Teardrops n Tiny Travel Trailers

Hello Everyone,

I already build the hatch frame. Now I'm at the point I need to bend the plywood over the frame. I am using a thickness that is less than 1/4" but a little thicker than 1/8". You know that now at the hardware stores they have all these measurements in MM. What ever happened to 1/8", 1/4" and so on? It's not a Benroy model but more of a teardrop radius. How can I bend it with out causing any spring back on my hatch or cracking the plywood? I have 6 ribs 3/4" thick and are 3" wide. That will avoid any spring back I hope. It's kind of hard to find good plywood so I went with the underlayment type plywood.

Now I need to find a hatch lock. I would like to use a lock with rods that go in to the side walls. Something like a garage door or a truck cap lock system.

Any suggestions on both issues will be helpful.

Thank you

Carlos

Carlos:

I use baltic birch plywood that's 3mm or 1/8" nominal. So I can't directly help you with your situation.

But here's my suggestion: I think you'll find that your plywood wants to bend one direction and not the other. So make sure you're bending it with the grain. (Flex it length-wise and side-ways and figure out which direction it wants to bend.)

Or go to a lumberyard (not a HomeCheapo) and ask if they can order you 5x5' sheets of 1/8" baltic birch. If you have to struggle to sheath your hatch, you could end up with a bit of spring back.

Tony

Try a hardwood/cabinet shop supply house or real lumber supply company. The home store stuff isn't really as good as 1/8" baltic birch (3mm). The BB bends easily for a hatch.

I used some rope to pre-bend the inner liner of my hatch for a couple of weeks, prior to skinning. Just made it a bit smaller radius & left it for a while. You could do a "progressive reduction" of the radius to tighten it a little at a time if your panel is too stiff. Make sure you clamp some slats along the edges where the rope pulls, so it doesn't look like a potato chip. Pre-finished with stain & urethane next, then did the skin. It took a set and was easier to work with on the fasteners when it's already curved a bit.

Heres a Post I made earlier. There are many ways to do this but in the end....The one that doesn't Leak, is the Best.

I've always had a different approach to building a hatch. Instead of building heavy to compensate for "Spring Back", Use materials that Don't "Spring Back"

I use FRP and Aluminum.

I build 2 outside rails, 1" thick (by using 2 pieces of 1/2") And cross spars. Then I cover the outside with FRP, good side in extending 1 1/2 past the rails on both sides.

FRP does not "Spring Back" and is strong enough when bowed around the hatch to not flex...as well as being stable enough to Triangulate the hatch.

I also install a second sheet of FRP on the inside, good side in as a finish.

2 sheets is more than enough, then sheath the outside with Aluminum.

I seal the outside edges with this;






I know, I know. But doesn't water get into the sides?

No! I build the sides in 3" at the hatch, and run the outside corner molding straight through. This is a very common area for leaks. The FRP/Aluminum extends 1 1/2" past the galley opening and I put a second outside insert molding on the inside of the galley.

This insert molding is 3/8" tall with a vinyl insert that acts as the hatch's seal. Plus I extend the offset Hurricane hinge past the galley opening.

For the water to get in it has to run down, make a right or left hand turn, run up hill and jump over a 3/8" tall molding that is under the FRP/Aluminum.

In addition the 2 outside corner insert moldings create a good Trough for the water to run down there by directing the water out and off the trailer.







Plus I extend the offset Hurricane hinge past the galley opening.


These shots are from 3 different trailers of mine, but the theory is still the same.

Happy Trails

Len

Thanks for all the replies. I have used a little bit of each of the comments. I had to use two 30" strips of plywood to reach the 5' width I need. One of them is bending better than the other but it's a slow process and I just have to take my time. I plan to start from the center and work my way towards the edges and the ends to make sure it doesn't buckle up. Right now I am just bending the plywood and once it's formed then glue and screws.

Will keep you posted on the results.

Carlos