DIY Composite Flatbed Camper Build

[Terra Ops]

Derek, surfaces should be clean. First I would use a blower then wipe down with damp cloth. Hope those mulch bags are heavy enough, they prohibit viewing contact of the skins.
If and when I do this again, I will build a type of press that will evenly provide pressure across the panel. I'm picturing small jacks placed on top of some plywood with the panel below. A fixed beam of sorts would be on top for the jacks to apply pressure against.

 

[Terra Ops]

Terra Ops said:


You stated "My FRP seems to have a light fabric on the back so I wonder if that will help adhesion. Light fabric?

In the video you can see that. It could be there to soak up adhesive and provide a better bond?

My concern is just the opposite. The epoxy does not bond well to plastics. Still unclear on glass content as link is down. I would think optimal contact adhesion is when both panel and foam are smooth.

 

[rruff]

If and when I do this again, I will build a type of press that will evenly provide pressure across the panel. I'm picturing small jacks placed on top of some plywood with the panel below. A fixed beam of sorts would be on top for the jacks to apply pressure against.

That would be a cool system if you were in production. Seems like a lot of hardware for a few panels though.

I've haven't done it, but the way this is commonly done is with a vacuum. It's pretty simple... just get some heavy plastic sheeting and cover the panel, and tape it onto the table or floor, then attach a vacuum pump. It would give very uniform pressure up to 14psi.

Another option is to use a thicker adhesive and trowel to apply it, so that the adhesive has more height. I did this with PLPremium on ply/XPS panels.

The epoxy does not bond well to plastics.

No it doesn't. I wonder if epoxy is the best thing to use, since none of the panel manufacturers I'm aware of use epoxy. PL Premium works decently IME, but I bet there are better options. I think it would be a good idea to ask the skin manufacturers what they recommend.

 

[Terra Ops]

That would be a cool system if you were in production. Seems like a lot of hardware for a few panels though.
Not really that complicated. I used my trailer as a bench/platform for panel construction. All I would need are some 2x4's to make a U shape hooks for around the platform, then use car jacks or another type of small jack for the pressure.

I've haven't done it, but the way this is commonly done is with a vacuum. It's pretty simple... just get some heavy plastic sheeting and cover the panel, and tape it onto the table or floor, then attach a vacuum pump. It would give very uniform pressure up to 14psi.
I have thought about this method, but I wonder if you would still need weight to ensure the panels dry flat and don't warp. Crooked panel = crooked box.

Another option is to use a thicker adhesive and trowel to apply it, so that the adhesive has more height. I did this with PLPremium on ply/XPS panels.

No it doesn't. I wonder if epoxy is the best thing to use, since none of the panel manufacturers I'm aware of use epoxy. PL Premium works decently IME, but I bet there are better options. I think it would be a good idea to ask the skin manufacturers what they recommend.
That would be interesting to know. I visited a manufacturer of mobile refrigeration boxes that made panels in house. They used a blue type of adhesive by 3M.
I went the epoxy route after seeing a wet lay up over foam. I think that was a build on the forum several years back by "home skillet"? I used the same epoxy after speaking with Soller to confirm that the fiberglass panel would adhere to the foam same as the wet lay up. This is why I think glass content in the frp may make a difference.
If there is a better adhesive that doesn't require mixing and long cure time, I'd love to hear about it.

 

[Stingy49]

Derek, surfaces should be clean. First I would use a blower then wipe down with damp cloth. Hope those mulch bags are heavy enough, they prohibit viewing contact of the skins.
If and when I do this again, I will build a type of press that will evenly provide pressure across the panel. I'm picturing small jacks placed on top of some plywood with the panel below. A fixed beam of sorts would be on top for the jacks to apply pressure against.

Good to know. I will wipe them down next time. Sawtooth Unlimited has a big vacuum table he homemade. Doesn't seem like a bad idea to get an even ~14 psi. I wonder if I could just get some sheets of mdf and layer them on top. I'd have to math out the effective PSI though. You basically did that the first time around right?

@Terra Ops and @rruff I found this interesting document on a boat build forum. Talks about polyurethane adhesives being used normally. https://drive.google.com/file/d/1fNiEo2C_C1puOBTCCaPuiOiWm-JK8Jva/view?usp=sharing

Also, that Australian panel company one of you told me to check out uses this stuff (https://www.henkel-adhesives.com/ro/en/product/structural-adhesives/loctite_uk_8101.html) and it is polyurethane based. So maybe I should try a polyurethane based adhesive.

 

[HAF]

One would think that placing the entire panel under a negative atmosphere would seemingly drive adhesive into the pores of both materials. The pores would be filled with 14.7 psi of air (typical atmospheric pressure). Drawing a negative with a simple regen blower would produce a vacuum of -10" Hg or -5 PSI. Thats nearly a 20 PSI differential. Air and things typically flow to a low pressure zone-in this case being the pores in the foam.

 

[rruff]

@Terra Ops and @rruff I found this interesting document on a boat build forum. Talks about polyurethane adhesives being used normally. https://drive.google.com/file/d/1fNiEo2C_C1puOBTCCaPuiOiWm-JK8Jva/view?usp=sharing

Good info; the heavier ones don't look too bad... but could we even get that foam in the US?

Link to the boat forum you are looking at?

Drawing a negative with a simple regen blower would produce a vacuum of -10" Hg or -5 PSI. Thats nearly a 20 PSI differential.

5 psi is the pressure you'd get. The max with a vacuum is atmospheric pressure. 5 psi is a lot though; that's 23,000 lbs on a 4x8 panel, and very evenly distributed.

I have thought about this method, but I wonder if you would still need weight to ensure the panels dry flat and don't warp. Crooked panel = crooked box.

...This is why I think glass content in the frp may make a difference.

I don't believe you'd need anything, since the vacuum supplies very even pressure. It'll smash the panel down to the shape of the substrate (floor or table). I haven't done it though. Like everything else it's good to read up and try some samples.

Are you sanding down into the glass before adhesion? If not, you are bonding the resin only. As I recall Stingy49's skins use polypropylene resin...? I'd guess most use polyester resin.

 

[Stingy49]

I think it's a special version of Dow highload which is very comparable to foamular 400-600-1000. They point out the planed finish for flatness and the available grooves for drawing/pressing glue into during the vacuum or pressing process. Their reccomendations for the reefer trucks are 43psi comp strength so that bodes well if I can get a good bond lol. Also good calculations at the end.

Boat forum link: https://www.boatdesign.net/threads/epoxy-over-xps-method.61414/

An argumentative bunch lol.

Yeah I googled around on diy vacuum setups today and it looks very interesting. Cheapo harbor freight pump is plenty and the bag materials aren't to expensive.

Also, got my brother's left over pour foam so I will make a little jig to try that out.

My stuff is polypropylene frp with a light cloth backing. I show it in the first video.

I'll report back on my latest lamination on Wednesday probably.

-Derek

 

[Terra Ops]

Good to know. I will wipe them down next time. Sawtooth Unlimited has a big vacuum table he homemade. Doesn't seem like a bad idea to get an even ~14 psi. I wonder if I could just get some sheets of mdf and layer them on top. I'd have to math out the effective PSI though. You basically did that the first time around right?

@Terra Ops and @rruff I found this interesting document on a boat build forum. Talks about polyurethane adhesives being used normally. https://drive.google.com/file/d/1fNiEo2C_C1puOBTCCaPuiOiWm-JK8Jva/view?usp=sharing

Also, that Australian panel company one of you told me to check out uses this stuff (https://www.henkel-adhesives.com/ro/en/product/structural-adhesives/loctite_uk_8101.html) and it is polyurethane based. So maybe I should try a polyurethane based adhesive.

Great document on foam. Interesting section on adhesives. If you could find the US version of the Loctite, it would be worth a test too.

 

[Terra Ops]

I think it's a special version of Dow highload which is very comparable to foamular 400-600-1000. They point out the planed finish for flatness and the available grooves for drawing/pressing glue into during the vacuum or pressing process. Their reccomendations for the reefer trucks are 43psi comp strength so that bodes well if I can get a good bond lol. Also good calculations at the end.

Boat forum link: https://www.boatdesign.net/threads/epoxy-over-xps-method.61414/

An argumentative bunch lol.

Yeah I googled around on diy vacuum setups today and it looks very interesting. Cheapo harbor freight pump is plenty and the bag materials aren't to expensive.

Also, got my brother's left over pour foam so I will make a little jig to try that out.

My stuff is polypropylene frp with a light cloth backing. I show it in the first video.

I'll report back on my latest lamination on Wednesday probably.

-Derek

Just checked out the "Sawtooth Unlimited" build. Very well documented. Definitely took me back to the beginning. Most questions and comments come up in that thread also.
One method I used during cold temps, was to enclose the panel with plastic and place a space heater at the end. Very easy to maintain 80 + degrees.

 

[stomperxj]

I don't believe you'd need anything, since the vacuum supplies very even pressure.

I still got a bit of warping on a couple panels even with the vac table. Adding weight would not be a bad idea at all.

Just checked out the "Sawtooth Unlimited" build. Very well documented. Definitely took me back to the beginning. Most questions and comments come up in that thread also.
One method I used during cold temps, was to enclose the panel with plastic and place a space heater at the end. Very easy to maintain 80 + degrees.

Again thanks for the inspiration Terra. Your thread was a huge help

 

[draaronr]

A nice escape to North Carolina's National Sea Shore

can you camp there again? I thought no more camping in OBX, or was a pole in the water?

 

[rruff]

Laminated a larger panel today. Also tried emulating dog hair brush scuffing on part of it.

I made a sample yesterday with epoxy/glass on 25 psi XPS. 60 grit, then the dog brush. It was very hard to pull the skin off. I cut through the foam a ways so I could get a good grip and still barely pulled it apart with my hands.

 

[Terra Ops]

can you camp there again? I thought no more camping in OBX, or was a pole in the water?

Yes there is camping for now. Unfortunately, it has been abused lately. In the last month, turtle nests destroyed, speed limits exceeded, large groups of rigs not observing Island rules, and a homicide. Still a beautiful place.

Cape Lookout National Seashore (U.S. National Park Service)

A boat ride three miles off-shore brings you to the barrier islands of Cape Lookout National Seashore. Horse watching, shelling, fishing, birding, camping, lighthouse climbing, and touring historic villages--there’s something for everyone at Cape Lookout. Be sure to bring all the food, water...

www.nps.gov

 

[Stingy49]

Feel weird posting an update in someone else's thread but here is the latest foam Testing. Even my ghetto dog brush definitely helped.