Tom's Top

[Craig]

Here are the results of this weekend's efforts on the hard top for my friend Tom's 55 footer. The initial design was for three layers of 1/4" ply. I tried to change the design to a honeycomb core but he was concerned about structural integrity. Weight is a bigger factor I think but it is his call. We have the ply layers done and 2/3 of the top glass done. My 25 year old beltsander let the some out half way through the project so we lost some time for a run to Sears. This thing is going to tip about 300 lb by the time it is done. bullit proof but heavy. German kids! Gotta love them. I need to work some cement ito this project somewhere to get a real German finish!!!!

http://members.cox.net/~loveylou/TT1.jpg

http://members.cox.net/~loveylou/TT2.jpg

http://members.cox.net/~loveylou/TT3.jpg

[warthog5]

QUOTE: I tried to change the design to a honeycomb core but he was concerned about structural integrity.

You were right on, but didn't have enough imfo to push the idea. Robert down a Dawson's Boat's in Pensacola.Fl. has built test panels and sent them out to the local test lab. The test lab has stoped charging him for testing, oh by the way. They have to much fun trying to tear his stuff up.

He showed me some panels that were 3/4 Nidacore. He had Vacuum bagged a layer of 1808 and 1 1/2oz mat on both sides. He went to pickup the parts and get the report on what they found. They gave him all these test data numbers. He said OK what does that mean in Layman's terms?

Can I put 30 people on this hardtop? [that would never happen]

They said you can put 300 people on this hardtop.

I didn't use any Nidacore in my Custom Mako, but I used Kledgecell and Divenacell.

[Craig]

Yea, this will hold his ski boat, let alone the dink and jet ski! He wanted a curved design first and so I recommended the solid ply. I didn' do the frames and the guy who did made them dead flat! I added an extra layer of glass to add some roll off to the roof for drainage. Should be plenty. After an afternoon of epoxy work Tom was very interested in vacume bagging. I got a couple 220v ac compressors from some old AC units at work but both were shot! That fancy stuff you use is too rich for us Swamp Boys over here Hog.

Where do you get this honeycomb core material? What sizes are availiable?

[Florin {VACATIONER}]

Craig,

I haven't done any vacuum bagging yet, although I thought about doing it sometimes, so I'm really not sure how big a vacuum pump you need for that, but I'll bet you the ones I have for HVAC/R would work just fine.

The A/C compressors can't come close to the vacuum level a vacuum pump can pull (the pump will go down to about 28-29inHg depending on altitude and the compressor after a good break-in procedure will maybe go to 5-10inHg). And the major problem is that the compressors are designed to pump oil thru the whole system... in other words if they don't circulate the oil they'll just sit there and get hot until they burn. Not sure how long this would take but I don't think I would leave one run overnight unsupervised.

Vacuum pumps are only about $300 CDN here and the one I have has been heavily used for the past 10 years at least. The trick is to change the oil in it on a regular basis if you want it to last. I know it's a bunch of cash to throw away at once but if one uses it a lot its probably worth it. Oh yeah, I leave mine run overnight on a contaminated system... and I've done that a lot without damaging the pump.

Maybe you guys can give me some imput on vacuum bagging.... What kind of material is used for this and how does it get sealed at the edges?

Is my pump rant worth anything?

Cheers

Florin

[Craig]

You are right Florin. The compressors don't make very good suction pumps, but for small stuff they would be OK I think. Warthog is doing some large projects over there and needs 1st class equipment. Large projects as in redesigning and reconstructing entire fishing boats. The basic premise is to lay up your piece with a woven slurping layer on the top of the piece and seal it all in an air tight bag or plastic enclosure. The enclosure has a vacuum port for a hose and QD to connect to the pump. The enclosure can also be an epoxy proof table with a plastic sheet over it taped at the edges. The suction draws out the air and presents a uniform pressure on all the parts. This squeezes out the excess epoxy and makes a stronger layup. The slurpy stuff traps the epoxy to keep it out of the hose and the suction pump and pells away when the poxy is cured.

[Guest]

Ahh, it appears to my febble eyes this thing is flat. If that is the case and this thing is free floating you are building a pothole for sure. But what do I know you know that. Time sags tops and bellies. If you intend on bending this upon fiinishing it with the glass, you will also not always end up with a true elipitcal curve. Dang, I can't take off two days around here.

[Craig]

Mike there is a tubular framework on the boat to support this. There is a very, very slight crown to the cross frames ( ~1/2

[Guest]

No mast deal. Thanks anyway. Oh well, too much time talking these days, and not enough action. It just keeps going out.

[Craig]

Check PM Mike.