My first teardrop - the Kampster, Final Posting

[bbarry]

Good tips, all! Well life interrupted teardrop progress today. Seems like anyone with their priorities straight would be the other way around!

1) First batch of test epoxy didn't go off? An hour later, it was still pretty soupy. I measured and mixed carefully (I thought).

2) A washer and dryer needed to be procured from a Craigslist ad and delivered to my cousin's new digs.

3) A second batch of epoxy went off fine (about 40 minutes at 65 degrees) in the pot but the little (from the same batch) I used to bond two pieces of scrap stayed gummy for hours. Is this normal? I'll check it tomorrow to see if it cured completely but it seems odd that the same epoxy should have such severely different curing rates.

4) Valentine's Day. Stopped by to buy the wife flowers, rushed home to clean up and start dinner. Tilapia with a mushroom cream sauce, basil couscous, blanched aspargus with sea salt. A little pinot noir, a little more pinot noir...

Alas, no progress, just trial and error today...maybe tomorrow?

Brad

[Miriam C.]

Hopefully this will not start a family fight but you can mix the epoxy in the house and that should let it heat up faster. You should still get a good work time out of it.

[Juneaudave]

Good tips, all! Well life interrupted teardrop progress today. Seems like anyone with their priorities straight would be the other way around!

1) First batch of test epoxy didn't go off? An hour later, it was still pretty soupy. I measured and mixed carefully (I thought).

2) A washer and dryer needed to be procured from a Craigslist ad and delivered to my cousin's new digs.

3) A second batch of epoxy went off fine (about 40 minutes at 65 degrees) in the pot but the little (from the same batch) I used to bond two pieces of scrap stayed gummy for hours. Is this normal? I'll check it tomorrow to see if it cured completely but it seems odd that the same epoxy should have such severely different curing rates.

4) Valentine's Day. Stopped by to buy the wife flowers, rushed home to clean up and start dinner. Tilapia with a mushroom cream sauce, basil couscous, blanched aspargus with sea salt. A little pinot noir, a little more pinot noir...

Alas, no progress, just trial and error today...maybe tomorrow?

Brad

The two batches of epoxy shouldn't go off differently at all....I would guess either measuring wrong (are you using pumps?) or not mixing enough (I recommend mixing for a full two minutes). That RAKA 350 has a fairly short pot life, but for glueing, I would guess it takes overnight for a good, hard, bond. I use MAS Slow almost exclusively now (because of epoxy sensitivity), and it for sure doesn't harden for a good 12 hours...and I'll leave it alone longer if I'm really going to stress the joint right away.

Now we're having fun!!!

[bbarry]

That RAKA 350 has a fairly short pot life, but for glueing, I would guess it takes overnight for a good, hard, bond. I use MAS Slow almost exclusively now (because of epoxy sensitivity), and it for sure doesn't harden for a good 12 hours

Ah...maybe we've found the area of my ignorance! It seems the "pot life" of a mass of epoxy (such as is in my mixing pot) is different (40 minutes to hard as a rock) than the time it takes to cure when spread thin to use as a bonding agent (evidently hours). I thought (incorrectly it would appear) that in any use, it would simply go off and be solid, if not fully cured, in the same same time (minutes, not hours).

As a side note, I was quite careful in measuring (by volume) in the RAKA cups and mixed for a good 4 minutes, being sure to scrape all the bottom and sides to get a complete mix. I'll go check on my scraps after church today and see what happened overnight. Maybe my first batch wasn't bad after all, my expectations of what it should do were wrong.

All epoxy users should have a paperweight consisting of a block of solid epoxy in the shape of the bottom two or three inches of a mixing cup with either a brush or a mixing stick bonded into it....

Angib - can I be part of the club now?



Thanks everybody for continuing my education!

Brad

[bbarry]

Okay, I'm a dope. Both batches went off fine. When I check them this afternoon, they were bonded completely. A chisel and hammer confirmed that the substrate gives way before the bond does. So, away we went and skinned one side of one side. Under this mess somewhere are 2 sheets of 5x5 1/8" birch ply being bonded to my profile. The concrete floor is not completely flat, so I used some sand clamps to ensure contact was made throughout the entire area.

[aggie79]

Thanks for your experiences.

I'm about to wade off into epoxy-land and have many of the same questions as you did. This stuff intimidates me more than any part of my build so far.

[bbarry]

Epoxy-land is not so bad! After all, they have:

A consulate - http://www.mikenchell.com/forums
Tourguides - Wolffarmer, Angib, Aunti M, Juneaudave, etc, etc.
Lots of shopping - http://www.raka.com

Come on in, drink the kool-aid and stick around a while!

Brad

[Miriam C.]

Gotta love those sand clamps! They work great for hatches too. Honestly we need to add them to the list of tools.

Keep up the good work.

[Rock]

Epoxy will cure faster in the pot than it will spread out over a large surface. The curing reaction is exothermic and the heat produced speeds the cure.

In the pot the heat is contained and speeds up the reaction. (The heat in the very center can't get out because it's insulated by all the epoxy around it.) If you had epoxy to waste you could perform an experiment. Mix equal batches in the exact same manner. Pour one on a cookie sheet for example, and leave another in the mixing vessel. The batch in the mixing cup will cure much faster. Of course this is a complete waste of both epoxy and a cookie sheet.

Eric

[bbarry]

Epoxy will cure faster in the pot than it will spread out over a large surface. The curing reaction is exothermic and the heat produced speeds the cure.

I knew this in theory, but didn't realized HOW big of a difference it makes!

Stopped by the shop to check out how the epoxy set up on the side skin. Looks great, it appears to be good and stuck! Here's a shot. The duct tape was used to hold the skins together while we maneuvered the frame on top of it. As you can tell, we didn't count on a joint right there and there is no reinforcement. I was planning on using different size skins, but ended up with 5x5 which put my joint in between "studs". This joint will get a reinforcement strip before buttoning up the walls.



Brad

[aggie79]

I was planning on using different size skins, but ended up with 5x5 which put my joint in between "studs". This joint will get a reinforcement strip before buttoning up the walls.
Brad

If you'd like some company, I'm in the same boat - 10' long teardrop, 2-5'x5' baltic birch ply skins, and no wall framing in the middle. My grand awakening was when I was laying out the framing for my insulated floor, and fortunately, I caught it there.

[bbarry]

If you'd like some company, I'm in the same boat - 10' long teardrop, 2-5'x5' baltic birch ply skins, and no wall framing in the middle. My grand awakening was when I was laying out the framing for my insulated floor, and fortunately, I caught it there.

Oh good...I'm always glad to have company in making bone-headed mistakes!

[Wolffarmer]

Epoxy-land is not so bad! After all, they have:

A consulate - http://www.mikenchell.com/forums
Tourguides - Wolffarmer, Angib, Aunti M, Juneaudave, etc, etc.
Lots of shopping - http://www.raka.com

Come on in, drink the kool-aid and stick around a while!

Brad

If I am a tourguide. You are going to end up with your boots bonded to the shop floor, one hand to the top of your head and the other to a fender.

[angib]

Brad, that is a 100% perfect example of the now-I-know-how-fast-epoxy-goes-off club membership emblem. And it has a nice crisp bottom 'edge' suggesting your mixing is good.

Generally, if your wrist doesn't hurt, you ain't mixed the epoxy thoroughly. Are all you Merkan boys taught to change hands at 100?

I find that paint roller trays make the ideal spreading-out container for epoxy - don't cost a fortune, come with a handy shelf to lay down your epoxy-soaked tools on and the epoxy just pops out of 'em when set. If you need to wet out small bits of cloth or tape before laminating it, the shelf is good for that too.

Top tip: twist the paint tray to release the cured resin - banging it often splits the tray.

This stuff intimidates me more than any part of my build so far.

It's like anything else, you have to practice to get familiar and making a few mistakes is part of the process. That's why some practice on scraps or out-of-the-way places is good, as the mistakes won't be visible.

And the big problem professionally with epoxy is keeping it off the toilet walls - everyone carefully undoes their oversuit and then lets it touch the stall walls......

Andrew

[Miriam C.]

What over suit? Got it in my hair (vinegar gets it out) and dumped a bowl of it on my pant leg. Those are the small things. My favorite yellow shirt has a huge Titebond III mark across it.

You all have fun! And keep the handy. Will be fun to show the grand kids the boo boo's.