Off the Reservation

[kmoose]

That is just effing beautiful!

[WildBill]

Nice work Dave

[martin]

Very nice work Dave.. I didn't see any bleeder holes.. Did the laminates squeeze the epoxy out the sides much.. Just curious...

[Blue_Heron]

Thanks, guys.

Martin,
I didn't drill any bleeder holes in the core material, just applied the thickened epoxy with a notched trowel. The grooves left by the trowel allow air to escape as the parts squeeze together. The bond looks to be very good. I had to trim along the edges of the core, and I cut out the engine notch. All the bits I removed have a continuous line of epoxy a little less than 1/16" thick between the cores.

I got some resin squeeze out through the holes in the transom laminate when I applied vacuum there. The bond with the outer skin looks solid too. I tapped across the whole thing with the butt of my pocket knife and didn't find anything that sounds hollow.

I've laminated the inner transom skin, but didn't vac bag it. I'll post more pics tonight or tomorrow depending on what I get done today.

Dave

[Blue_Heron]

The stringers in this boat will have a non-structural foam core, so the laminate will have to carry the entire load. I know I want 1/8” laminate, but the roll of 1808 I bought didn’t have technical info on the label, so I didn’t know how many layers it would take to make 1/8” thickness. I decided to make two test cards with three layers of 1808. I wet them both out with epoxy, put peel ply on both sides, and rolled out the excess resin. Then I put release film and bleeder cloth on one and vacuum bagged it to consolidate it. I was surprised how much excess resin squeezed out of the bagged card. The cured thickness of the bagged and unbagged cards was .10” and .15” respectively. That translates to a much higher glass to resin ratio and a much better strength to weight ratio in the bagged card.

So I started thinking about how to bag my stringer layup to get that high strength to weight ratio. The problem is that by the time I got all the glass wet out and rolled in place, it would already be starting to gel, and vac bagging would have limited benefit. The only way I thought I could pull it off would be to bag it first, and then wet it out. In other words, resin infusion.

Having never done resin infusion before, I decided to experiment with the chine reinforcement I was planning to do. There are lots of Youtube videos on the subject, so I had a general idea about the process. Here’s what I did:

I placed three layers of 1808 in 6”, 9”, and 12” widths.



I covered the glass with peel ply.



Added spiral cut polyethylene tubing for vac manifold and resin lines.



Added tacky tape.



Bagged it and hooked up the vacuum pump.



And then fed it some resin.



And the laminate fully wet out.



Now, I should say that my first attempt was about as close as you can get to a pure fiasco without actually screwing up the end result. I spent about an hour chasing leaks in the vacuum bag before I could feed the resin to it. I wasted about two quarts of resin because I overestimated how fast it would infuse, and it kicked in the bucket. For a while there, I thought it would kick off before it infused all of the glass. In the end, it turned out okay.



That was yesterday. Today, I did the same thing on the other side, but it went much more smoothly.







Yesterday, after finishing the infusion, I got started on cutting out the stringer cores:



That brings the progress report up to date. I’ll be doing family Christmas stuff next weekend, so it may be a while before I can post more progress pics.

Dave

[flyingfrizzle]

Looking good! You made that look ez, and it turned out well and looked very professionally done.

I am planning on doing some infusion laminates on the race boat to keep it light as well. I got plenty of tacky tape (bead mask from metal sheeting), spiral tube (wire guard from electrical control wiring) and some of the peel ply but curious where you got your bagging connectors from. Are you using the aluminum reusable type? I have seen them on flea bay a few times but would like to find a good supplier for bagging materials before I start trying it.

[Bushwacker]

That's beautiful work Dave! Are you using epoxy or vinylester? Did you try chilling the resin in fridge to keep it from kicking off to fast?

[Blue_Heron]

Originally Posted by Bushwacker

Did you try chilling the resin in fridge to keep it from kicking off to fast?

Hey, Denny, interesting you should ask. I actually went the other way. I'm using epoxy, which is higher viscosity than vinyl or poly resins to start with. As it cools, it gets even more viscous. Temps in my shop this weekend were in the mid 60s, so I warmed the resin to about 75° so it would flow better. When I started, I wasn't sure whether it would be better to warm the resin, or warm the glass the resin was being infused into. Now I know.

on the second attempt, I left the resin at ambient temperature and used a heat gun to encourage flow as needed. Worked much better.

Originally Posted by flyingfrizzle

Looking good! You made that look ez, and it turned out well and looked very professionally done.

Thanks for the kind words, Mr. Frizzle.

Originally Posted by flyingfrizzle

I am planning on doing some infusion laminates on the race boat to keep it light as well. I got plenty of tacky tape (bead mask from metal sheeting), spiral tube (wire guard from electrical control wiring) and some of the peel ply but curious where you got your bagging connectors from. Are you using the aluminum reusable type? I have seen them on flea bay a few times but would like to find a good supplier for bagging materials before I start trying it.

I would be careful with substitute materials until you try them on a very small infusion. As an example, I bought tacky tape from two sources and there was a noticeable difference in performance. I don't know if a tape that's not formulated for vac bagging will perform like you want. It has to stick well enough to seal, but it needs to peel of easily without leaving residue after you're done.

Your spiral tube shouldn't be a problem if it will hold up to 25" of vacuum without collapsing. You want to make sure your bag will hold every inch of vacuum your pump will pull. If it won't, you have a leak that will infuse air into your laminate as it cures. Did I mention you want to make sure you have the right tacky tape?

I got my materials from US Composites, Merritt Marine Supply (both in Palm Beach) and Lowes. Bagging film, peel ply, and the better quality tacky tape came from US Composites. The polyethylene tube, both spiral and plain, came from Merritt.



The fittings that seem to work best are simple 3/8" nylon hose barb tees you can pick up from Lowes, Home Depot,or Ace. I wrapped the base of the barb in tacky tape and squeezed the bag down over it to seal. Here's one after debagging the laminate:



The starboard side turned out pretty good and was a lower stress process. Still learning...



Dave

[flyingfrizzle]

Originally Posted by Blue_Heron

The fittings that seem to work best are simple 3/8" nylon hose barb tees you can pick up from Lowes, Home Depot,or Ace. I wrapped the base of the barb in tacky tape and squeezed the bag down over it to seal. Here's one after debagging the laminate:
Dave

That's good to know that something that simple will work for a connector, and thanks for the heads up on the tacky tape. I have several different types of masking from metal building construction and don't know if it will work well. It sticks good but might not come up well like you said. The spiral I have is HD stuff, better than most you see used for vacuum bagging and should hold up fine to the 25"hg that my pumps rated at. The connectors I have thought about getting are these pictured. The plastic ones wont stick to the resin (either type resin) and are good for 250 +degrees. They suppose to remove easily too. The second aluminum type look good but not sure how well they will clean up if the resin gets in them and hardens and they are $30 each. The third looks good too, and has a silicon sealing connector for the hose. I am going to try some different things far as the connectors go and see what works best for me.

Curious, How far down dose your pump pull? do you get a full 25"mg of vac? and also how well did it flow with the resin you used and what type of us composite resin did you use? the 635 Thin resin? I have some of that myself and it seems thin but, I bought some VE infusion resin and it is much much thinner than the 635.

[Blue_Heron]

Originally Posted by flyingfrizzle

... The connectors I have thought about getting are these pictured. The plastic ones wont stick to the resin (either type resin) and are good for 250 +degrees. They suppose to remove easily too. The second aluminum type look good but not sure how well they will clean up if the resin gets in them and hardens and they are $30 each. The third looks good too, and has a silicon sealing connector for the hose. I am going to try some different things far as the connectors go and see what works best for me.

I looked at all of those and decided on the $2.39 vinyl tees. I don't want to throw out a $30 part because it's clogged with resin, and the tees work.

Originally Posted by flyingfrizzle

Curious, How far down dose your pump pull? do you get a full 25"mg of vac? and also how well did it flow with the resin you used and what type of us composite resin did you use? the 635 Thin resin? I have some of that myself and it seems thin but, I bought some VE infusion resin and it is much much thinner than the 635.

My vacuum pump is getting a little long in the tooth. It's an old Gomco medical pump and it's older than I am. It used to make the full 29" Hg, but it will only make about 20" lately. The good news is, Santa's bringing me a new one.

I'm using the 635 resin with the medium hardener. It's thicker than I would want, but it will thin out nicely with a heat gun and the heat gun won't make it kick off right away like it would with poly. The VE infusion resin should be just what you want. I considered VE for this build, but I've been happy with the 635, it's less expensive, and that drove my decision. That being said, it would be nice to have the flexibility with working time that you get with a catalyzed resin like VE. I'll probably be doing some polyester infusions later in the build, so I guess I'll see.

Dave