Sawtooth XL Build

[indiedog]

Hi Dan. Something I did several years ago now was to get onto a wooden boat forum and ask about epoxy and glass for a plywood camper I was contemplating. The information received was awesome. I can see a number of applications to the Sawtooth project including glueing panels together as well as protective coatings. Most popular product for this here is BoteCote but there it would indeed be West Systems. For the external surfaces the way to go would be laying glass down and flooding with epoxy worked into the glass and ply. You don't need heavy glass for this as the lighter stuff has been shown to add nearly as much impact protection as the heavier stuff. You then add more coats of epoxy as required to fill the glass weave and sand, sand, sand, until it's smooth. If you plan your joints in the glass then you can hide any laps to reduce amount of sanding needed. Internally, especially if you will get condensation, go 3 coats wet on wet of epoxy only to seal it all. Good thing about using the epoxy as a glue is it then seals the ends as well as glueing it all together. Also, large panels can be done laying down flat prior to assembly where the corners are glued up.

In summary, I'd be going for a glass reinforced epoxy on pretty well all external areas (ONLY epoxy used, no CPES) and then 3 coats of epoxy internally. This is how they build sailing boats.

If I get time I'll link a video or two but if you just google "stitch and glue" boat building or kayak building you will see heaps on youtube.

Always good to find a great supplier of products who knows his stuff. Sounds like you'll be back to that timber store!

EDIT: Here's just one video found on youtube; https://www.youtube.com/watch?v=MR06qBluKTc You will see some do a pre-coat with just epoxy but others don't and lay the cloth on the bare wood. Both seem to work fine. I think the pre-coat is for when you are likely to get rapid changes in temp which can cause air bubbles.

 

[twiisted71]

You will see some do a pre-coat with just epoxy .......

Exactly what I was getting at. I didn't know what you were intending to seal with and do for a final over all coating, but we'd always put several coats of resin on the ends and around the edges before glassing something. Since you'd mentioned undercoating I didn't know if you were going with the popular trend of 'painting' the entire job with it.

 

[DanCooper]

indiedog and twisted71, thank you for your thoughtful comments.

I will do it the right way and seal with CPES before assembly. CPES is an epoxy that just penetrates the wood a little better than most other epoxies. The assembly will be with 3M 5200 Fast Cure and Kreg pocket hole screws on the inside walls to the roof, floor, front, and rear panels. I am trying to minimize any fastener penetrations of the outer skin. All the window, door (including holes for hinge bolts), lighting, and roof vent openings are cut and I will be able to treat them with CPES. The electrical entry will be made using a marine grade through-hull fitting and the hole edges will be treated. Windows, hinges, vent, and the like will receive Pro-Flex sealant treatments.

The coatings will be CPES, WEST System epoxy (two coats) and Monstaliner (two coats). I am not going to put cloth over the entire trailer, but I am contemplating taping the edges. I've never worked with fiberglass before and I'm not keen on making a major mistake and having to start all over again.

If the weather holds, I will get started treating all the panels tomorrow!

 

[stomperxj]

Yeah whatever you do, DON'T do it like I did. I ended up with a lot of end grain delamination. Mostly due to my trailer sitting outside in the weather for nearly 2 years but I also applied the CPES incorrectly. My trailer was doomed from the start in retrospect.

Keep up the good work Dan-

 

[b63215b]

Subscribed, nice build, this kind of trailer will be my next build.

Sent from my SM-G920V using Tapatalk

 

[DanCooper]

Yeah whatever you do, DON'T do it like I did. I ended up with a lot of end grain delamination. Mostly due to my trailer sitting outside in the weather for nearly 2 years but I also applied the CPES incorrectly. My trailer was doomed from the start in retrospect.

Keep up the good work Dan-

Ha! You did a fantastic job! But I do now have a plan to treat all the panels with CPES before assembly at one time. Let's just say it involves lots and lots of landscape blocks . . .

 

[DanCooper]

Subscribed, nice build, this kind of trailer will be my next build.

Sent from my SM-G920V using Tapatalk

Thank you, it's another form of adventure.

 

[DanCooper]

Trailer Frame

On Sunday, we finished off the trailer frame. Rear stabilizers welded on.



At first glance, the wheel adaptors looked like the holes for the lug studs were too large.



But these lug nuts centered everything up beautifully.



Tabs for the Harbor Freight tongue box are welded on.



Some tabs for the tongue jack.



Axle, electric brakes, brake drums, and wheel adaptors are all on and snugged up tight.



Trailer on the trailer.



Final adjustments.



And off I went. Of course, the Hood Canal floating bridge was open for a sailboat, which stopped traffic and slowed up the trip back to Lofall. But it is all there, and today I will hopefully get it off the trailer and give it its treatment of POR 15 so it can be painted and be fully assembled.

We also got a good start on a rear tire carrier for the Subaru, which I will hopefully get finished next weekend. Right now, I have to get my tired sagging rear off this couch and get to work because the Northwest Overland Rally is only two weeks away. Can I get it finished enough to bring the trailer?

 

[DanCooper]

Slow Start Today

It seemed today started slowly, but I was able to accomplish a few things. Moved the trailer frame off the trailer onto a tarp and under a cover. Takes some effort,that does. It is ready for cleaning, etching, and painting tomorrow.



Tried out the sides on the floor to check fit. Good thing I did, as I found I needed to trim 1/8 inch off the bottom on one side. It's coming along okay.





Got out the bondo, filled some screw holes, etc. and got the first coat of CPES on the bottom of the floor.



I was really happy that I bought a respirator and even happier that I used it. That epoxy kinda smells like one of those places where folks get their nails done. I left both doors open for cross ventilation overnight. I will take a box fan up there tomorrow to assist the natural ventilation.

 

[DanCooper]

Moving It Along

In spite of the rain yesterday and today, I was able to move some of the parts along. Yesterday morning I cleaned and prepped the frame, which called for a shot of espresso.



Yes, that's a spork. I use it to spoon the coffee into the Bialetti and scrape off the excess. It is the highest and best use for a spork unless you grind the tines off.

Then I was able to lay two coats of POR-15 on the top and sides of the frame. The local yard cat came by and walked on the first coat while the paint was still wet. It then set a land speed record getting off the frame. Not much traction on a wetted surface like that, but it launched like a Tomcat off a carrier deck.



Between coats, I worked on the outer panels for the entry doors. I put the sheet of 1/2 inch Birch under the side panel to draw it so it will fit more or less exactly. The plans call for the door gap to be 3/16 inch. After casting about the shop (I left my tracing wheels at home), I found a piece from the Dremel tool set that is 3/16 inch from the inner hole to the outer circumference. Voila! A tracing tool!





The fenders showed up at the end of the day. They will need some fine tuning to fit, but they are stout as can be.



Today I spent most pf the day working on doors and getting the mounting tabs positioned and glued (3M 5200) to the bottom of the floor. This, of course, required setting the floor on the frame. And it all fits.





Also got out all the lighting to verify what was going to go where.



Hopefully, the weather will give me a break over the next few days so I can get the body assembled and on the frame. Maybe do the major panel assembly on Friday? Still a lot to do.

 

[DanCooper]

Well, there won't be assembly tomorrow. I thought the doors would take about two hours each, but I'm a little over four hours into the first one and still not done. Almost, done, but not. But the trailer frame has two coats of rust proofing paint and is up on its wheels.







The door fits and looks like it will work.







The inner panels will be from a Birch door skin. The plans call for 1/8 inch panels, but the Birch door skins measure 7/64ths. I believe they will work just fine. I used them as paneling on a camper conversion I did in a '61 VW van in 1971. At the time, you could buy Alaska Yellow Cedar, too. It made for a light weight structure that held up very well.

I did spend about two hours trying to find some grade 8 bolts for a project on the Subaru. Could not find them anywhere in Poulsbo. Home Depot had them in the back, but they were not going to be available until Monday when the vendor comes to put them out on the shelf. Apparently Home Depot employees are not allowed to touch the vendor's reserve stock. So I am driving to Bremerton to visit Tacoma Screw and get what I need. Another hour out of the day. And I can't find fiberglass tape to use on the corners either.

But I will follow the advice of Chief Dan George in "The Outlaw Josey Wales." I will endeavor to persevere.

 

[DanCooper]

We Build It

I found this sign on the back of the shop I am using:



After the trip to Bremerton, I was able to bolt on the tongue jack wth the correct grade 8 bolts and lock nuts.



I spent the next several hours working on another project. When I came back to the trailer, I got the shocks on, contemplated the wiring issues, measured for wire, and contemplated the almost finished trailer chassis.





The rest of the afternoon was spent on the first door, getting the tee-nuts set correctly, and making sure the door swings properly on its hinges.





Probably taking tomorrow off, so no updates for a few days.

 

[stomperxj]

WOW Dan looking really really good! What is off about the fenders?

 

[DanCooper]

The Fenders

The fenders were bent on the brake to the proper angle, but they sprang back. They are made of 18 gauge galvanized with an epoxy coating. Apparently they have a better memory than I do. The measurements are all correct, just the angles are wrong. I know another metal guy in Port Angeles and he may see them tomorrow, plus perhaps a weld or rivet on the corners to hold them at the proper angles. The plans call for the insides of the corners to be cut so the angles come together, but the guy who did them for me (for free, so no real complaints) didn't think that was necessary. It looks like the corners must be cut and then fastened together. But I understand welding galvanized is tricky, so it may have to be riveted. Or maybe start over with different steel that has less memory and that can be easily welded. I'm pretty sure my 25 ounce made in America ball peen hammer won't budge this stuff.

 

[compactcamping]

Few thoughts on exterior finishes for plywood based trailers.

First and foremost, when not in use, store indoors.

I did a test with a piece of Okoume plywood, coated in Durabak bedliner, over the last 6 years it saw low 20’s – low 100’s, Oregon rain, snow for weeks at a time, many freeze-thaw cycles and baked in the sun. Held up just fine, for more details visit Durabak Plywood Test Panel Finish Wrap Up. Expect similar results with Monstaliner. Bedliner sticks great to plywood, I prep with a 40-80 grit sand out. Sealing any exposed end-grain with a couple coats of CPES couldn't hurt. Be sure to let it cure at least a few days and scuff to up good with 40-80 grit paper. I normally do at least three coats.

No need to epoxy coat the whole surface with something like West Systems when coating in bedliner. Epoxy coating is best used a base if you plan on doing a automotive type paint job. Glassing corner joints is more about strength than sealing. If a plywood "box" can flex at a corner joint, you will get fractures.

Also keep in mind, boat building recommendations are base on a structure being in constant contact with water.