enclosed space. One important tip, both surfaces MUST be above 60F for the stuff to dry properly. And since it's a contact cement, both surfaces must be dry before contact.

Other than the price, I thought it was a good choice.

<Chas>

well, I bit the bullet and got a gallon of the green. I will be using it on both inside and outside skins for walls, ceiling, and floor. so I am guessing I will go through more than a quart. will update as I start using it.

plan right now is to use a brush to paint it on. anybody get bad results this way?

As was already mentioned, temperature is critical to a good bond, perhaps the most important part of using this glue. Next in line is dust, try to have a dust-free area to work in. If you don't think it will be warm enough, don't use it! Brush, roller or spray will all work well enough, but do a test pass on some scrap to make sure of temperature, drying times & bonding. High humidity can really slow things down.

A heat gun or shop heater are what you need to insure a good bond. A hard roller is good also, to provide enough pressure to make the bond, once the sheets are in place. Don't do any trimming until all the parts are bonded, or you will have a layer of dust which will keep the bond from working. Dust acts like small ball bearings between the glued surfaces & will create trouble later on. Take your time & it will turn out well.

Make sure you have enough hands to position things correctly the first time. Once that stuff grabs, it has to be in the right place as you won't be able to slide it around. Best of luck. tim

P.S. We are talking about a water based adhesive, correct (Fastbond 30)? The solvent base (Fastbond 10) shouldn't be near any pilot lights, electrical switches or ignition sources!

Yes, fastbond 30. At a whopping $130 a gallon! I hope my foam appreciates this glue!

Thanks for the advice. My garage is uninsulated and only mildly heated (a single forced air register) so it's good to know I may need to bust out the electric heater to warm up the work area before attempting to glue anything.

I am going with the clamp and weight method. Should I also get a roller to press down/out the contact before applying the weight/glue?

You must use a roller or something to create the bond. Contact cement works like thousands of small pins at the surface. It is typically used in laminating, because a roller can provide enough surface pressure to make the mechanical attachment.

It works great on formica counter tops & we also used it for cloth headliners in aircraft work. The roller is what "sets" the bond. Clamping & weights are fine to make the panel set up over time, but some type of localized pressure (a roller) is better to make the initial grab. With foam, you don't want to break down the surface with too much applied pressure, just make the initial connection with a small roller (metal or rubber).

Try some scrap first to see what I mean & it will make more sense. Do several smaller parts & experiment on them before you try the big pieces.

Fastbond30 is Great Adhesive!! It works so much better than any of the other brands that are water based. And your brain cells will thank you.

Use a roller similar to one ofthese. Lots of pressure rolled all over

Hmmm, I thought that this glue contains toluene and methanoal that will affect or dissolve XPS or EPS foam, or not?

http://multimedia.3m.com/mws/media/66128O/3mtm-fastbondtm-30-nf-30h-nf-contact-adhesive.PDF

OP827 wrote:Hmmm, I thought that this glue contains toluene and methanoal that will affect or dissolve XPS or EPS foam, or not?

http://multimedia.3m.com/mws/media/66128O/3mtm-fastbondtm-30-nf-30h-nf-contact-adhesive.PDF

That spec sheet says "less than 5% tolulene and methanol." And no it does not dissolve EPS foam. I used Fastbond 30 to attach my EPS foam insulation to the interior walls of my teardrop. I brushed it on the aluminum skin and on the foam. When it changed color, I simply stuck the foam sheet to the wall. I did not use a roller (brayer) nor did I weight or clamp it. Six years of use, being stored outdoors 24/7/365 and none of the foam panels have come loose.

I chose it because I did not want a solvent based adhesive at application time, or later when the skin gets hot. BTW, it's not uncommon for the skin of my teardrop to reach 140F on a hot day, it's dark brown. 3M recommends Fastbond 30 for high temperature applications, including specifically bonding metal to foam.

<Chas>

Thanks, that is good to know.
Do you think this glue is what A-liner and maybe other trailer manufacturers are using for walls and roof sandwich (aluminum-or-FRP+EPS foam+ interior panel)?
It seems to be matching the production line videos of factory tours.

so it turns out that I am using a LOT of this stuff. I have finished the floor and walls and have maybe a quart left. I don't think I can finish the front wall/roof and hatch with what I have. I am brushing on and following the directions as far as coverage /drying.

thanks for all the advice on heating up the shop and having a second set of hands. both tips turned out to be invaluable. (waiting almost 1.5 hours the first time because the humidity shot up as the outside temp fell stunk)

anyways, wanted to give some feedback on my original question. turns out that to glue both outside and inside sheathing to foam for a 5x10 tear you will need at least a gallon. at least that is my experience.

Thanks for sharing your experience here. If it needs a gallon that costs similar to epoxy (130$ per gallon), I would personally try to go with epoxy as it also penetrates and reinforces wood and provides the strongest bond. I personally found that using epoxy for laminating plywood to foam was quite economical with regards to amounts required as epoxy does not require a think layer applied for the bond to work, but I took the time to dry fit surfaces to match nicely.

OP827 wrote:Thanks for sharing your experience here. If it needs a gallon that costs similar to epoxy (130$ per gallon), I would personally try to go with epoxy as it also penetrates and reinforces wood and provides the strongest bond. I personally found that using epoxy for laminating plywood to foam was quite economical with regards to amounts required as epoxy does not require a think layer applied for the bond to work, but I took the time to dry fit surfaces to match nicely.

If I had epoxy experience, I would probably go that route. Getting an extra gallon of epoxy would have been cheaper than this where I got my epoxy (raka) and I'm not super impressed with the bond. Don't be get me wrong, it will work well, but it isn't crazy, gorilla glue strong. Plus, epoxy is much more fun!

Final update on the 3m fastbond experience. I have about half a cup left from my original gallon. I used it to bond the inside and outside ply to foam on the floor and both walls, so a little less than 250 Sqft total. I had enough to glue the foam to the inside ply on the front wall/roof, but I will not have enough to apply the outside ply on the front wall/roof. I also did not do the hatch or the bulkhead with 3m fastbond. So I would need another quart to half a gallon to finish.

Also I probably should have used more on the wood side of my bonds, I put an extra coat on the roof and it has preformed much better than the walls and floor did. But that uses even more product!

I cannot say what would work better, but I will be trying my hand with PL Premium adhesive to finish the roof and build the hatch. It is not worth it to spend the money on another 2 quarts of 3M fastbond. I wanted to love it, but either due to my technique or to its own limitations I have found it less than ideal. Especially when you consider the price.

I have had similar experience; takes a lot more product on porous surfaces (wood and foam); takes a long time to tack up in even just somewhat humid conditions; is expensive; and doesn't bond as well as expected. I think some of the latter issue is because you really can't go at the foam hard with a roller, as recommended (though I suppose you could flip it and roll the wood down onto the foam... but that isn't very practical from an assembly stand point).

If I were to do it again I would go straight to epoxy. i had very little epoxy experience at the start of my project and was reluctant to go there, too, but now it is like an old shoe that fits right and is the best tool for the job much of the time.