Tom & Shelly's build

[Tom&Shelly]

No pictures, but a quick follow-up: while I was out early this morning crewing for friends who own a balloon (this is Albuquerque), Shelly filled in around the third brake light holder a little more, and put a 2nd coat of black epoxy on the galley hatch rim.

On the way home, I tried to pick up some primer we ordered from Home Depot and had shipped to the store, but it seems many of their workers called in sick for some reason, and the returns and pickup lines were getting too long for my patience. I'll try again during the week after the sporting event has been settled.

Tom

[rjgimp]

On the way home, I tried to pick up some primer we ordered from Home Depot and had shipped to the store, but it seems many of their workers called in sick for some reason, and the returns and pickup lines were getting too long for my patience. I'll try again during the week after the sporting event has been settled.

Tom

I hear there was a great multitude of rodents that came out of the ground today, many of which were handled by humans. I imagine such rodent-handling could cause all manner of illness.

Of course the sportsing thing could have something to do with it...

[Tom&Shelly]

Another epoxy day. We flipped the hatch over and I applied a coat to the gussets, and other plywood around them, including the notchs that will hold the rubber seals



That was a layer of regular epoxy, then a some thickened epoxy (with cabosil) to fill in a few imperfections in the wood. After it cures, and I sand, I'll put on a coat (or several) of black epoxy, then apply a coat of satin finish polyurethane varnish for UV protection. Hopefully the satin will keep it from being too shinny. Like the sides of car doors, this should be something folks hardly notice (in my opinion).

Also decided to epoxy the oak spars on the top and bottom of the hatch, for superior water protection. We will likely just sand and varnish the top and prime and Monstaline the bottom.

Decided the black epoxy we applied to the galley edges wasn't smooth enough, so I sanded some, actually cutting through to the clear epoxy in places, and recoated this morning



Once that cures in a few days, I plan to sand with 600 grit (don't want to cut through the black again!) and varnish.

A drip of black epoxy down the side convinced us that we should apply black epoxy to the edge of the floor in the galley, so I did



I tried to make a neat line between the vertical and horizontal surface, and mostly succeeded . At this rate, the whole teardrop could end up black! Actually, we could repaint the galley floor, but we're not crazy about the paint we used anyway: sand finish, like on diving boards. Shelly now thinks a strip of rubber diamond plate is in order--she loves to fix mistakes with new, unproven (to us) technology!

For those who haven't seen the thread in the building section, we are thinking of using 1/8" rubber sheet with diamond plate on one side in lieu of aluminum diamond plate on the front and sides, for rock protection. Cost and weight are comparable. The question is whether we can find an adhesive to bond SBR to epoxy. BASF suggests we test Masterweld 948, so that will be our next move in that direction.

Tom

[Tom&Shelly]

Put some black epoxy on the hatch gusset, and channels that will hold the rubber seal, this morning



Decided it will need a second coat. I'd first put on a coat of clear epoxy a few days ago, and sanded it yesterday. The black does not fully cover the clear everywhere. I also applied it a little heavy on the gussets and so will have to sand the runs out. My experience has been that it is better to let it cure for two days or more, then sand it smooth and apply another coat, rather than apply a second coat within twenty four hours, then sand.

I had blue masking tape on to keep the epoxy off of the varnish, and pulled it off as soon as finished, so the epoxy wouldn't cure on the tape. Kept the epoxy off of the varnished ceiling

I have a varnished compartment door that I will later screw to the bottom inside of the hatch. That allows access to the wiring for the lights, including both trailer lights and a dome light for the area around the galley. I also need to add a "black box" that separates the signals from the tow vehicle so we can have separate brake lights and turn signals.

I also plan to apply some sort of wood trim between the gussets and ceiling.

Decided to also epoxy the oak spar at the top of the hatch, where the hinge will be attached



Might have left that so the oak showed under a layer of clear epoxy, but this way the ends of the plywood, on each side, won't show. Left the bottom spar with just clear epoxy. Per Tony's suggestion, we'll later prime that and Monstaline it to match the rest of the exterior.

Tom

[Tom&Shelly]

Installed the hinge for the galley hatch today:



Also added some bling--the handle, light frames (the lights will snap in at a later date, after we Monstaline), and license plate holder. The California plate is a souvenir from Pelican Bay State Prison, where I used to make them as an inmate. I was the one who hand painted "California" in cursive on each one! Just kidding. Actually, I was self-committed to LA LA land for about 12 years 'til I couldn't stand it any longer and moved to rural parts here in New Mexico.

I left the recommended 3/8" overhang on each side of the hinge



Of course, me being me, I couldn't let the project go without making a few mistakes. Way back last Fall, while using dry wall screws to hold the ceiling down while it glued, I managed to break one off. Well today I found it! Which is why there is no hinge screw in the one hole. Guess I'll dribble a little epoxy in the hole to seal it from rain, and then probably put a 1/4" screw in for looks. I also did a similar thing on the two ends of the butt of the hatch.



A while ago, I added the third brake light holder and made fillets out of cabosil laced epoxy. It only then occurred to me I should have included a little compartment for some connectors. Fixed that on Friday by drilling and chiseling into the soft pine. I'll use epoxy later to waterproof it.



This week, I plan to build a prop, weigh the hatch in the manner recommended by Dan Lott, and order gas struts. I will have them reversed: Mounted high to the galley walls, and lower (when closed) on the hatch lid. I'll mount oak blocks to the hard points on the sides of the galley walls. I'm also thinking I will use them to screw through the walls from the outside to mount the rear side marker lights. With the struts in, I can design and build the galley and electrical panel around them.

Tom

[S. Heisley]

Looks like you'll be done in time to camp this spring!

[Tom&Shelly]

:thinking: Looks like you'll be done in time to camp this spring!

Thanks Sharon! That is our plan. Shelly retires (from teaching) at the end of May.

Think we now have most of our painting supplies: Primer and the Monstaliner kit, extra Monstaliner rollers (per Tony's suggestion), Gloss black enamel for trim, etc. so we'll be ready to roll (literally) during Spring break. Then, we just have to build the galley, including an electrical box to tie the wires together.

Tom

[Tom&Shelly]

We have our gas struts in!



Really should have designed all this before starting the build, but I didn't, and after considering the problem, decided "reverse" struts" (where the attachment to the galley walls is above the hatch, when closed) works best for our design.

For mounting on the hatch, I picked the wide part of the gussets



Only problem there is that I could have done a much neater job insetting the T nuts before building the hatch, when I could have used the drill press with a Forstner bit. As it was, I did the job with the Forstner bit and a hand drill, trying to hold it perpendicular to the gusset. Might have also made a jig. In any case, we plan to fill in around the nut with black epoxy. I also used some scrap 1/8 inch Baltic Birch to align the balls with those on the galley walls.

On the galley walls, the issue was that I didn't originally plan for hard points when I made the foam-sandwich walls. Solved that by running oak boards right to the bulkhead, and putting the screws where there is 3/4" plywood in the walls. I countersunk the screws far enough that I can add oak buttons later, although I realize that several would interfere with the gas cylinder. So...since these flip over from open to closed, can I assume the hatch will be open most of the time, and by flipping them over I'm really saving our seals?



This also gives us some hard points for the rear running lights to tie through the wall to, and the right one will give Shelly some wood to screw in hooks for hanging things.

On the left, I'll build our electrical box to fit between the oak and the counter top. Looks just right for the PD4045, a 120 vac outlet, 12 vdc outlet, USB outlet, battery switch, and meter. Inside the box there will be lots of terminal strips. I have yet to design this in detail.

To find the required strength of the gas struts, I modified (reverse engineered) Dan Lott's calculator. Instead of setting the prop stick near the center of the hatch, I set it a little further back, but I think I understand moment arms and correctly adjusted for that in the calculations. Then I reversed the measurements I used for the distance from the hinge center to the attachment points, since the short length is now to the galley wall, while the longer one is to the hatch. Anyway, I came up with only 35 lbs required per strut, with safety factor. Quite a bit less than would be required the other way around! But the lowest force I could find on struts in our length requirements (and budget) were 50 lb struts. So that's what we have.

They hold the hatch closed admirably. They do seem a bit weak holding it up, however. The next size up is 100 lbs, so we may try those, and send back whichever pair we don't want. So what happened? I'm speculating that it might be the fact that our struts are not nearly vertical when the hatch is open. For us mechanical engineering fakers, I think the missing quantity is a "cosine factor". Oh well, we'll get it right!

Tom

[tony.latham]

Excellent job. Isn't turning the strut corner a damn big deal?

So...since these flip over from open to closed, can I assume the hatch will be open most of the time, and by flipping them over I'm really saving our seals?

Grant Whipp --longtime-teardrop-builder that I greatly respect-- always put his struts in the "wrong" configuration. He said he did this because when they start leaking, they leak back into the strut body, not into the galley and as he put it, "they will leak sooner or later." Apparently, it's a bad mess.

So pick your poison.

Me? I keep my seals wet. But I haven't had a leaker yet.



Tony

p.s. When's the first can of Monstaliner cracked open?

[Tom&Shelly]

Excellent job. Isn't turning the strut corner a damn big deal?

So...since these flip over from open to closed, can I assume the hatch will be open most of the time, and by flipping them over I'm really saving our seals?

Grant Whipp --longtime-teardrop-builder that I greatly respect-- always put his struts in the "wrong" configuration. He said he did this because when they start leaking, they leak back into the strut body, not into the galley and as he put it, "they will leak sooner or later." Apparently, it's a bad mess.

So pick your poison.

Me? I keep my seals wet. But I haven't had a leaker yet.



Tony

p.s. When's the first can of Monstaliner cracked open?

I may try Grant Whipp's method, just for the clearance issue. Never seen a strut leak, but I'll bet that is a mess!

BTW, I set the lights, hatch access panel, and license plate holder on the back of the hatch, and with that little extra weight it began to close, so I definitely need to change the struts. Found a company that sells them with similar extended and compressed sizes, and 10 lb increments, so I'll try them--after painting.

We were waiting on Spring Break (for Shelly to be off) to prime and Monstaline, but the break came to us this year. Shelly wants me to clean up around the garage and teardrop first, so that's today's job.

Tom

[twisted lines]

Something to look at, https://www.amazon.com/TUFF-Coat-Textur ... B003NTM0V2

I planed on ordering my paint Tuesday, but Something came up
I am not sure I can roll it on with a 9" roller, any know reason they don't offer them with Monstraliner?
Does the material look the same?
Thanks TL

[noseoil]

I cheated on the strut calculations. We had the boss's son in our truss office (mechanical engineering student at the time) when I was looking at hatch weight & strut calcs. He ran all of the numbers & came up with about 80#-85# per side, I just decided to give it 100# per side & called it good. This was actually a bit better, as I hadn't figured on hanging the speakers, a paper towel holder & the rear bumpers (SS bathroom grab rails) at the time. All's well that ends well, they are a bit weak when it's down to 20 degrees outside, but for "normal" camping in summer temps they do the job well enough. There's always a nominal measurement for this stuff, then there's not enough & too much. Usually, I'm trying to be on the fat side of too much & call it good...

[Tom&Shelly]

Thanks Tim! I (re) calculated 70 lbs as the required force for our struts, with an appropriate safety factor. (Posted on another thread.) Since you have a similar configuration, and an ME student computed 80-85 lbs, it makes me think I may have done it right the second time.

I found a pair at 71 lbs on Amazon. (Which, surprisingly, is still delivering regular stuff. Friend who drives for UPS says his job is secure--they've been declared an essential service.)

I will try those (after we paint and re-assemble) and if we need stronger, I'll trade the 50 lb McMaster-Carr struts for 100 lbs. I figure the less force the better, as long as it's sufficient.

Tom

[S. Heisley]

Some paints will actually make foam disintegrate. Some paint rollers have a foam base and some are all foam.
You might consider asking the manufacturer.

[tony.latham]

I am not sure I can roll it on with a 9" roller, any know reason they don't offer them with Monstraliner?
Does the material look the same?

Other than the length, the material looks the same as the ones from Monstaliner. Certainly, it's the right color.

Tony