Waterproof exterior (but still lightweight)

[Larry C]

Again, a layer of glass is great... but, if you don't use the correct wood, epoxy and methods... you're wasting your time... moisture will find its way in.

[Edit: Don't forget... epoxy MUST be UV protected, or it will breakdown. Maybe that, and/or certain fastening methods being employed, is why some are having problems.]

Larry C... as you can see from my comments above... and other posts of mine in other threads... I agree with you. That's why I mention, above, "methods" and "fastening methods" and why in other posts I have mentioned/recommended "taped seams, epoxy fillets," etc. Having already said all of that... my primary point above was to highlight the fact that epoxy, properly applied and protected, does not crack. By the way... I too have experience with plywood core composite boat building and have never had ANY moisture intrusion related problems.

Michael, I certainly agree with you and others that have boat building experience.

I agree that epoxy applied to a surface does not crack. I am just trying to emphasize that edges should be glassed even if the rest is just epoxied and UV protected. I wasn't disagreeing with you at all.
I am merely trying to add to what you and others have already said.
My goal is to help others with procedures which I have experience, and hope other will help me with my issues.

Larry

[Cliffmeister2000]

That is a very cool build. Lots of different options for core material. I've used foam (Divinycell) instead of plywood for some parts of boats. BUT... I really want a "woody finish"

You might consider a woody overlay. That way, if and when it is damaged, you can replace it.

[Billy K]

I did not read where anyone advised automotive clear coat over CPES.

Any thoughts ....??

[kennyrayandersen]

http://tnttt.com/viewto ... 650#711650

I think there have been several examples on the board here where paint only (even though its epoxy) has failed. The link I posted is from another on-going discussion of whether fiberglass in needed. Some think it isn't and some think it is. I posted two quotes from boat-building sites and both recommend using fiberglass in addition to the epoxy. You might be able to get away without it... what are you willing to bet?

[michaelwpayton]

http://tnttt.com/viewtopic.php?p=711650#711650

I think there have been several examples on the board here where paint only (even though its epoxy) has failed. The link I posted is from another on-going discussion of whether fiberglass in needed. Some think it isn't and some think it is. I posted two quotes from boat-building sites and both recommend using fiberglass in addition to the epoxy. You might be able to get away without it... what are you willing to bet?

I think there may be some confusion floating around the forum re the difference between "epoxy paint/coatings" and epoxy resin. Also, I haven't seen much discussion of the differences in behavior re various species of wood. For example, a lot of boats are/have been built with marine "fir" plywood... but, many... myself included... believe the mahogany species is a much better choice. Don't forget... when selecting plywood... the species of wood used in the ply, in addition to how the ply is composed (e.g. following the BS1088 and BS6566 standards or not) will have a lot to with how the ply reacts to being exposed to the elements.

[DesertSkies]

Michael, you're correct about the confusion and this thread has completely answered my questions about using resins. I've done small fiberglass/resin jobs on model aircraft with thinned-out epoxy adhesive but nothing larger. This has been most informative.

One more question before I squeeze the trigger on buying resin: Should I choose fast or slow for my teardrop? I'll be working at high temps with roller or brush application so I'm considering buying a gallon of the Silver Tip resin with slow hardener. Does that sound right?

Also, mine will be painted. I'm planning on using an enamel.

[michaelwpayton]

Michael, you're correct about the confusion and this thread has completely answered my questions about using resins. I've done small fiberglass/resin jobs on model aircraft with thinned-out epoxy adhesive but nothing larger. This has been most informative.

One more question before I squeeze the trigger on buying resin: Should I choose fast or slow for my teardrop? I'll be working at high temps with roller or brush application so I'm considering buying a gallon of the Silver Tip resin with slow hardener. Does that sound right?

Also, mine will be painted. I'm planning on using an enamel.

SilverTip is good stuff. I've never had good luck with fast hardener. All too often I've wasted a batch that was kicking in, before I was ready for it to. It's a personal preference thing... but, slow will give you more time to work out your pour/bubbles, get to your next step when working wet on wet, etc. They used to sell a "trial kit," which had samples for you to try before you spent "big money."

What ever you buy/use... read/follow the directions, experiment a little at first, buy a box of latex gloves and a few squegees... and have fun

[Miriam C.]

http://www.steve-frederick.com/shopman05.html

For those who want information on building a TD at their fingertips, with personal back up might want to order Steve's shop manual.

[michaelwpayton]

:o http://www.steve-frederick.com/shopman05.html

For those who want information on building a TD at their fingertips, with personal back up might want to order Steve's shop manual.

Very good point Miriam... I agree... I own it... Steve is a true craftsman.

[parnold]

I'm considering buying a gallon of the Silver Tip resin with slow hardener. Does that sound right?

There's a tip I've seen mentioned several times here on the forum that bears repeating here. You can refrigerate the resin and hardener to slow it down even more!

[kennyrayandersen]

I've been pondering how to make a TD water tight for a while, the basic plan that I've been leaning towards is to fiberglass and epoxy the heck out (all sides, edges and holes) of plywood and then skinning the exterior in aluminum (protection in layers). And though I've been vacillating on this, not insulating.

Reading this thread my latest brainwave is to use a hydrophobic blanket under the aluminum so even if a weakness is found in the aluminum shell the water would quickly drain out and it would also add a smidge of insulation, and the aluminum would then be able to act as a radiant barrier. Anyone have any thoughts, or a suggestion of a good hydrophobic material (fleece?).

Thanks, Beej

That might be overkill (and that from a paranoid stress guy!). If it is sealed OK, you’ll be OK. You just have to pay attention to the details.

[J.Heyboer]

I had a similar question?

If I am skinning the exterior of my trailer in Aluminum, could I just use polyeurethane under the aluminum and inside the cabin?

or am I just asking for problems?

John

[GPW]

JH, from my humble experience , the thinned poly trick seals the wood Very well ... I painted over mine after poly-ing inside and out .. No problems ... Aluminum should work fine over that.. and since the poly sinks in , there's no trouble using epoxy,contact cements , etc... once you do this carpenters glue doesn't stick as well as to the bare wood ... Just FYI

[kennyrayandersen]

http://tnttt.com/viewtopic.php?p=711650#711650

I think there have been several examples on the board here where paint only (even though its epoxy) has failed. The link I posted is from another on-going discussion of whether fiberglass in needed. Some think it isn't and some think it is. I posted two quotes from boat-building sites and both recommend using fiberglass in addition to the epoxy. You might be able to get away without it... what are you willing to bet?

I think there may be some confusion floating around the forum re the difference between "epoxy paint/coatings" and epoxy resin. Also, I haven't seen much discussion of the differences in behavior re various species of wood. For example, a lot of boats are/have been built with marine "fir" plywood... but, many... myself included... believe the mahogany species is a much better choice. Don't forget... when selecting plywood... the species of wood used in the ply, in addition to how the ply is composed (e.g. following the BS1088 and BS6566 standards or not) will have a lot to with how the ply reacts to being exposed to the elements.

True dat, but the websites I posted from the boat-building sites were in fact using epoxy resins, not just epoxy paint (I think both are inadequate for a teardrop -- the paint more so than the resin0only approach). I still wouldn't do it without fabric. Of course, I value my time and I don't like doing things more than once, and my least favorite thing is doing something over that, save for doing it a little different, I wouldn't have had too. I realize that this is only my opinion, but I think it is the most conservative (safest) approach.

[J.Heyboer]

Thanks GPW! I will follow you advice.