Gas Scale hydro builds

[Tim Strange]

So the New Year is upon us, and I need to get moving on this Gas Scale project! I hope to get her ready for primer by the end of the month...

I have adopted Mikey's 8255 Speedy Blue project, of which the basic hull is completed and needs the sponsons and decking finished.

Can anyone that has built the 8255 tell me in what order to install the angled sponson sides? Not sure if it will be better to install the top angle first then the lower and then the very bottom or what... Any help in building the sponsons in general will be greatly appreciated.

Thanks and Happy 2013!

Note: My first post of 2013 is on page 13 of this thread...how odd...

 

[Dan Kramer]

i always start at the top (deck side) and work to the ride surface last,

 

[Mike Luszcz]

I do the lower sponson non trip first, then the upper non trip that touches the deck skin second which allows the lower portion of the upper non trip to hang slightly over the lower non trip. With a little epoxy and silica u can use that overhang to create the spray rail. Then i install the inside air relief sheeting, then finally the ride pad last. Doing the ride pad last allows u to feather the outside edge of the outside sponson so water can flow under in a turn without tripping the boat.....and the outside edge of the inside sponson u can leave the overhang..and with the help of epoxy and silica, create a blunt edge so the water flowing past the outside edge of the inside sponson can break away clean. Confused yet???? I will try and find some pics and post soon. Mike

 

[Tim Strange]

I think that I follow you...but yet I am confused LOL. Yes, if you have some pictures please share.

Another bit I am concerned about is the lack of gluing area. Is it a good idea to put some 1/4 square stock on the stringers?

Thanks, Tim

 

[Tim Strange]

Anyway...here is where I am going with this...

I have added a 1/4" aluminum plate for the turn fin bracket to the right sponson and today I added 1/4 x 1/14 stock to the bulkheads on the lower sponsons. I have also have cut, sanded, and filed some foam to fit certain areas of the sponsons. My thinking here is...Why not have the foam have a use other than added weight. Hopefully, it will add a bit of strength to the 1/16 ply I plan to skin the sponsons with and even more hopefully will help keep the sponsons together. I chose to use Pink and Blue home insulation foam not only because I had it on hand, but they do not retain water and oil like pool noodle foam...plus it can be shaped and epoxied just like wood...plus plus it is much lighter to begin with!

I did a bit of research and found that 2.7 ounces of foam will keep 5 pounds of weight afloat (which is what I figure is how much weight the motor, header, hardware will weigh). Therefore, I will try to keep the foam weight down to 3 Oz. per sponson.

Today's state of affairs....

 

[Tim Strange]

 

[Dasboatman]

"Why not have the foam have a use other than added weight. Hopefully, it will add a bit of strength to the 1/16 ply I plan to skin the sponsons with and even more hopefully will help keep the sponsons together."

Hey Tim,

I have used the blue Styrofoam for years, and it will add significant strength. I routinely build sponsons and boats using solid Styrofoam blocks carved and sanded to shape.Sponson inside and rear plates are 3/32 birch 5 ply. non trips 1/32 and sponson bottom is 1/16 birch ply. I build sponsons heavier forward so I won't have to use weight to balance the hull to CG.

I believe you will be happier if you bring the foam further down, and then sand it to the frame structure. This way your entire bottom sheet will bond to the sanded Styrofoam and not leave the void you presently show between the sponson bottom sheet and the Styrofoam.

CHEERS !!! Bob

 

[Tim Strange]

Thanks for the input Bob. I intend to do exactly as you mentioned about sanding the foam down to the frame. Some of the side pieces will need to be redone however. I am interested in what you say about using 1/32 for the non trips...that would make doing the sides of the sponsons so easy. Unfortunately, I don't have any 1/32 on hand.

I have considered fiberglassing the the sponsons without adding any ply. This would require a lot of effort to get the fitment of the foam, the flat surfaces and corners perfect. Think I'll stick with sheeting and maybe add 1oz cloth like Greg Hahn shows in his video. He makes it look so easy.

 

[Dasboatman]

Hey Tim,

Remember, I'm walking about 1/32 ply over Styrofoam. I have never tried simply glassing over sponsons. I like the sharp edges/corners I get using ply, and I overhang quite a bit to clear water away and avoid capillary action.

I carve cowls out of Styrofoam and put a couple layers of cloth over that. Then I hog out the unwanted Styrofoam, sand it to clear everything and glass the inside also. Built in, sealed flotation, and cowl only limited by your imagination and ability.

I generally cover the front half of my boats, top and bottom with 3/4 ounce glass cloth and West Systems epoxy. After reading Greg Hahn's method, I'll try that the next boat I build. I had been using West's straight, having read a recommendation from West, not to thin it out. So I was doing a lot of block sanding. I'll give Greg's method a try thinned an equal part with Denatured Alcohol. I didn't know about glass cloth with out starch either. Less sanding is right up my alley.

This Stanley Surform file/rasp, a hack saw blade, sharp knife and a good size sanding block with 30 grit on one side, 60 grit 3M hardwood floor sanding paper (it's black in color and comes in rolls) and you are ready to attack Styrofoam and hold your own in the face of adversity - - Har, Har !!!

CHEERS !!! Bob

 

[Tim Strange]

I used to have one of those Stanley rasps...it took me a day to find it, but I did find my smaller palm rasp. I do have a similar tool that I got from one of the bed/bath/kitchen places. It's called a Microplane and is actually a Zester. It's not near as aggressive as a rasp though.

Most of the cutting has been with a band saw and a hot wire foam cutter so far. Kind of a tedious task sizing a piece of foam up and then running out to the garage to make a cut and then running back inside only to run back out to make another. I guess if I wasn't such a sissy, I would have just stayed outside LOL.

Anyway, I scoured the area for some 1/32 ply and no joy there. Looks like I will continue with the 1/16. Still thinking about glassing...

 

[Dasboatman]

Hey Tim,

I have been buying ply from National Balsa http://www.nationalbalsa.com/default.asp the last 10 years or so since Lone Star Balsa stopped stocking 12" X 48" sheets of ply. Their stock includes basswood, Sitka spruce for stringers (expensive but much stronger than basswood). numerous hardwood, Don Smith epoxy, and CA glues.

Once I start cutting Styrofoam, I'm usually out in the garage for the duration. My wife objects strongly to the "Blue Trail" I leave through the house, and the blue haze in the garage, so I'm not welcome inside until the foam butchery is completed. I knew we should have bought a house with laundry room inside the house instead of in the garage. Luckily, we are a lot warmer here in Houston area than where you are. I was introduced to winters in the Chicago area in 1969. Coming from Miami - - I was poorly prepared. Har, Har !!!

I usually do most of my rough cuts on the band saw, and only use the Surform rasp, to shape the crowm on sponsons and decks. I'd hurt myself with a foam cutter. CHEERS !!! Bob

 

[Tim Strange]

Bob, maybe you should switch to PINK foam. That might go better with the wife. For me, (not sure it I am fortunate or not sometimes) I don't have a wife to tell me no. But when it comes time for sanding foam...that will definitely occur outside I don't care how cold it is!

Don't be afraid of the wire cutter. The one I am using is a handheld made for model railroaders. Fairly expensive for what it is, but it works and it has a button that needs to be pushed in order for it to work. This is a great feature to have since it will prevent damage to yourself, any other object or the chance to burn your home down. Being a fireman I am very keen with the latter. http://www.wholesaletrains.com/Detail.asp?ID=20010614&gclid=CKWtl8Xk_rQCFYLd4AodvQEAYw

I have done business with National Balsa before...great prices and service. I just don't need anymore delays at this point. Also I did order some of the 1 Oz cloth that Greg Hahn uses. Not certain that I will do the entire boat or not.

 

[Don Brown]

Tim

Now I know how you get away with painting your boats in the bathroom.

DonB

 

[Dasboatman]

Hey Don,

The truth comes out. Key word and tricky phrase here is "SINGLE". I've been married so long I have forgotten what that was like. Paint in the bathroom??? All I do is occasionally wet sand color in the bathroom in a white tub. Clean to us, isn't even close to clean to them. Enjoy your house while you can Tim - The only thing in our house that belongs to me is the garage and ............ Hummm. I do have a recliner , a bed, and a small section of the frig to hold small cans of Coke for my Cuba Libras. ****, I shouldn't think too much. Har, Har !!! CHEERS !!! Bob

 

[Bigbird]

This is my ML Boatworks 78 Miss Madison. 108 hull.

 

[Bigbird]

78 miss m

 

[harvknox]

Mike ,looks good.Will you have it ready for the Evansville races this season?

 

[P THOMAS]

78 miss m

Looks good Mike get the bottom and deck on, lets race.

 

[catxtreme]

Sorry I may have missed it but what pipes are you guys running in the gas scales like the 8255? Steel ie: hotpipe or aluminum ie: Hanson? Thanks

Jeff Lee

 

[harvknox]

Jeff,my gas scale is a T-6 with a Gizmo modded K-30 rear exhaust engine.It has a 7/8 header with a Gizmo, aluminum 2" flat band aluminum pipe with an internal stinger.You may have a problem getting the excess heat out with a steel pipe.