Coosa floor installation

[jmonk]

A little background - (If you're just looking for my step by step experience skip to "Day One") This endeavor is the result of a discussion in a separate thread.

The cost of Coosa Composite Board was the single greatest consideration in the in the decision making process. Here's the cost comparison:

5/8" Coosa Bluewater 26 - $213 per 4x8 sheet

5/8" Coosa Bluewater 20 - $183 per 4x8 sheet

5/8" subfloor plywood - varies widely, good plywood can likely be found for $35 per sheet.

Price is a tough pill to swallow. The do it yourself type will have to consider the possibility of doing it again or an extremely difficult repair down the road. Do you want to risk having to do this twice?

If you're paying someone else to do this then the cost increase associated with using Coosa would be a consideration, but it shouldn't be more than just the increased cost of the material. Restoration from the deck down is expensive and the addition of Coosa would probably drive the overall cost up by 5% to 7% if you're going the whole plumbing, axle, belly pan, etc. route. Factor in major frame repairs and the overal cost goes up while that percentage goes down. This is based on one quote from a highly reputable source. No, I won't say who.

Other considerations discussed were the ability to hold a screw. There are several methods of getting around this, but as yet I have no direct experience with it.

Stiffness and strength were also discussed. This is the big difference between the bluewater 20 and 26. The numbers reflect the pounds per square inch that the material is compressed with during manufacture. The higher the number the more dense the product. The more dense the product the stronger and stiffer it is.

Bluewater 26 is touted to be a one for one swap for plywood of equal thickness.

Blue water 20 would be depending on the flooring that goes on top of it. Stiff, quicklock laminate like Pergo would be fine. Flexible, soft vinyl or linoleum is not recommended. The concern isn't as much with the flexibility as it is with the likelihood of denting the material if something heavy is dropped on it.

Most adhesives will work with Coosa if that route is chosen. As with any adhesive/coating/laminate/material combination one must consider cure inhibition. Certain materials will stop certain adhesives from curing. The Coosa manufacturer representative I spoke with didn't know of any adhesives that didn't work with Coosa, but problems have been encountered with adhering coated metal fasteners to holes drilled in the Coosa. The coating was the suspect in the scenario.

Availability is also a little tricky depending on where you are. You'll have to find a distributor or possibly someone in your area that uses the stuff in a commercial capacity. Boat manufacturers may be helpful. I spoke with Scout Boats near me but only about the use of the material not purchasing through them. I chose to go with Advanced Plastics. I spoke at length with Tim at the Nasheville branch and he was extremely helpful and patient. They deal in myriad composite and plastic materials and Tim shared a wealth of knowledge over the course of a fairly lengthy conversation. He was also instrumental in arranging the availability and pick up of material at their Birmingham branch. We were passing through on a trip and called to check availability. Tim called around and voila, 7 sheets for pick up the following day, maybe it was two.

There are two reasons that availability can be problematic: one; unless a distributor has some just sitting in their warehouse the minimum order is 5 sheets. two; lead time for a run of 5 sheets can be weeks. Tim really pulled things together for me and things just worked out in a miraculous way. I also get the impression that 5/8" is considerably less common.

Day One - The material was light enough that it was easier to carry it one sheet at a time from the truck to my workspace (about 50 yards) than it would have been to reconfigure my driveway. The cut pieces then had to be carried 35 or 40 yards back to the frame for dry fit. The thought of it seemed dumb, but it really wasn't to bad. I've toted a great deal of 5/8" material (plywood, OSB, partical board, and drywall) and this wasn't unpleasant at all.

I tried marking the cuts with a ball point pen and it just didn't work. Perhaps a better pen would have worked. Pencil may have been fine, but I opted for fine tipped permanent marker.

The stuff cut super easy with a worm drive circular saw. I have an old Black and Decker circular that's been thrown down the steps a time or two and it would have been more than adequate. Jigsaw/Sabre saw worked fine for the curves as well.

The dust was really fine like sheetrock dust but with bits of fiberglass in it. All I had was a cheap dust mask and it worked fine, but if you've got something better it might be wise to use it. The dust is heavy enough that nearly all of it falls immediately so it's not like cutting sheetrock with a table saw which I've actually seen done and it's hilarious. I was wearing lightweight running shoes and socks that breathe really well and wound up with more dust between my toes than on my face.

I'll be prepping wheel wells for dry fit tomorrow and then waiting on supplies from Vintage Trailer Supply to get things moving. Meanwhile here are some photos; a wide shot of the trailer, A tighter shot of the surface of the sheet, and a tight shot of the edge that was cut with the circular saw. The surface shot reveals the chopped fiber in the materal and the edge shows the woven fiber that's deeper in the material.

I'm thinking the next post will include a picture of an 8 inch wide 48 inch long scrap between two sawhorses with bricks piled on it to show the strength and stiffness.

[2bkidfree]

How are you attaching the Coosa to the frame? I've got mine about to go on but I still have some frame work to do. I noticed that there is a layer of fiberglass just below the surface and I think it would be best not to completely cut through it to keep the strength. The Coosa reminds me of drywall in that you don't want to cut through the paper layer. The Coosa has some compressibility so I think an elevator bolt should work if I use a forstner bit to just take off the top portion.


I am wondering if the Coosa is firm enough to hold a standard elevator bolt without it spinning or if I need to get some with fangs to keep them from spinning.

Last thing, are you going to epoxy and mesh the seams to keep it smooth and help reduce movement.


Thanks,

[jmonk]

Kidfree,

Part of the stuff coming from Vintage Trailer Supply is a large quantity of the standard elevator bolts. That's the plan with nylon insert lock nuts.

Countersinking shouldn't be a problem as the woven fiberglass is deep enough that it won't get compromised.

I actually haven't decided what to do about seams yet. The flooring plan is floating Pergo so other than making sure things are sealed up adequately there really aren't too many other considerations. If you're using some kind of soft flooring then yes, you'll have to fill those seams with something and smooth them out. The talk around that subject was chopped fiber and polyester resin, but anything compatible with fiberglass would work. Epoxy was mentioned with regard to holding screws. The downside of that is in the event you decide to remove the screw. It's coming out in chunks.

There was a discussion with Tom at Coosa that revolved around cutting through layers but it was with regard to using 3/4" and routing down the edge to bring it to 5/8" around the perimeter for the u channel. (c, u, j, whatever) Tom seemed to think that being that close to the edge that it wouldn't see enough stress to be a problem, but I'd be leary of it. He did specifiy that routing 1/8" down would be getting close to the woven glass and that being the case you shouldn't have to go that deep to countersink elevator bolts. I'll be countersinking mine and don't foresee a problem.

[2bkidfree]

Sounds like a good plan. I'm putting vinyl down so I'll need to smooth things out a little. So far the material is easy to work with if not a little itchy if you don't watch out. It sands and cuts easily, almost too easy so you have to pay attention.

Let me know if the elevator bolts spin.

Good luck.

[skyguyscott]

Tony used lap joints at the seams for added strength and to halve the number of bolts needed. I believe he used a router to make the cuts. You can search the forums for his thread.

[jmonk]

As Promised; The Coosa scrap measures 8" x 48". The photos with no blocks are after everything was put on and taken back off. The level in the "after" photos shows how well the coosa straightened back out after the load was removed. I think the photos speak for themselves. This stuff is remarkably strong.

[rmkrum]

Neat test. Shows how good the Coosa board material is.

[2bkidfree]

I did a quick test of installing an elevator bolt into the coosa and it compressed nicely. I won't need to use a forstner bit. The elevator bolt didn't spin at all and went down flush to the top of the coosa. This should keep the coosa nice and strong.

Now I have to figure out what to use as a barrier/gap filler between the floor and the frame. With all the frame imperfections the boards will never lay flat. In the old days the fiberglass installation that the factory used would level things out.

[jmonk]

Obviously this isn't calendar days. My elevator bolts came in and I wish I had paid closer attention to Kidfree's post prior to this message. I used a forsner bit to countersink and the elevator bolt spun on my first attempt. I'm using a nylok nut so that is likely a factor, if not the culprit, but I've just ordered fanged elevator bolts to rectify the problem.

The good news is I didn't even see an indication of the woven glass layer when countersinking.

This is the exact product I've ordered from McMaster-Carr. https://www.mcmaster.com/92221a246

The new bolts should be here in a couple days and I may be able to resume progress.

The Coosa is, as stated in other posts, almost too easy to work with. There are a number of things that may have contributed to this present problem. My bit wasn't the best so I may have wallowed out the hole a little where it counts most. The shoulders on the elevator bolt didn't even try to grab. The added resistance of the nylok nut contributed to the problem, but I'm determined to use them.

More in a couple days.

[jmonk]

I really should reconsider what I'm calling these progress posts. It's been much longer than three days but had everything been in place I suppose it could have all been done in that length of time with full time effort.

The floor is bolted down. I did manage to get a square shoulder (traditional) elevator bolt to go in properly with a nylok nut but must have gotten a bad batch of bolts. I broke two much easier than I thought they should have so I put a torque wrench on the third and it snapped like a dry twig at less than 15 pounds. It was a lot of work to get the traditional elevator bolt in so I was more than willing to surrender the time to get more fanged elevator bolts. I ran out about a dozen short, hence the attempt at the traditional elevator bolt, which I already had on hand. The second fanged order came in yesterday and I just finished drilling and torquing.

All looks great. I put a jack under the rear of the frame to take out the sag from the axle back before drilling/assembly and the Coosa is holding everything straight without the jack. I wouldn't tow it outside of the yard or any faster than walking speed like that, but it's nice to see that it stays straight with just the Coosa.

[skyguyscott]

Thanks for the update!

Bolts snapping @ 15lbs.!?! I would return them and not purchase anymore from that vendor.

At least you have the satisfaction of knowing you'll end up with a trailer that will last a lifetime. I wonder if the next generation will realize such a thing was once not only possible, but expected and even common place.

I think the term was "durable goods"

[jmonk]

It's been quite a while since updating, but not because nothing was getting done.

I bolted the channel down and all the through bolts (stainless steel square shoulder bolts went in fine as expected.

The curved sections got stainless steel screws which was the first confrontation with screw retention. I did some asking around and found myself talking with a guy who used to be a national rep for Bondo. He knew a lot more about the materials than I did for sure and directed me to Gorilla Glue. I pre-drilled the holes through the aluminum and the Coosa, shot the hole full of glue until I got a drop out the other side and screwed everything down one hole at a time. You won't be pulling any of the screws out without a fight and/or some serious leverage. My test piece (a scrap of .032 aluminum and a scrap of Coosa) unscrewed without tearing anything up, but I couldn't pull it straight out like you might a nail, didn't try it with a hammer though. Bottom line; I'm not concerned about screws pulling out.

As far as the Coosa install went that was really the end of what most people would run across that would be different than plywood, other than the expense of course.

I did cut holes for coolant lines. We're installing a multi-zone mini split system. Coosa is so easy to work with, but man is it itchy. I sat on the floor cross legged and the stuff went through my jeans. It felt like I sat on fiberglass insulation sans clothing; not fun.

Like I said, it's been a while since posting but we've been hard at it non stop. Coolant lines are in, the belly pan is on and the shell is riveted down. We're watching Hurricane Dorian with baited breath but we can evacuate with the trailer if necessary.

[TXMedic]

I hope the rebuild went well. Any additional lessons learned or pointers? I'm quite certain I will be going with Coosa for the rebuild of my 61 Ambassador.

Thanks!

[Disco Stu]

We found some sheets going for half price from a boat yard in Brisbane so gave it a try. Sikaflex 11FC joined them together, a combination of self tappers into the ganlanised chassis and 6mm stainless bolts with large panel washers underneath.
Polyester resin bog tidied up the joints etc and the Marmoleum is pretty smooth. I'd do it again, but probably not at full price.

[GPurcell]

Using Coosa for mine. I'm super excited to see how it turns out. Looking at those photos I may run a coat of resin over mine