Questions about building with foam

[tlsallada]

Well, I'm starting my 2nd build . . . .the first was built using traditional plywood techniques. Now I'm sold on the use of foam but have a couple questions:
1) What is the best method of making the connection between the foam sidewall and the plywood floor of the trailer? I saw one post where they had an inset on the sidewall which fit into the trailer, sort of mortise and tenon style. It seems just 'sitting' the foam sidewall in the trailer floor is lacking somewhat.

2) How do most folks 'finish' the interior ceiling of their foamies? Paint - fabric & paint - etc ??

3) There seems to be discussion of gluing foam to foam and what type of glue to use. The connection I wonder about most is where the foam roof glues (attaches) to the sidewall. The topic seems to go back and forth between Glidden Gripper and Gorilla Glue. And to further complicate things, which Gorilla Glue??

Thanks in advance for any insights!!

[ghcoe]

Well, I'm starting my 2nd build . . . .the first was built using traditional plywood techniques. Now I'm sold on the use of foam but have a couple questions:

1) What is the best method of making the connection between the foam sidewall and the plywood floor of the trailer? I saw one post where they had an inset on the sidewall which fit into the trailer, sort of mortise and tenon style. It seems just 'sitting' the foam sidewall in the trailer floor is lacking somewhat. I do not know the best method. It can be done a couple of ways such as you have stated. Remember it is not just the glue, but also the fabric that is wrapped under the floor that also helps hold all things together

2) How do most folks 'finish' the interior ceiling of their foamies? Paint - fabric & paint - etc ??Well that would be up to what you want. I suppose you could just paint it but for added roof strength I would use fabric. It has also been discussed to use paper such as magazine, comic, or newspaper to do the interior with. Also, wood could be used

3) There seems to be discussion of gluing foam to foam and what type of glue to use. The connection I wonder about most is where the foam roof glues (attaches) to the sidewall. The topic seems to go back and forth between Glidden Gripper and Gorilla Glue. And to further complicate things, which Gorilla Glue??Glidden Gripper I think has fallen from direct gluing favor. Most cases you want to use Gorilla Glue or Great Stuff. I have used both in my construction and have good results with both. Each has there own plus and minuses so it depends on what I am gluing at the moment to what product I would use. For my roof wall attachment I used Great Stuff, but I know others have used Gorilla Glue. As far as I know there is only one Gorilla Glue.

Thanks in advance for any insights!!

[tlsallada]

Which type of Great Stuff is recommended, the 'regular' or the minimal expansion type used for doors and windows?

[ghcoe]

I use the red can, but the minimal expansion might work better. I have not tried it yet. Sometimes the expansion is a good thing and sometimes it causes some problems. Read through my build. I address how to control some of the issues with packing tape. Also, if you spray it and then mash it up a bit with a stick or scrap piece of foam it helps keep it from expanding so much.

[Mary C]

first I did not use any other glue but TBII I tried some other but I hate GG so went TBII all the way.

second the thing about the foam in the can and the different types it does depend on where you want to use it. I used the regular original foam in places that I needed to sand. The door and window yellow type does not sand and it is harder than heck to remove but I found it is a great glue.

third, The outside finish is really important because it makes the stability of the foam . While the inside is important to finish I found putting a shower hat on (Wallmart type Plastic bag and use TBII to glue on whatever. The TBII will wash off after a little while in the shower. I used canvas and then paint and now I plan to put up some maps for my Big Out West trip in 2016. in 2017 I will Paint and put up Maps for my Big Up north trip in 2017.

Fourth, The initial thought of a Foamie was Thrifty and for some reason people forget that little trait. Our whole idea is making it without spending a whole lot with a minimal amount of work. To keep it simple and doable as a camping trailer-hard tent. With that being said, have fun and know that we are here for questions.

Mary C.

[tlsallada]

Thanks so much for the replies!! I know I received a lot of great help for my first 'traditional' plywood build and I see the 'foam people' are just as helpful!!

[tac422]

Well, I'm starting my 2nd build . . . .the first was built using traditional plywood techniques. Now I'm sold on the use of foam but have a couple questions:
1) What is the best method of making the connection between the foam sidewall and the plywood floor of the trailer? I saw one post where they had an inset on the sidewall which fit into the trailer, sort of mortise and tenon style. It seems just 'sitting' the foam sidewall in the trailer floor is lacking somewhat."

I think you're referring to The Big Pink. Here's where Mike attached the walls:
http://tnttt.com/viewtopic.php?f=55&t=44091&start=80
and here : http://tnttt.com/viewtopic.php?p=829675#829675

2) How do most folks 'finish' the interior ceiling of their foamies? Paint - fabric & paint - etc ??

I covered every exposed foam surface with canvas and paint. And every corner with corner bead.

[KCStudly]

I went with thin plywood on the interior for a traditional feel inside, and the added strength.

I used 2x2 cedar sills along the bottoms of my walls and screwed up thru the floor rim into the bottom of the wall with deck screws and PL. The wood sills were very helpful as solid reference points and made handling the walls easier during construction; having a hard edge to slide the walls on, such as when lifting them onto the workbench or slipping them into their storage location between operations really helped. Especially considering that I fully finished my interior before standing the walls up.

Thrifty and simple was the genesis of "the modern foamie method", and there are some purist, but you can pretty much use the proven techniques however you want to build whatever you want. The foam is light and the canvas, glue and paint have the potential to create a very strong, yet light composite structure.

Key things are to build tight for strength (just like any other method); add hard points where needed (a lot of thought needs to go into this before the skins go on); and think about the structure as a whole with the strength coming from the skins. No one piece creates the strength, all of the pieces together make the whole thing strong.

As Mary says, we are here to help; welcome to the foamie family!

[GPW]

... and we must mention the now legendary Foamie durability ... able to live outside , where others could not ... No ROT !!!

Ps. Gorilla Glue works just fine if you adjust to the local Humidity. The idea is to spray with water for dry conditions or Not , for Humid conditions (like we have here) ... the more water , the more it expands. It Will dry with No water at all .... just takes a little longer... there’s always some humidity in the air ...
Some expansion should be allowed for or the entire assembly blocked and clamped so it doesn’t ... We’ve tested all that now ...

[dales133]

Is this the transparent, foams up as it sets gorilla glue that comes in a PVA style bottle?.
The stuff I buy local branded gorilla glue is as described a polyurethane glue. ( unlike PL adhesive though)

[KCStudly]

Apparently GG has a variety of types now. I use the original brown gel like stuff: Gorilla Glue.

[dales133]

Thanks once again kc

[dales133]

Anything like this? This isn't water activated though.
I'm looking for something I can glue my spars to my varnished walls that's easy to clean up witch isn't realy PL.
http://www.mitre10.co.nz/shop/paint_dec ... ml_370831/

[GPW]

Dale , I know this may sound Crazy , but what about that double stick tape the cargo trailer folk use to stick Al to Steel ... Supposed to be VERY Sticky... and would hold varnished surfaces with a little bit of flexibility too ... (like everything else , best “test” that idea first)

[KCStudly]

I have tried to always keep raw wood where ever I plan to glue, or mask the area and sand back the poly and stain before gluing.