CF 3.5 Rigger Project

[MikeP]

Using Hammerheads ideas I decided to build a carbon fiber 3.5 rigger. I have wanted to do this for some time now but had no resources on how to do it. Hammer suggested I start a topic showing my process along the way. Input and questions are very much appreciated.

Here is the pic of the sheeting for the sponsons 3 layers of 5.7 oz. 3k CF in a vacume bag, between glass and mylar. Also the bottom mold for the hull. Will post a pic in 2 days of the sheet after it's removed from the bag.

-Mike

 

[TomMoorehouse]

cool... yea keep us updated!

 

[Hammerhead]

Way to go Mike!

Looking forward to seeing how you are doing on this.

You went and spent some bucks on a vacuum system, I see.

Good luck to you!

Hammer

 

[MikeP]

Hello, here is a pic of the finished plate it turned out better than I thought. The glass side is very glossy and the mylar side is semi-glossy. It came out to be .038 to .036 inches thick, close enough for heat racing. The hull is next. The sponsons have been laminated on top and inside and are ready for the side and top profile shaping.

-Mike

 

[TomMoorehouse]

wow man... that is COOL!

 

[Hammerhead]

Looking great! How many layers of cloth did you use?

Adding the Sponson diagram to this post.

Hammer

 

[Hammerhead]

Wow! I don't know what happened, but the picture turned out much better posted in this thread than it did attached to your mail. I would print it off here.

Hammer

 

[MikeP]

Here is a pic of the hull in the vacume bag. No problems with tight corners.

-Mike

 

[Hammerhead]

Hey Mike!

Would you answer a question for me?

When you are making your plates, is it required to

sandwich them with mylar when using the vacuum bag?

Can you use the bag over and over again?

Thanks Hammer

 

[MikeP]

Hammer,

You can use the bag as many times as you want. The bag is a nylon material and holds up well but is pretty thin. You need something to protect the bag from glue. The bag doesn't form around the mold well if it is sticking to the glue, it needs to slide and move as needed. Also the bag tends to get wrinkles, I use mylar to protect the bag and to give it a nice finish. There is some stuff called peel ply that epoxy wets into then peels off, the finish is rough and is a better gluing surface. I was told wax paper works ok as well.

Mike

 

[TimD]

Mike,

peel ply is good for reducing the weight in the finished part as it absorbs the excess resin from the cloth. Works very well!

On the sponson with the turnfin attached, are you going to reinforce the inside edge to reduce flex?

Tim.

 

[MikeP]

Tim,

I wish I would of got some peel ply sounds like it would of helped. I get some resin squezing out of the mold that gets all over the inside not a problem but is kinda messy. I also think it might of let some of the trapped air out. Some things you learn along the way. I would like to know what to use to cover the inside of a female mold with complex curves like the inside of a cowling.

Maybe you could explain some reinforcements of the turn fin side sponson, I planned on having an outer and inner wall for the mounting tubes, and a brace from the tub to the turn fin.

Thanks for you interest and feed back with your ideas.

-Mike

 

[TimD]

Mike,

I'm not sure I am following you in regards to the cowl question, but I'll tell you that we don't vac bag cowls for riggers. we just lay up in a negative mould using chopped strand glass rather than cloth. admittedly not as light but cowls are not that heavy anyway. Let me know if this answers your question - if not I'll try a different approach.

As for the sponson reinforcing I didn't have anything in mind - I was just curious to see if you thought the CF was rigid enough by itself.

Oh yeah, have you got a trap in your vaccuum line at all? Very important.

 

[Hammerhead]

Mike, On the inside of the turnfin side sponson, I have a slab of tapped aluminum. Works well, but I don't know if you want to add the weight or not.

 

[TimD]

Mike,

I was having a brain fade yesterday and didn't think too much about your cowl question. If you want to have the carbon pattern on the outside of the cowl then the chopped strand glass method is not an option. What you would have to do is make a silicone insert for your mould. You would then lay up the CF cloth in the mould, then put in the silicone insert then vaccuum bag it. Tight bends will be a problem though. Hope this helps.

Tim.

 

[MikeP]

Ok, I have a "plug" now for the cowling. I need to make a neg. mold of it, what type of products are there to make it with. I have seen stuff that looks like body putty and you pour it over the plug, I don't know what it is called or where to get it. The silicone stuff for an insert sounds good where would I look for that.

-Mike

 

[Hammerhead]

I have just what you need mike, I will send it to you if you give me your address in an email. I owe you one for the vid. I will send you a square meter of random weave 100% carbon fiber mat. It will go into any of those corners. After it sets up, you can put a layer of teflon or CF cloth over the top for to get the looks. .

Hammer

 

[Hammerhead]

I got the blue prints copied on and ready to go. I think I will be able to mail them on Tuesday. Probably to late.

You have probably already got a good start on them.

Anyway you will be able to use them with your next boat or spares for this one. Of course I will mail the matting too.

Got a good look at your rear sponsons. They are exactly like the ones on my boat. I thought that you were going to make them on the sides of your boat. What caused you to change your mind? I also noticed that you had to use a little putty. I did too. for some reason, when you

have an angle like that, the tend to hook. Hmmmm?

Looking good. I'd like to see the pics that you have been sending me in this thread. If you have a chance could you post some of them.

Thanks Hammer

 

[MikeP]

Here is a picture of most of the parts. The carbon tubes are wrapped with 4 layers of 1.7 OZ. kevlar cloth, they will be for the sponsons and the hull. I am not sure of The rear sponsons, I don't like how the outside sponson sides are not parallel to the hull front to back. Bulkheads 2 and 3 are made of foam and CF sheet, transom is 3/8" cherry. I have scrapped the first front sponsons and I am starting over. Looks like I may scrap the rear sponsons as well. Going to spend a half day at a machine shop(C+M Mfg. Team Cobra) next week to fabricate a motor mount.

www.ad.kengarff.com/mikep/3.5/cfparts.jpg

-Mike

 

[Hammerheadatoffice]

Looks like you have too much angle in the rear sponsons. How much to they measure out in relation to the bottom of the hull. You should try to get at close to 3 degrees as you can.

Hammer