The Poet Creek Express - Foamie Hybrid

[KCStudly]

Last night I sanded the shine off of the test sample panels and used spring clamps to clamp them to the edge of the table while I routed the 1/8 inch round over along the cedar edge, letting the clamps dent the face on both sides near the edges. Then I poked at the panel with the end of a clamp to make a pair of dents with a torn edge. Then I used 100 grit on the small hand block to sand a shallow valley, but made sure to also press too hard and chunk out some rough area at one end of the valley. I did all of this at each end of each sample because the plan is to cut each panel in half to get a total of four sample coupons.


I thought it would be a good idea to circle the distressed areas with sharpie to help tell the difference between potential air bubbles and white spackle. Here’s a close up of a dent with tear.


Sanding tear out.


1/8 inch round over. You can also see the slight crease between the foam and cedar that will also get spackle.


Spackle applied. I didn’t go crazy with this (… I’m already crazy).


Okay, we’re getting to the good stuff. I cut two strips of 6 oz BID weave 2 inches wide on a 45 deg bias and two sheets big enough to cover the panel with a little excess. This is the stuff I used: JPS Racing Hull.

I used a paper plate under the cup on the scale to protect against spills. Just as I got done pouring the resin the scale display started flashing -BATT- indicating that the battery was starting to die. Oh Crap! I figured if I shut the scale off it might reset, but then I had to figure out how to reset the zero. Used an empty cup on the plate to reset, and while fiddling with it the -BATT- goes off again. Damn, I don’t have a fresh 9v battery on hand, but when I touched the scale it would go back to reading, so I crossed my fingers and hoped that the -BATT- reading was just a warning and not the end of the road. Sure enough, so long as I was pouring a trickle of hardener it would read, but as soon as I stopped pouring it would revert to -BATT-. Whew. I did 60 grams of resin and 12 grams of hardener. Room temp was 68 degrees F. A little cool but still well within the range for the product specs I was using.

With the techniques that Michael suggested foremost in my mind, I wet the strips out on a plastic shopping bag (not the best choice, but okay for a small test), brushed some epoxy on and laid the first strip along the 1/8 inch radius edge of the cedar. It was really hard to pick the strips up off of the plastic w/o stretching them out and making them go narrow by about 1 inch. I was able to pull them back wider again, but the edges unraveled some and it was hard to keep a really straight edge.

Still, it went around the radius without trouble and I squeegeed out the excess. Next I put the larger precut piece over the main part of the panel, dry this time. At first I let this piece hang over the 1/8 inch radius a tad and started wetting, but quickly realized that I should hold it back from the edge, rather than try to trim over the radius. I caught it early enough to nudge the sheet back a little then finished wetting all the way past the 3/4 radius along the other edge, with plenty of excess cloth (too much really) hanging off.

Then I came back with the second piece of bias strip and capped off the cedar end again. The plan was to lay a second piece over the main panel, as well, but I decided to see if one layer would be enough.

Here it is.




I’m already gaining a lot of confidence and can see improvements from my previous efforts.

Just handling the glass and cutting these small pieces I was already feeling itchy on my arms. Just so happens that we use these Tyvek sleeves at work. I had to put a pair on today to do some sampling, so rather than throw them out, I brought them along. Seemed to help and I didn’t need to worry about getting epoxy in my arm hair (… or arm hairs in my epoxy).


I had hoped to let it get to the firm trim stage so that I could trim the excess overhang with a razor, but it hadn’t kicked off enough after an hour sitting there staring at it, trying not to mess with it, so I decided to deal with it later, probably with a Dremel cutoff tool.

If I had been more organized (mentally) I would have tried another test just using a single piece of the cloth and seeing if it could take the 1/8 radius on a 90 deg orientation, and/or to try some of the fine 90 deg BID tape that I have, but I went “deer in the headlights” instead.

I think I would rather keep things as simple and (relatively) thrifty as possible, so I will wait on buying peel ply or bias tape until I test those other options.

I will get to the canvas tests, too, but didn’t want to bother getting the big roll out, making a spot big enough to roll some out to cut a swatch tonight. In fact I might just go pick up a single yard, rather than fight the big roll just yet.

[OP827]

KC, at a room temperature, epoxy usually hardens enough with medium hardener in about 4-5 hours to start cutting the edges, but you will find that you can cut them later with razor knife as well because 1 layer 6oz is quite thin. I never used dremel to cut the egde.
You could also test and try dry on dry layup, or at least dry on wet, as that was much easier for me to layup nicely and I feel it works fine for my build, as it is not a racing boat we are building, as Michael noted. Also 1 layer of 6oz seems to be enough for me, for one-two days it felt a bit soft, but after several weeks the epoxy hardens more and more and now it feels fine. I am still trying doing on wet surface and can not manage that well as being working alone with a large glassing surface. If you are concerned about filling the voids under the cloth you can fill them with epoxy with microspheres and let it cure and then sand before glassing, but you seems to be already have a nice faired surface so that may not be necessary. Just my thoughts and you are doing great, all it takes is a little bit of practice and testing:

[KCStudly]

Thanks for the first hand knowledge, OP, and again to all who support this effort; and in general to all who support the TNTTT board.

As noted previously, I really have very little firsthand experience with composites. Other than a few small epoxy patch like situations that I can't even remember the details of, a very crudely made speaker kick panel I did for my old beater Sonoma, and the successful reinforcement of the front radius, I have not used the stuff.

Keeping it to one ply sure would be nice, both from a cost and time perspective.

People with much more experience are probably getting a chuckle out of my lack of confidence and slow progress, but this time is critical for me to go thru all of the areas on the build in my mind that might give me trouble; things I may have already consider for the canvas (maybe even with over confidence) that I am now taking a more serious "think" about. Like the door headers; and the area under the locker bump out that still needs the Kregg screw holes to be filled. Also trying to break it down into more manageable chunks and considering what sizes of strips and peel ply would be best for wrapping the doors and hatch seal areas (Karl has advised that it might be bad if I went past the wood and tried to pull peel ply from the foam, so getting the right configuration to butt into the inside corners while still wrapping the outside corners and not running off of the wood onto the foam may be a minor challenge. I'm not sure that I am up to doing all of the jamb work and a full side in one layup.

Another thing is that I am only finding cloth up to 60 inches wide, whereas my canvas is 72 inches wide. My plan had been to cover the sides wrapping up on to the roof a couple of inches, then cover the roof wrapping on to the sides about the same. With only 60 inches of glass cloth, at 64 inches wide, the lap seams will have to be on the roof. No biggie, but had to work this out to be sure I could still wrap the 53 inch tall (approx.) sides, still get a good wrap under the floor and at least three inches on the roof for a one inch overlap (assuming that 60 inch wide FG cloth is actually 60 inches wide).

I'm anxious to do more tests, including canvas tests and get to a final decision. I have started to make lists again; new things and products to research, going over things in my head.

The word "rotisserie" was spoken out loud last night (not by me) and on the ride home I started wandering off in my mind thinking about hanging posts off of the steel beam in the loft so that I could suspend and rotate the cabin at will. Adjustable height would be nice to be able to lift so that the corners can swing thru, and then lower to get back to an optimal working height. Only half serious, maybe only 10/ct serious. I can picture a scenario where the rear edge of the galley floor is clamped, and I suppose I could run some temporary screws into the locker bump out or front floor edge. Finding the vertical CG (balance point) might be a little tricky, but the computer model may have that close enough to be useful.

At first this sounds like a major side track, but when I think about how much more accessible it would make things, being able to work down on the door headers and under the sides of the floor; and knowing that it would allow me to do a better job, it almost starts to make sense.

[Atomic77]

One of the advantages of doing a dry on wet lay up is to keep the piece from stretching. Keep in mind the smaller piece the more it seems to want to stretch where bigger pieces seem to resist better. Regardless of that issue, we will never do dry on wet at the race shop because of the chance of having a dry area somewhere. We don't get bothered by seams unraveling or other minor things. We just get it laid up and the epoxy and bubbles all squeegeed out. It can all be cut mid-kick as OP suggested or just hit with a grinder after the fact. Once it's finished out it doesn't matter anyway. (Carbon fiber is even worse at these things.)

Here's a tip. We stopped using Tyvek awhile ago because it's so hot! Keep a big bottle of baby powder on hand at all times. Rub it generously on your arms especially underneath. After all these years I'm pretty immune to it on lay-ups, but I never touch a grinder to fiberglass without copious amounts of baby powder. It will protect your pores and the fiberglass can't get to you. We learned this from the guys that work over at the boat factory. It's almost like magic!

Good job KC... You'll be a Pro in no time!

[dales133]

Ill just add mu 2 cents from the pmf fraternity. .. its ridiculously easy.
My fiberglass in experience comes from fiberglass in some ply frames into a boat floor to screw gel coated pedestals to with plastic seats.
I gave that boat curry for 6 years or so in far bigger seas than it was built for and id never knock fiberglass ever.
But it's messy,its expensive,it takes alot of precision.
You could have done alot less work to go fiberglass.
My canvas looks exceptional after 4 coats of dulux,s best exterior paint
I only wiped it gently with 250 grit prior to the last coat.
Its a fantastic finish

[KCStudly]

Plan for tonight is to trim and inspect the FG sample, and layup a couple of canvas samples.

[KCStudly]

Okay, so Friday I stopped by Jo-Ann’s Fabrics and picked up a foot of 60 inch wide cotton duck to use for testing. It didn’t say what weight it was on the bolt tag, and the clerk couldn’t say what weight it was, but it looked to be similar to the big roll of 10 oz I bought from Big Duck. I figure the $3.33 was worth my time not to have to set up an area, pull the big roll out, and make sure that I wasn’t shorting myself by taking too much from one corner (even though I added extra into my rough estimate, I had not allowed for the extra needed for the doors… because you need to be able to wrap the door jambs and the doors, so you can’t just use the wall cut outs for the doors; so I’m hoping that, if I do use the canvas, that the extra I allowed will be enough for the doors; either way I will probably glass the tongue box).

I did manage to open up the roll and snip a small corner piece off for comparison to the Jo-Ann’s. The small triangle is the Big Duck. Weighing the Jo-Ann’s confirmed that it is also about 10 oz/sq yd. You can see that the Big Duck has a finer, tighter weave for the same weight. Cost was about the same.


I wasn’t sure and thought that the Big Duck may have been prewashed, but when I dribbled water on both it beaded up pretty strong, so I decided that I had better wash the sample pieces first. I cut three test pieces slightly over size and brought the whole lot home to wash.

On the epoxy/glass sample I was able to trim it with a razor knife, but it was tough and the sample was so light that it wanted to move around on me a lot, making it a somewhat dangerous affair. Scuffed the edges with the small block and 100 grit to dull them up a bit and take the sharp edges off.

I hadn’t weighed the test sample beforehand, but the other three samples where very close to each other (two at 2.35oz and one at 2.30oz). We figured that 2.35oz was close enough and did some weighing and figuring to see how I had done. This is what the surface looked like close-up.


I used one of the 2.35oz blank samples to zero the scale…



…then weighed the trimmed test piece to find the added weight; 0.80oz added. (You can see a little white along the cedar edge where it lifted from me pulling on it with the razor knife.)


The scrap of cloth we weighed figured out at only 5.5 oz/yd^2 (spec’d as 6oz nominal)
and the sample piece figured to have about triple that rate added, so about 2 to 1 epoxy weight vs. cloth weight. To look at the weave it is all well saturated with no signs of dry spots, no pooling or ridges of epoxy, and all of the weave pockets are visible (not over filled), so I figured that I had done pretty well. We did a conservative estimate and figured one ply would add about 22.5 lbs to the whole camper.

I haven’t looked it up yet, but OP suggested that 1:1 glass epoxy ratio should be expected, so I was a little surprised. Maybe I should recheck my long hand math using a calculator? Some of this may be due to the fact that the cedar edge has two plies that overlap the main panel ply, and I did not account for that, but since that is such a small percentage of the total area covered, I wouldn’t think that it could account for such a difference.

I wrote the details directly on the back of the sample.


We had a cold front come in overnight and I'm not sure if that slowed the cure, but with just one ply I was able to dent it with my finger if I applied moderate pressure. With light pressure it just felt a little springy. This prompted me to consider a second ply.

Anyway, yesterday I brought the washed canvas and did a couple of test samples with TB2. The canvas came out of the dryer horribly wrinkled, and I hadn’t bothered to baste the edges, so there were a lot of stringy threads (more than shown here). Even after ironing you can still see plenty of creases, although I didn’t have any distilled water for the iron, so may have been able to do a better job ironing if I had.


After trimming just one edge crisp for along the edge of the cedar (where I intended to start) the oversized piece weighed 0.70oz.


I put a nice fresh piece of plastic coated freezer paper on my blotter (the cut out from one of my door windows; 5mm ply over 1-1/2 inch foam) to use as a work surface.


And here you go. I used 2 parts TB2 to 1 part water. The wrinkles where greatly diminished just by laying it down in the glue, and as you will see, as they dried the creases diminished further, almost disappearing.


As expected there was no problem handling the 3/4 radius at 90 deg to the weave.


The 1/8 inch radius seemed to go fine as well. On this sample I wrapped about 1/4 inch of canvas all the way under, whereas in the other one I lined the cut edge up with the bottom edge of the cedar (as it will be on the inside corner of my door flanges.


The wrapped piece seemed to be drying fine, but on the unwrapped one that side of the canvas (along the 3/4 inch edge) lifted. I was able to open it up a little to get some full strength glue in there, and I think it will stay stuck down now. Maybe something to do with the thinned glue on the relatively sap/resin rich cedar, dunno.

First impressions. It’s true, the PMF is much easier to deal with than real epoxy and glass. No itching, no special PPE (other than rubber gloves and eye protection), simple water cleanup, reusable cups, brushes, etc. We shall see on the durability/armor. Again, it was cold and wet; low 50’s and 75/ct, so maybe not ideal conditions.

I decided to lay another ply of glass on the epoxy test piece, both to see if it added enough armor to justify doing a full second ply on the camper, and to see if it would go around the 1/8 inch radius on a 90 deg orientation. Yes the 1/8 inch radius is no longer 1/8 inch, but pretty close, so IMO still a valid test.

I prepared the piece by wet scrubbing with a well-used piece of greenie pad (to remove any amine blush) then drying well with a paper shop towel and fanning the piece. Just a little light sanding at the seam between the main and 45 deg strips to knock off the prickly bits. I didn’t bother trying to fair this seam for the test, just to see what the next ply would do.

I tried to be more aggressive with my squeegee work (using an old Ho-De-Po gift card) but when I did I started seeing starved glass as evident by the lighter crystal like sparkle. Dripped a little more epoxy on in those areas and dragged it again with less force. As before, I think I got it pretty good with no puddles, ridges of epoxy, and the pockets in the weave pattern still visible (as opposed to being soaking full). There was a ridge of wetness along the edges just off of the foam, so I expect it to be harder to trim, but I didn’t want to mess things up by trying to fuss with the part that will be trimmed off anyway. Doing this dry on dry it seemed to take more epoxy to fill the dappled surface underneath than it had the smooth surface of the foam, and it seemed more sensitive to extra squeegee force (i.e. easier to take too much away).





The extra ply really seemed to blend the jagged line of the seam, to the point that I wouldn’t bother trying to fair that area first.

Back to the canvas you can see that most of the wrinkles have disappeared.



Took the 1/8 radius fine, except as noted for the lifted flap on the butt edge sample.


If I go with the canvas I may have to rough up the cedar better and use full strength glue in those areas.

Getting a late start today, but am on my way to check things out now that things have had a chance to dry.

[tony.latham]

Anticipation!



Tony

[dales133]

Be interested to see witch way you go.
I Curly did some more pmf yesterday and mixed it closer to 60/40 tb2 to water and it worked fine.
I've been making a habit of brushing neat tb2 around the edges on top of the canvas and working it into the we've.
I also roll tb2 in the same ratio over the top

[KCStudly]

After trimming, the second ply of glass and epoxy added only 0.75oz (3.90oz total minus 3.15 oz previous). So very consistent 0.80 and 0.75 oz/ply.


Checking my math again, based on the 78 sq in of surface, that’s actually only a 1.5 to 1 ratio of epoxy to glass, so maybe not so bad. If I use the 6 oz nominal cloth weight instead of the 5.5 measured it get even better.

I had to really press to get it to take a thumb print depression, but in general was a lot firmer.

The TB2 and canvas samples after trimming.


I lost track of which blank was the 0.05oz lighter one, so I’m using the 2.35oz baseline for all samples now. Here on the back you can see the difference in how they were wrapped around the back with the one on the right having slightly more canvas and weighing about 0.05oz more. Interesting that the canvas and glue weight is very consistent with the epoxy and glass; 0.80 and 0.85oz


The canvas didn’t really seem to stiffen the foam much; it was still very springy and I could dent it about the same as without the canvas. What it did do was make the foam much less fragile; no worries about gouging or chuncking pieces out with a lot more than incidental contact (unlike raw foam). Bending in the direction that tended to stretch the canvas was much more rigid, as well.

I whacked one of the canvas samples on the corner of the bench a couple of times, which left dents. When I did the same with the double layer of glass I could not find any marks, or locate the impact points.

I set one of the canvas samples aside to (maybe) get paint (maybe primer, too), then mixed about an ounce of epoxy to top coat the other one. My thought being that it might help the canvas stiffen up even more to use epoxy over it, but because you can’t see thru the canvas, doing the full lamination with epoxy might not wet well enough with the dry on dry process I would prefer to use. I had to really stretch the epoxy to get it fully covered, but came back shortly thereafter (with some of the left over epoxy from my next efforts) and went over it again. Here it is after both applications. The lighter blotches are in the canvas, I guess variation from the TB2 saturation.


Another small batch of epoxy squeegeed over the glass sample just to see how it fills the weave. As I was mixing the batch I realized that I hadn’t done anything to clean off any amine blush or to scuff the panel. Oh well, it’s just a test. If I had any micro balloons on hand I probably would have used a slurry mix of those. I didn't think the filler I do have would be appropriate (affirmed by the label on the can), so I didn’t use any filler. Here it is wet after squeegeeing off the excess.


I didn’t expect it to fully fill the weave, but probably enough for paint, and I don’t mind a little texture.

The last sample I wanted to try was to glue canvas to foam with epoxy. Unconventional, I know, but I already purchased canvas, so before fully committing, one way or the other, I figured it wouldn’t hurt to test. Poured some epoxy on the foam, squeegeed it out thin. Did the same to the back side of the canvas and found that it did soak in quite a bit, pretty well saturating even though I went pretty lean. After getting the canvas in position (which was very much easier than with glass; no warping of the weave and no loose strands to fight), pressing it down with my gloved hands, and dragging it with the squeegee to pull out slack, there seemed to be some dry spots around the edges (I had worked from the middle out); so I drizzled a little more epoxy where the lean spots seemed to be and worked that in with the squeegee. I don’t expect the epoxy to shrink any, so the wrinkles/creases are probably there to stay.


Again, the flap edge of the canvas didn’t seem like it really wanted to stay in some places. Perhaps the 1/8 inch radius is too tight, or the vertical surface behaves differently? Packed a little more epoxy into the fabric and pressed down with gloved fingers. We’ll see.

So what does this all tell me? That I am having a hell of a time deciding which way to go. I like the durability of the epoxy and glass, and its implied permanence. And I am getting more and more comfortable handling it (at least in small doses), but the PMF is so much more user friendly. I can tell you from examining the glass sample that I really don’t have much concern for delamination, even using the dry on dry layup.

Dale, I’ll be interested to see which way I go, too. Maybe I should take a vote over in the polling forum? (Waffle, waffle)

Hey Tony, maybe you should fire off another batch of popcorn, this appears to be turning into something of a saga.

[ghcoe]

I am mixing 50/50. I apply to the canvas and onto the surface the canvas will be mounted to. The mix gets a bit tacky after sitting a few minutes and then I lay the canvas and roll it flat with a 4" paint roller.

I have been using 3 brushes (1",2",4") and a 4" roller since I started my canvasing six weeks ago. Still using the same brushes and roller pad today. Just keep the brushes in a bucket of water. The roller is a bit hard, but that is ok. Just add some water before I start rolling and all is good. In fact I use the same brushes if I need to add any paint too. That is what I like about the canvas method, it is easy. No laborious setup or take down. Mixed glue is in a closeable jug, open, use, when done seal back up, brush in water, done. And the smell and the harsh chemicals.......there is none.

[KCStudly]

Thanks George, I forgot to mention that I used your trick of the dry roller, in fact I didn't even take the plastic sleeve cover off of the roller.

It'd didn't make much of a difference on these small test samples, but I can see where it would help on a much larger surface.

You make all of the good arguments for PMF.

I did start a poll over on the polls forum, so please, everyone, feel free to vote: PMF vs Epoxy/Glass - TPCE Wants Your Vote.

[OP827]

KC, if you cut your glass cloth close to the edge, there should be no lift up, separation issue. The handbook for Moldless construction that Tony L. copied us a few days ago also has such tip. After epoxy is fully cured in a week or so with two layers of glass you'll need a hammer to put a dent, not a thumb. Good research and testing, and moving forward!

[KCStudly]

Yeah, I read that, too. I only left the end at the big radius long where it was hanging down vertically. Figured the extra weight of the canvas couldn't really hurt there. Along the sides I only left about 1/2 inch, maybe a little more and it didn't seem to be detrimental.

At the small radius I am trying to avoid having to use the two stage, back gouging/peel ply method shown in the Rutan instruction. I think I might step up the radius around the doors and hatch seal to 3/16 inch, just to be on the safe side. I wanted to keep the gaps as tight as practical for aesthetic reasons, but there really isn't much difference by the time it gets covered.

I'm thinking my next move is to step up and do the tongue box in glass, both the battery compartment and outer skin, and maybe even the inside. That will give me some experience on a larger scale project and will really toughen up the box against road debris and abuse. May even help me decide what to do on the cabin.

Please vote ^.

I reconsidered my math on the overall weight estimate for two layers of glass (kept coming up with different figures). Seems pretty clear that the sample has 78 square inches of coverage (7 wide x 11 and a bit long, including the 3/4 inch edge of the cedar and the 3/4 inch radius) and that the weight of 2 plys with epoxy is about 1.6oz, so that's about 3oz/sq ft (1.6oz / 78 in^2 x 144 in^2/ft^2 = 2.95oz/ft^2). So by conservative rough estimation 5 sides of a 10 ft x 5 ft x 5 ft box should be not more than 200 ft^2 (10x5 side + 10x5 side + 10x5 top + 5x5 end + 5x5 end = 200 ft^2). The highest point on the side wall is only about 53 inches, but allowing for over lap it's closer to 5 ft. Did not take off for rounded corners, and figure that this more than accounts for wrapping door jambs, etc. Now that's 600oz's (200 ft^2 x 3oz/ft^2 = 600oz), or 37.5 lbs (600 oz / 16 oz/lb = 37.5 lbs).

It always pays to use stoichiometry when doing unit of measure math.

[GPW]

On a plane , 37.5 # would be a lot .... on a trailer .... not so much ... Wouldn’t save much by going with canvas...