Tom & Shelly's build

[Tom&Shelly]

Sorry if this "clogs" up your thread, but I hope you find it to be helpful information and that it contributes to your decision making process.

Not at all KC. Thank you all for the very helpful discussion!

Tom

[Tom&Shelly]

When you say 6 oz, how big an area weighs 6 oz? A square yard or a square foot?

I'll be using 450gsm mat for the walls and probably 600 gsm for the underside. My build is a slide in pod so the base needs to be fairly tough.

I should add that I use GRP at work for flat roof coverings so I have the materials on the shelf.

James

Hi James,

I think "6 oz" means 6 oz/square yard. (Just tried to find it in my notes. I remember seeing it somewhere, but guess I didn't note it.)

Is gsm mat compatible with epoxy (or are you planning to use Polyester resin)? How did your weekend start go?

Think my epoxy/fiberglassing will be easier, or at least will follow what many others have already done. If anyone sees a problem with my thinking, please comment!

Tom

[Tom&Shelly]

I am about to the epoxy stage on mine. This guy did a very good review on 6 brands, including the Raka 350 http://www.oneoceankayaks.com/Epoxresl.htm

Good stuff! Thank you Carl!

I like slow! I'm new to this and my shop may be ~80+ degrees when we glass (depending on whether we get thunderstorms in the afternoon). So this tends to suggest Raka 350 is a good way to go. There are always things to do around the shop while the epoxy hardens, and I made a vow of patience when I started this project.

His method of measuring with beer cups is identical to Steve Fredrick's. I'm inclined to want to use that, rather than pumps. Anyone have thoughts?

Tom

[Tom&Shelly]

All,

So here are our tentative thoughts going forward. Please comment, especially if you think we're about to make a mistake!

Use exclusively Raka 350/127. The slow cure time is not an issue (and hopefully 80 degree shop temps, which will speed up cure, will not be an issue). We plan to measure by pouring into calibrated beer cups, eliminating the need for pumps.

We are debating the need for respirators. We will be in a garage that happens to have the unusual feature of a garage door at each end, so we have a good cross breeze. We will wear latex gloves and probably bunny suits (apparently my late father-in-law had some, for some reason). Do you all wear respirators when epoxying outdoors?

For our floor, we plan about two coats of plain epoxy on the bottom, for protection from the road. We will also use epoxy to waterproof bolt holes. Evidently the Raka 350/127 is thin and has good penetration properties, so we may as well use that, rather than "the mix". For the top of the floor, we are thinking about using a pigment to color the epoxy, and putting down several coats for protection, water proofing (especially in the galley) etc. I don't think the top of the floor needs any filling, but if we find cracks, we may add some filler to the epoxy and fill those in. Later, for the part of the floor in the galley, I guess we'll want to varnish over the epoxy for UV protection, but we don't think that would be necessary inside the cabin, which will be fully covered with a mattress most of the time anyway. I suppose we should leave the edges of the floor uncovered, so we can glue the sides on. I'm assuming TB3 won't bond well with an epoxy coated surface? Later, after assembling the sides, we can go around the seams with epoxy to waterproof those.

For the sides, we plan to make 8 x 10 panels by joining 1/4" AC plywood, as Steve Fredrick did, using 6 oz cloth, then cut the panels using a router and template. (Does glassed 1/4" plywood cut okay with a router? Will it destroy the router bit?) I really like the idea of glassing the sides before assembly, as we can do them horizontally. Also, the AC plywood we have does have a few cracks in the A side, which we can fill with epoxy and filler, before laying out the glass.

For the roof, we also plan to use 6 oz glass. I'm interested to see how large of a round over we decide to make at the edge, and how well the roof glass will transition at the sides. There will be some experimentation involved before going to the actual teardrop. (Guess I should make up some test panels as we do the sides.) By the time we will be ready for the roof, it may be Fall/Winter, and we will have significantly cooler temperatures.

Finally, we plan to paint or cover the exterior of the teardrop with bedliner. Types and method TBD.

Any thoughts? Any glaring errors?

Thanks!

Tom

[tony.latham]

...but want to coat at least the underside with epoxy...

Consider coating the floor of your galley with epoxy too. We get a few drops of water from our water jug or a leaky cooler from time to time.





Tony

[Carl01234]

I have used 5 or 6 different brands of epoxy. My bigger uses were to build large aquariums with plywood. I never went heavier than 4 oz cloth. 4 oz will be easier on the corners. I have never wore a respirator while applying, but you definately want one while sanding. Your router will not have a problem with the glassed plywood. But wear very good eye protection and long sleeves.

[KCStudly]

The pumps are really helpful to control the dispensing process, avoiding over pouring and wasted material around the necks of the cans. It is a much neater and controlled process for getting material out of the cans, so even though I am using a cheap $13 digital scale, I still use the pumps. I would second think about getting a gram scale; the first time you screw up a batch and waste a yard or two of cloth, it just paid for itself, not to mention your effort to clean up the mess and try again (I had an area on my hatch that never set up, so I switched to the scale instead of trusting my ability to count using just the pumps... haven't had an issue since).

Epoxy by itself is not very sturdy (nor is the glass cloth). But together they are greater than the sum of their parts. Wood can still check, dent and/or splinter (especially under stress) and straight epoxy can't really offer much shear or tensile strength to resist that. If you are expecting it to some how magically "armor up" a surface... not so much. IMO, if you are using epoxy as a sealant and want it to be extremely durable, go ahead and use at least one ply of glass cloth to get the best benefit. Sure, you will have to spend more time and money to fill the weave and apply a top sealer coat, but in for a penny in for a pound. Doing it part way is almost not worth doing it, IMO, because you could be wasting the added expense to a short term result; especially on bent (i.e. stressed) plywood. YMMV.

I saw mat mentioned above. As I understand it the binders in mat are only compatible with poly and vinyl-ester resins, not epoxy.

Yes, glass cloth ounce weight is by the square yard, unless specified otherwise.

[Feen]

My bad, I haven't researched the epoxy/polyester thing. I'm just sticking with what I know.

I'm afraid to ask about the pros and cons of each.

Incidentally Tom, I've just bought a 3/4" round over cutter for my router. It's as big a cutter as I'd like to use in a hand held. Although (currently) I'm not planning to use trims on the external corners, I think I'll probably paint them on just to add some detail against the white walls. I'd opt to do them in bedliner (Upol Raptor) along with a stone chip area around the skirt.

James

[tony.latham]

Epoxy by itself is not very sturdy...

KC:

You're right of course with that statement. However, when epoxy is applied to wood, it wets into the surface and becomes a wood-fiber/epoxy matrix. It's not like a sheet of brittle plastic glued to the wood. (I use Raka's 127 thin resin for sealing, but I would think any slow-set epoxy would end up with a good wetting.)

The plywood I've epoxied on our teardrop hasn't changed in five years and a few thousand miles of use. It still seems bulletproof.

(But I have yet to discharge a weapon at it.)



Tony

[Tom&Shelly]

Epoxy by itself is not very sturdy...

KC:

You're right of course with that statement. However, when epoxy is applied to wood, it wets into the surface and becomes a wood-fiber/epoxy matrix. It's not like a sheet of brittle plastic glued to the wood. (I use Raka's 127 thin resin for sealing, but I would think any slow-set epoxy would end up with a good wetting.)

The plywood I've epoxied on our teardrop hasn't changed in five years and a few thousand miles of use. It still seems bulletproof.

(But I have yet to discharge a weapon at it.)



Tony

Doesn't anyone make a Kevlar add-in for their epoxy systems?

Reminds me of a story Shelly tells about a friend of her ex's who accidentally shot their truck (while no one was aboard) with a rifle he (obviously) hadn't sighted in very well. Naturally, the guy was embarrassed, so he offered to let Shelly shoot his truck as compensation. A few years after telling me the story, Shelly happened to mention the guy's name, and he's someone I knew from work! Didn't seem like there was any advantage to mentioning the connection, or incident, to him though. I like to think Shelly hangs around with a better crowd now.

Thanks for the advice about epoxying the floor of the galley Tony. That is in our plans.

Tom

[Tom&Shelly]

My bad, I haven't researched the epoxy/polyester thing. I'm just sticking with what I know.

I'm afraid to ask about the pros and cons of each.

Incidentally Tom, I've just bought a 3/4" round over cutter for my router. It's as big a cutter as I'd like to use in a hand held. Although (currently) I'm not planning to use trims on the external corners, I think I'll probably paint them on just to add some detail against the white walls. I'd opt to do them in bedliner (Upol Raptor) along with a stone chip area around the skirt.

James

My Dad used fiberglass with polyester resin in the 60's and early 70's to build model airplanes, so that's what I thought was used with fiberglass. (We also used it for repairing ice/salt damage to our cars.) Seems like everyone now uses epoxy for teardrops and small boats, and I've seen Youtube videos where guys are using it these days for model airplanes.

The polyester resin has a very strong smell. My Dad was a bit "old school" about most personal protective equipment, but he bought and wore a respirator when working with that stuff (in a basement with no ventilation).

We did use 5 minute and several hour epoxy glues, and it's the same deal as with the epoxy used with fiberglass--one has to get the ratios correct. Too much hardener causes it (ironically) not to harden as quickly or as well.

Our wall skins will be 1/4 inch plywood and roof two sheets of 1/8 inch plywood, so I think that may constrain us to about a quarter inch radius round-over, unless we're willing to cut down to the blocking.

Tom

[Feen]

There you go

https://www.ecfibreglasssupplies.co.uk/ ... -1-mt-wide

James

[Tom&Shelly]

I have used 5 or 6 different brands of epoxy. My bigger uses were to build large aquariums with plywood. I never went heavier than 4 oz cloth. 4 oz will be easier on the corners. I have never wore a respirator while applying, but you definately want one while sanding. Your router will not have a problem with the glassed plywood. But wear very good eye protection and long sleeves.

4 oz and 6 oz are the same price from Raka too. I should think about this. Thanks Carl!

Tom

[Tom&Shelly]

The pumps are really helpful to control the dispensing process, avoiding over pouring and wasted material around the necks of the cans. It is a much neater and controlled process for getting material out of the cans, so even though I am using a cheap $13 digital scale, I still use the pumps. I would second think about getting a gram scale; the first time you screw up a batch and waste a yard or two of cloth, it just paid for itself, not to mention your effort to clean up the mess and try again (I had an area on my hatch that never set up, so I switched to the scale instead of trusting my ability to count using just the pumps... haven't had an issue since).

Epoxy by itself is not very sturdy (nor is the glass cloth). But together they are greater than the sum of their parts. Wood can still check, dent and/or splinter (especially under stress) and straight epoxy can't really offer much shear or tensile strength to resist that. If you are expecting it to some how magically "armor up" a surface... not so much. IMO, if you are using epoxy as a sealant and want it to be extremely durable, go ahead and use at least one ply of glass cloth to get the best benefit. Sure, you will have to spend more time and money to fill the weave and apply a top sealer coat, but in for a penny in for a pound. Doing it part way is almost not worth doing it, IMO, because you could be wasting the added expense to a short term result; especially on bent (i.e. stressed) plywood. YMMV.

I saw mat mentioned above. As I understand it the binders in mat are only compatible with poly and vinyl-ester resins, not epoxy.

Yes, glass cloth ounce weight is by the square yard, unless specified otherwise.

So you measure by weight, KC? Looks like Raka and West Systems both go by volume. Is there and advantage either way? (I mean if one measures the volume with calibrated marks on cups, rather than merely by eye.) I already have gram scales if that is better.

I see what you are saying about the pumps being easier than pouring and leaving less waste around the edges of the cans.

I like your comments about having small projects ready to use the rest of a batch of epoxy after the main job is done. I'm afraid I'll waste some left over until I get better organized!

Tom

[Tom&Shelly]

There you go

https://www.ecfibreglasssupplies.co.uk/ ... -1-mt-wide

James

Guess maybe that's what the American Army uses to make their helmets out of these days