Fiberglass Weight for a Foamie Camper Build

[dt400]

Hey all.
Planning a full foamie, zero wood in the structure but maybe for door/window screws (trying to see if a nylon or poly plastic inserted nailer/screwer?, would be better) and interior paneling...we shall see.

I absolutely despise the way conventional camper are built, they WILL leak and you will have problems. There is a much better way.

2" XPS for all 6 sides, no galley, 5wx8lx4t, glassed inside and out in a manner to have a chemical bond for the complete outside 6 sides and then the inside 6 sides with the only mechanical bond to be where the glass wraps into door/window/vent openings.

My biggest question is what weight of fiberglass to use? I saw a YouTube vid where a guy did tests with 6oz glass and is was impressive but wasn't a long span, I have seen many boat builders and other crafts with wood talk about using 1708...which is 3 times the weight as 6oz and this requires 3 times the epoxy adding to 3 times the resin cost and weight gain. I'm not apposed to the weight or cost but it really seems like overkill.
Right now I am planning on 7.5 oz E-cloth and epoxy.

I'm thinking 2 layers, or just getting thicker cloth for the roof interior for more strength. There will be no weight other than the Maxxair fan. Any roof rack will be fully supported by the sidewalls with a custom load structure with no point loads. and at this point is just going to be a place to carry a solar panel and possible a Road Shower type set-up.

Thoughts on glass thickness or any other input?

Thanks

Darrell

 

[KCStudly]

Two (2) plies of 6oz works for me and TPCE.

 

[dt400]

Two (2) plies of 6oz works for me and TPCE.

Was that 2 plys PER SIDE or just one side?

Darrell

 

[KCStudly]

I used 5mm (3/16 inch) thick okoume marine ply for my interior.

 

[Tony Latham]

Was that 2 plys PER SIDE or just one side?

He's saying he used two layers of 6 oz cloth, I believe.

Tony

 

[dt400]

He's saying he used two layers of 6 oz cloth, I believe.

Tony

I understand that two layers were used. My question was it one inside and one outside, or two on one side, or 2 on each side.
Based on his response above I believe it was two on the outside and plywood on the inside.
I will do glass on inside and outside to give the wall much more rigidity. I'm just not sure how many plys and of what weight glass per side.

Darrell

 

[Tony Latham]

I will do glass on inside and outside to give the wall much more rigidity.

I'll argue that a layer of 1/8" Baltic birch will give you more rigidity than two layers of 6 oz cloth, and it'll look a **** of a lot better.

But... unless you have a framework, you're probably out of luck to use plywood.

Tony

 

[Pmullen503]

A couple things about epoxy/glass and foam. Structurally, one layer inside and out is more than adequate. The next question is dent resistance. If you are OK with steaming out occasional small dents, one layer is fine. If you aren't, then lots of glass or sheath with thin plywood first and then a layer of glass.

The second thing to remember is glass needs a radiused corner to wrap around. For 6 oz a minimum of 1/2" and 1" radius is better. There are ways to get it to go around a tighter radius but it requires more work.

The next thing it how you handle overlaps. Over wood you can sand. On boats, I've gone from six layers down to one and you can't tell where one layer ends and the next begin.


Over foam because the substrate is soft, it's REALLY hard to sand that kind of blend. What I recommend is do one layer, lay a straight line of tape a couple inches from the overlap. With the next layer, cover a bit of the tape and trim along the tape line when the epoxy is still partially set up. Then pull up the tape. This requires a bit of timing. The epoxy/glass has to be set up enough to cut cleanly but not so set up the it's hard to cut and peel off the tape. You'll have a visible seam but at least it's straight.

Spend the money to get proper non-blushing laminating epoxy and buy the pumps. Don't bother with cheap casting epoxy. Yes, people have made it work but proper laminating epoxy is MUCH easier.

I just finished a wood trailer that was glassed and if I did again I would have glassed the both sides of the walls (maybe the roof too) before assembly while laying flat and then taped the corners. I did do the insides that way.

 

[dt400]

I'll argue that a layer of 1/8" Baltic birch will give you more rigidity than two layers of 6 oz cloth, and it'll look a **** of a lot better.

But... unless you have a framework, you're probably out of luck to use plywood.

Tony

I'll argue that a layer of 1/8" Baltic birch will give you more rigidity than two layers of 6 oz cloth, and it'll look a **** of a lot better.

But... unless you have a framework, you're probably out of luck to use plywood.

Tony

Agreed, the plywood has a more aesthetic look and warmer feel than raw or gelcoat glass on the inside. I would still use some sort of thin ply on the inside for that reason but it would be bonded to an interior layer of glass. The glass would be for structure and rigidity of the composite layup. A single layer on each side is much more rigid than 2 layers on one side and the plywood bond would be marginal compared to the epoxy/glass bond if used to provide the other side of the composite structure as well as not actually adding any strength in the corners like glass would. Then other ideas will be used to create a more finished look. The ceiling will be a white gelcoat to give the up facing perimeter LED rope light a more broad filling of the space which I prefer over hot spots or focused lighting designs. Of course I haven't even started buying stuff so who knows what will change as I get it built.

Darrell

 

[dt400]

A couple things about epoxy/glass and foam. Structurally, one layer inside and out is more than adequate. The next question is dent resistance. If you are OK with steaming out occasional small dents, one layer is fine. If you aren't, then lots of glass or sheath with thin plywood first and then a layer of glass.

The second thing to remember is glass needs a radiused corner to wrap around. For 6 oz a minimum of 1/2" and 1" radius is better. There are ways to get it to go around a tighter radius but it requires more work.

The next thing it how you handle overlaps. Over wood you can sand. On boats, I've gone from six layers down to one and you can't tell where one layer ends and the next begin.


Over foam because the substrate is soft, it's REALLY hard to sand that kind of blend. What I recommend is do one layer, lay a straight line of tape a couple inches from the overlap. With the next layer, cover a bit of the tape and trim along the tape line when the epoxy is still partially set up. Then pull up the tape. This requires a bit of timing. The epoxy/glass has to be set up enough to cut cleanly but not so set up the it's hard to cut and peel off the tape. You'll have a visible seam but at least it's straight.

Spend the money to get proper non-blushing laminating epoxy and buy the pumps. Don't bother with cheap casting epoxy. Yes, people have made it work but proper laminating epoxy is MUCH easier.

I just finished a wood trailer that was glassed and if I did again I would have glassed the both sides of the walls (maybe the roof too) before assembly while laying flat and then taped the corners. I did do the insides that way.

Thanks for all the tips...much appreciated.

Dent resistance is definitely a concern. The camper will get entirely covered in a bedliner of some sort...not sure if pro or DIY product. Other than price my concern with pro applied is it is hot sprayed at around 140 degF I think and I'm pretty sure the epoxy resin will be fine with that temp and it will as it will cool pretty rapidly anyway.
The bedliner would give great scratch resistance and UV protection, but not add to much to the dent resistance since it's flexible but would give some extra protection against punctures...I guess I could weld on some AR plate...that'll fix it. LOL.

The above being said I am not needing to have a paint/gelcoat perfect surface...as long as the bedliner covers it I'm good to go.

I've thought about laying up the inside before assembly and then taping the corners once the outside is completed, but I really want as few mechanical joints as possible. The goal is to have the entire outside (all 6 sides) done and cured then do the same for the inside with the only mechanical overlay being where the wraps go into the door/window/vent openings.

Maybe over thinking things but that's just how I'm wired. Am I doing it the hard way probably. But the easy way usually isn't the best way right.

Darrell

 

[KCStudly]

Yes, two ply 6 oz on the outside, 5mm ply on inside. Yes, sharp, or nearly sharp, corners require a floxed edge (see my build), which takes time and effort. For good adhesion between foam and epoxy/glass, before anything more than super rough fairing of foam joints, if I had it to do over I would make sure to scuff the foam, then apply a lightly thickened coat of fairly wet epoxy first. Let that set up, clean amine, then sand and fair to a decent fairness and for tooth, before doing the glass layup. The foam is too soft to fair well without putting a hard coat on it first. If you can schedule the time to do marathon glass sessions, you could maybe do more of a chemical bond, but I never seemed to have the ability to last that long or have a weather window long enough, so always broke my epoxy sessions down into smaller, more manageable sessions. This definitely took more time due to all of the amine washing and extra sanding between layups, but I just couldn't do enough in any given session. You can't do it all at once anyway while maintaining a horizontal orientation with gravity working with you; plan accordingly. Don't underestimate how much work and planning is required even for the most simple construction. Once you get to the glassing stage your investment in time and materials will dictate "no screw ups". Screw ups mean discouraging rework, more materials, and time; or a sub-standard outcome. Then again, a wise man (and professional composite specialist, Atomic Michael) once told me, "your opinion is the only one that matters, and you are the only one you need to please". That said, I didn't abide by a few experienced recommendations that I later wised I had. Think about the finished product and everywhere you might want to sink a screw to join or attach anything (everything... lighting, coat hooks, door latches, etc, etc, etc. If you have no wood framework or blocking, you will most likely have to have a slug of filled epoxy that can take a fastener. Even with plies on both sides, you still need something solid in more places than you might imagine when only looking at the initial "big picture" to avoid localized crushing from point loads. You want that blocking to all be in place before you laminate you glass skin because it's better to lay the glass over a faired surface, both to maintain the strength of the glass weave (uninterrupted flat straight strands of glass) than it is to try and fair lumpy, crooked, interrupted glass after the fact.

 

[dt400]

I'll argue that a layer of 1/8" Baltic birch will give you more rigidity than two layers of 6 oz cloth, and it'll look a **** of a lot better.

But... unless you have a framework, you're probably out of luck to use plywood.

Tony

Plywood would add rigidity to bending of the wall but not the corners. The only concern is the actual proper contact between the ply and foam. The foam is the weak link so square inches of coverage is best. Glass is easy to get 100% coverage where as wood. Unless you have large expensive presses, a large vacuum bag set-up and have refined your technique with destructive testing is IMHO a crap shoot at best. So I would rather use wood inside for looks not as a structural member I am relying on.

Not trying to start an argument or criticize anyone...these are just my thoughts and reasons....

Darrell

 

[dt400]

Yes, two ply 6 oz on the outside, 5mm ply on inside. Yes, sharp, or nearly sharp, corners require a floxed edge (see my build), which takes time and effort. For good adhesion between foam and epoxy/glass, before anything more than super rough fairing of foam joints, if I had it to do over I would make sure to scuff the foam, then apply a lightly thickened coat of fairly wet epoxy first. Let that set up, clean amine, then sand and fair to a decent fairness and for tooth, before doing the glass layup. The foam is too soft to fair well without putting a hard coat on it first. If you can schedule the time to do marathon glass sessions, you could maybe do more of a chemical bond, but I never seemed to have the ability to last that long or have a weather window long enough, so always broke my epoxy sessions down into smaller, more manageable sessions. This definitely took more time due to all of the amine washing and extra sanding between layups, but I just couldn't do enough in any given session. You can't do it all at once anyway while maintaining a horizontal orientation with gravity working with you; plan accordingly. Don't underestimate how much work and planning is required even for the most simple construction. Once you get to the glassing stage your investment in time and materials will dictate "no screw ups". Screw ups mean discouraging rework, more materials, and time; or a sub-standard outcome. Then again, a wise man (and professional composite specialist, Atomic Michael) once told me, "your opinion is the only one that matters, and you are the only one you need to please". That said, I didn't abide by a few experienced recommendations that I later wised I had. Think about the finished product and everywhere you might want to sink a screw to join or attach anything (everything... lighting, coat hooks, door latches, etc, etc, etc. If you have no wood framework or blocking, you will most likely have to have a slug of filled epoxy that can take a fastener. Even with plies on both sides, you still need something solid in more places than you might imagine when only looking at the initial "big picture" to avoid localized crushing from point loads. You want that blocking to all be in place before you laminate you glass skin because it's better to lay the glass over a faired surface, both to maintain the strength of the glass weave (uninterrupted flat straight strands of glass) than it is to try and fair lumpy, crooked, interrupted glass after the fact.

Thanks. Yes a chemical bond is the goal for the outside as a unit then the inside as a unit.
About half will be done on the vertical plane...I am watching a bunch or boat building guys to get tips on vertical layup. It will be an entire day per session I am sure, but the end result will be worth it and I won't be wishing I had done it better. Taking my time and getting things just right isn't something I have a problem with...spending too much time to get something just they way I want it is.

I am going to get a few materials (foam, epoxy, different weights of glass) and do a bunch of destructive testing. I'm just trying to find out a good starting point.

I've been in construction and remodeling as a GC for almost 30 yrs...so yes, I am well aware that things rarely go as quickly as you planned or hoped. So I probably have a much more realistic understanding than most. My philosophy is "it'll take as long as it takes and in a few years the extra time will be forgotten but a poor job will not"

I have been working on plans for this thing off and on for 3 yrs. where all the wiring will go and how, where does blocking go how is airflow going to work the most efficiently and on and on and on.
The design of the trailer is a completely different design process to be able to not pull apart. I've never seen a premade trailer that I wouldn't have to cut half apart to make work so making my own was the logical choice.
Actually mocked up and exact size box and set up "camp" in it and spent several hours running through scenarios Sleeping, watching a movie, boiling water inside for meals in very bad weather, how I wanted the switching to be and exactly the wiring runs, what I wanted where and how me, my dog and everything would work and fit together as efficiently as possible. How the roof rack will be designed to carry the load on a structure that isn't designed for point loads.
I could go on and on but I bet your getting bored...LOL.

Darrell

 

[Pmullen503]

Don't over think foamie construction. People obsess about the strength of the skin to foam bond doing a peel test. It doesn't matter because the foam layer just beneath the glue has a weak bond to itself.

The important thing to remember is you have huge surface area in the direction that matters: under tension.

Lots of beginners with zero skills build foamies that do not blow up on the highway or fall apart after a year. The system is very forgiving.

 

[dt400]

Don't over think foamie construction. People obsess about the strength of the skin to foam bond doing a peel test. It doesn't matter because the foam layer just beneath the glue has a weak bond to itself.

The important thing to remember is you have huge surface area in the direction that matters: under tension.

Lots of beginners with zero skills build foamies that do not blow up on the highway or fall apart after a year. The system is very forgiving.

LOL. Easier said than done. (the overthinking part)

Darrell

 

[KCStudly]

It's actually the shear strength that makes it work (like trying to pull a tablecloth off of a table by grabbing the hem). Also, plywood sticks to foam just as well as cloth if the proper glue technique is used. (Any problems I have had with incomplete adhesion when laminating plywood to foam I attribute to lack of proper contact and inadequate point pressure when using contact adhesive, which has insufficient gap filling capability and requires relatively high roller point loading; vacuum or randomly placed gravity clamps don't get it done. If I had used slightly thickened epoxy, or faired with it first then used more to laminate the one wall and bulkhead plies that I used contact adhesive on, I think it would form just as strong of a bond as glass weave to foam. The epoxy soaks into wood fabulously and when thickened has great gap filling capability. Any other glue that I have tried has issues because the foam does not absorb excess water-based moisture.)

 

[ncw]

Hey all.
Planning a full foamie, zero wood in the structure but maybe for door/window screws (trying to see if a nylon or poly plastic inserted nailer/screwer?, would be better) and interior paneling...we shall see.

I absolutely despise the way conventional camper are built, they WILL leak and you will have problems. There is a much better way.

2" XPS for all 6 sides, no galley, 5wx8lx4t, glassed inside and out in a manner to have a chemical bond for the complete outside 6 sides and then the inside 6 sides with the only mechanical bond to be where the glass wraps into door/window/vent openings.

My biggest question is what weight of fiberglass to use? I saw a YouTube vid where a guy did tests with 6oz glass and is was impressive but wasn't a long span, I have seen many boat builders and other crafts with wood talk about using 1708...which is 3 times the weight as 6oz and this requires 3 times the epoxy adding to 3 times the resin cost and weight gain. I'm not apposed to the weight or cost but it really seems like overkill.
Right now I am planning on 7.5 oz E-cloth and epoxy.

I'm thinking 2 layers, or just getting thicker cloth for the roof interior for more strength. There will be no weight other than the Maxxair fan. Any roof rack will be fully supported by the sidewalls with a custom load structure with no point loads. and at this point is just going to be a place to carry a solar panel and possible a Road Shower type set-up.

Thoughts on glass thickness or any other input?

Thanks

Darrell

Why no galley out of curiosity?

ncw

 

[dt400]

Why no galley out of curiosity?

ncw

A few reasons actually.

Long version:

1) I have been camping out of a tent when I do the trips the camper will be brought on, and the back of my Scout has a very efficient kitchen set-up in it (fridge, drawers, water system etc) It's just very easy to use.

2)The way I set up my camp in regards to placement of the Scout, tarp, and tent (camper) entrance creates a sun, rain, snow, wind protected area so I can get out of the tent (camper) and cook or lounge without getting wet. It's a very comfortable area and has worked for over a decade in this form. This will usually require me being able to turn the camper 90 deg, by hand.

3) I need to keep the camper as light as possible while having the frame strong enough to handle off-road...not gravel road but actual 4-low and locked sort of trails, and in the rare circumstance that I may need to unhook the trailer and park it down or up off the road to get the Scout backed out, turned around and then backed back to the trailer and hooked up to go back the way I came in, due to what ever reason. I wouldn't intentionally get into this sort of predicament but it does happen.

4) If I'm going to do this I do want it to be comfortable to be lived in during times of extended bad weather (I was once caught in a major rain event for 6 days on a mesa in southern Utah, with the only way off being long and very steep, off camber bentonite clay roads. Due to the severity of the storms I was tent bound for a lot of the time, when I finally was able to leave, the damage caused in the area from all the flooding was quite impressive) while also be as short as possible to still be maneuverable, inches can count here. I am 6'5" 280# and 58...comfort is beginning to be more of a priority. And the trips are usually 2-3 weeks.

5) I have another full size camper if I am only going out to areas to base camp out of for say an extended ATV trip where the atv is used for exploring not the Scout.

There are lots of concessions to be made and even after 3 years of off and on designing I'm still making small changes.

Short version:

Basically as small as possible while being comfortable for myself and an 80lb dog, hand maneuverable with-in reason, strong frame, be able to tow on all but the tightest of trails...if I full size pick-up can make it I should have a good chance of getting the trailer through.

Darrell

 

[Pmullen503]

My foamie has a small galley that I used exactly once. It's been storage ever since.

Similar to Darrell, I wilderness or canoe camped out of a tent for decades and accumulated very lightweight gear. I still enjoy that kind of rather Spartan style of meal prep.

For many (most?) a more elaborate style of meal prep is an important part of the fun of camping. And a well designed and equipped galley is a must. I have a sister that prides herself on how elaborate a meal she can prepare in a tiny pop up kitchen.

To each his own.

 

[6912]

have you got your foam ? 2'' is a waste of space space most of the time 2'' is used to make up for a weak build on these small trailers . you know the easy way to build is a glue and go . you don't have to even cut a straight line
520 lbs on a 4.5 x4.5 by 8 foot trailer
Many times, epoxy is a con bs . and a lot of BS work We make flat panels that float in a double ring, As we don't buy the epoxy lie . We make are skins with ploy resin 1.5 mat 7ozz woven 3/4 mat NO BS sanding on the outside like a trailer from just expo and woven Then 1'' RIGHT FOAM then wet lay up 3/4 mat 7oz woven 3/4 mat